3D Monte Carlo modeling of the SEM: Are there applications to photomask metrology?
Author(s):
J. S. Villarrubia;
A. E. Vladár;
M. T. Postek
Show Abstract
The ability to model the effect of fields due to charges trapped in insulators with floating conductors has been added to
JMONSEL (Java Monte Carlo simulator for Secondary Electrons) and applied to a simple photomask metal on glass
geometry. These capabilities are prerequisites if model-based scanning electron microscope (SEM) metrology is to be
extended beyond wafer to photomask applications, where such samples must frequently be measured. Model-based SEM
is an alternative to the customary threshold- or gradient-based approach. It is more demanding inasmuch as it requires a
model of the physics of image formation, but the reward is greater accuracy, lower sensitivity to secondary sample
characteristics (e.g., edge shape) that affect the intensity, and information about 3D geometrical shape (not simply the
width) of the measured features. The prerequisites are ability to measure a signal, such as the SEM image, that is sensitive
to changes in the parameters one wishes to measure and a model that describes the relationship between the signal and the
parameters. The simulation shows the development of the potential energy barrier to electron escape during an initial
transient charging-up phase, accompanied by increasing electron recapture and stabilization of the average yield.
A novel approach for scanning electron microscopic observation in atmospheric pressure
Author(s):
Yusuke Ominami;
Kenji Nakahira;
Shinsuke Kawanishi;
Tatsuo Ushiki;
Sukehiro Ito
Show Abstract
Atmospheric scanning electron microscopy (ASEM) for observing samples at ambient atmospheric pressure is
introduced in this study. An additional specimen chamber with a thin membrane allowing electron beam propagation is
inserted in the main specimen chamber. Close proximity of the sample to the membrane enables the detection of backscattered
electrons (BSEs) sufficient for imaging. A probability analysis of the un-scattered fraction of the incident
electron beam and the beam profile further supports the feasibility of atmospheric SEM imaging over a controlled
membrane-sample distance. An image enhancement method based on the analysis is introduced for the ASEM.
Does your SEM really tell the truth? How would you know? part 3: vibration and drift
Author(s):
Michael T. Postek;
András E. Vladár;
Petr Cizmar
Show Abstract
This is the third of a series of papers discussing various causes of measurement uncertainty in scanned particle beam instruments,
and some of the solutions researched and developed at NIST. Scanned particle beam instruments especially the
scanning electron microscope (SEM) have gone through tremendous evolution to become indispensable tools for many and
diverse scientifi c and industrial applications. These improvements have signifi cantly enhanced their performance and made
them far easier to operate. But, ease of operation has also fostered operator complacency. In addition, the user-friendliness
has reduced the need for extensive operator training. Unfortunately, this has led to the concept that the SEM is just another
expensive digital camera or another peripheral device connected to a computer and that all of the issues related to obtaining
quality data have been solved. Hence, a person (or company) using these instruments may be lulled into thinking that all of
the potential pitfalls have been fully eliminated and they believe everything they see on the micrograph is always correct.
But, as described in this and the earlier presentations this may not be the case. The fi rst paper in this series discussed some
of the issues related to signal generation in the SEM, including instrument calibration, electron beam-sample interactions
and the need for physics-based modelling to understand the actual image formation mechanisms to properly interpret SEM
images. The second paper, discussed another major issue confronting the microscopist: specimen contamination and methods
of contamination elimination. This third paper, discusses vibration and drift and some useful solutions.
Investigations on CMOS photodiodes using scanning electron microscopy with electron beam induced current measurements
Author(s):
A. Kraxner;
F. Roger;
B. Loeffler;
M. Faccinelli;
S. Kirnstoetter;
R. Minixhofer;
P. Hadley
Show Abstract
In this work the characterization of CMOS diodes with Electron Beam Induced Current (EBIC) measurements in a
Scanning Electron Microscope (SEM) are presented. Three-dimensional Technology Computer Aided Design (TCAD)
simulations of the EBIC measurement were performed for the first time to help interpret the experimental results. The
TCAD simulations provide direct access to the spatial distribution of physical quantities (like mobility, lifetime etc.)
which are very difficult to obtain experimentally. For the calibration of the simulation to the experiments, special designs
of vertical p-n diodes were fabricated. These structures were investigated with respect to doping concentration, beam
energy, and biasing. A strong influence of the surface preparation on the measurements and the extracted diffusion
lengths are shown.
