A Novel SEM Image Processing Approach for Evaluating Sterilization Effects on Polymeric Medical Devices: Validation Against Traditional EDX Analysis.

Dynamic modeling of the formation damage and mud cake deposition using filtration theories coupled with SEM image processing

Contact detection for nanomanipulation in a scanning electron microscope

The importance of line-width roughness (LWR)/line-edge roughness (LER) in relation with leakage current has made it a critical process parameter, especially when device downsizes to 32nm era. Critical dimension scanning electron microscope (SEM) is still the most popular tool to characterize LWR in semiconductor manufacturing. However, true LWR metrology by SEM has been a challenge because of metrology noise and induced damage. Method of repeating multi-shot or long scanning time [5-8] on the same field of view have been proposed to effectively eliminate metrology noise caused by SEM tool variation and image processing. By such method, however, line damage (non-conformal critical dimension enlargement) caused by charging is found and damage level depends on the property of surface material, e-beam energy, and total scanning time. In this article, the impact of damage on LWR metrology and optimal metrology condition are studied. Following the proposed method [8], polysilicon lines both with and without oxide mask are investigated under different e-beam energy and number of shot. LWR metrology noise decreases along with e-beam energy and saturates at 1400eV while damage level is proportional to beam energy. In similar way, the larger number of repeating shot, the more effective of noise rejection and the more damage of line will be at the same time. The damage not only increases metrology noise, but also degrades the LWR, that are verified in both simulation and experiment. In the final, the optimal conditions of true LWR metrology by SEM for both polysilicon line with and without oxide mask are proposed.

Automatic nanohandling station inside a scanning electron microscope

The machining of ceramic components using conventional techniques is slow and expensive due to low yields. High power lasers are capable of machining these materials at far greater speeds. Recast layer microcracking is the Achilles heel of laser processing of ceramics. Techniques for the reduction of the thermal shear caused by laser beam interaction have been investigated. A method for the numerical characterization of microcracking was developed for this work and was based upon scanning electron microscopy image processing. Optimization of the pulsed Nd:YAG laser drilling and cutting cycles enabled repeatable, high quality processing to be undertaken. Heating of the partially stabilized tetragonal zirconia (PSTZ) substrates to high temperatures before and after laser processing was found to reduce the thermal gradients that cause microcracking. Holes with a mean diameter of 679 μm were percussion drilled through the 8.3 mm thick substrates in 0.75 s, and had limited tapering (<150 μm). Single pass, full depth cutting was achieved at a rate of 100 mm min−1. Laser drilling at 1300 °C caused, on average, half the level of microcracking found in the ambient temperature drilled substrates. Laser cutting using the same comparison led to a 6.7× reduction in microcracking. The cutting process overall was found to be less damaging to the ceramic substrates by a factor of 12×. A thermal gradient prediction was used to explain this effect, and was based upon the influence of thermal diffusivity, thermal conductivity, and the effect of the impinging assist gas jet.

Boosting the Rate Performance of Li–S Batteries via Highly Dispersed Cobalt Nanoparticles Embedded into Nitrogen-Doped Hierarchical Porous Carbon

Chapter 2 - New Image Processing Methods for Advanced Metallization in Micro- and Nano-Electronics

In order to perform nano-manipulation more accurately, it is necessary to study the relationship between the scanning electron microscope (SEM) image and the actual length. In this paper, based on the secondary electron image, the displacement of 1.81nm in SEM was measured the actual displacement was obtained according to the change of the pixels, so as to realize the nanometer displacement calibration and real-time measurement of the nano robot manipulator in SEM. According to the magnification, resolution and scale bar of SEM image, the mapping relationship between pixels and actual length was established. The obvious feature point and area in the SEM image were selected to be marked. The driving signal was applied to the manipulator of the nano robot, and the template matching algorithm was used to track the feature point and area in real time. The change of the feature point in the SEM image was obtained, and the actual displacement of the manipulator was calculated according to the mapping relationship between the pixel points and the actual displacement. We calibrated the displacement of the nanorobots and measured the actual displacement in real time, which laid a foundation for the precise control of the nanorobots in the future.

Image noise is an important factor that influences the accuracy of strain field measurements by means of digital image correlation and scanning electron microscope (SEM) imaging. We propose a new model to quantify the SEM image noise, which extends the classical photon noise model by taking into account the brightness setup in SEM imaging. Furthermore, we apply this model to investigate the impact of different SEM setting parameters on image noise, such as detector, dwell time, spot size, and pressure in the SEM chamber in the context of low vacuum imaging.

