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Spicer dual (2x) magnetic field cancelling system actively eliminates image interference in ferroelectric material research

Tue, 02 Jan 2024 12:05:41 GMT

Enabling high resolution TEM performance in hostile working environments

The performance of an electron microscope operating at high levels of magnification can be affected by a whole host of external factors – such as vibrations and temperature variations – limiting the quality and resolution of the images generated. Magnetic field interference can be especially problematic, and equally challenging to rectify, often requiring the instrument to be placed in ‘quiet’ locations that do not best serve the lab workflow. Fortunately, dedicated magnetic field cancelling systems can be employed to actively eliminate external fields, allowing microscopes to perform to their specifications, producing high resolution images even in challenging locations. In this case study, Jinming Guo, Professor of Materials Science and Engineering at Hubei University in China, describes how a dual (2x) Spicer Consulting SC24 Magnetic Field Cancelling System is assisting in the study of ferroelectric materials at an atomic level.

Ferroelectric materials are dielectric substances that remain permanently polarised after the removal of an applied electric field; they are routinely used in applications ranging from energy conversion to data storage. The School of Materials Science and Engineering at Hubei University has an active ferroelectric research program, largely focused on understanding the relationship between the microstructures and macroscopic properties of these valuable substances. Prof. Guo explained: “We employ transmission electron microscopy (TEM) to study ferroelectric materials at the atomic scale, allowing us to gain valuable insights into the key mechanisms responsible for their unique characteristics. For example, we can use TEM to determine the polarisation vectors in perovskite unit cells. The relative displacement of ions that occur in these structures is in the order of tens of picometers, so such minute changes are only detectable at an instrument’s highest magnification and resolution settings.”

Unfortunately, the laboratory is just 70 meters away from a sandwich-structure road network containing a busy metro line (underneath), a high street and an overpass, which generates a large magnetic field with a strong gradient, causing intolerable levels of image distortion. Prof. Guo highlighted the scale of this problem: “To put this issue into perspective, our Thermo Scientific™ Spectra 300 TEM is rated to withstand external fields of up to 20 nanoTesla (nT), but the field generated by the subway is almost 4,000 nT – orders of magnitude higher than the acceptable limits. Such intense and non-uniform magnetic field interference was, therefore, severely compromising image quality, making our research activities extremely difficult. While passive shielding provided us with some protection against AC fields, we were still in need of a solution for our DC field problems.”

Hubei University considered solutions from several suppliers before choosing the SC24 Magnetic Field Cancelling System from Spicer Consulting. Prof. Guo explained the reasoning behind this decision: “We compared the SC24 to alternative systems, and concluded that its superior specifications made it the ideal solution to overcome the harsh environmental conditions present in our laboratory. Additionally, the expert advice and service from Ke Chieh Tech Ltd. – Spicer Consulting’s distributor in China – left us reassured that we were in safe hands.”

“After installing the Dual SC24 Magnetic Field Cancelling System on our Spectra 300 TEM, the external interference has been attenuated to well within the manufacturer specified range, and all values at X, Y, Z directions ranging from height of 3 meters to 0.5 meters are below 20 nanoTesla obtained by 4 detectors, allowing it to operate at its highest magnification and resolution levels with no issues from magnetic interference. The SC24 system is also incredibly easy to use, and it is remarkable to see the real-time difference in image quality when switching the unit on and off. Crucially, we know that comprehensive after-sales support is just a phone call away – backed by the joint expertise of Spicer Consulting and Ke Chieh Tech – so we would absolutely recommend the SC24 system to any other parties looking to purchase active magnetic field cancelling systems,” Prof. Guo concluded.

About Spicer Consulting Limited

Spicer Consulting magnetic field cancelling systems protect electron beam instruments, including SEMs, transmission electron microscopes, electron beam lithography tools and SEM-based metrology and inspection tools. They are located in some of the world's leading laboratories, universities, semiconductor manufacturing plants and test facilities of electron and ion beam equipment manufacturers. The company’s magnetic field, vibration and acoustic analysis systems have also been adopted as the standard for conducting site surveys by leading equipment manufacturers. Spicer Consulting is located in Stewartby, Bedfordshire, United Kingdom and prides itself on it's UK manufacturing heritage and commitment to excellence.

About Ke Chieh Tech Ltd. (K.C. Tech)

K.C. Tech is an advanced precision instrument and electron microscope imaging equipment supplier, using its experience and technical expertise to deliver professional nano imaging solutions to customers across Taiwan, China and the Asia-Pacific region. Website: https://kechieh.com .

Meet Spicer Consulting at ISTFA 2023

Tue, 24 Oct 2023 10:59:13 GMT

We are pleased to announce that our distributor, Herzan LLC., will represent Spicer Consulting at ISTFA 2023. The ISTFA conference will be held on November 12-16th at Phoenix, Arizona.

If you would like to learn how our Magnetic Field Cancelling System and SC28 Monitoring System may help improve the images of your electron microscopes, electron beam lithography systems, CD-SEMs, and focused ion beam tools, please stop by Booth #423.

Contact Spicer Consulting Limited

Contact Herzan LLC

Optimising electron microscope performance via continuous environmental monitoring

Fri, 05 May 2023 11:00:21 GMT

The unparalleled magnification capabilities of electron microscopes (EMs) make them indispensable for applications requiring nanometre scale imaging. However, the sensitivity required to operate at such high magnification levels leaves them vulnerable to magnetic field perturbations, vibration and changes in temperature and humidity, all of which need to be kept to a minimum to ensure peak performance. Keeping track of such environmental factors is no mean feat, but dedicated continuous monitoring systems are now available to detect changes in instrument surroundings in real time, simplifying troubleshooting procedures and ensuring optimal device performance.

Blurred lines

The superior magnification offered by EMs stems from the use of electrons instead of light to probe a sample; the wavelength of these particles can be many orders of magnitude shorter than photons on the visible spectrum, enabling them to resolve much smaller features. The beam of electrons is focused on the specimen, and interacts with atoms in the sample to produce signals that contain information about surface topography and composition. Seeing details at such a small scale requires the beam to be perfectly positioned and focused, which can be compromised by external interferences from acoustic noise and vibrations, leading to blurred images. Additionally, since the electrons are charged particles, EM performance is also greatly affected by external magnetic fields. This leads to distinct artefacts appearing in the image; AC fields often show up as sharp jagged edges, while DC fields create wavy lines. EM manufacturers therefore precisely map and specify the degree of interference that their instruments can handle before the image quality drops below the acceptable limit.

Surveying the problem

Optimal EM performance relies on careful monitoring of the surroundings, both before and after device installation. Purpose-made survey systems can be used to evaluate if a room is suitable to host such sensitive equipment, identifying vibrations and noise – for example, from nearby traffic or elevators – as well as magnetic fields that come from surrounding equipment or other less obvious sources, like heating or air conditioning systems. It is just as important to check for these perturbations once installation is complete, particularly for applications such as the quality control and failure analysis process of semiconductor manufacturing, where even small interferences can affect EM performance and make it difficult to identify product defects. However, until recently, there was no technology available on the market that would allow uninterrupted, long term monitoring of magnetic fields, sounds, vibrations, temperature and humidity, meaning few EM users had access to the relevant environmental data when an issue with imaging performance arose.

Continuous environmental monitoring

Delays caused by blurry or distorted images can cost users precious time – potentially halting the progress of research or decreasing manufacturing productivity – making it crucial to resolve imaging issues quickly and efficiently. Unfortunately, pinpointing the root cause of poor image quality can be a lengthy process. When something is wrong with an EM image, it can be hard to discern if the issue is internal – originating from faulty instrument components – or if some external disturbances are affecting electron beam focusing. For most EM users, the first point of contact to resolve performance issues will be their EM manufacturer or service organisation, who will send an engineer to investigate the problem. However, if no obvious fault can be found with the instrument, the manufacturer will then reach out to a magnetic field expert, as well as vibration and acoustic protection suppliers, to help them diagnose what is wrong, which results in a lengthy process and multiple site visits.

Continuous environmental monitoring offers a convenient solution to help eliminate this protracted diagnostic process. If a problem with EM performance occurs, users can quickly and easily review the magnetic field, acoustic, vibration, temperature and humidity data – organised into date-stamped files and viewed using bespoke software – from the time of image quality loss, immediately identifying if the problem is the result of an issue with the instrument itself or an external factor. This data can even be supplied to relevant external parties – equipment manufacturers or service organisations – to allow more effective diagnosis of instrument problems without visiting the site, significantly reducing the downtime and ensuring any necessary on-site interventions are as efficient as possible.

Environmental monitoring can also provide an early warning system if parameters exceed user-defined limits, minimising the chance of unnecessary downtime for EMs used in semiconductor inspection. This warning system can be either visual – a traffic light tool that is green when the environmental parameters are within the user-specified range, and turns red when an issue is spotted – or electronic, sending an email notification to the user with a short summary of the situation. This technology will also be of great value for EM manufacturers during the production of electron microscopes, as they can easily check whether issues with their instruments are caused by hardware problems or perturbations in the surroundings, something that can be equally useful during instrument assembly.

Bringing EMs into focus

Blurry or distorted EM images can cause a variety of issues for researchers and engineers alike, making it crucial to be able to quickly determine the root cause of these problems. Fortunately, EM users now have access to a dedicated environmental monitoring solution that can help pinpoint whether an issue is caused by internal factors, or is a result of external interferences. The new SC28 monitoring system (Spicer Consulting) can track magnetic fields, acoustic noise and vibrations – as well as temperature and humidity – to provide EM users with the environmental data essential for timely and efficient diagnosis of imaging performance issues. This system can even notify the user when these parameters are beyond the allowed limits, saving precious time and giving EM operators full confidence that their instruments are operating under appropriate conditions.

Click here for more information about the SC28 monitoring system

About Spicer Consulting Limited

Spicer Consulting magnetic field cancelling systems protect electron beam instruments – including scanning electron microscopes (SEM), transmission electron microscopes (TEM), electron beam lithography tools and SEM-based metrology and inspection tools – in the world's leading laboratories, universities and semiconductor manufacturing plants, as well as in the test facilities of electron and ion beam equipment manufacturers. Its magnetic field, vibration and acoustic analysis systems have been adopted as standard equipment for conducting site surveys by leading equipment manufacturers. Spicer Consulting is located in Stewartby, Bedfordshire, within the United Kingdom’s golden triangle of elite universities in London, Cambridge and Oxford.

Continuous environmental surveillance guarantees high-quality electron microscope imaging

Fri, 05 May 2023 09:57:32 GMT

Electron microscopes (EMs) are vital quality control (QC) tools in semiconductor production, helping manufacturers to guarantee a high standard of product. However, the precision of EMs and the resolution of resulting images can be hindered by external interruptions, such as acoustic noises, vibrations and magnetic fields. Low resolution and perturbed images can make it hard to detect faults in semiconductor products, which could in turn decrease the yield and performance of manufactured goods. Therefore, continually assessing the quality of the imaging environment and pinpointing any potential sources of disturbances is critical to maintaining a high standard of production. Fortunately, there are dedicated systems on the market designed especially for continuous monitoring of the environment surrounding sensitive EMs, which now provide uninterrupted and automatic logging of various environmental parameters to revolutionise electron beam (EB) instrument applications.

Failure analysis is an important component of QC in semiconductor production, which can ultimately help to enhance yield and guarantee a high standard of manufacturing excellence. However, smaller and smaller semiconductor devices are being developed, making it increasingly difficult to perform failure analysis and locate defects in products. Various high-resolution EM tools – including scanning electron microscopy (SEM), focused ion beam scanning electron microscopy (FIB-SEM) and transmission electron microscopy (TEM) – are helping to analyse the structure of even the smallest devices. This is crucial for localising and characterising defects and electrical problems that may affect performance, solidifying these EM instruments as cornerstones of the QC process.

Unfortunately, the environment in which the EM is located can have a significant impact on image quality, as external factors – such as acoustic noises, vibrations, and magnetic fields – lower the resolution and make it harder to find defects. In addition, these disturbances can also cause instability or shifts in the EB, resulting in significant reductions in resolution, so that instruments perform below their intended design specifications. It is therefore important to the quality of imaging that these types of disturbances are identified when the instrument is first installed within a semiconductor manufacturing or research environment. They must also be continually monitored throughout their use, as subsequent or transient changes to conditions can cause ongoing problems for operators.

Surveying the environment

Surveillance of the environment prior to installation should be a standard when investing in any EB instrument, in order to ensure that the microscope or lithography machine is placed in an appropriate location that will enable it to operate to its desired specifications. There are purpose-made survey systems for this application – such as Spicer Consulting's SC11 family – which are able to measure both vibrations and external magnetic fields. Once installed, many EB instrument users also perform long-term surveillance of the environment to help identify any drifts in continuous fields or transient disruptions that could impact performance. However, until recently, the technologies available for this ongoing environmental monitoring have been missing one critical feature – the ability to measure several parameters simultaneously without any interruptions in data collection.

Continuous feedback

An innovative monitoring system (SC28 Monitoring System, Spicer Consulting) that continuously logs magnetic fields and floor vibration in three axes, as well as acoustic levels, temperature and humidity, has recently launched onto the market. This system can be controlled via a computer connected to the same local area network, and all the gathered information is automatically stored in date-stamped files by the software. This program can also be used to define environmental specifications, either as minimum/maximum values, or as a spectrum of maximum amplitude versus frequency. The software constantly compares the measured values for each parameter with the user-defined specifications, and real-time results are displayed in a small window. The SC28 can be configured to send an email to the user if any parameters shift beyond the allowed margins. This can be done either once or at a specified frequency, making sure that the issue is dealt with in a timely manner. In addition, a traffic light beacon can be used to give a visual warning, something that can be useful in a manufacturing environment such as semiconductor production.

The program supports six scales and three different formats – scope, spectrum and chart – showing up to 14 graphs simultaneously (see Figure 1). A dedicated tool, SCplot, also allows users to handle large data sets and visualise changes in the environmental parameters over a long time period. For example, Figure 2 shows a week’s worth of magnetic field data extracted from nearly 70 Mbytes of data in 335 files, each containing 30 minutes of logging at one point per second of 3-axis magnetic field, 3-axis vibration, acoustics, temperature and humidity. The plots can be saved either as images or appended to a text file to simplify reporting. Furthermore, SCplot enables macro scripting, allowing the user to save command sequences and re-run them later.

A solution shared by EM manufacturers and users

EM tools are often used in applications that rely on precise, high quality images, such as advanced research or inspection and QC in the semiconductor industry, so it is important to protect them from environmental disturbances. Unfortunately, users of EM systems typically cannot identify external interference instantly, and it can take some time to determine the underlying cause of image distortion, delaying research or manufacturing activities. The SC28 monitoring system can provide 24/7 environmental monitoring for these tools, and help to quickly diagnose issues arising from external perturbations. It can also be used as an alarm system, constantly comparing the measured environmental readings to the microscope specifications or user-determined thresholds, allowing local visible warning and sending an error report if a parameter is out of specification. This provides EM operators with complete peace of mind about the long-term stability of their instrumentation.