A novel transmission electron imaging technique for observation of biological samples on a plate
Author(s):
Yusuke Ominami;
Masato Nakajima M.D.;
Tatsuo Ushiki M.D.;
Sukehiro Ito
Show Abstract
We introduce a novel transmission electron imaging method to clarify the internal structure of single whole cells by
scanning electron microscopy (SEM). In this method, whole cells are cultivated on a transparent flat plate in advance,
which is made of a scintillator that emits photons by irradiating an electron beam. The detector developed here can
obtain both the secondary electron (SE) surface images and transmission electron (TE) images. Observations of whole
mount cells by this technique clearly show that the cellular internal structure can be observed as transmission images
which are produced by photons emitted from the scintillator plate by electron beam irradiation.
Three-dimensional surface reconstruction using scanning electron microscopy and the design of a nanostructured electron trap
Author(s):
Renke Scheuer;
Eduard Reithmeier
Show Abstract
This paper gives an overview of the possible methods for a three-dimensional surface acquisition in the micrometer scale. It is pointed out that Scanning Electron Microscopy is a capable method for measurement tasks of this kind; therefore, it presents possible ways for implementing this technique in a three-dimensional surface reconstruction. The improved photometric method promises the best performance; its further implementation is developed and explained. Therefore, some modifications of the employed Scanning Electron Microscope (SEM) are described, for instance, the integration of two supplemental detectors, a modified collector grid and a gun shielding. All modifications were evaluated using FEM-Simulations before their implementation. A signal mixing is introduced in order to still be able to use the improved photometric method with four detectors in spite of the fact that it was designed for a two-detector system. For verification purposes, a sphere normal is measured by means of the modified system. It can be seen that the maximal detectable slope angle could be increased compared to the old photometric method. In addition, we introduce an electron trap consisting of nano structured titanium. The structure is tested regarding its ability to catch electrons of different energies and compared to non-structured titanium. The trap can later be implemented on the bottom of the electron gun to catch unwanted backscattered electron (BSE) emission which could otherwise affect the three-dimensional reconstruction.
Shear force microscopy using piezoresistive cantilevers in surface metrology
Author(s):
Teodor Gotszalk;
Daniel Kopiec;
Andrzej Sierakowski;
Paweł Janus;
Piotr Grabiec;
Ivo W. Rangelow
Show Abstract
In this article we describe application of piezoresistive cantilevers in surface investigations carried out with the use of
shear force microscopy (ShFM). The novel piezoresistive cantilevers integrate a Wheatstone piezoresistive bridge was
used to detect the cantilever deflection, thermal deflection detector and planar tip protruding out of the spring beam.
Because the planar tip deflection can be detected and controlled electronically the described technology is very flexible
and can be applied in many surface investigations. In this article we will present operation theory of the described
solution, experimental setup, methods for calibration of the tip deflection detection and actuation The analysis will be
illustrated with example results of topography measurements performed using the described technology.
High throughput data acquisition with a multi-beam SEM
Author(s):
Anna Lena Keller;
Dirk Zeidler;
Thomas Kemen
Show Abstract
Conventional scanning electron microscopes are limited in their ultimate data acquisition rate at a given resolution by
statistical electron-electron interaction (so-called Coulomb interaction) as well as band width of detectors and deflection
systems. We increased imaging speed dramatically by using multiple electron beams in a single column and parallel
detection of the secondary electrons. The multi-beam SEM generates multiple overlapping images during a single scan
pass, thereby covering a larger area in shorter time as compared to a single-beam SEM at the same pixel size. This
addresses the upcoming need for high speed imaging at electron microscopic resolution to investigate larger and larger
areas and volumes.
