NANOPHYSICS B.V IS AN INDEPENDENT ANALYTICAL SERVICE LAB PROVIDING SEVERAL CHEMICAL- AND PHYSICAL ANALYTICAL TECHNIQUES. WE HAVE CUSTOMERS FROM ALL KINDS OF INDUSTRIES E.G., SEMICONDUCTOR, AUTOMOTIVE, PHARMACEUTICAL, RENEWABLE ENERGY, UNIVERSITIES AND NANOTECHNOLOGY RESEARCH INSTITUTES, ETC.
Located at the University of Twente in The Netherlands we provide services for Failure Analysis, Quality Control and Material characterization. Typical customers are R&D departments of High Tech Companies. In case they have an issue with their materials, we need to get involved.
NanoPhysics B.V. is highly skilled in Focused Ion Beam (FIB), Integrated Circuit edit (circuit edit), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and advanced TEM sample preparation and imaging (STEM-HAADF), but also operates with several high qualified partner laboratories offering complimentary techniques to ensure an integral solution to your request.
With deep analytical knowledge and a balanced view of strategy, process and technology NanoPhysics B.V. helps you to understand and improve your product. Looking forward to become part of your team.
Scanning Transmission Electron Microscopy (STEM) is an invaluable tool for the characterization of nanostructures. It provides elemental composition and crystal information at atomic scale. The Scanning TEM works on the same principle as a normal scanning electron microscope by focusing an electron beam into a very small spot which is scanned over the TEM sample. The difference with SEM is that one has to prepare ultrathin specimens of 200 nm or less (except for nanoparticles) so that the accelerated beam of electrons passes through the sample. This electron beam interacts with the TEM sample and the transmitted beam is collected by a detector. This can either be a CCD chip (when operating in TEM mode) or a High Angle Annular Dark Field (HAADF) detector.
HR-TEM
High Resolution STEM image
When operating in Transmission Electron Microscopy mode, dense areas as well as areas that contain heavy elements appear dark due to more scattering of the electrons within the sample. In STEM mode the opposite is realized, making the HAADF detector very sensitive to differences of the element irradiated based on the atomic number (Z-contrast). See the example images below of the metal oxide catalysts.
catalyst STEM HAADF metal oxide
STEM imaging can be combined with several material analysis techniques like Electron Energy Loss Spectroscopy (EELS), Energy Filtered TEM (EFTEM) and Energy Dispersive X-ray (EDX). EELS is a technique that provides elemental information on a nanometer scale when coupled with TEM. The energy of the incident electrons is altered as they pass through the sample. This Energy Loss can be characterised using EELS to provide elemental identification. Compared to EDX, EELS provides improved signal to noise, spatial resolution (down to 1 nm), energy resolution (<1 eV for EELS) and sensitivity to the lower atomic number elements. In the example at the right side Energy Filtered TEM is used to elucidate the diffusion of Ti through the Pd layer.
Photon Emission Microscopy (PEM) or (EMMI) is a high efficient Failure Analysis technique for fault localization on IC's. In principle EMMI or PEM consists of a highly-sensitive CCD or InGaAs detector capable of detecting photons. These photons are emitted when an electron-hole pair recombines in the active area (FEOL). Both detectors have a typical wavelenght range but InGaAs has a better efficiency covering the complete range. Typical seminconductor related failures are:
Junction leakage
Gate oxide defect
ESD failures
Latch Up
Leakage currents
Photon Emission is complementary to OBIRCH but is more related to FEOL issues, where OBIRCH is suitable for FEOL as well as BEOL defects. Just like OBIRCH, EMMI analysis can be performed either Frontside or Backside. A backside analysis is advised and has the advantage that no large metal tracks will block the emitted photons. Preparing a sample for Backside analysis requires more steps and special tools inlcuding skills. Frontside analysis suffice with a simple decapsulation or boil-out. Electrical connection can be made using dedicated test sockets or using probe needles.
Failure analysis (FA) is the process of determining how or why a part has failed. This is often performed as a series of steps known as FA techniques. A failure is defined as any non-conformance of the device to its electrical and/or visual/mechanical specifications.
Failure Analysis is necessary in order to understand what caused the failure and how it can be prevented in the future.