The SC28 is not only useful for EM operators, but it can also be used by EM manufacturers to gather data about the instrument and upload it to the cloud so that a service engineer can analyse it remotely whenever there is an issue with the EM’s image resolution. This can allow the engineer to quickly determine whether the problems are related to the environment or to the instrument itself, ensuring that issues can be identified and corrected as soon as possible. The SC28 can also be used by EM manufacturers to monitor ambient conditions as the instruments are assembled, helping to diagnose and solve problems created by unexpected external disturbances.

Conclusion

QC activity relies on important performance data, and the introduction of a continuous environmental monitoring solution is a gamechanger that helps to ensure the operational standard of EM and lithography systems. The SC28 offers continuous monitoring of vibrations, magnetic fields, acoustic waves, temperature and humidity – without any need for user intervention – helping to identify potential resolution issues stemming from external interferences, whether continuous, intermittent or transient, and giving users more control over their processes and environment.

About Spicer Consulting Limited

Tablet Donation Aids Computing Skills Development at Local School

Thu, 04 May 2023 10:52:13 GMT

Spicer Consulting donated new Microsoft tablets to Clophill St Mary's Lower School and Nursery, and pay for the setting up and installation. We are thrilled that the tablets will be used by the children to complete their computing work. See details: https://www.facebook.com/clophillstmarysschool/posts/pfbid02tojRSLop1oFZfNz8d6HTwJQvYCgF7TVRXG9dmEpqS6gHc5ivX9C5P6gjThhyfEddl

Spicer Consulting helps to bring Andalusian electron microscopy images into focus

Fri, 02 Dec 2022 15:41:15 GMT

Magnetic fields are everywhere, radiating from such diverse sources as power networks, electrical equipment and even the earth’s core. For the most part, they do not interfere with everyday activities, but state-of-the art technologies operating at extreme levels of precision can be susceptible to even the most minute disturbances. For example, the image resolution of scanning electron microscopes (SEMs) can be negatively affected by magnetic field interference, preventing the equipment from being used to its full potential. Fortunately, magnetic field cancelling systems can attenuate such disturbances, and the University of Granada in Spain has recently installed an SC24 Magnetic Field Cancelling System to enhance the performance of its SEM set-up.

Electron microscopes are used across a wide range of scientific disciplines, imaging everything from the inner workings of human cells to the complex crystalline structures of engineering materials, making access to state-of-the-art microscopy equipment essential for both academic and private researchers. Rocío Márquez Crespo, a technician at the University of Granada's Scientific Instrumentation Centre, explained: “I’m responsible for the Scanning Electron Microscopy Unit – located in the Faculty of Pharmacy – which provides services to research groups both here at the university and to other academic centres across Spain, as well as for many public institutions and private companies. As you can imagine, the applications we support are incredibly diverse, but the common thread running between them is the requirement for extremely high resolution images, and we accomplish this by providing access to both field emission and dual beam SEMs.”

SEMs are well-known for their ability to measure features at the atomic level, but their precision and repeatability are heavily dependent on their surroundings, with factors such as vibration, temperature and humidity all affecting image quality. They are especially susceptible to external magnetic fields, since the images are generated using a beam of charged particles, which can be easily deflected by magnetic field disturbances. Rocío continued: “During the installation of our dual beam microscope, we noticed that images at the highest magnification settings were becoming distorted, and we suspected that it was due to magnetic field interference. An environmental survey carried out by the microscope manufacturer confirmed this to be true, and we were encouraged to purchase a magnetic field cancelling system to negate these effects. We’ve been recommended Spicer Consulting products many times in the past by colleagues and local researchers who’ve had positive experiences with them, so the SC24 Magnetic Field Cancelling System was the obvious choice.”

The SC24 system comprises a magnetic field control unit, up to two magnetic field sensors,

and three orthogonal axis multicore cables installed in the room where field cancellation is required. It stabilises the ambient field by dynamically creating nearly equal and opposite field changes, improving microscope performance. “Once the system was installed by Eloïse SAS – a local supplier – the high magnification image distortion disappeared at the flick of a switch. It was that simple,” Rocío concluded.

About Spicer Consulting Limited

Spicer Consulting magnetic field cancelling systems protect electron beam instruments, including SEMs, transmission electron microscopes, electron beam lithography tools and SEM-based metrology and inspection tools. They are located in some of the world's leading laboratories, universities, semiconductor manufacturing plants and test facilities of electron and ion beam equipment manufacturers. The company’s magnetic field, vibration and acoustic analysis systems have also been adopted as the standard for conducting site surveys by leading equipment manufacturers. Spicer Consulting is located in Stewartby, Bedfordshire, within the United Kingdom’s golden triangle of elite universities in London, Cambridge and Oxford.

About Eloïse SAS

Eloïse SAS is a leading French scientific equipment company with 20 years of expertise in distributing and servicing electron microscopes and accessories. It offers the full Ted Pella/Pelco portfolio to French speaking countries, along with: vibrational & magnetic active compensation solutions (Spicer Consulting with K&S advanced); metallization and carbon evaporation equipment for sample preparation (Cressington); CCD-CMOS cameras for both on side and on axis TEM (Emsis); and nm resolution µ-electronic diffraction units for TEM, featuring 4D STEM with precession (NanoMEGAS). For more information, demos and training, visit Eloïse SAS at its Tremblay CDG AppLab, or explore the website at www.eloise-sarl.fr .

The SC22 system assists in failure analysis-MCS case study

Tue, 24 May 2022 15:00:00 GMT

Failure analysis is about finding out why a product is behaving in a faulty way, and when it comes to electronics, finding the error requires the parts to be examined at nanoscale. When looking at such small features, extremely high resolution is crucial. This is why MCS – a company specialising in helping customers to solve product issues – decided to purchase a new scanning electron microscope (SEM) that would allow better imaging. Suzanne Costello, Chief Operating Officer at MCS, talks about how a Spicer SC22 magnetic field cancelling system allowed the company to get the most out of its new instrument.

MCS was founded in 1999 with the goal of helping electronics companies perform failure analysis. The backbone of the company is its expertise in material science, which is used to answer customers’ questions and support product design, manufacturing and qualification. MCS handles products of various sizes, from tiny semiconductors to massive bolts for wind turbines. Although the company is small, its customer base stretches across the world, from Silicon Valley in California to Europe and even New Zealand. Suzanne explained: “Our job is to figure out why a product is not working as it should, as well as finding the cause of the error. I like to think of it as a forensic lab; instead of looking at cadavers to figure out the cause of death, we look at dead products to find the reason behind the malfunction. We are mostly interested in what has happened in the material or the microstructure that prevents the product from performing in the way our clients expect it to.”

“What is special about our approach is that we do not use just one method to solve a problem, but a whole suite of technologies. This is something that is highly appreciated by our clients, since it means we can almost always find a solution to their problem. In our lab, you can find a number of different optical and electronic microscopes, as well as a Fourier-transform IR spectrometer, which allows us to study organic matter. We seek to constantly update and improve our equipment, which is why we recently purchased a new SEM that would provide even higher levels of magnification and resolution than our older instrument.”

“Soon after purchasing the instrument, we noticed that we could not operate it at the higher end of its magnification capabilities without losing resolution. To fix this issue, we decided to purchase a Spicer SC22 Magnetic Field Cancelling System, which came highly recommended by the manufacturer of the microscope. The Spicer system can cancel out stray magnetic fields, which are known to lower the performance of any electron microscope set-up.”

“I was surprised by how smooth the installation process was, and amazed by the difference the Spicer system made. We even tried switching the SC22 on and off while looking through the microscope, and saw how a grainy image became a perfectly clear picture when the noise was cancelled out. In summary, we had a great overall experience with Spicer, and will definitely buy another one of the company’s systems when we next upgrade one of our electron microscopes.”

About Spicer Consulting Limited

Supporting positional accuracy in the latest electron beam lithography systems

Mon, 10 Jan 2022 16:02:49 GMT

James Watt Case Study

Electron beam lithography is a technique used in research or industry for highly accurate nanofabrication of materials for a range of applications, including in semiconductor devices or for metamaterial production. In this process, a focused beam of electrons is used to draw shapes onto the surface of various materials to alter their function, with sub-10 nm resolution. Magnetic fields and vibrations can have a detrimental effect on beam shift and therefore the precision of this sensitive work, which has led researchers at the James Watt Nanofabrication Centre to rely on Spicer Consulting’s cancelling systems to restore their required accuracy.

The James Watt Nanofabrication Centre (JWNC) is a cleanroom facility at the University of Glasgow that is involved in research and international collaboration using micro- and nanofabrication technologies, such as electron beam lithography (EBL). It houses over £35M of state-of-the-art fabrication and metrology equipment, and has diverse capabilities spanning a range of materials and processes. Stephen Thoms, a Senior Research Technologist in the School of Engineering and JWNC, explained how the centre uses Spicer’s SC24 Magnetic Field Cancelling System to support precise EBL work for various projects. “JWNC undertakes fundamental, applied and commercial research, as well as small industrial prototyping and production runs. We provide a service to PhD students and postdocs from here in the School of Engineering, as well as chemistry and physics, where they tend to use the EBL system intensely throughout their years at the university. We also support companies for commercial work, and have collaborations around the United Kingdom and across the world; there's a whole list of different universities and companies who have work done here at Glasgow.”

“We use EBL for a wide range of projects, including distributed feedback (DFB) lasers, transistors and quantum work. Quantum work is a big area at the moment, and we see a lot of research into areas such as the miniaturisation of atomic clocks – to make them portable – and the fabrication of gravity sensors, which can be used to map gravitation fields to look for, for example, underground pipes. It’s often a collaborative effort of multiple universities, and I tend to support these researchers by helping them to write patents. Many of the students here at Glasgow carry out a lot of biological research, and so we support them on projects such as the creation of a highly textured surface for cells to grow on for stem cell differentiation. Another biological area is metamaterials – small structures around 100 nm in size that can be used to focus light, particularly to enhance Raman spectroscopy in different wavelengths. A lot of metamaterial work is used to make sensors, which can pick up different features depending on the surface of the material we create.”

“The EBL system basically acts like a highly accurate printer; we design small patterns using CAD (computer aided design) solutions, with resolutions down to a couple of nanometers, and the electron beam tool writes that pattern onto flat surfaces. As we are writing such small patterns, positional accuracy is absolutely key; the beam needs to go exactly where we ask it to, and we steer it using magnetic fields. This is where Spicer comes in, as it is imperative that we don’t have any stray magnetic fields. Having the SC24 Magnetic Field Cancelling System ensures that the conditions remain stable, allowing our instruments to run optimally so that we can provide a high quality service to our users.”

“We have been using EBL for over 40 years and are now on the third generation of our system. Over the past couple of decades, the main push for this technique has been the ability to write more accurately and faster. This means that the latest version of the EBL tool is more sensitive, making the beam position more crucial than ever. Our instrument is now in a building underneath an IT service department, which generates a lot of electronic noise that causes interference. The EBL tool is also around 500m from the underground line, and the DC magnetic fields from passing trains would shift the beam several nm if they were left uncorrected. You can’t shield from a magnetic field very easily, it’s much easier to correct it to maintain positional accuracy. That’s why we use the cancelling system. The SC24 is able to effectively tell us when there is a change in the magnetic field and stabilise it, so that our EBL tool remains unaffected. Spicer was helpful in the quick installation and introduction to using the instrument; it’s a really straightforward but effective system. Another group at the university doing a lot of TEM work witnessed the same problems with nearby interference, and has also installed an SC24 to solve the problem, and we use one for one of our SEMs too. Spicer’s SC24 is extremely popular within the physics department as well, as they also have a lot of high tech and sensitive equipment.”

“We have always asked Spicer to perform a site survey before installation of our EBL systems, and even to check potential sites – including greenfield and brownfield land – that we may move to sometime in the future, to see if we would encounter problems with magnetic fields. The survey equipment can even detect things like issues from nearby doors slamming, as EBL is particularly sensitive to vibrations. This is such a useful service and helps us to consider our options if we ever move to a different site. Wherever we end up though, we know we’ll want a Spicer system,” Stephen concluded.

About Spicer Consulting Limited

Spicer Consulting magnetic field cancelling systems protect electron beam instruments, including Scanning Electron Microscopes (SEM), Transmission Electron Microscopes (TEM), Electron Beam Lithography tools, SEM-based metrology and inspection tools in the world's leading laboratories, universities, semiconductor manufacturing plants, as well as in the test facilities of electron and ion beam equipment manufacturers. Its magnetic field, vibration and acoustic analysis systems have been adopted as standard equipment for the conduct of site surveys by leading equipment manufacturers. Spicer Consulting is located in Stewartby, Bedfordshire, within the United Kingdom’s Golden Triangle of elite universities in London, Cambridge and Oxford.

Magnetic field cancellation for optimal TEM performance - Cataler Corporation in Japan

Tue, 07 Dec 2021 15:27:40 GMT

Today’s transmission electron microscopes (TEMs) offer high resolution and magnification capabilities but, to maximise an instrument’s performance, external interferences – such as vibrations arising from sounds or motion and magnetic fields created by other electronic equipment – must be eliminated. Researchers at Cataler Corporation have turned to Spicer Consulting to help them to optimise their equipment for investigations into non-homogeneous catalysts.

Cataler Corporation specialises in the development and manufacture of catalysts and activated carbon products for the automotive industry. Masanao Sato worked for several years building up expertise in TEM technology, and is now applying his knowledge as an engineer in the analytical electron microscopy (TEM/SEM) department at the company. The department is working on the development and analysis of catalysts for exhaust purification, as well as materials for next generation vehicle batteries. Masanao described the work carried out by his group, and how they rely on accurate TEM imaging: “The catalysts we are investigating are non-homogeneous, and their performance is often affected by their ultra-fine structures. It is very important to perform structural analysis using high-end TEM during the research phase, so that the results can be fed into the development plans for new products.”

“It was important for our work that we maximised the performance of our TEM by removing any interferences, including external vibrations and stray magnetic fields from other electronic devices in the vicinity. We therefore installed the TEM in a seismic isolation structure that has an independent base, to guard against

vibration, whether from nearby traffic or elevators. We then conducted an environmental survey, and decided to purchase the Spicer Consulting SC24 magnetic field cancelling system as a countermeasure to prevent the effects of external magnetic fields.”

The SC24 magnetic field cancelling system detects external magnetic fields with built-in sensors, and creates a new magnetic field, in an opposite direction, so that the two fields cancel each other out. Masanao is very satisfied with the system’s performance and how easy it was to integrate and use: “The SC24 had been in continuous operation since the TEM was installed and it still runs faultlessly. Since it is so compact, it was very easy for us to find space for it in our lab, and we could start using it straight away. Another thing that I

really like about the instrument is how easy it is to operate; you do not need any knowledge about it in advance to start using it.”