On the limits of miniature electron column technology
Author(s):
Lawrence Muray;
James Spallas;
Dan Meisburger
Show Abstract
Miniature columns or microcolumns are a relatively new class of electron beam columns fabricated entirely from silicon
using advanced micromachining processes. The main characteristics of these columns are thermal field emission (TFE)
sources, low voltage operation (typically <3keV), simple design (two lenses, no crossover), microfabricated lenses, and
all electrostatic components. Current production versions of miniature columns achieve <10nm resolution at 1keV, and
have demonstrated <6nm resolution at higher beam energies.1,2 While this performance is suitable for most applications,
previous studies of the electron optics of miniature electrostatic lenses show better performance should be attainable
under “ideal” conditions.3 In practice, achieving these conditions is challenging because, in addition to the
manufacturing errors from the miniature optics, other subsystems can impose additional constraints. An understanding
of the major contributors to column performance, whether optical or mechanical, is essential, and can provide a roadmap
for further improvements in the existing technology.
Assessing the viability of multi-electron beam wafer inspection for sub-20nm defects
Author(s):
Brad Thiel;
Michael Lercel;
Benjamin Bunday;
Matt Malloy
Show Abstract
SEMATECH has initiated a program to accelerate the development and commercialization of multi-electron beam based
technologies as successor for wafer defect inspection in high volume semiconductor manufacturing. This paper develops
the basic electron-optical performance requirements and establishes criteria for tool specifications. The performance
variations within a large array of electron beams must be minimal in order to maximize defect capture rates while
simultaneously minimizing false counts, so a series of experimental evaluations are described to quantify the random and
systematic variations in beam current, spot size, detector channel noise level, and defect sensitivity.
Rigorous quantitative elemental microanalysis by scanning electron microscopy/energy dispersive x-ray spectrometry (SEM/EDS) with spectrum processing by NIST DTSA-II
Author(s):
Dale E. Newbury;
Nicholas W. M. Ritchie
Show Abstract
Quantitative electron-excited x-ray microanalysis by scanning electron microscopy/silicon drift detector
energy dispersive x-ray spectrometry (SEM/SDD-EDS) is capable of achieving high accuracy and high
precision equivalent to that of the high spectral resolution wavelength dispersive x-ray spectrometer even
when severe peak interference occurs. The throughput of the SDD-EDS enables high count spectra to be
measured that are stable in calibration and resolution (peak shape) across the full deadtime range. With this
high spectral stability, multiple linear least squares peak fitting is successful for separating overlapping peaks
and spectral background. Careful specimen preparation is necessary to remove topography on unknowns and
standards. The standards-based matrix correction procedure embedded in the NIST DTSA-II software engine
returns quantitative results supported by a complete error budget, including estimates of the uncertainties
from measurement statistics and from the physical basis of the matrix corrections. NIST DTSA-II is
available free for Java-platforms at: http://www.cstl.nist.gov/div837/837.02/epq/dtsa2/index.html).
First experiences with 2D-mXRF analysis of gunshot residue on garment, tissue, and cartridge cases
Author(s):
Alwin Knijnenberg;
Amalia Stamouli;
Martin Janssen
Show Abstract
The investigation of garment and human tissue originating from a victim of a shooting incident can provide crucial
information for the reconstruction of such an incident. The use of 2D-mXRF for such investigations has several
advantages over current methods as this new technique can be used to scan large areas, provides simultaneous
information on multiple elements, can be applied under ambient conditions and is non-destructive. In this paper we
report our experiences and challenges with the implementation of 2D-mXRF in GSR analysis. Currently we mainly
focus on the use of 2D-mXRF as a tool for visualizing elemental distributions on various samples.
Developing a quality assurance program for gunshot primer residue analysis
Author(s):
Thomas R. White
Show Abstract
The Texas DPS Crime Laboratory Service analyzes an average of 45 gunshot residue (GSR) kits a month using three
different SEM/EDS systems and involving four different analysts. To maintain the volume of cases, we have developed
a robust, cost-efficient method to ensure that all three systems are performing automated GSR analysis within laboratory
specifications, and yielding consistent results across all three systems.
This analysis commonly includes analysis of GSR kits collected from suspects’ hands, but can also include kits from
screening of suspects’ clothing for GSR. Analysts have developed procedures for cleaning and monitoring areas where
clothing and GSR stubs are processed and analyzed in order to ensure that casework stubs were not contaminated in the
laboratory.