Failure analysis starts with failure verification. It is important to validate the failure of a sample prior to failure analysis in order to conserve valuable FA resources. Failure verification is also done to characterize the failure mode. Good characterization of the failure mode is necessary to make the FA efficient and accurate.
After failure verification, the analyst subjects the sample to various FA techniques step by step, collecting attributes and other observations along the way. Non-destructive FA techniques are done before DPA Destructive Failure Analysis. Also, the results of these various FA techniques must be consistent or corroborative. Any inconsistency in results must be resolved before proceeding to the next step. For example, a pin that exhibits a broken wire during X-ray inspection but also shows an acceptable curve trace during curve tracing cannot happen, so this inconsistency must be resolved by verifying which of the two results is correct.
In general, the results of the various FA techniques would collectively point to the real failure site. The FA process is finished once there is enough information to make a conclusion about the location of the failure site and cause or mechanism of failure.
Material contrast backscatter SEM
We can distinguish:
Failure Mode - a description of how a device is failing, usually in terms of how much it is deviating from the specification that it is failing, e.g., excessive supply current, excessive offset voltage, excessive bias current.
Failure Mechanism - the physical phenomenon behind the failure of a device, e.g., metal corrosion, electrostatic discharge, electrical overstress.
Root Cause - the first event or condition that triggered, whether directly or indirectly, the occurrence of the failure, e.g., improper equipment grounding that resulted in ESD damage, a system problem that caused the usage of an incorrect mask set.
The objective of a failure analysis engineer when conducting FA is to determine the failure mechanism that led to the failure mode of the device. Once the failure mechanism has been determined, the process owner or expert can work with the failure analysis engineer to determine the root cause of the problem. The process owner must always address the root cause of the failure mechanism, not just the intermediate failure causes that occurred after the root cause has already happened.
WE OFFER YOU THE FOLLOWING FAILURE ANALYSIS TECHNIQUES:
Scanning Acoustic Microscopy (SCAM or SCAT)
X-ray inspection 2D and 3D
Dual Beam FIB cross-sectioning
Conventional cross sectioning i.c.w. Optical or Electron Microscopy
Scanning Electron Microscopy with EDX
Decapsulation of Integrated Circuits
FIB chip modification / probe pad deposition
OBIRCH fault localization
Photon Emission (PEM) fault localization
TEM analysis
One of the FIB services NanoPhysics has to offer is circuit edit, which is a powerful technique to enhance the development of a new integrated circuit. When failures arise after first time tests FIB Circuit edit can modify the chip rapidly and debug the chip without waiting preparing a new mask.
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FIB chip modification can be done from frontside so only decapsulation is required. But we also offer backside circuit modification. This can be performed on all kind of packages like WLCSP, QFN, flip-chip, SOT and even BGA's in some cases. For this backside circuit edit we need to thin down the bulk silicon of the die. After that we can trench a big hole in the silicon to get access to the active area of the chip (see image below on this page).
By applying FIB milling unwanted connections on the chip can be removed and new metal tracks are deposited. FIB milling uses a beam of finely focused Ga+ ions that are accelerated to 30 KeV and scans the surface of the sample. So the FIB can mill away materials starting from the surface into a chip for instance. When gases are used during milling, metal tracks or insulated layers can be deposit. This way FIB circuit edit is a fast microsurgery tool for first silicon debugging. Our circuit edit include both Aluminium and copper based chips for front as well as backside modification.
NanoPhysics B.V. uses a FEI V600CE (V600 Circuit Edit) and a FEI V400ACE (V400 Circuit Edit) with a navigation driven stage for precise FIB milling within nm resolution. NanoPhysics B.V. guarantees a fast turnaround time for your circuit edit and offer competitive pricing. Together with our years of experience makes NanoPhysics your choice for circuit editing.
CHIP DEPROCESING
Quite often the next step after Fault Localization like OBIRCH or Photon Emission is Destructive Physical Analysis DPA of the hotspot. This can be either planar lapping or deprocessing of the chip to have a detailed look at the layers underneath the surface of the chip. Also an option would be backside deprocessing of the silicon chip (see below te explanation) . We can perform FIB cross sectioning to achieve high resolution X-section images. But in that case we need very accurate fault localization as well as navigation capabilities in the DualBeam FIB/SEM. Optical Microscopy might be an option but it will only show irregularities in the top metal layer of the chip. The underlaying metal layers are optically blocked by the ones on top.