About Spicer Consulting

Technolab Inc. is Spicer Consulting Limited’s distributor in Japan. They provide technical and sales support for Spicer’s products. Visit http://www.technolab.jp/ for more details.

SC11 and SC28 Comparison

Tue, 02 Nov 2021 12:21:58 GMT

The SC11 Analysis System is for making surveys and the SC28 Monitoring System is for long term monitoring of the environment of electron microscopes and related tools. They use some of the same sensors, but

for different purposes.

The SC11 has higher performance, flexibility and automation for making surveys and troubleshooting at different sites. Our new SC28 is designed for continuous long term monitoring. It is suitable to be placed in one location and let it continuously log timestamped charts and spectra while also alerting you when the environment is out of specification. This provides electron microscope operators with complete peace of mind for the long-term stability of their instrumentation. Click here to see more comparisons between SC11 and SC28.

Spicer Consulting Limited launches SC28 for continuous, long-term monitoring of the room environment for electron microscopes

Tue, 12 Oct 2021 07:41:52 GMT

Spicer Consulting Limited is excited to introduce our new SC28 monitoring system. The SC28 enables long-term, uninterrupted monitoring of magnetic fields, vibrations and acoustics – as well as temperature and humidity – within the lab and semiconductor fab. This system is purposed-designed to monitor the environment for electron beam instruments, including Scanning Electron Microscopes (SEM), Transmission Electron Microscopes (TEM), Electron Beam Lithography tools and SEM-based metrology and inspection tools.

Detecting stray magnetic fields, vibrations and other disturbances in the lab is very important for electron microscope applications since these can all negatively affect image quality and resolution. Based on customer feedback – especially from the semiconductor industry – Spicer Consulting Limited has developed the SC28 monitoring system to provide continuous measurements of the magnetic fields and vibrations in all three axes, as well as acoustics, temperature and humidity. The system’s software automatically records the live data and saves it to date-stamped files, making long-term monitoring of the lab seamless and easy. It can also be used as an alarm system to flag any issues, constantly comparing the measured environmental readings to the microscope specifications or user-determined thresholds, sending an error report if a parameter is out of specification. This provides EM operators with complete peace of mind for the long-term stability of their instrumentation.

SC28 Product link

www.spicerconsulting.com/sc28-monitoring-system

Identifying and overcoming the source of magnetic field interference

Thu, 07 Oct 2021 11:01:37 GMT

The University of Queensland Case Study

Electron beam lithography is commonly used to fabricate small devices used in computers, photonics and sensors. Since the technology relies on accurate positioning of the electron beam, it is very sensitive to interferences like vibrations and stray electromagnetic fields. Elliot Cheng, Electron Beam Lithography (EBL) Specialist, and Roger Wepf, Director of the Centre for Microscopy and Microanalysis (CMM) at The University of Queensland, describe how they solved this problem using a Spicer SC24 magnetic field cancelling system.

CMM is an electron microscopy facility involved in research and teaching, as well as providing consultancy services. The centre offers expertise in different electron microscopy technologies and has recently built a new clean room where computer, photonics and sensor devices are fabricated using EBL. However, the new facility immediately began to present real challenges to the researchers when they started seeing unexplained background noise showing up in their data. Elliot explained: ”The devices we’re making are extremely small and it is crucial that the electron beam is accurately positioned, something that is greatly affected by any magnetic interferences. Ideally, levels on this kind of application should not be higher than 0.5 milligauss, but we were seeing peaks located around 50 Hz that were significantly higher than that, which jeopardised the accuracy of the instrument.”

“We used the Spicer SC11 analysis system to scan for factors that might cause this interference around the lab, and it was extremely convenient to have a portable sensing system that allowed us to chase down the sources of noise without having to call in an external contractor. We started by investigating the vibrations, which we quickly realised were not causing the problem and moved on to checking the AC magnetic fields, looking at the contributions from various frequencies. When that proved fruitless, we analysed the DC fields and found that this was the root of the issue. This led us on a ‘ghost hunt’; we walked around with the SC11, turning different instruments on and off, moving the elevators, all while constantly measuring the changes in the field. After a while, we could attribute some of the spikes to the elevators, which was not surprising, but another source remained unknown. It was periodic, with a one-minute cycle and eventually we figured out that it was caused by the inductive heating of the lab.”

“We had the answer but it didn’t really help us solve the issue. We couldn’t remove this source of interference, and started to schedule our runs during hours when no one else was in the building, which was between 11pm and 4am. Some of the processes were automated and we could get around this by programming them in advance, but this really limited the usability of the instrument. We therefore decided to purchase the Spicer SC24 magnetic field cancelling system, and immediately noticed a great improvement in the noise reduction – going from around 2 to just a few tenths of a milligauss – and we no longer have to worry about moving elevators or the nearby traffic. We still need to optimise the location of the sensors to get the best performance out of them, but the instrument is already doing a great job now that the problem of interference has been mostly eradicated.”

Roger continued: “I have worked with Spicer for a long time; I started using their products around 1996 and have always used its instruments to perform an environmental survey every time we have installed a new instrument. I believe that it is absolutely essential to have a Spicer analysis system in every EM lab, because it saves a lot of time, and gives the team the freedom to perform on-site measurements as soon as they are needed, or if changes to the environment occur.”

About Spicer Consulting Limited

Spicer Consulting magnetic field cancelling systems protect sensitive equipment in the world's leading laboratories, universities and semiconductor manufacturing plants, as well as in the test facilities of electron and ion beam equipment manufacturers. Its magnetic field, vibration and acoustic analysis systems have been adopted as standard equipment for the conduct of site surveys by leading equipment manufacturers. Spicer Consulting is located in Stewartby, Bedfordshire, within the United Kingdom’s Golden Triangle of elite universities in London, Cambridge and Oxford.

Resonate Systems is Spicer Consulting Limited’s distributor in Australasia. They provide technical and sales support for Spicer’s products. Visit www.resonatesystems.com.au for more details.

Planning your microscopy installation – reducing or eliminating interference

Tue, 05 Oct 2021 10:58:50 GMT

A crucial element of establishing a stable environmental is a rigorous site survey prior to installation by either an independent service provider or the equipment supplier, to determine the presence of any disruptive external factors that may have adverse effects on image quality. Typically, this will include measurement of acoustic levels, magnetic fields and floor vibrations in X, Y and Z directions, and direct comparison with the environmental specifications of the equipment to be installed. Where necessary, action can then be taken to eliminate any unwanted interferences, such as installing a magnetic field cancelling system.

Site surveys

With more and more equipment being squeezed into laboratories, bench space is increasingly more valuable. Electron microscopists face the challenge of working in a crowded environment surrounded by other apparatus that depends on electricity to function, which potentially impacts on image quality. Site surveys have a vital role to play when investing in microscopy instrumentation, and can help to troubleshoot and resolve issues that may arise at a later date, especially as cities and towns grow and become more urbanised, increasing the potential for interference. In addition, in the drive to continually improve resolution and image quality, manufacturers’ environmental specifications are becoming ever more stringent, with top end microscopes with spectrometers only able to withstand up to 10 or 20 nanotesla of interference; finding an environment that is as suitable as possible can be extremely challenging.

Mitigating interference

In many cases, microscopes are installed into an existing facility, either to complement the equipment currently in use or as part of a new laboratory set-up. In this situation, there is generally little that can be done about the prevailing infrastructure and space constraints, and it is often a case of choosing an installation site as far removed from potential interferences as possible and installing a magnetic field cancelling system.

New purpose built laboratories provide the opportunity to design an environment optimised to microscope performance; all the interested parties can communicate from the outset to incorporate the optimal infrastructure and choose the ideal location, as far removed as possible from internal and external influences. For example, air conditioning units can be installed in a separate plant room away from the laboratory, electrical power cables routed to minimise any potential interference, and consideration given to appropriate siting of other equipment to reduce any likely effects on the microscopy instrumentation. Even the location of the car park in comparison to the microscopy room can be considered!

How can interferences be eliminated?

Where relocation is not possible, additional measures can be taken to combat the severity of vibrations and magnetic fields. Concrete blocks are a popular choice for isolating the microscope system from the rest of the building. This reduces the vibrations from building sway that transmit through the floor and into the structures of the microscope, causing them to resonate at different frequencies. Another option is active vibration isolation, which uses a platform of transducers to move the system in the opposite way and is able to respond fast enough to ensure that any phase lag is minimal.

To find out more about Spicer’s comprehensive pre-installation site surveys and magnetic field cancelling systems, contact us here .

About Spicer Consulting Limited

Optimising Performance of Your Electron Microscope

Tue, 05 Oct 2021 10:03:06 GMT

New technologies are continually being developed, leading laboratories to introduce more machinery and electronic equipment into their workflows and making space within these labs more precious than ever. A busy indoor setting, combined with the growth of noisy and bustling cities outside, causes significant disruption to electron microscopy due to interference from vibrations and external magnetic fields. Therefore, electron microscopy relies heavily on maintaining a stable environment, so areas should be surveyed meticulously before set-up to ensure that the image quality produced will be unaffected by these external factors.

What causes interference?

The performance of an electron microscope is affected not only by interference within the room in which it is positioned, but also by the location of the building itself. There are several possible sources of interference, but the most commonly encountered problems will arise as a result of vibrations through the floor or the air – acoustic vibrations – or from magnetic fields.

Vibrations can come from any apparatus that has the ability to move or rattle – whether intentionally or not – including other machinery, doors opening and closing, air flow from an open window, the engine of a vehicle or laboratory personnel simply moving around. Similarly, magnetic fields can arise from multiple sources, both within the building and externally. The major source of this kind of interference is from power lines in the walls, with magnetic fields across the world normally occurring at two main frequencies – 50 and 60 hertz. Internal interferences also include magnetic fields generated by other equipment, lights (particularly fluorescent tubes) or nearby lifts. It is important to remember that external factors may also be involved, such as vehicles including trains and the electric trams that are growing in popularity in many urban areas. Magnetic fields generated from these can extend for hundreds of metres, unknowingly affecting electron microscope image quality, unless a site survey is conducted to uncover any problems and take suitable preventative measures.

Variations in temperature can also interfere with the instrument’s imaging capabilities by causing specimen drift in the microscope electronics and changes in the mechanical tolerances of components.

For more information on how Spicer can help you optimise your EM, contact us to find out here .

About Spicer Consulting Limited

How site survey technology has evolved in the pursuit of perfecting electron microscope performance

Fri, 23 Apr 2021 10:10:17 GMT

Spectrum Analysis– In-depth Analysis of Magnetic Field, Vibration, Acoustics

External magnetic fields and vibrations can often impact the performance of an electron microscope, reducing the image quality and resolution. Pre-installation site surveys are vital for uncovering any potential sources of interference, and are the first step to creating a stable environment, but require purpose-designed equipment for the measurement and analysis of acoustics, and magnetic fields and vibrations in X, Y and Z directions. This article discusses the importance of comprehensive site surveys for identifying and mitigating potential sources of interference of electron microscopes (EMs) and similar sensitive equipment, and describes how one company has addressed this through the continual evolution of its measurement instrumentation.

Hidden interference

Electron microscopes are powerful yet sensitive tools, and are commonly used to investigate the intricate structures of cells, materials and nanoparticles for many technical disciplines, such as metallurgy, chemistry and biology. All electron microscopy techniques – including the two most common, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) – use a beam of accelerated electrons as a source of illumination for the sample. Electrons have a shorter wavelength than visible light protons, which allows electron microscopes to have a significantly higher resolving power than light microscopy, revealing the detailed composition of smaller specimens. However, day-to-day equipment can cause interference through acoustics, vibrations or magnetic fields, causing this electron beam to deflect, which decreases the resolution and quality of the images obtained.

Eliminating interference

Ongoing technological advancements mean laboratories continue to expand and invest in an increasing amount of electronic equipment, so making space within these labs is more challenging than ever. Electron microscopists often find themselves working in a crowded environment, surrounded by other apparatus that creates magnetic fields, vibrations or acoustic interference, which potentially adversely affect image quality. This busy setting, combined with the growth – and noise – of towns and cities, causes a significant problem for electron microscopy. In addition, in the drive to continually improve resolution and image quality, manufacturers’ environmental specifications are becoming increasingly stringent, with top end microscope spectrometers only able to withstand up to 10 or 20 nanotesla of interference; unsurprisingly, finding a suitable environment can be extremely challenging.

Investigations of microscopy instrument performance often begin with a crucial site survey. This can help to troubleshoot and resolve issues that may develop at a later date, or as a result of environmental changes that introduce sources of interference. The performance of the instrument is affected not only by conditions within the room in which it is installed, but also by the location of the building itself. Anything that moves or rattles – whether regular or random – can potentially create vibrations, including other electronic equipment, air conditioning systems, people simply walking around the laboratory, doors opening and closing, traffic in the street, nearby railways and even ocean waves. External factors, such as magnetic fields generated by trains and electric trams that are hundreds of metres away, and unexpected influences like the proximity of the car park to the microscope, can make a tremendous difference.

Surveying the site before set-up allows measures to be put in place to ensure that interference is mitigated and the environment is stable enough for microscopy. Typically, this will include measurement of acoustic levels, magnetic fields and floor vibrations in X, Y and Z directions, and direct comparison with the environmental specifications of the equipment to be installed. Measuring and understanding the magnitude of such effects will enable action to be taken to alleviate unwanted interferences, for example, by installing a magnetic field cancelling system, to ensure that the image quality produced is unaffected by external factors.

Keeping up with technology

As technology has advanced over the years, microscopes have become more sensitive to interference, and sensing equipment has had to keep pace to ensure that the environment meets the manufacturer’s specifications for optimal instrument performance. Today, purpose-designed site survey equipment is available for vendors and consultants to examine new installations effectively, or to measure and analyse interference with an existing microscope to troubleshoot any technical issues. But how has this progressed over the years?

Advances in hardware

In the early days of EM, labs relied on some quite crude magnetic field sensors to monitor the environment, with limited options for measuring fluctuations in noise levels. There was a clear need for a single system that could monitor the entire lab situation around a microscope and, in 1996, Spicer Consulting launched an instrument based on an AC magnetic field sensor, with added inputs for an accelerometer and a sound level meter, that would do just that. This system could make all the measurements required, although the user still had to physically turn the vibration sensor in each direction to measure interference in the X, Y and Z axes.

The system was later upgraded to collect a greater bandwidth of data, and evaluate higher frequencies on the spectrum analyser. Further upgrades, including a move to USB connection, enabled site surveyors to perform more comprehensive measurements with extra sensors. A plug-in for DC sensors was added – so that AC and DC fields could be measured – along with three accelerometer inputs, allowing measurement in all three directions at the same time, instead of having to turn the sensor around sequentially. While the original instrument only had one magnetic field sensor input, later versions had two, enabling the simultaneous measurement of fields at two heights. This feature was important for TEM environments, which typically have tight field specifications over a length of more than two metres.