An electro-conductive organic coating for scanning electron microscopy (déjà vu)
Author(s):
Bryan R. Burnett
Show Abstract
An organic compound, originally marketed as an antistatic, can form an extremely thin electro-conductive coating upon
drying. A scanning electron microscope (SEM) application for this compound was first explored in the late 1960s. A
coating of this compound eliminates the need for carbon or gold coating in some applications. It is well suited for the
viewing of fabric samples and associated gunshot residue (GSR) in the SEM and makes it possible to quickly analyze
fabric bullet wipe and bore wipe GSR. Fabric samples can also be examined for GSR from intermediate-range shots to
estimate muzzle-target distances.
Scanning
Using the Hitachi SEM to engage learners and promote next generation science standards inquiry
Author(s):
D. E. Menshew
Show Abstract
In this study participants will learn how the Hitachi TM3000 scanning electron microscope (SEM) played a central role
in one school’s movement towards Next Generation Science Standards (NGSS) and promoted exceptional student
engagement. The device was used to create high quality images that were used by students in a variety of lab activities
including a simulated crime scene investigation focusing on developing evidence based arguments as well as a real
world conservation biology study. It provided opportunities for small group and independent investigations in support of
NGSS, and peer-peer mentoring. Furthermore, use of the device was documented and were included to enhance
secondary students’ college and scholarship applications, all of which were successful.
Integrating electron microscopy into nanoscience and materials engineering programs
Author(s):
Robert D. Cormia;
Michael M. Oye;
Anh Nguyen;
David Skiver;
Meng Shi;
Yessica Torres
Show Abstract
Preparing an effective workforce in high technology is the goal of both academic and industry training, and has been the engine that drives innovation and product development in the United States for over a century. During the last 50 years, technician training has comprised a combination of two-year academic programs, internships and apprentice training, and extensive On-the-Job Training (OJT). Recently, and especially in Silicon Valley, technicians have four-year college degrees, as well as relevant hands-on training. Characterization in general, and microscopy in particular, is an essential tool in process development, manufacturing and QA/QC, and failure analysis. Training for a broad range of skills and practice is challenging, especially for community colleges. Workforce studies (SRI/Boeing) suggest that even four year colleges often do not provide the relevant training and experience in laboratory skills, especially design of experiments and analysis of data. Companies in high-tech further report difficulty in finding skilled labor, especially with industry specific experience. Foothill College, in partnership with UCSC, SJSU, and NASA-Ames, has developed a microscopy training program embedded in a research laboratory, itself a partnership between university and government, providing hands-on experience in advanced instrumentation, experimental design and problem solving, with real-world context from small business innovators, in an environment called ‘the collaboratory’. The program builds on AFM-SEM training at Foothill, and provides affordable training in FE-SEM and TEM through a cost recovery model. In addition to instrument and engineering training, the collaboratory also supports academic and personal growth through a multiplayer social network of students, faculty, researchers, and innovators.
Teaching K-12 teachers and students about nanoscale science through microscopy
Author(s):
Nancy Healy
Show Abstract
The National Nanotechnology Infrastructure Network (NNIN) is an integrated partnership of 14 universities across the
US funded by NSF to support nanoscale researchers. NNIN’s education and outreach programs are large and varied and
includes outreach to the K-12 community in the form of professional development workshops and school programs.
Two important components of nanoscale science education are understanding size and scale and the tools used in
nanoscale science and engineering (NSE). As part of our K-12 endeavors, we educate K-12 students and teachers about
the tools of nanoscience by providing experiences with the Hitachi TM 3000 tabletop Scanning Electron Microscope
(SEM). There are three of these across the network that are used in education and outreach. This paper will discuss
approaches we use to engage the K-12 community at NNIN’s site at Georgia Institute of Technology to understand size
and scale and the applications of a variety of microscopes to demonstrate the imaging capabilities of these to see both the
micro and nano scales. We not only use the tabletop SEM but also include USB digital microscopes, a Keyence VHX-
600 Digital Microscope, and even a small lens used with smart phones. The goal of this outreach is to educate students
as well as teachers about the capabilities of the various instruments and their importance at different size scales.