Modern industry routinely uses sophisticated microscopic methods for quality control and for predicting the performance of manufactured products. These processes typically exploit optical emission and scattering phenomena—such as electron backscattered diffraction and energy-dispersive x-ray spectroscopy—using equipment attached to conventional scanning electron microscopy (SEM). In silicon-based metal oxide semiconductor (MOS) devices, residual stresses may remain from the manufacturing process owing to a mismatch in thermal expansion coefficients between constituent materials. Thermal fatigue and electromigration (displacement of atoms induced by electric current) phenomena can also affect the devices’ micromechanical state. Up to now, SEM has not been applied to these problems for two reasons. First, the effects of strain on electronic transitions arising from band-gap or optically active point defects, as well as their interaction with the electron probe, were not fully understood. Second, no comprehensive algorithm could be found that took into account the superposition of several chemical, physical, and mechanical effects (i.e., temperature gradients, self-absorption, chemical gradients) to extract the stress information from the luminescence spectrum. Yet, the spatial resolution of the SEM would be highly advantageous in residual stress assessment. We recently developed a spectroscopic method for analyzing materials and devices in the SEM that works by visualizing surface and subsurface stress fields. Further, we have used the technique to solve a number of important industrial problems, for example, the stress stored in interconnect structures (like inFigure 1. An SEM image (a) and a CL/PS stress image (b) of the immediate neighborhood of the crack tip in a gallium nitride crystal. The stress map represents the spatial variation of the trace of the stress tensor acquired with a spatial resolution of 30nm.

The MeX™ software is a useful tool for tridimensional data collection for surface evaluation and could be relevant to evaluate the same specimen in different phases of the study, assuming repeated measures of dental enamel roughness. The aim of this study was to evaluate the influence of sample metallization for dental enamel roughness analysis with 3D images reconstructed using MeX™ software from Scanning Electron Microscopy (SEM) images. The influence of 74.98% (%mol/mol) argon-oxygen plasma for carbon layer removal on surface roughness of the metallized specimen was also evaluated. Dental enamel specimens were prepared for SEM analysis with and without carbon metallization using conventional or environmental modes. Argon-oxygen plasma for carbon layer removal was used and surface roughness was re-evaluated. Roughness obtained by SEM and MeX™ reconstructed images, with or without metallization, did not differ. No significant alteration on surface roughness after carbon layer removal using plasma was found. SEM baseline evaluation using conventional mode without sample preparation and in environmental mode were not comparable. Roughness of enamel 3D images reconstructed with MeX™ software from SEM images, with or without metallization was similar. The 74.98% (%mol/mol) argon-oxygen plasma removed the carbon layer with no effect on enamel roughness.

Single-Crystalline Mesoporous Palladium and Palladium-Copper Nanocubes for Highly Efficient Electrochemical CO ₂ Reduction

To analyze concentrations of actinides in the molten salt electrolyte of nuclear fuel electrorefining systems, a scheme is currently being developed based on alpha spectroscopy. The ultimate objective is to determine elemental as well as isotopic composition in molten salts in near real-time in a high-radiation, high-temperature environment. Because of the low penetration length scales for alpha particles, it is necessary to produce a thin actinide layer directly onto a semi-conductor substrate that will be assayed using the alpha spectrometer. In order to achieve this objective, techniques for making a good quality actinide metal deposit are under investigation. The deposit needs to be relatively thin; otherwise the alpha particles will not reach the detector itself due to self-shielding. The deposit needs to be as uniform and as dense as possible, without excessive dendritic structures. The deposition regime will obviously affect deposit composition (in case of multiple actinides present), and so good control over the deposition conditions is mandatory. For practical purposes, thorium and depleted uranium were used in our experiments as representative actinides. Alumina crucibles containing LiCl-KCl eutectic salt with ThCl­­4 and/or UCl3 were heated to 773 K. A three-electrode setup was employed. The reference electrode was [Ag/AgCl(100%)] enclosed in a mullite tube. The counter electrode was a reactive Zr metal rod. The working electrode was a stainless steel coupon – a surrogate to a semiconductor detector surface, which is being developed simultaneously in a partner lab. The stainless steel coupon has the advantage of being inexpensive, being easily machined, and being easily analyzed using scanning electron microscopy (SEM). Chronoamperometry (CA) and chronopotentiometry were investigated to evaluate optimum conditions for high quality deposits with about a 1 mm thickness. These deposits were imaged using SEM with energy dispersive X-ray spectroscopy (EDS). EDS indicated that primarily actinides deposited on the stainless steel coupons with very little Zr contamination. It was found that large overpotentials result in fast deposition rates but poor deposit quality. These deposits either easily flaked off the coupon during salt dissolution phase (a phase where the coupon was immersed in stirred water to dissolve excess solidified salt) or exhibited dendrites on the surface rather than a uniform metal deposit. Dendrites are undesirable because of the potential for alpha particle shielding. Very slow deposition rates result in more favorable morphology, but the increased time needed to achieve the deposition is arguably beyond reasonable time frame of near real-time measurement. Thus, pulsed CA was investigated that featured short bursts of high overpotential (to promote nucleation) and long relaxation times of low overpotentials (to grow these nucleation sites). This approach shows some promise. However, the control of deposit composition as well as the determination of passed charge was found to be problematic. Electrochemical cell data and SEM images will be presented for the various methods attempted to date with discussion of path forward for optimizing the deposits.