Advances in software

Naturally, the software of newer systems also had to be updated along with the hardware. On first release, three separate programs were required – an oscilloscope, a chart recorder and a spectrum analyser – to make the necessary measurements, but the user needed a good understanding to be able to set them up correctly. This was made far easier by the creation of a software wizard to guide the user through the process of measuring for different types of microscope. Users were able to simply turn the machine on, select the instrument they wanted to measure for, and the wizard would bring up the correct program to make that specific measurement. Graph plotting software was also developed, which allowed results to be viewed more easily than with the original method, which was based on Microsoft Excel® macros. While the wizard software was capable of running a single measurement, further iterations saw the launch of an automation program capable of running a whole sequence of measurements to simplify the survey workflow even more. Today, users have access to a completely automated system capable of repeat surveying without human intervention. This enables long-term measurements, expanding the surveying snapshot to study the environment at different times of the day.

Finding a pragmatic solution

Implementing a magnetic field cancellation system can eliminate any magnetic field interference that is identified during a site survey. This presents further challenges, requiring a three-axis magnetic field sensor of the necessary bandwidth with low noise levels and low drift. It should include a control unit that can drive the cables to form a stable negative feedback loop, and be easy to set up without complex adjustments. Finally, effective placement of room sized cancelling cables that make uniform orthogonal magnetic fields and are practical for use in microscope labs or clean rooms of all shapes and sizes must be determined. Alternatively, suitable frames can be constructed to support cables and there are also techniques for installing them inside existing enclosures.

Spicer Consulting supplies control units that provide readings in three axes, plus total magnetic field readings – including AC and DC simultaneously for some models – with performance tailored to the application. These are convenient to use and enable fields to be cancelled to the demanding levels required by today’s high-resolution electron microscopes. Automatic set-up can provide helpful error and warning messages, and some cancelling systems support a dual-sensor option that creates a virtual sensor where a physical sensor cannot be placed, such as ‘inside’ the EM column. A wide range of cables for different types of microscope in various types of room are also available.

The future of magnetic field cancellation

Technology for mitigating magnetic fields is continually developing to match increasing demand as the ever-improving resolution of electron microscopes makes them more sensitive to magnetic fields. While the technology is already quite advanced, it is expected that users will seek even better magnetic field sensors, incremental improvements to control units and easier ways to install cancelling cables in the future. Contact us here for site survey service or a site survey kit.

About Spicer Consulting Limited

Electron microscope site survey data interpretation – part 2

Fri, 14 Aug 2020 11:15:28 GMT

Following on from our first article on the subject, here are some other examples showing site survey data and the resulting improvements in microscopy performance that can be achieved after identifying the cause of the interference and taking appropriate action.

Underground train systems

Both vibrations and magnetic fields should be measured when studying the effects of an underground system. As the frequency of public transport systems increases due to demand, so does the level of interference. Cancelling systems are frequently needed to overcome the effects of the world becoming busier.

Lifts

It is often tricky to determine how close you are to a lift. It might seem as if you’ve walked along a few corridors to get to a microscopy room, but, in fact, you may have simply looped round in a square, bringing you back within metres of a lift. As lifts move up and down floors, they trigger interference gradients that constantly change over different heights, causing images to wander and jump around the screen due to large changes in magnetic fields. The interference is often so apparent that it is even possible for site survey readings to pinpoint which floor a lift is on. Lifts provide essential accessibility and ease of movement around facilities, so they are often unavoidable. In these instances, a cancelling system is the only solution.

Vehicles

The movement of vehicles in close proximity to microscopy rooms can create varied levels of interference, with larger magnetic field peaks coming from heavier vehicles, such as lorries or buses. A magnetic field cancelling system is often required to overcome these disturbances, as it is increasingly difficult to find areas that are not in the immediate vicinity to busy roads.

Magnets

Although it may seem obvious that magnets have magnetic fields, large systems built around magnets – such as NMR platforms – are designed to keep as much field inside as possible, and therefore the extent of their effect should, in theory, be minimal. In reality, it is unknown without conducting a site survey. In the situation even at a distance of 25 metres the field is multiple orders of magnitude above what can be tolerated by an electron microscope, and it is advisable to move the instrument and magnet further apart.

Miscellaneous sources

Site surveys commonly uncover unexpected causes of interference. There was significant interference from an unknown source, and a survey was able to locate the source of interference as coming from a hearing loop that had been left behind ceiling tiles. In this case, the problem was easily rectified by renovation work.

Conclusions

As the world becomes a busier place and more technology is incorporated into laboratories, there are undoubtedly challenges in setting up and maintaining a stable microscopy environment, but measures can be put in place to ensure these are mitigated. The key is to think ahead and engage in discussions with microscopy suppliers, site surveyors and, in the case of a new build, architects, at the earliest possible opportunity. Having an experienced site surveyor with the right equipment is vital to identify common and unusual causes of interference and understand the magnitude of their effects. They can then advise on the best way to counteract these problems. This will allow electron microscopy to be installed in the most stable environment possible, whether it is in an existing facility or a newly set-up laboratory, ensuring the highest quality imaging is maintained.

For further information on Spicer site survey services and cancelling systems, contact us here .

About Spicer Consulting Limited

A special problem requires a custom solution-UCL case study

Fri, 14 Aug 2020 10:25:24 GMT

The system comprises custom-designed high field cables in conjunction with the SC24 cancelling system.

Having a separate room for each instrument is a luxury that no one can afford. However, when it comes to electron microscopes and electron beam lithography (EBL) tools, running lots of scientific equipment in close proximity can have a detrimental effect on beam shift and image resolution due to magnetic field interference. This proved to be the case when the performance of a £2 million Elionix G100 EBL platform offering sub 10 nanometre resolution was compromised at the London Centre for Nanotechnology. The department turned to Spicer Consulting for a custom solution to magnetic field cancellation.

The London Centre for Nanotechnology (LCN) is a collaboration between University College London, Imperial College London and King’s College London, performing multidisciplinary research across chemistry, physics, materials science, medicine and engineering in all three universities, as well as other academia and industries both nationally and internationally. LCN has, since its inception in 2003, applied nanoscience and nanotechnology to global issues in healthcare, energy and the environment, and information processing.

Where the magic happens

The heart of the facility is a 255 square metre cleanroom, housing a broad selection of equipment for various processes such as photolithography, metallisation, ion milling and characterisation, as well as EBL on a RAITH150 Two. In addition, three Carl Zeiss focused-ion-beam (FIB) platforms are located in the basement lab. Suguo Huo, electron and ion beam manager, explained: “The EBL, SEM and FIB machines we work with offer highly accurate fabrication and imaging for nano-scale research, and they all require magnetic field cancellation, as ambient magnetic field interference can shift the beam and affect the accuracy of measurements. We have been using the SC24 magnetic field cancellation system from Spicer Consulting until now and its ability to cover interference up to 100 milligauss was more than sufficient.”

Trouble in paradise

In 2019, the lab received a grant for quantum computing research and used it to buy an Elionix G100 EBL, which offers better than 10 nanometre resolution. However, unfortunately, when it came to using the new platform, the scientists soon discovered that the magnetic field interference in the environment far exceeded 100 milligauss and resulted in an electron beam shift of around 1,100 nanometres.

Suguo continued: “This interference came from more than just one source, which complicated the matter. The Elionix is on the first floor just above five superconducting magnets, operating on the ground floor at high fields: 14 Tesla, 12 Tesla, 8 Tesla, 3 Tesla and 2 Tesla. Furthermore, hosting the platform on the first floor required a thick, steel brace for support in which a magnetic field was being induced. On top of that, we had also installed a new AC magnetic field furnace close to the Elionix in the cleanroom. In short, if all magnets were in operation, the combined magnetic fields and resulting interference led to a loss in performance and resolution.”

A tailored solution for a perfect fit

LCN approached Spicer Consulting for a custom solution and, after visiting the lab in April 2019 to take measurements, the team from Spicer soon discovered that the magnetic interference went as high as 550 milligauss. The interference came from five different magnets in separate locations and the lab has a complicated layout, both of which meant that finding a solution was not that straightforward and required a lot of work.

Suguo explained: “The biggest challenge during the design phase came from the fact that the room layout housing the Elionix couldn’t be altered. In addition, I needed a solution that was easy to maintain without requiring support from a third party, which basically meant that it couldn’t have too many coils. Spicer was very helpful, responding to my requests, implementing changes and, ultimately, developing a working simulation. The solution lay in using custom-designed high field cables in conjunction with the SC24 cancelling system, and it was installed successfully in September 2019.”

“We restored the platform’s resolution to better than 10 nanometres, and the machine is back up and running. There is now a solution for the worst-case scenario with all the magnets running concurrently, that was delivered within a remarkably short timeframe considering what was required. I know the people at Spicer well and they listened and understood my requirements throughout the design process; they were very helpful. If we buy more platforms and require further improvements to our magnetic field cancellation, I know I can call them, and I have no doubt that when they say they can get it done, they can get it done,” Suguo concluded.

Spicer Consulting provides solutions to reduce magnetic field interference for higher resolution electron microscopy. Contact us to find out here .

About Spicer Consulting Limited

The SC11 – from origin to the gold standard for site surveys

Tue, 26 May 2020 14:01:01 GMT

The importance of a suitable environment for the best electron microscope performance is well known. As technology has advanced over the years, microscopes have become more sensitive to interference, which can originate from all manner of causes, including vibrations and magnetic fields from nearby equipment, doors opening and closing, traffic, power cables, trains and lifts, as well as problems in the power supply, such as badly wired fluorescent lighting and ground loops.

This is why Spicer Consulting developed the SC11 Analysis System in 1996, purpose designed to perform site surveys, so that you know whether the environment is in spec for the instrument that you require.

Nowadays, the SC11 is the gold standard for screening environments where a new microscope might be installed, or for troubleshooting technical issues with an existing microscope by measuring and analysing any interference. In both scenarios, a site survey measures magnetic fields and floor vibrations in X, Y and Z directions, as well as acoustic levels, directly comparing these values with the environmental specifications of the equipment to be installed. Any problems can be identified from this analysis, and solutions proposed, such as the installation of a magnetic field cancelling system.

But how has the system adapted to the needs of our customers over the last 20 years?

The hardware
The SC11/Basic was developed in response to the need for a system that could measure the entire environment of a microscope. Although systems existed before this, they often included poor magnetic field sensors, and so the SC11/Basic was based on one of Spicer’s AC magnetic field sensors, but with added inputs for an accelerometer and a sound level meter. This system could make all the measurements required, but the user had to physically turn the vibration sensor in each direction to measure interference in the x, y and z axes!

From there, the system was upgraded so that more bandwidth of data could be collected, and higher frequencies could be evaluated on the spectrum analyser. Further rounds of upgrades, including a move to USB connection, led to the development of the SC11 sensor interface – SC11/SI – which allowed the SC11 to perform better measurements with more sensors. Then, a plug-in for DC sensors was added – so that AC and DC fields could be measured – along with three accelerometer inputs, allowing measurement in all three directions at the same time, instead of having to turn the sensor around. While the original only had only one magnetic field sensor input, later versions had two, enabling the simultaneous measurement of fields at two heights. This feature was important for TEM environments, which typically have tight field specifications over a length of more than two metres.

What about software?
The SC11 software has developed in parallel to changes in the hardware, and we are now on version 5.6.4. On first release, three separate programs were required – an oscilloscope, a chart recorder and a spectrum analyser – to make the necessary measurements, but the user needed a good understanding to be able to set them up correctly. To address this, we created the Wizard, which was able to guide the user through the process of measuring for different types of microscope. This was perfect for individuals who didn’t use the SC11 very often; they were able to simply turn the machine on, select the instrument they wanted to measure for, and the Wizard would bring up the correct program to make that specific measurement. We also created our own graph plotting software SC Plot, which allowed results to be viewed more easily than the original method using Excel macros. While the Wizard software was capable of running a single measurement, the next development, the Survey automation program, was capable of running a whole sequence of measurements to simplify the workflow for users even more.

Today’s SC11
Today, the SC11 is the most comprehensive purpose-designed surveying tool, standing the test of time over the last 20 years and used by leading electron microscope manufacturers worldwide. The SC11/Auto is now a completely automated system, capable of repeat surveying without human intervention. This enables long-term measurements, useful for expanding the surveying snapshot to study the environment at different times of the day.

So, if you are planning the installation of your next electron microscope or experiencing technical issues with your existing system, see how the SC11 could help by visiting https://www.spicerconsulting.com/which-sc11-you .

Electron microscope site survey data interpretation – part 1

Tue, 26 May 2020 11:16:55 GMT

It is important to measure both vibration and magnetic field interference at different locations and heights when conducting a site survey, to see how signals change amplitude in all three axes. This helps to locate the cause of any problems, so that it is easier to implement measures to reduce or eliminate interference. It can be as simple as relocating the microscope, taking out the cause of the interference, or installing a cancelling system to improve microscopy performance as demonstrated in the following examples.

Power cables
Power cables run through many areas of a building and can be a common cause of interference for electron microscopes. The live wire in a power cable carries electric current to an appliance, while the neutral cable completes the circuit, to form a path for the current to flow back to the mains. These two wires should effectively cancel each other out but, as the currents in the wires get larger, the current difference between the wires grows and this leads to large magnetic fields.

Distribution boards
Distribution boards are essentially central hubs that distribute power around various circuits in a building or lab. They are a source of large magnetic fields, and every effort should be taken to place an electron microscope as far away as possible because, even at a small distance away. The interference levels are much higher than the tolerance level of the microscope.

Earth leakage current
In some instances, site surveys can actually uncover problems in the power supply. Large leaks down the earth wire produce huge magnetic fields, which can often be identified by turning off different areas of power supply.

Lighting
Typically, lights are turned off in microscopy rooms during imaging, but occasionally lighting can still cause interference. In general, LEDs tend to be the best to use for electron microscopy labs, whereas fluorescent lights should be avoided. Changing the lights is often the simplest solution to overcoming the problem.

Trains and Trams
Trains produce interference that is far greater than the levels than can be tolerated by electron microscopes, depending on how far away the tracks are. The rate of train runtime can also determine the amount of disruption as regular activity – not only from vibrations as trains pass by, but also from magnetic fields running along the power lines – can affect instruments hundreds of metres away.

Similarly, trams can also produce vibrations and magnetic fields that can be disruptive. The tram line itself is set on a hill and this influences the level of interference, based on whether a tram is going up or down the slope. However, in this situation, a microscope was still installed but with the addition of a magnetic field cancelling system to disrupt the impacts of interference.

For further information on site survey services and magnetic field cancelling systems, contact us here .

About Spicer Consulting Limited

Supporting miniaturisation in the semiconductor manufacturing industry

Wed, 04 Mar 2020 14:18:48 GMT

The production of semiconductor components on a nanometre scale has become more practical than ever, thanks to advancements in manufacturing. Electron microscopy – such as TEM, SEM and FIB-SEM – is an important quality control tool in the manufacture of these semiconductors, allowing structural analysis of devices to detect any problems. However, the image quality of these instruments is commonly affected by interference from surrounding magnetic fields, making it more challenging to identify manufacturing errors.