Project NANO (nanoscience and nanotechnology outreach): a STEM training program that brings SEM's and stereoscopes into high-school and middle-school classrooms
Author(s):
Sherry L. Cady;
Mikel Blok;
Keith Grosse;
Jennifer Wells
Show Abstract
The program Project NANO (Nanoscience and Nanotechnology Outreach) enables middle and high school
students to discover and research submicroscopic phenomena in a new and exciting way with the use of optical and
scanning electron microscopes in the familiar surroundings of their middle or high school classrooms. Project NANO
provides secondary level professional development workshops, support for classroom instruction and teacher curriculum
development, and the means to deliver Project NANO toolkits (SEM, stereoscope, computer, supplies) to classrooms
with Project NANO trained teachers. Evaluation surveys document the impact of the program on student’s attitudes
toward science and technology and on the learning outcomes for secondary level teachers. Project NANO workshops
(offered for professional development credit) enable teachers to gain familiarity using and teaching with the SEM.
Teachers also learn to integrate new content knowledge and skills into topic-driven, standards-based units of instruction
specifically designed to support the development of students’ higher order thinking skills that include problem solving
and evidence-based thinking. The Project NANO management team includes a former university science faculty, two
high school science teachers, and an educational researcher. To date, over 7500 students have experienced the impact of
the Project NANO program, which provides an exciting and effective model for engaging students in the discovery of
nanoscale phenomena and concepts in a fun and engaging way.
Design, technology, and application of integrated piezoresistive scanning thermal microscopy (SThM) microcantilever
Author(s):
Paweł Janus;
Piotr Grabiec;
Andrzej Sierakowski;
Teodor Gotszalk;
Maciej Rudek;
Daniel Kopiec;
Wojciech Majstrzyk;
Guillaume Boetsch;
Bernd Koehler
Show Abstract
In this article we describe a novel piezoresistive cantilever technology The described cantilever can be also applied in the
investigations of the thermal surface properties in all Scanning Thermal Microscopy (SThM) techniques. Batch
lithography/etch patterning process combined with focused ion beam (FIB) modification allows to manufacture thermally
active, resistive tips with a nanometer radius of curvature. This design makes the proposed nanoprobes especially
attractive for their application in the measurement of the thermal behavior of micro- and nanoelectronic devices.
Developed microcantilever is equipped with piezoresistive deflection sensor. The proposed architecture of the cantilever
probe enables easy its easy integration with micro- and nanomanipulators and scanning electron microscopes.In order to
approach very precisely the microcantilever near to the location to be characterized, it is mounted on a compact
nanomanipulator based on a novel mobile technology. This technology allows very stable positioning, with a nanometric
resolution over several centimeters which is for example useful for large samples investigations. Moreover, thanks to the
vacuum-compatibility, the experiments can be carried out inside scanning electron microscopes.
Particle deformation induced by AFM tapping under different setpoint voltages
Author(s):
Chung-Lin Wu;
Natalia Farkas;
John A. Dagata;
Bo-Ching He;
Wei-En Fu
Show Abstract
The measured height of polystyrene nanoparticles varies with setpoint voltage during atomic force microscopy (AFM)
tapping-mode imaging. Nanoparticle height was strongly influenced by the magnitude of the deformation caused by the
AFM tapping forces, which was determined by the setpoint voltage. This influence quantity was studied by controlling
the operational AFM setpoint voltage. A test sample consisting of well-dispersed 60-nm polystyrene and gold
nanoparticles co-adsorbed on poly-l-lysine-coated mica was studied in this research. Gold nanoparticles have not only
better mechanical property than polystyrene nanoparticles, but also obvious facets in AFM phase image. By using this
sample of mixed nanoparticles, it allows us to confirm that the deformation resulted from the effect of setpoint voltage,
not noise. In tapping mode, the deformation of polystyrene nanoparticles increased with decreasing setpoint voltage.
Similar behavior was observed with both open loop and closed loop AFM instruments.