Accurate identification and classification of atmospheric particulates can provide the basis for their source apportionment. Most current research studies mainly focus on the classification of atmospheric particles based on the energy spectrum of particles, which has the problems of low accuracy and being time-consuming. It is necessary to study the classification method of atmospheric particles with higher accuracy. In this paper, a convolutional neural network (CNN) model with attention mechanism is proposed to identify and classify the scanning electron microscopy (SEM) images of atmospheric particles. First, this work established a database, Qingdao 2016–2018, for atmospheric particles classification research. This database consists of 3469 SEM images of single particulates. Secondly, by analyzing the morphological characteristics of single particle SEM images, it can be divided into four categories: fibrous particles, flocculent particles, spherical particles, and mineral particles. Thirdly, by introducing attention mechanism into convolutional neural network, an Attention-CNN model for the identification and classification of the four types of atmospheric particles based on the SEM images is established. Finally, the Attention-CNN model is trained and tested based on the SEM images database, and the results of identification and classification for four types of particles are obtained. Under the same SEM images database, the classification results from Attention-CNN are compared with those of CNN and SVM. It is found that Attention-CNN has higher classification accuracy and reduces significantly the misclassification number of particles, which shows the focusing effect of attention mechanism.

Microscopy is the art and science of visually observing small objects. Electrons are electrically charged subatomic particles typically responsible for the flow of electrical current. Scanning is a method of observation where the focus of attention is moved in a chosen pattern and desired information is gained by assembling observations in sequence. In a scanning electron microscope (SEM), a beam of electrons is scanned in a regular pattern over a small object, and the image of the object appears on a screen by displaying the image points in synchrony with the movements of the electron beam on the object.A familiar example of image scanning is a television receiver, where a picture is created on a screen by rapidly scanning an electron beam across the phosphor face of the television tube. The beam striking the phosphor produces light, which is seen as a picture. The signal that modulates the electron beam in a television set is created in a television camera, which is scanned in the same way that the television screen is scanned. In a SEM, the signals come from special detectors in the microscope, not from an optical camera. Otherwise, the image display in a SEM is very similar to television. Although it is typical for SEM images to be scanned at a slower rate than are television signals, some SEMs display images at the same speed as television.The most common signal for detection in a SEM is the secondary electron signal. Secondary electrons are low‐speed electrons (having energies less than about 50 eV) that result from the interaction of the primary (i.e. beam) electrons with the sample. The secondary electrons are detected, usually by a scintillator/photomultiplier detector, and the resulting signal modulates the display screen.Secondary electrons are popular because they provide a kind of shading that gives a three‐dimensional appearance to an image, making it easy to visualize the structural relationships of parts of the sample (Figure 1).Other signals provide information of a more analytical nature. The signal produced by backscattered electrons is directly (although not exactly proportionally) related to the atomic number of the material being struck by the primary beam. Diffracted electrons provide information about crystal spacings and orientations in the sample. Induced‐current signals are particularly interesting for studying the response of active electronic components.The resolution of a SEM image depends on the quality of the optical system that forms the electron beam, including the nature of the electron source. Most SEMs can typically resolve objects as small as 10 nm. The resolution of specialized SEMs is better than 1 nm. In contrast, the resolution of light microscopes is limited by the wavelength of light to about 500 nm.The magnification of a SEM is not directly related to the optical system, very unlike a light microscope. The magnifying power of a SEM is related to the ratio between the size of the scan on the object compared to the size of the scan on the image display. In this way a SEM functions like a mechanical pantograph that was used, typically in older days, for copying drawings. If the arms of the pantograph were of equal length, the drawing would be copied the same size. If the arms were adjusted to different lengths, the drawing could be magnified or reduced.The primary advantage of a SEM is that it provides familiar‐looking images of surfaces with higher resolution and greater depth‐of‐field than an optical microscope. Although the images are typically familiar looking, the contrast mechanism in a SEM is not the same as the contrast provided by light, and an observer expecting always to interpret a SEM image the same way as a light image could easily be fooled.As the electron beam consists of electrically charged particles, the sample for SEM observation must either be inherently electrically conducting or must be made electrically conducting to yield good images. Otherwise, electrical charge builds up on the sample, the yield of secondary electrons is changed, and the scanning beam can become erratic. Low‐voltage or low‐vacuum SEMs can be used to reduce the charging problem.