The benefits of smaller components

The semiconductor industry is under constant pressure to make components smaller. The desire to continually increase computing speed and power – while saving costs – means that more transistors are needed within each chip. However, placing additional transistors on a chip produces more heat. One way to keep the transistors cooler is to make them smaller, as the distance that the electrons have to move to do the same job is smaller, and therefore takes less energy. This also makes the whole system faster, which is more economical, as there is more functionality built into the same space on a silicon wafer.

External factors can limit resolution

Despite the advantages of creating smaller components, miniaturisation poses a challenge during manufacture, as a higher level of magnification is needed to inspect the parts. Electron microscopy is often used to perform due to the high resolution that this technique provides. When imaging features on a chip with an electron microscope, the electron beam must be positioned with a level of accuracy that is similar to the size of feature being examined to achieve required resolution. Unfortunately, electron microscopes are particularly sensitive to magnetic fields, which can deflect the electron beam. The smaller the object, and therefore higher the necessary resolution, the more sensitive the technique is to the surrounding magnetic fields – as well as vibrations and sound.

The manufacturing environment will often experience a lot of magnetic field interference, as the most problematic frequency – around 60 Hz – is produced by an abundance of different machinery. As the space within most manufacturing sites is valuable, this leads to as many instruments as possible being packed into a given area, and this close proximity results in microscopy interference. In addition, newer semiconductor factories often feature ceiling-level monorail systems to transport components between stations for automatic loading and processing, which also helps with traceability of materials. These overhead systems typically create a 9 kHz magnetic field, which is incredibly detrimental to image quality and must be cancelled in order to improve resolution. Other contributing sources of magnetic field interference within semiconductor factories include magnetic stirrers used in plasma etchers and voice-coil actuated stages in lithography machines.

Finding the most stable environment

In the semiconductor industry, manufacturers often have highly-sensitive electron microscopes working alongside large pieces of industrial equipment – which produce various types of radiation – so it’s important to find a way to allow them both to work in harmony. This level of sensitivity requires areas to be surveyed meticulously before microscope installation, to ensure that the image quality produced will be unaffected by any external factors. Instruments such as Spicer Consulting’s purpose-designed SC11 Analysis System are routinely used by microscope vendors and consultants to perform site surveys for SEMs, TEMs and similar equipment. These instruments measure and analyse magnetic fields, vibrations and acoustics in X, Y and Z directions, displaying results graphically and allowing the user to perform a direct comparison between the fields encountered and the microscope specifications. This information is invaluable to ensure that electron microscopes are installed in the most stable environment possible – whether that is in an existing facility or a new laboratory – ensuring the highest possible image quality.

Improving image resolution

Top-end microscopes can only withstand minimal interference, so finding a suitable environment for the equipment can be extremely challenging. It is becoming increasingly common for electron microscope users to seek expert advice to find solutions to mitigate unwanted interferences, such as installing a magnetic field cancelling system. Spicer’s proprietary field cancelling technology has been developed over many years, and there are now thousands of these systems in use worldwide. All Spicer cancelling systems – including the popular SC24 – consist of a Magnetic Field Control Unit and one or more Magnetic Field Sensors, as well as three multicore cables, which are installed around the electron microscope. There are two different types of sensors that can be used depending on the interference present; the first only measures AC fields, whereas the other more complicated and high performance sensor can detect both high frequency AC and low frequency fields down to DC. The control unit includes power amplifiers that drive currents through the cables when interference is present, creating a nearly equal and opposite field. This dynamic response – which automatically compensates for field changes within 100 μs – stabilises the ambient field, restoring resolution.

Conclusion

There are many technical challenges involved in miniaturisation of semiconductor components, and both surveying instruments and cancelling equipment are essential in supporting the advancements within this industry. With a broad install base around the world, Spicer Consulting’s solutions have proven to be highly effective in restoring resolution in electron microscopes in manufacturing environments.

For more information on how Spicer can help you optimise your EM, contact us to find out here .

About Spicer Consulting Limited

Managing magnetic field interference for electron microscopes in the semiconductor industry

Tue, 21 Jan 2020 16:47:17 GMT

Transmission (TEM) and scanning electron microscopes (SEM), as well as focus ion beam (FIB) instruments are sensitive to interference from the environment, often arising from magnetic fields or vibrations. Active Solution Company Ltd. provides Spicer Consulting’s magnetic field cancelling systems to companies working with electron microscopes in the Korean semiconductor industry – for TEM, SEM and FIB platforms – to overcome the problems associated with interference.

Advancements in semiconductor manufacturing have made production of tiny components on a nanometre scale more practical than ever before. Electron microscopy – such as TEM, SEM and FIB-SEM – is a vital quality control tool in the manufacture of these semiconductors, used to structurally analyse devices for any problems. However, image quality is commonly affected by external factors, and can make it challenging to identify faults. Jong Hwa Hur, President of Active Solution Company Ltd., explained: “When a customer experiences technical issues with their electron microscope, I visit their site and conduct a survey to measure and analyse for any interference and vibrations. This allows me to identify the causes and propose effective solutions. We supply Spicer Consulting’s magnetic field cancelling systems and active vibration isolation tables to help the semiconductor industry across Korea overcome electron microscopy problems.”

“Magnetic field interference is normally caused by a 60 Hz frequency, commonly present from the abundance of different machinery in these manufacturing facilities. Additionally, the newest semi-conductor factories often feature monorail systems that have been installed in the ceilings to transport components such as silicon wafers between stations for automatic loading and processing. These systems are frequently overlooked, but can cause image interference if they are located too close to microscopy rooms.”

Jong, who has been in the semiconductor industry since 1985, concluded: “I came across Spicer when I was first looking for a solution to magnetic field interference. Spicer is highly reputable and its magnetic field cancelling systems – the SC22, SC24 and SC26 – are very intuitive to use, requiring minimal training which can easily be conducted over email. My relationship with the company has developed ever since, and all of my customers are extremely satisfied with the Spicer products and how well they resolve image distortion issues. The additional features such as the real-time monitoring and auto-reset functions also make these systems excellent.”

For more information on Spicer’s magnetic field cancelling systems, visit https://www.spicerconsulting.com/products .

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SC11 helps Hitachi High-Technologies to optimise performance of their electron microscopes

Fri, 13 Dec 2019 11:57:07 GMT

Electron microscopes are sensitive to magnetic and acoustic fields in the environment, and determining the cause of, and tackling, interference is vital to ensuring optimal performance. Global company Hitachi High-Technologies is using sophisticated surveying and cancelling systems to overcome the challenges faced when installing and maintaining this equipment.

Hitachi High-Technologies is an international corporation that offers a wide range of cutting-edge products and services in four areas: science and medical systems; electronic device systems; industrial systems; and advanced industrial products. As part of its scientific systems, the company manufactures a variety of electron microscopes suited to all applications, as Carl Hordines, Southeast District Service Manager in the US, explained: “Hitachi offers a range of scanning and transmission electron microscopes which range in size from desktop to more than 10 feet tall taking up multiple rooms. Installation of these complex instruments is not always straightforward; they can be affected by electromagnetic interference (EMI) – caused by factors from transformers to elevators and metal doors – acoustic interference – from things like heating, ventilating and air conditioning (HVAC) systems – and even vibration – traffic, nearby building works or even someone just walking down a corridor.”

“As part of the installation process, we survey the site using the SC11 Analysis System from Spicer to identify anything that might affect the microscope’s performance and recommend any preventative measures – such as field cancellation systems or vibration isolation tables – that might be required. For example, I recently surveyed a site where a large crane was in use and it was evident at the outset that this was going to cause interference with the microscope being installed. I was able to use the SC11 to measure the DC field while the crane was moving, and this confirmed what I had anticipated. This type of information helps us to advise the customer, perhaps suggesting where an instrument might be better placed in relation to external factors, as well as powerlines, and water and gas sources.”

Carl continued: “We had already used a Spicer magnetic field cancellation system to prevent interference on a number of projects, when we saw a demonstration of the SC11 Auto Survey System. It was evident from this that our survey equipment needed upgrading and we decided to purchase several for our installation teams. The SC11 is purpose-designed for surveying sites for electron microscopes and other sensitive equipment, and offers a higher quality microphone and more sophisticated sensors than our previous system. We no longer have to move the sensor numerous times to gather multiple readings, and the report generation is much quicker. I can use the macros to run a survey that gives us a really good snapshot of a location in around 25 minutes.”

“The SC11 also increases the efficiency of data collection because the whole process is integrated into the system – it’s all automated. The software is compatible with Microsoft® Office so it’s easy to pull up data without the need to copy and paste between different programs. I have an Excel® spreadsheet for each model of microscope we offer, that will read raw data and populate the tables against the specifications for that particular instrument. This allows me to determine which models will work best in a specific space or facility, without the need for multiple site visits.”

“For studies that are more complex, we can leave the system in place for extended periods of time. It is straightforward to schedule multiple runs or to start recording data when an interference hits a set level or, when the need arises, we ship a kit to a customer site if they unexpectedly encounter a problem. The system is very robust and comes with a durable shipping case, and it’s so easy to use that anybody can set it up with minimal instruction – even with no prior experience.”

“The SC11 systems are now solely responsible for all of our internal and external surveying, which ensures continuity throughout our work, and we’re so happy with them that we have recently added two more to the four we already own; they are so efficient, we wouldn’t be without them,” concluded Carl.

For more information on how Spicer can help you optimise your EM, contact us to find out here .

About Spicer Consulting Limited

Case Study-Fixing Magnetic Field Issue at Lawrence Berkeley National Laboratory

Mon, 19 Aug 2019 12:09:21 GMT

Cancelling magnetic field interference from unknown sources

Electron microscopy is the method of choice in material science and biology research when high resolution imaging is required, however, environmental interference is a common problem that can affect image quality. Scientists at the Lawrence Berkeley National Laboratory (LBNL) are using a Spicer SC24 field cancelling system to help overcome these problems and enhance microscope performance.

LBNL, based in the USA, is a national laboratory with a focus on bringing together multidisciplinary teams of researchers to advance scientific discovery. Within the laboratory is the National Centre for Electron Microscopy – a Molecular Foundry (MF) facility – that houses cutting-edge instrumentation for high resolution imaging and analytical characterization of a broad range of materials, which are available to researchers around the world. Peter Ercius, a MF staff scientist, explained this collaborative environment: “We have eight transmission electron microscopes – three of which are aberration corrected – and each has its own speciality. We offer everything from routine systems to the most advanced, atomic resolution 3D electron tomography. Researchers from any country are able to write a proposal and, if accepted, they are invited to come and use our facilities here, with the support of a team of experts on site.”

Environmental interference limits the performance

Electron microscopes are sensitive pieces of equipment that are susceptible to environmental interference from temperature fluctuations, mechanical vibrations and electromagnetic fields.

These perturbations can shift the electron beam, lowering the image resolution and making it hard to get the most out of the instrument. Peter continued: “Although the newer systems are not as easily affected by interference, it still causes problems and affects the image quality, something that we experienced with one of our own microscopes. The images weren’t as good as I knew the system could produce – having used the same system during my undergraduate degree – objects that were round or should have had a sharp interface looked very jagged, so we knew the beam was unstable.”

“It was apparent from the pattern of our interference that the frequency of the perturbation was 60 Hz, and most likely was being caused by power cables. However, the problem was often intermittent, and we didn’t know exactly where it was coming from, or how to fix the issue, suggesting that there were power surges occurring. The microscope was located at the end of the building, so was more susceptible to outside influences, and was also positioned near a door with a magnetic lock.”

Looking to Spicer for a solution

The facility already used a Spicer magnetic field cancelling system with one of its microscopes, and so the lab contacted Spicer Consulting’s USA distributor, Vibration Engineering Consultants (VEC), to discuss the new problem.

Peter continued: “We also considered a number of other systems, but compared to Spicer they came up short and we decided to invest in a Spicer SC24, primarily because of its ability to cancel AC and DC magnetic fields. VEC helped with the installation and performed a site survey, uncovering that a chiller located near the microscope, and the opening and closing of the outside door were causing some of the interference we were experiencing, but we weren’t able to identify all of the sources.”

“We considered placing all mechanical items on proper isolation padding, in combination with using the field cancelling system. However, installation of the SC24 proved to be a simple solution to a complex problem, significantly improving the image quality. The system is very intuitive, you just turn it on and, at the flick of a switch, the fields are cancelled in all three directions, allowing you to remove any interference. VEC supported us throughout the entire installation and, although there is a lot of expertise in our department, it was great to have additional backup and know-how during the process. We’re so happy that the issue has been overcome, and we are generating images of much higher quality,” concluded Peter.

Spicer Consulting provides solutions to reduce magnetic field interference for higher resolution electron microscopy. Contact us to find out here .

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Case Study Peking University

Tue, 04 Jun 2019 08:48:33 GMT

Cancelling out interference to improve the resolution of electron microscopy images

The quality of electron microscope images can be affected by interference from magnetic fields that are created by everyday equipment out of the researcher’s control, such as lifts and trains. Scientists are using field cancelling systems to escape this disturbance, increasing the performance of the instrument and, therefore, the resolution of images. Researchers at Peking University, China, have recently installed one of these set-ups to overcome the image distortion caused by external interference from magnetic fields.

Electron microscopes are powerful, but sensitive tools used for obtaining high resolution images in many technical disciplines – from cell biology to materials science and engineering – and are integral to understanding the intricate structure of many biological and inorganic specimens. However, interference from surrounding magnetic fields generated by day-to-day electrical equipment can affect the resolution of electron microscopes, decreasing the quality of images obtained. Users of these sophisticated microscopes often turn to cancelling systems that drastically reduce both AC and DC magnetic fields to overcome these problems. Dr Jing Ju, a researcher in the College of Chemistry and Molecular Engineering at Peking University, China, explained: “My lab is the core facility for use of the scanning electron microscope (SEM), and we assist many departments and research groups with a range of projects, from studying bacteria and materials to the analysis of nanoparticle crystal structures. For SEM, we need a very high resolution image – typically a 200,000x magnification of the sample – with minimal interference.”

Unwanted interference

“Our laboratory is in a very old building and, unfortunately, there is a large electricity power cabinet emitting AC interference nearby, as well as a subway 100 metres away contributing to high levels of DC magnetic fields and acoustic noise from vibrations. This level of interference deflects the electron beam of the microscope, distorting the image. Our SEM system ideally needs to operate with an external magnetic field of less than one milligauss, but DC fields measured on the z-axis were 19 milligauss and AC fields on the x-axis were more than 21 milligauss. Both AC and DC magnetic fields were regularly out of range in our lab according to the SEM requirements, and so we explored using a cancelling system to stabilise the field by creating forces to oppose those from external factors.”