FRONT SIDE DEPROCESSING
We can accurately grind/polish down the layers on top one by one to achieve good sight on the feature of interest. Additional Optical, SEM microscopy or both can be applied to obtain the best images of the failure location. Quite often the sample is still suitable for FIB cross section or even TEM analysis. For example for TEM analysis in a memory region it is required to remove the top metal layers just to navigate to there right column and row.
We can also prepare your sample for transistor characterization measurements. This means we polish the sample down till contact level. This way you will be able to measure suspicious transistors using nano probe equipement.
BACKSIDE DEPROCESSING
This technique is used to obtain high resolution images of the backside. For example to determine if the gate oxide is still good or to see the physical gate length or just to get a function block layout. In a nutshell what we do is take the chip and put it upside down and remove all the bulk silicon. This can be a thin chip with a thickness of 75 µm but we can also deal with chips with full wafer thickness of 700 µm. When all the bulk silicon is removed we can have a detailed look at the STI Shallow Trench Isolation and GateOxide .
In case electrical characterization and OBIRCH fault localization is performed you may want to proceed with DFA Destructive Failure Analysis. Quite often backside preparation is performed to obtain quick and the most detailed images of the failure. This can be subtle pinholes in the gateoxide but also EOS Electrical Over-Stress signatures between transistor junctions.
For competitor analysis purpose backside analysis is a quick and low cost way to obtain a lot of information of the chip. Like for example what is the functional block layout or the process node of the chip.
Some applications:
Technology node determination of the latest Integrated Circuits
Gate oxide defects inspection like pinholes
Reverse Engineering to get smooth functional block layout
EOS events in the FEOL
New nanotechnology materials enable scientists to improve bulk physical properties for different applications and, with the resulting products, open new markets for the nanotechnology industry. The physical properties of nanotechnology materials are strongly correlated with their crystalline structure. It is, however, the real structure complete with interfaces and defects that is of importance and not just the ideal crystalline structure. Hence a thorough understanding of interfaces and defects is required to be able to correlate microscopic structures with macroscopic physical properties. High resolution transmission electron microscopy (HRTEM) is the key to understand these real structures down to the atomic level.
HR-TEM layer analysis
TEM layer analysis
A transmission electron microscope is constituted of two or three condenser lenses to focus the electron beam on the sample, an objective lens to form the diffraction in the back focal plane and the image of the sample in the image plane, some intermediate lenses to magnify the image or the diffraction pattern on the screen. If the sample is thin (< 200 nm) and constituted of light chemical elements, the image presents a very low contrast when it is focused. To obtain an amplitude contrasted image, an objective diaphragm is inserted in the back focal plane to select the transmitted beam (and possibly few diffracted beam): the crystalline parts in Bragg orientation appear dark and the amorphous or not
Braggoriented parts appear bright. This imaging mode is called bright field mode BF.
If the diffraction is constituted by many diffracting phases, each of them can be differentiated by selecting one of its diffracted beams with the objective diaphragm. To do that, the incident beam must be tilted so that the diffracted beam is put on the objective lens axis to avoid off axis aberrations This mode is called dark field mode DF. The BF and DF modes are used for imaging materials to nanometer scale.
EFTEM: material analysis at nanometer resolution
Because of its high resolution, it is a valuable tool to study nanoscale properties of crystalline material such as semiconductors and metals. TEM imaging can be combined with several material analysis techniques like Electron Energy Loss Spectroscopy (EELS), Energy Filtered TEM (EFTEM) and Energy Dispersive X-ray (EDX). EELS is a technique that provides elemental information on a nanometer scale when coupled with Transmission Electron Microscopy. The energy of the incident electrons is altered as they pass through the sample. This Energy Loss can be characterised using EELS to provide elemental identification. Compared to EDX, EELS provides improved signal to noise, spatial resolution (down to 1 nm), energy resolution (<1 eV for EELS) and sensitivity to the lower atomic number elements.
A powerful technique in Material Analysis is Scanning Electron Microscopy (SEM). Here a sample surface is scanned with a finely focussed electron beam. The resulting electron bombardment leads to the emission of secondary electrons, backscattering of high energy primary electrons and creation of element specific X-rays. Several detectors are available in Electron Microscopy all with their advantages. SE detectors only collects low energy secondary electrons originate from the top nanometers of the sample. This give excellent surface topography images with very reasonable resolution.