Cancelling out the noise

“We started using the SEM in around 2014, but it was only recently that we were introduced to different options for removing unwanted signals. After discussing with local advanced laboratory equipment supplier, Ke Chieh Tech, it was suggested that we tried one of Spicer Consulting’s systems, and the company performed a live demonstration of the cancelling equipment for us to see. We were so impressed with the efficiency of the instrument that, at the beginning of 2018, we purchased Spicer’s SC24 magnetic field cancelling system, and are amazed at the increase in quality of images we can produce. In fact, we can now reach a magnification of 300,000x, which is a huge improvement in resolution. The dynamic nature of the SC24 means that it detects and reacts to field changes within 100 microseconds, ensuring any interference is quickly cancelled out, which is very important in such a busy laboratory.”

A trusted partnership

“Our local supplier assisted in the installation of the SC24 system and we were taught how to maintain the equipment, which is very straightforward to do even for someone with minimal experience. Whenever we have needed support, the company has been readily available by phone or email to answer any questions and provide solutions to our problems, which have always been quick to fix. We are planning on moving the SEM to a new site soon, and will be using the company’s consultation service to assist in surveying the new environment, in order to detect any possible sources of interference and confirm whether it will be a suitable location. We are incredibly pleased with the performance of the cancelling system, and the support that we have received, and look forward to continuing to work with Spicer instruments in the future,” Jing concluded.

Spicer Consulting provides solutions to reduce magnetic field interference for higher resolution electron microscopy. Contact us to find out here .

About Spicer Consulting Limited

Restoring resolution of electron microscopy

Tue, 04 Jun 2019 08:25:05 GMT

The continuous development of new technologies means that laboratories are investing in increasing amounts of electronic equipment, making space within these labs more precious than ever. This busy setting, combined with the growth – and noise – produced by surrounding cities, causes a significant problem for electron microscopy, which relies on maintaining a stable environment, free from vibration and external magnetic fields. The sensitivity of electron microscopy requires areas to be surveyed meticulously before instrument set-up, to ensure that image quality will be unaffected by these external factors.

Pre-installation site surveys are performed by either an independent service provider or the equipment supplier. These surveys can uncover potential sources of interference from, for example, power cables, trains, lifts and fluorescent lighting, as well as problems in the power supply, such as large leaks down the earth wire which produce huge magnetic fields. Typically, surveys measure acoustic levels, magnetic fields and floor vibrations in X, Y and Z directions, and directly compare these values with the environmental specifications of the equipment to be installed. Where necessary, action can then be taken to alleviate any unwanted interference, such as installing a magnetic field cancelling system .

While there are undoubtedly challenges in setting up and maintaining a stable microscopy environment, measures can be put in place to ensure these are mitigated. The key is to think ahead and engage in discussions with microscopy suppliers, site surveyors and, in the case of a new build, architects at the earliest possible opportunity. Having an experienced site surveyor with the right equipment is vital to identify common and unusual causes of interference, and to understand the magnitude of their effects. They can then advise on the best way to counteract these problems. This will allow electron microscopy to be installed in the most stable environment possible, whether it is in an existing facility or a newly set-up laboratory, ensuring the highest quality imaging is maintained.

Spicer Consulting offers pre-installation and trouble - shooting service. Contact us to find out more.

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Anticipating magnetic field interference issues prior to installation

Wed, 06 Mar 2019 09:49:58 GMT

Electron microscopes offer unparalleled image resolution and are widely used in research laboratories to investigate the structure of various biological and inorganic structures. These powerful tools are, however, susceptible to interference from magnetic and acoustic fields, which decrease the image quality. ZEISS, an internationally renowned optical expert, is therefore using sophisticated surveying equipment to inspect sites prior to system installation.

ZEISS is one of the world’s leading manufacturers of optical systems and provides a wide range of services and products used for semiconductor production, research and quality technologies, medical devices and vision care. An example of this is the use of the company’s high resolution scanning electron microscopes (SEMs) for surface topology imaging in life sciences and materials research. The installation of such high tech equipment requires careful planning to ensure that they perform as well as the customers expect them to. Christian Hegele, International Service and Support Engineer at ZEISS, explained: “It is very important that the site is adequately surveyed before setting up an electron microscope; you need to ensure that the room is big enough, and check for interference that could decrease the image quality. Since electronic and acoustic interference, as well as floor vibrations, can have a huge impact on the performance of electron microscopes it is crucial to detect any problems that may arise in order to provide a solution.”

Dedicated equipment to scan for interference

ZEISS has been using the SC11 Sensor Interface Analysis System from Spicer Consulting since 2008, allowing the company to survey the environment and check if laboratories are suitable prior to installation. Christian continued: “The system is very user-friendly and the results are displayed graphically on connected laptop screens, allowing us to reliably assess the area. We have created templates specifying the requirements of each of our microscopes, which can simply be run on the SC11 system using the Spicer Wizard software; everything is automated, making it extremely easy to use, even for less experienced service engineers. The templates are available online and can be accessed by our staff around the world, and since the majority of our service engineers are now using Spicer equipment, it means that we can ensure consistently high quality results. It’s an excellent way to standardise the service that we provide, and allows us to have confidence that each survey will be performed with accuracy and reliability, and to ensure that our staff is familiar with the benefits of the systems.”

Long collaboration with Spicer

Spicer was recommended to Christian by one of his colleagues, a former service engineer who had years of experience with its magnetic field cancelling systems. Christian continued: “I went on a two-day course organised by the company before I started performing the surveys, where I learned more about the system as well as how to train our own engineers. This was a really interesting experience, and the products were fantastic. We are now working on establishing an in-house training programme for new engineers, or those switching over to the Spicer systems. On top of that, we also use Spicer’s purpose-designed SC22 Magnetic Field Cancelling Systems, which can reduce stray magnetic fields – both AC and DC – and also handles vibrations. The SC22 increases the resolution and accuracy of our SEMs and, when surveying our customers’ sites, we often recommend this tool to enhance the performance of our systems, as it is incredibly effective at removing interference.”

“We work extremely closely with Spicer in order to deliver the best possible service to our customers. Both the SC11 and SC22 are intuitive and easy-to-use, and if we ever encountered any problems or simply wanted to make changes to the systems, our enquiries were quickly and efficiently addressed. We have an excellent relationship with the team after years of using their products, and are incredibly impressed with what they do. We work very well together and are looking forward to continuing our collaboration with Spicer in the future,” Christian concluded.

Contact Spicer Consulting Ltd for our SC11 site survey kit or magnetic field cancelling system here .

About Spicer Consulting

Since it was established in 1988, Spicer Consulting has built a world-wide reputation in magnetic field cancelling for Electron Microscopes and similar instruments. Today, working with equipment manufacturers and users alike, the company is recognised as an industry expert in maximising the performance of electron microscopes, electron beam lithography systems, CD metrology and focussed ion beam tools.

Spicer Consulting magnetic field cancelling systems protect sensitive equipment in the world's leading laboratories, universities and semiconductor manufacturing plants, as well as in the test facilities of electron and ion beam equipment manufacturers.Its magnetic field, vibration and acoustic analysis systems have been adopted as standard equipment for the conduct of site surveys by leading equipment manufacturers.

Why do I need two magnetic field sensors?

Mon, 10 Sep 2018 14:37:09 GMT

Spicer Consulting magnetic field cancelling systems can be used with one or two sensors. Why provide the option and how does it work?

1. Why provide the 2 sensor option?

A magnetic field disturbs the image of an electron microscope by making unwanted deflections of the beam. The cancelling system cancels the field at the sensor location. Therefore the ideal sensor location is close to the electron beam. However, there are two reasons not to place the magnetic field sensor next to a TEM column.

a. A TEM illuminates the specimen with electrons and then projects an enlarged image of the specimen onto a phosphor screen (or camera) using a number of magnetic lenses. See the figure below. These lenses contain windings that generate magnetic flux at their pole pieces. The current in the windings is adjusted to change the strength of the lenses in order to set the magnification and focus of the microscope. When the magnification is changed, the lens currents are adjusted substantially and the field outside the column changes enough to overload the magnetic field sensor. Therefore we recommend that sensors are placed at least 40 cm away from a large TEM column. Similarly, sensors should be not be placed adjacent to the columns of some SEMs and dual beam systems that have operating modes requiring different lens currents.

b. A TEM column is effectively a large piece of iron that distorts the magnetic field around it. For example, take a uniform vertical field. When a TEM column is placed in this field, the high-permeability iron column attracts the field to go through it rather that the surrounding air. As a result, the field next to the column is lower than the original field. Also the field near the top and bottom is bent as the flux lines are concentrated by column. Therefore a sensor next to the column does not measure a true representation of the field to be cancelled. it is better to place the sensor some distance away from the column.

It is absolutely fine to place the sensor some distance from the column if the disturbing field and cancelling field are uniform, because in this case, the field will be cancelled fine at all locations. However, this is rarely the case. The purpose of the two sensor option is to allow the field to be cancelled at the column using two sensors, both of which are some distance away from the column, even if the field is somewhat non-uniform.

2. How does the two sensor option work?

The signals from the two sensors are sent to a mixer that adjusts the proportion of signal that comes from each sensor. The mixed field is thus a weighted combination of the sensor outputs, creating an adjustable “virtual sensor” between the two sensors. The mixed field is displayed on the control unit front panel and sent to the inputs of the cancelling amplifiers. When the two sensors are placed either side of the microscope column, the virtual sensor can be inside the column. The field is therefore cancelled at the column even though the sensors are some distance away. There are 3 controls to adjust the X, Y and Z channels independently. The optimum mixer settings are found by observing the microscope image and tuning for the best image improvement.

Electron Microscope In-Cabinet Cancelling System at the University of Cambridge

Mon, 18 Jun 2018 12:39:48 GMT

When the University of Cambridge Department of Biochemistry was looking to install a Thermo Fisher (former FEI) Titan Krios electron microscope, the location proved problematic due to a range of magnetic field interference.

The team from Spicer Consulting also faced the challenge of not being able to run cables across the floor due to the Krios having a large dewar of liquid nitrogen that needs an unobstructed floor.

The resulting solution is an SC24 Field Cancelling System with the Z-axis cable running around the room, whereas the X- and Y-axis cables are installed in the enclosure of the microscope itself.

We asked Dr Dima Chirgadze, Cryo-EM Facility Manager what was causing the interference and why the Department had chosen Spicer Consulting:

What sort of magnetic field interference do you experience and how are they caused?

Our building is located in the city centre and because of that we have quite a number of different interference entering our environment. That certainly effects the performance of even those state-of- the- art instruments. For that reason, we do need to have an ability to counteract these interference by a variety of methods and we decided to choose one of the techniques provided by Spicer Consulting.

The main reason why we needed a field cancelling system is because of the close proximity of our instruments to the NMR facility, which is located just across the hall. That gave us magnetic fields in our environment that were affecting the high resolution measurements that we could achieve with our electron microscopes.

Why did you choose a Spicer Magnetic Field Cancelling System?

The reason why we’ve chosen Spicer Consulting is because of word-of-mouth. We talked to other customers of Spicer Consulting and they gave us stellar recommendations, not only on the performance of the machines but also on the installation procedures, planning etc. And, I have to say, we were not disappointed. The planning was absolutely spot-on. The actual speed of installation was also really good. And finally, the performance of the machine, as we hope, is going to be top-notch and will affect, in a positive way, our research projects.

A Brief History of Magnetic Field Cancelling

Tue, 28 Nov 2017 14:01:02 GMT

Our founder, Denis Spicer, was sorting through some old files today and found some documents from the early days of Spicer Consulting. There is an application note , explaining how to improve SEM imaging performance using magnetic field cancelling - the fundamentals remain the same today, although the technology has moved on. There is also a product data sheet for one of the first generation magnetic field cancelling systems - the SC07LF. This was the version of the SC07 with an extended low frequency range that was needed before we introduced DC cancelling systems. Both these documents date back to 1991.

Are pacemakers affected by magnetic field cancelling?

Mon, 24 Apr 2017 15:40:03 GMT

In normal use, a magnetic field cancelling system does not affect a pacemaker.

The level of field that affects a pacemaker is several orders of magnitude higher than the level of field that affects an electron microscope. Our systems actually reduce the levels of field at the microscope and make changes to the levels of field of the same order of magnitude as the pre-existing ambient field in other parts of the room. The only place our systems make stronger fields is right next to the cancelling cables. Therefore it would be inadvisable to press your pacemaker right up to a cancelling cable.

Magnetic Field due to a Moving Gas Cylinder

Fri, 27 Jan 2017 15:58:29 GMT

How it affects a TEM and what to do about it

We were asked whether moving gas cylinders on the floor above a large TEM would cause a problem with its magnetic field environment. We made measurements of the DC field fluctuations at different positions as a large gas cylinder was wheeled past on a trolley. The results show that a non-uniform field fluctuation was created by the cylinder, which would exceed the specifications of the microscope. It would require a dual magnetic field cancelling system to bring the field back into specification. It should be noted that the cylinder was a standard type used in many laboratories, but we only made measurements for one cylinder. Other cylinders may give different levels of field.

Introduction

A large high resolution TEM with monochromator and energy analyser can image with sub-Angstrom resolution, but is very sensitive to magnetic fields in the environment. Typically the field is required to be stable to within 30 nT Pk-Pk, but some models have tighter requirements.

We were asked whether moving gas cylinders on the floor above a large TEM would cause a problem with its magnetic field environment, so we decided to make some measurements. It was not convenient to measure the field below the cylinder, so we measured the field above it.

Procedure

The steel gas cylinder was made to BS 5045-1. It was 1.5m long and 0.22m diameter. It was found to be slightly magnetised, with fields up to about 4 times the Earth’s field on the surface of the cylinder. No special effort was made to magnetise or de-magnetise the cylinder, so it may be regarded as typical. It was placed on a standard steel trolley designed to carry gas cylinders.

A Spicer Consulting 3-axis DC sensor was placed at various different heights. The cylinder trolley was pushed under the sensor for a distance of 5m in the Y direction relative to the sensor. The Earth’s field is X=120, Y= 140, Z=-440 mG, relative to the sensor. The sensor was reset each time to remove the Earth’s field from the measurement.

The SC11 Chart Recorder was used to chart the magnetic field waveform in 3 axes. The resulting waveforms were extracted from the chart recorder results and plotted using SCplot. The peak to peak change reported by SCplot was adjusted to remove the AC (50 Hz) that broadens the trace on the chart. The height of the cylinder was subtracted from the height above ground to obtain the distance from the cylinder. The results are summarised in Table 1 and Chart 1 below.

Results

Discussion

It should be pointed out these results apply to a particular gas cylinder at a particular location. Other cylinders may be different in size and differently magnetised. Part of the field change recorded is due to distortion of the Earth’s field. The steel in the cylinder has a high permeability, so magnetic field flux lines are attracted to run along the cylinder rather than through the air next to it. Therefore the direction of the Earth’s field affects the field changes made by the cylinder. We have not attempted to quantify the range of fields that different cylinders might make in different locations. We present these results as what they are. Some general conclusions can be drawn, even if the actual field levels are twice or half these results.

The results show that the Y and Z fields were much larger than the X field. Some errors in the smaller X field were introduced by vehicles moving past in the road outside. The overall trend is clear: The cylinder makes a non-uniform change in DC field level as it is wheeled past. At 0.5m from the cylinder it is over 1000 nT Pk-Pk and at 4m it is down to 10 nT Pk-Pk.

Now let us estimate the effect of wheeling a cylinder in the room above, directly over a TEM. Assume that the TEM electron gun is at 2.8m and GIF is at 0.5m. Assume that the TEM room is 4m high with a ceiling 0.3m thick. The cylinder is at 4.3m height and is 1.5m from the gun and 3.8m from the GIF. It would make about 200 nT Pk-Pk at the gun and about 12 nT Pk-Pk at the GIF. This is outside the specifications of the TEM at the gun. It may be outside the spec at the GIF, depending on the type of TEM.

Fields of this level can be cancelled using a Spicer Consulting SC24 Magnetic Field Cancelling System. However, the non-uniformity of the field is a concern. If a single SC24 system is installed in the TEM room, a substantially uniform cancelling field can be produced. When cancelling is turned on, this uniform field is superimposed on the ambient field. If the sensor is at mid-height of the TEM, the result will be good cancelling at the sensor, but over-cancelling at the GIF and under-cancelling at the gun. The Magnetic fields at the TEM will not be in specification.

A dual magnetic field system can cancel this. It has one system installed in the upper half of the TEM room and another installed in the lower half. The upper system cancels the field at the gun and the lower system cancels the field at the GIF. The overall cancelling field varies along the column between the two values, roughly matching the shape of the cylinder field and giving good cancelling all along the column.

New SC11/AC sensor

Thu, 17 Nov 2016 15:12:49 GMT

Spicer Consulting is pleased to announce the new SC11/AC sensor. This new sensor is for use with the SC11/SI and is not for use with cancelling systems. It has the same magnetic field bandwidth and range as the SC11/Basic sensor, but no built-in inputs. It gives the SC11/SI the same AC field measuring capabilities as the SC11/Basic.

We no longer recommend any other AC sensor for use with the SC11/SI. If you would like to know which magnetic field sensor you should use, check out our guide .

New SC26 Magnetic Field Cancelling System

Thu, 14 Jul 2016 11:23:40 GMT

Spicer Consulting is pleased to announce the new SC26 Magnetic Field Cancelling system.

Spicer Consulting is pleased to announce the new SC26 Magnetic Field Cancelling system.
It is a replacement for the SC20Fast with LCD screen and automatic set-up. The SC26 is not a replacement for the SC22 or SC24. It is only for use in 300mm wafer fabs with overhead wafer transports that create 9 kHz magnetic fields.

The key features are:

· Makes the ambient magnetic field “OK” for electron beam tools in 300 mm wafer fabs

· Real time, wideband cancelling from DC to > 9 kHz fields

· Adapts to field amplitude and frequency changes within 10 μs

· Touch screen intelligent user interface with automatic set-up and DC reset

· Simultaneous AC & DC field display with choice of Tesla or Gauss units

· Mixes dual sensors to create virtual sensor “inside” the EM column

· Built-in test field generator

· Ethernet and USB ports for remote operation and monitoring

There are more details at http://www.spicerconsulting.com/sc26-magnetic-field-cancelling-system

Which magnetic field sensor should I use?

Thu, 21 Jan 2016 00:00:00 GMT

In 2015, Spicer Consulting released two new magnetic field cancelling systems – the SC24 and SC26 which replaced the SC20 and SC20Fast. At the same time we changed our range of sensors. We renamed some to go with the new cancelling systems. We also created some new types of sensor. This article explains our thinking behind the sensor changes.

Which sensors are now available?

SC24/AC (Green). This new AC sensor replaces the SC20/AC sensor. It has a lower bandwidth of 25 Hz. It is designed for cancelling 50/60Hz AC power frequency fields and harmonics. It is also suitable for use with a TEM or dual beam instrument that puts out large steps in magnetic field when changing magnification or operating mode. The large field change temporarily overloads the AC sensor, but the 25 Hz lower bandwidth means that it automatically recovers very quickly.

SC24/DC+AC (Black). This sensor has bandwidth DC – 10 kHz so that it can be used to cancel slowly varying fields below 25Hz as well as 50/60 AC power frequency fields and harmonics. There is no need to use it in conjunction with an AC sensor for this purpose. This is actually the same sensor that we called SC20/DCMR – but we renamed it to indicate that it works with the SC24 and can cancel AC as well as DC fields.

SC26/AC (Blue). This fast AC sensor has a lower bandwidth of 25 Hz and sufficient upper bandwidth to cancel the 9 kHz fields that come from overhead wafer transports in semiconductor cleanrooms. It is the same as the SC20Fast/AC sensor and is now only for use with the SC26 cancelling system. (Previously we supplied this sensor for SC22 systems that were used with TEMs because they recovered faster from overload than the SC20/AC sensors. The new SC24/AC sensor recovers just as quickly, so we do not need to use the SC26/AC sensor for this purpose.)

SC11/Basic (Grey). This AC sensor is not compatible with cancelling systems. It has a lower bandwidth of 1Hz and an upper bandwidth of 20 kHz. It has double the dynamic range of the cancelling system sensors. It has built-in inputs for an accelerometer and sound level meter. It used with the SC11 software to make magnetic field measurements in microscope environments. The system using this sensor is very portable and excellent for measuring AC fields, including 9 kHz. With software filters, it can detect the presence of slowly varying fields down to 0.1 Hz, but cannot measure them accurately.

SC11/AC (Red). This new sensor is for use with the SC11/SI and is not for use with cancelling systems. It has the same magnetic field bandwidth and range as the SC11/Basic sensor, but no built-in inputs. It gives the SC11/SI the same AC field measuring capabilities as the SC11/Basic. We no longer recommend any other AC sensor for use with the SC11/SI.

What happened to the Grey AC sensor?

SC20/AC (Grey). This sensor has been withdrawn and replaced by the SC24/AC. It had a lower bandwidth of 5 Hz, which meant that it recovered slowly from overload. There are relatively few situations where fields between 5 Hz and 25 Hz need to be cancelled and these can be covered by the SC24/DC+AC sensor.

Which sensors can I use for Magnetic Field Cancelling?

The following table lists the currently supported sensor options

1 The SC24 works with AC sensors, but the lower cost SC22 is usually recommended when there is no DC field problem.

Which magnetic field sensors can I use with the SC11 Analysis System?

The following table lists the currently supported sensor options

1 The SC11/SI works with any combination of AC and DC sensors, but the above are preferred.
2 The SC11/AC sensor requires SC11 5.5 or later software.
3 The MEDA uMAG-01N works with the SC11/SI, but the SC24/DC+AC is usually preferred.

New SC11 software version 5.4

Fri, 13 Nov 2015 00:00:00 GMT

Spicer Consulting is pleased to announce a new version of the SC11 Analysis System software. This release supports all versions of SC11 hardware and all versions of Windows from XP to 10.

New features include much faster reset for the latest DC sensors and some extra macro commands in the Survey program.

Many bugs have been fixed, including the display of the specification in the Spectrum Analyser and the export of RMS and Pk-Pk files from the Chart Recorder. Many small issues with SCplot are also corrected.

SC11 5.4 is available as a free upgrade to all users of SC11 5.0 or later. There are two formats:

Download via the internet (for USB-based hardware only)
DVD and user manual via mail to your postal address

To receive the upgrade, please contact us and let us know which format you prefer

Electron Microscope Environment Survey at King’s College London – protecting your investment

Wed, 09 Sep 2015 00:00:00 GMT

Spicer Consulting’s Dr Robert Christy talks about an electron microscope environment survey at the Centre for Ultrastructural Imaging (CUI) at KCL.

We’re measuring the environment for some new microscopes at King’s College London. The microscope suite has five rooms. That could mean five to seven new microscopes being installed. To protect the investment in these, we want to make sure that the environment is good. As part of our Site Survey Service, we’re measuring magnetic fields, vibration and sounds levels to see if there are any issues.

Tracking down the source of fields

We’re in a large city so some of the problems they face could be caused by traffic, but this site is mainly pedestrian, so that doesn’t seem to be an issue. However we’re close to London Bridge Station and we’re picking up signals from trains. There are other signals but the trains are a big issue here.

We’re also picking up AC fields problems which are linked to the wiring. We therefore also aim to track the source of these fields, whether that’s in the floor, walls or ceiling.

Some of this wiring might be able to be removed when they remodel the rooms, but some of the problems are being caused by wiring which might not be able to be removed. It probably means they will need some kind of field cancellation system.

Informed decisions lead to better images

After completing the survey, we’ll analyse the results and report back to CUI with our findings and recommendations. This will help them make informed decisions on what’s needed to create the best environment for the new microscope equipment.

If you’re planning to upgrade your microscopes, contact us to find out more about our Site Survey Service.

Investing in future life science microscopy at the Centre for Ultrastructural Imaging

Mon, 10 Aug 2015 00:00:00 GMT

Spicer Consulting recently interviewed Dr Roland Fleck, Director for the Centre for Ultrastructural Imaging (CUI) at King’s College London, whose microscope facilities and capabilities are due to undergo a major transformation

CUI’s key role within life science research

My role is managing the facility, guiding the scientific direction and overseeing the current changes we’re proposing. We’re looking to upgrade the instrumentation from what’s been established over the last ten years or so, to new, modern, current generation technology.

The University is principally life-science focused , we do have some users from physical and chemical sciences, but the unit itself has largely come out of the life science environment.

We carry out routine diagnostic work, such as renal biopsies for the NHS. We also do life science research which is very varied and includes research into cancer, neuroscience, age-related issues, infectious disease, hepatitis C and malaria.

The unit also acts as a core facility, providing all the electron microscopy for King’s College London.

Increasing microscopy capabilities through much needed upgrades

Our current equipment is at least ten years old and in some cases, considerably older. We have microtomes which are around 36 to 37 years old, so coming to the end of their usable working life. As the new director, I’m taking the opportunity with the University to upgrade the instruments and take CUI in a new direction.

When the instruments were last upgraded, LaB6 would have been considered a high end instrument and very appropriate for this type of environment. There would have been a large focus on more routine microscopes at lower accelerating voltages and basic scanning electron microscopes, with very little focus on Cryo techniques. Because of the way the industry has developed and the advancement of scientific techniques, there’s been a greater focus on higher-resolution TEMs. So we’re bringing in 200kV field emission systems, we’re upgrading our SEMs to bring in capabilities such as 3D imaging and focussing more on Cryo techniques, including Cryo microscopy and high pressure freezing.

Creating an environment free from field interference

Preparation is absolutely critical for the design phase, so we’re going through a series of steps within King’s to look at the current infrastructure. The building hasn’t been touched since it was built in the mid-1980s. The instruments we’re installing are high specification and we’re taking the opportunity to refresh the environment. In that, we require a detailed understanding of what we have to do to bring it up to modern standards.

One of the issues for Central London is fields that we have, undergrounds, overgrounds and other various problems. We have lots of power going to other aspects of the building and there’s a large NHS hospital nearby, which is also drawing significant amount of power.

So we’re undertaking a survey with Spicer Consulting to understand what fields are present and whether or not our new instruments would be within specification and how to mediate things if we have to.

SC11 Survey

simon.spicerconsulting@gmail.com (spicerconsulting ) — Thu, 09 Apr 2015 00:00:00 GMT

The SC11 Survey program automates a complete survey by calling the SC11 instruments using Active X technology. It is like the SC11 Wizard except that it uses a macro that can run several measurements and automatically save the results. Survey guides you through the choice of sensors, a self test to ensure all the sensors are working and then the survey itself. Survey enables first-time users to set up the equipment and run a standard survey using a macro and setup files that have already been created by an expert user.

This program is designed to work with the full SC11/SI system with 2 DC magnetic field sensors, 3 accelerometers and a precision microphone. Self test can be customised to omit magnetic field, or vibration or acoustic tests if required. Survey macros are very flexible, but once written, they require the sensors for which they are designed.

The Show Presentation button on the Start page opens a document that shows in detail how to connect the sensors, run a self test and perform a survey for the full SC11/SI system. It is possible to customise this presentation for other hardware configurations.

Self test works by comparing the output of 2 magnetic field sensors or 3 accelerometers. It also uses the self-test feature of the precision microphone. The self test report includes spectra comparing the sensors and a pass/fail result. If self test fails, it advises the user to ask for support before continuing with the survey. The report can then be sent to an expert user so that they can diagnose whether a sensor is faulty or advise the user how to get it working.

To run a survey, the user follows the instructions in the presentation and then selects the required survey from a predefined list. Surveys may be repeated at fixed intervals to show how the environment changes with time. SCplot can show this in a waterfall plot.

Survey macros are written by an expert user as follows: First set up a measurement in the scope program and save the setup file. Then turn on macro recording and run through the process of loading the setup, making the measurement and saving the results. Save the macro. Repeat for the spectrum analyser and chart recorder. Do the same with SCplot to create the graphs required and append them to a survey report in Microsoft Word. Manually edit the recorded macros together, adding Wait and Exit statements to make a complete survey macro. Save the setup files and the macro together in a folder ready for SC11 Survey to use. Macros contain simple statements that run in sequence. However the statements can be directly used in Microsoft Visual Basic if more complicated programming is required.

Cancelling systems in adjacent rooms

simon.spicerconsulting@gmail.com (spicerconsulting ) — Thu, 09 Apr 2015 00:00:00 GMT

Can we put magnetic field cancelling systems in adjacent rooms?

There are two main concerns:
1. Will the two systems interact with each other and cause instability?
2. Will the field from one system cause the field in the adjacent room to be non-uniform?

1. Will the two systems interact with each other and cause instability?
Two Spicer Consulting cancelling systems will work fine in adjacent rooms. This is because the amount of crosstalk is typically less than 12%. Each cancelling system can cancel any field made by the other one at its sensor position. Therefore this concern is not usually a problem.

There is one proviso – do not place a cable from one system on the other side of the same wall as the cable of another system. These would couple strongly to each other causing instability in both systems. If fitting wall-mounted cables in adjacent rooms, put at least one of the cables on the far wall away from the other room.

2. Will the field from one system cause the field in the adjacent room to be non-uniform?

Yes it will to some extent. This could be a problem if the non-uniformity in the field exceeds the specification of a large high resolution TEM in one of the rooms. It is not a problem with small columns such as SEMs and Dual Beam machines. The size of the non-uniformity depends on the size and position of the cables and the size of the field that is being cancelled.

As an example we have two adjacent rooms of size W=5m, D=5m and H=3m. We want to put a TEM in the centre of each room. We fit double loop room cables in the first room, centred on the room and we calculate the field that this installation makes in the centre of the second room. Let’s say the second room is in the X direction from the first room. Then the Z cables make a non-uniform X field in the second room. The field over the length of the TEM column is about ±4% of the field in the centre of the first room, approximately zero at 1.5m and with opposite sign at the top of the room compared to the bottom. If the Z field to be cancelled is 500 nT pk-pk, then a non-uniform X field of 20 nT pk-pk will be created at the column in the second room. An X field in the first room makes a ±2% non-uniform field in the Z field of the second room. Other smaller non-uniformities are also created.