SE image of particle
SE image of particle
Backscatter detector only collects primary electrons. These high energy electrons, on the other hand, is determined by the average atomic number of the sample material. The corresponding images clarify the distribution of different materials (Z-contrast images). This is perfect for layer determination, as each layer contains different element it is easily to distinguish. In Backscatter mode, the information depth is in the range of 1 µm. In other words you can obtain information till about 1 µm underneath the surface. One other detector we would highlight is the Inlens- or Through Lens Detector. This detector is placed in the electron column and is coaxial to the electron beam. The sample surface needs to be close to column for optimal performance. This detector is not recommended for surface topography but it does achieve the highest magnitudes possible.
A big advantage of SEM compared to optical microscopy besides high magnitudes is the depth of focus. With SEM a particular surface can be inspected using angled view while the surface is in focus throughout the whole image.
EDX elemental analysis
Energy Dispersive X-rays Spectroscopy (EDX or EDS) is an analytical capability were element specific radiation is used for chemical characterisation of the surface near volume. With the aid of proper detectors, the energy or the X-rays is determined. It can be coupled with several applications including Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Scanning Transmission Electron Microscopy (STEM).
EDX, when combined with SEM, provides elemental analysis on areas as small as nanometers in diameter. The impact of the electron beam on the sample produces x-rays that are characteristic of the elements found on the sample. The measured intensities yield quantitative information on the element composition and distribution. The depth from where the X-rays originate depends on the material and the used primary electron beam energy. For typical primary energies of 10 to 20 keV it is in the µm range.
Samples for SEM and/or EDX need to be high vacuum compatible. However for some applications like moisturous or non-conductive samples Environmental SEM (ESEM) is also possible allowing chamber pressures up to 1 mbar.
SOME APPLICATIONS:
Identification of metals and materials
Particle contamination identification and elimination
Classification of materials
Product and process failure and defect analysis
Examination of surface morphology (including stereo imaging)
Analysis and identification of surface and airborne contamination
Powder morphology, particle size and analysis
Cleaning problems and chemical etching
Welding and joining technology quality evaluation and failure investigation
Paint and coating failure and delamination investigation
Identification and elimination of corrosion and oxidisation problems
Contamination or stain investigation
Structural analysis
Reverse engineering of products and processes
A Focused Ion Beam (FIB) instrument uses a finely focused ion beam to modify and image samples. FIB is chiefly used to create very precise place specific cross sections (below 100 nm accuracy) of a sample for subsequent imaging via SEM, STEM or TEM or to perform circuit modification. Additionally FIB can be used to image a sample directly, detecting emitted electrons. The contrast mechanism for FIB is different than for SEM or S/TEM, so for some specific examples FIB can provide unique information. A Dual Beam FIB integrates these two techniques into one tool thus enabling sample prep with FIB and SEM imaging without exchanging the sample.
AN EXAMPLE:
FIB cross-section showed interruption of plating
FIB cross-section showed interruption of plating
For an electrical connector, it is important that the gold plating is thick enough and has good wear- resistance over its lifetime. To get a good image of such plating a Focused Ion Beam (FIB) is used. A tiny hole is milled and the resulting polished surface is analyzed using an electron microscope. In most case this electron microscope and FIB are combined in a so called DualBeam system.
FIB CROSS SECTION FEATURES:
FIB has revolutionized sample preparation for TEM samples, making it possible to identify sub-micron features and precisely prepare cross sections
FIB-prepared sections are used extensively in SEM microscopy, where the FIB preparation, SEM imaging, and elemental analysis can happen on the same multi-technique tool.
FIB-prepared sections are also used in Auger Electron Spectroscopy to provide elemental identification of subsurface features quickly and precisely
It is an ideal tool for examining products with small, difficult-to-access features, such those found in the semiconductor industry and for sub-surface particle identification.
NO mechanical stress is applied to your sample
NO contaminants like grinding/polishing slurries are applied
It is a good alternative for products that are difficult to mechanically polish, such as a soft polymers.
SOME APPLICATIONS:
Thin film coatings
Plating thicknesses
Elucidate a specific IC structure or Failure Analysis hotspot
Reverse engineering (e.g., reveal proces node of IC)
Reveal a particle or feature (like grain boundary or an inclusion)