Why is my vibration spectrum so large at low frequency?

Thu, 09 Apr 2015 00:00:00 GMT

Q. When measuring a vibration spectrum, I see a large signal at the low frequency end. Is this a real vibration?
A. The issue is caused by the 1/f noise limit of the accelerometer.

The Wilcoxon 731A accelerometer bandwidth is 0.1Hz - 500Hz. At large low frequency vibration amplitudes the bandwidth is the limiting parameter. At the very low amplitudes we need to measure for electron microscope environments, the 1/f noise of the accelerometer is the limiting parameter.
To derive displacement in microns from the accelerometer output the SC11 has to divide its output by frequency squared. Please see page 111 of the SC11 user manual.

This fundamental physics noise limit means that vibration spectra results at low frequencies must be interpreted carefully. Most of the signal you see on spectra below 1Hz is probably not vibration. Vibration specialists call this issue the system noise floor.

Viewing SC11 Results

Thu, 09 Apr 2015 00:00:00 GMT

Versions of the SC11 Analysis System software prior to 4.3 saved results in a text file format but did not include any results viewing program. Instead an Excel spreadsheet called "SCview.xls" was provided free of charge and could be downloaded from the web site.

From SC11 version 4.3 onwards, the SCPlot program is included as standard. SCplot can open files from earlier versions of SC11 as well as the different file format introduced in version 5.0

If you are still using SC11 version 4.2 or earlier and you need SCview.xls, please contact us and we will send it to you free of charge. It requires Excel 97 or later. If you are using SC11 version 4.3 or later, then please use SCPlot. It is quicker to use than SCview. SCview cannot open files from SC11 5.0 or later.

SC12 Case Studies

Thu, 09 Apr 2015 00:00:00 GMT

Samsung, USA - Johnson Matthey - Motorola - Leica Lithography Systems

Samsung, USA improves imaging to 99%
Having carried out an in-house survey which detected an EMI of 60HZ, Craig Lopp of Samsung, Austin consulted with their Electron Microscope supplier JEOL as how best to overcome the interference it was causing. JEOL suggested that Vibration Engineering, Spicer Consulting's agent in the USA, should be asked to look at the problem affecting the 2 instruments. "Vibration Engineering came in and agreed to set up an SC12 Field Cancelling System for each microscope" explained Craig Lopp, "If they worked, we agreed they would be purchased. They did and the images are now up to 99% of what it should be. They're really simple to use. Once the system was demonstrated to work, we fed all the cables, hooked them up and they've worked ever since."

Johnson Matthey eliminates the risks associated with electromagnetic fields
When Johnson Matthey were planning the installation of their new SEM, they made the decision to install the SC12 as a precautionary measure. As Mr Spratt from the company explains, "We are aware that when examining very small features on a powerful SEM, temperature, vibration and magnetic fields can all cause deviations. We had a survey carried out, prior to installation and although the magnetic field was not excessive it was apparent. It is always better to install a system like the SC12 before the microscope is installed so you can put the loops in the floor and ceiling. When you are making a big investment you have got to be certain that it won't fall over. You have to eliminate as many risks as possible."

The SC12 overcomes beam distortion at Motorola
When Motorola purchased and set up a new Hitachi CDSEM machine for semiconductor work at their East Kilbride plant, they discovered that the beam was being distorted, due to interference from two other machines in the clean room. On Hitachi's recommendation, Sandy Millar who was in charge of the installation, contacted Spicer Consulting, who carried out a full survey, then proposed and commissioned an SC12. "So far, we've never had a problem. All we have had to do on one occasion, when someone knocked one of the sensors, was to press the reset button. I worked quite closely with Spicer Consulting when they came up and you get the feeling that they know exactly what they are doing. I'd recommend them to anyone who had the same problem." [Motorola has since beome Freescale Semiconductor]

Protecting the investment in electron beam technology at Leica Lithography Systems
Leica Lithography Systems at Cambridge have had a long relationship with Spicer Consulting. "It's a matter of cost." summed up Don Wilderspin from Leica, "E-beam clean rooms are vastly expensive to move or shut down because of a problem. If we can fix a problem at source, that's best. If not the SC12 or similar has to be the answer.You'll find that things change in an installation also. The environment does change. Suddenly more load is put on a cable than before and you have a problem that can be the most difficult case of all to sort out unless you have protected yourself from the problem in the first place. The SC12 Field Cancelling System is very easy to use, it's strength is in the fact that it's totally transparent." [Leica Lithography Systems has since become Vistec and merged with Raith]

What sensors work with SC20Fast?

Thu, 09 Apr 2015 00:00:00 GMT

The SC20Fast is for use with clean room CDSEM tools. It is able to cancel the approximately 9 kHz fields made by overhead wafer transport systems. This post explains the rules for selecting the sensors for use with the SC20Fast.

1. The SC20Fast has two sensor inputs "Sensor1(left)" and "Sensor2(right)"
2. The sensors plugged in to the two inputs must be the same.
3. You must not plug "Sensor SC20/AC" or "Sensor SC20/DCMR" into these inputs.
The system will oscillate. It probably will not break.
4. If you are using one "Sensor SC20Fast/AC" it must be in "Sensor1(left)"
The mixer will be disabled.
5. If you are using two "Sensor SC20Fast/AC" (one in each input) the mixer is enabled.
6. If you need DC cancelling you need a DC combiner. (This is not a mixer)
It has inputs for one "Sensor SC20Fast/AC" and one "Sensor SC20/DCMR".
The Combiner output is plugged into "Sensor1(left)". (The mixer is disabled)
This Combiner contains a 25Hz crossover network.
The SC20Fast uses "Sensor SC20/DCMR" below 25Hz, "Sensor SC20Fast/AC" above 25Hz
7. If you need better AC cancelling at 60Hz you need an AC combiner. (this is not a mixer)
It has inputs for one "Sensor SC20Fast/AC" and one "Sensor SC20/AC".
The Combiner output is plugged into "Sensor1(left)". (The mixer is disabled)
This Combiner contains a 800Hz crossover network.
The SC20Fast uses "Sensor SC20/AC" below 800Hz, "Sensor SC20Fast/AC" above 800Hz
You position "Sensor SC20Fast/AC" in the tool for best 9kHz cancelling
You position "Sensor SC20/AC"in the tool for best 60Hz cancelling

Why choose Spicer Consulting for Magnetic Field Cancelling?

simon.spicerconsulting@gmail.com (spicerconsulting ) — Thu, 09 Apr 2015 00:00:00 GMT

This post outlines some of the reasons to choose Spicer Consulting magnetic field cancelling systems in preference to other competing products.

There is little to be gained in comparing specifications. Different manufacturers may make different underlying assumptions that make direct comparison difficult. Parameters that compare poorly may be omitted. In any case, some of the most important performance characteristics of a cancelling system are determined by the laws of physics relating the cable geometry to the shape of the magnetic field generated and therefore are not specific to any particular product. However, we can point out some the outstanding features of Spicer Consulting cancelling systems:

The New SC22, SC24 and SC26 are modern designs with colour LCD displays and a simple user interface.

There is a readout of the total magnetic field in addition to the X, Y and Z components.
The SC24/SC26 can show AC and DC fields in X, Y, Z and total all at the same time.
The readings are in a choice of units mG, nT or uT.
There is a Field Ok light and trip and indicators to show which axis has a problem.
There are clip indicators to show if the sensor is overloaded.
The screen shows you if the sensors/cables are connected
The setup results give error messages which help you to fix any installation problems.

All our systems support 2 sensors and a mixer, making a virtual sensor adjustable in position along a line between the physical sensors. This enables the physical sensors to be located further away from the column. This flexibility enables you to reduce sensor overload when a large TEM changes its magnification, or to avoid places where the field is distorted by the column or chamber iron. The mixer can be tuned in to optimise the microscope image.

The SC22 is for AC cancelling only and is competitvely priced. It does not have lots of adjustments. You just press SETUP and it sets its own gain and phase. The SC22 has a USB interface and remote monitoring software.

The new SC24 and SC26 replace the SC20 and SC20Fast. They have the same simplicity of setup as the SC22, using an LCD touch screen. They also have a built-in mixer. The SC24 and SC26 have USB and Ethernet interfaces and remote monitoring software.

The SC22/SC24/SC26 automatically detects if it is oscillating and shuts itself down. This could happen if someone moved the sensor while it was cancelling.

The SC24 and SC26 have an auto reset feature, which allows them to keep working without user intervention after the microscope has put out a big change in DC level. This happens when a TEM changes magnification. Even some SEM or dual beam systems do this when they change operating mode.

The SC24 and SC26 have the ability to generate magnetic fields for trouble shooting and setup purposes.

We provide a variety of ready built standard cables (Helmholtz for frames, single loop and double loop room cables, single or double loop fast cables for SC20Fast/SC26).

Our systems are Nemko certified, which majors on product safety. Nemko regularly visits us to check on our manufacturing quality and documentation.

Introduction to Magnetic Fields

simon.spicerconsulting@gmail.com (spicerconsulting ) — Wed, 04 Feb 2015 00:00:00 GMT

Magnetic Field Basics

This section provides background information on magnetic fields with reference to electron microscopes and similar instruments. Magnetic fields are created by electric currents in the space around where the currents flow. Currents which do not change with time (called direct currents or DC) make constant magnetic fields which we call DC fields. A gradual change in a direct current creates a corresponding gradual change in the DC field. By convention we refer to unchanging fields and fields which change in this slow non-periodic manner as DC fields.

Currents which change sign in a regular manner with time are called alternating currents or AC and give rise to corresponding AC magnetic fields.

The most common AC fields are created by power lines and usually have fundamental frequencies of 50 or 60 Hz (referred to as "line" frequency) often with harmonics up to about 5 kHz. AC fields at other frequencies may be generated by rotating machines containing permanent magnets. Examples are magnetic stirrers and plasma etch machines which may make fields at about 0.3 Hz.

The units used to measure magnetic fields are as follows....
SI unit of magnetic field strength: Amp/metre (A/m)
SI unit of magnetic flux density: Tesla (T)
CGS unit of magnetic flux density: Gauss (G)

The SI units are the modern units but the old CGS unit, the Gauss, is still so widely used that it has been kept in the Spicer Consulting systems. The old CGS unit of magnetic field strength, the Oersted, is now rarely used.

The Amp/metre unit is commonly used by the electricity supply industry as it relates directly to the currents which are generating the magnetic field. The Tesla and Gauss are units of the flux density created by the magnetic field and are the most common units used in measurement of fields. The relationship between the units (in air or space) is as follows...
1 Amp/metre = 1.257 microTesla = 12.57 milliGauss

The Earth's Magnetic Field

The planet earth is surrounded by a DC magnetic field which is created by a direct current flowing in the earth's molten core. The current flow and the magnetic field are sustained by the "dynamo" effect. Magnetic field is a vector quantity, that is, it has a magnitude and a direction. The magnitude of the earth's field is about 0.5 Gauss (50 microTesla). The direction of the magnetic field vector is approximately vertical at the north and south poles and horizontal (pointing north) at the equator.

The earth's field undergoes significant changes (including sign reversal) rather randomly on a time scale of thousands of years. There are also small changes of 1 to 5 mG daily which are thought to relate to the solar wind interacting with the earth's ionosphere. The figure below is a chart recording of the changes in the earth's field over a period of three days measured in our Stewartby Lab. using the SC20/DCMR magnetic field sensor. The sensor Y axis is aligned with magnetic north, the X axis points east and the Z axis is vertical.

Electron Microscopes

Electron microscopes control the motion of their electrons using electric and magnetic fields inside the part of the instrument called the "column". Focussed ion beam systems are similar. The column usually comprises a stack of electron optical components, "lenses" to focus the electron beam and "deflectors" to position the beam. The column is mostly made of ferromagnetic iron which serves as the magnetic circuit for the lenses and the mechanical structure of the column. The magnetic fields inside some of the lenses can be as large as 10,000 Gauss (1.0 Tesla) i.e. 20,000 times the earth's field. The iron structure of the column serves as a partial barrier to magnetic fields entering the column from outside and the large internal lens fields leaking out.

Ambient magnetic fields penetrate the electron beam column from outside (to some extent) and add to the magnetic fields in the lenses and deflectors. AC fields, and DC fields which change during operation of the microscope, may degrade the performance of the microscope. Usually, DC fields penetrate the column more than AC fields. This is because AC fields are also attenuated by the mechanism called "eddy current shielding".

Changing DC fields, which cause a problem for electron microscopes, can be created by steel objects moving and locally distorting the earth's field. Examples include cupboard doors, chairs, motor vehicles and elevators (lifts). Large changing DC fields can be created by electric trams and commuter trains which draw direct current from an overhead wire, returning it through the rails. Superconducting magnets in research facilities are also not good news for electron microscopes because they can radiate large DC fields for tens of metres.

The earth's magnetic field also penetrates the electron beam column but, for most electron microscopes, it can be considered constant since it changes slowly compared with the time taken for a micrograph. Its effect is adjusted out with the instrument controls during routine operation of the microscope and the operator is generally unaware of its presence. For electron beam lithography machines used to write reticles for IC chips (or to write directly on a silicon wafer) the changes in the earth's magnetic field during the write time (several hours) may significantly degrade the accuracy of the written pattern. Some EBeam lithography machine manufacturers are now specifying maximum field changes of 0.1 mG. Since the earth's field changes much more than this on a typical day, magnetic field cancelling would be necessary for these machines to meet specification.

Electron microscopes form their image either by projection (TEMs) or by scanning to form a TV like image (SEMs, STEMs). The effect of DC or AC fields on projected images is to move the whole image and the result is loss of resolution on the image screen. The effect of DC or AC fields on scanned images is to move parts of the image. AC line fields typically produce wiggly edges on the image often called "edge tearing" or "ragging". DC fields may cause discontinuities in the image and cause straight edges to look like mountain ranges. Some microscope manufacturers design their scanning sytems to operate synchronously with the 50 or 60 Hz line. This removes the edge tearing caused by the AC line fields but introduces distortion into the image (e.g. the image of a square grid is bent). However, distortion is generally less visible than edge tearing and may be acceptable for some applications.

Typical SEM Installation

simon.spicerconsulting@gmail.com (spicerconsulting ) — Wed, 04 Feb 2015 00:00:00 GMT

The Spicer Consulting Magnetic Field Cancelling Systems comprise a Magnetic Field Control Unit, AC or DC Magnetic Field Sensors and three multicore cables which are installed in the room where the field is to be cancelled.

The Control Unit power amplifiers drive currents through the cables to create a field which is the opposite sign to the changes in the ambient field. The magnetic field sensors measure the resulting field and real time negative feedback reduces the ambient field by the loop gain of the system.

The systems are dynamic, automatically responding to field changes within 100 µs.