Wavelet transform-based method of compensating dispersion for high resolution imaging in SDOCT
Author(s):
Haiyi Bian;
Wanrong Gao
Show Abstract
The axial resolution is an important parameter in Optical Coherence Tomography (OCT). In OCT a
broadband light source is used to achieve high axial resolution imaging. However the dispersion results
in a broadening of the coherence envelope. The dispersion mismatch between reference and sample
arms then needs to be minimized to achieve optimal axial resolution for OCT. In this work we propose
a new numerical dispersion compensation method to obtain ultrahigh resolution in SDOCT, in which
wavelet transform instead of Fourier transform is used to obtain the signal in different frequency
domain. And a series of the phase signals of different interfaces of the sample can be obtained. Under
the homogeneous medium approxiamtion, the phase signal is a linear function of the wave number.
Thus based on linearization of the phase signal of different interface and the wave number, the axial
resolution can be improved.
Scan mirrors relay for high resolution laser scanning systems
Author(s):
David Kessler
Show Abstract
Two dimensional beam deflection is often required in medical laser scanning systems such as OCT or confocal
microscopy. Commonly two linear galvo mirrors are used for performance in terms of their large apertures and scan
angles. The galvo mirrors are placed at the vicinity of entrance pupil of the scan lens with a “displacement distance”
separating them. This distance limits the scan fields and/or reduces the effective aperture of the scan lens. Another
option is to use a beam or pupil relay, and image one galvo mirror onto the other. However, beam (or pupil) relays are
notoriously complicated, expensive and can add significant aberrations.
This paper discusses a simple, all reflective, diffraction limited, color corrected, beam relay, capable of large scan angles
and large deflecting mirrors.
The design is based on a unique combination of an Offner configuration with a Schmidt aspheric corrector. The design
is highly corrected up to large scan mirrors and large scan angles down to milliwaves of aberrations. It allows
significantly larger scan field and or scan lenses with higher numerical aperture as compared with scanners using galvos
separated by the displacement distance. While this relay is of exceptionally high performance, it has one element
located where the beam is focused which may present a problem for high power lasers. Thus modifications of the above
design are introduced where the beam is focused in mid air thus making it usable for high power systems such including
laser marking and fabrication systems.
Using scanning near-field microscopy to study photo-induced mass motions in azobenzene containing thin films
Author(s):
A. D. Vu;
F. Fabbri;
N. Desboeufs;
J.-P. Boilot;
T. Gacoin;
K. Lahlil;
Y. Lassailly;
L. Martinelli;
J. Peretti
Show Abstract
Scanning near-field optical microscopy (SNOM) is used to study the photo-induced deformation of layered structures
containing azobenzene derivatives. This approach is particularly relevant since it allows detecting in real-time, with the
same probe the surface topography and the optical field distribution at the nanoscale. The correlation between the local
light pattern and the ongoing photo-induced deformation in azobenzene-containing thin films is directly evidenced for
different light polarization configurations. This unveils several fundamental photodeformation mechanisms, depending
not only on the light field properties, but also on the nature of the material. Controlling the projected electromagnetic
field distribution allows inscription of various patterns with a resolution at the diffraction limit, i.e. of a few hundreds of
nm. Surface relief patterns with characteristic sizes beyond the diffraction limit can also be produced by using the nearfield
probe to locally control the photo-mechanical process. Finally, the photo-mechanical properties of azo-materials are
exploited to optically patterned metal/dielectric hybrid structures. Gratings are inscribed this way on thin gold films. The
characteristic features (enhancement and localization) of the surface plasmons supported by these noble metal structures
are studied by near-field optical microscopy.
Nanoscale imaging by micro-cavity scanning microscopy
Author(s):
Andrea Di Donato;
Gianluca Ippoliti;
Tullio Rozzi;
Davide Mencarelli;
Giuseppe Orlando;
Marco Farina
Show Abstract
In this work we describe a novel kind of scanning probe microscope carried out through an optical fiber extrinsic microcavity.
The micro-cavity is realized by approaching a single mode fiber to a sample placed on a piezo-scanner. The distal
end of the fiber and the sample realize the optical resonator. The probe is fed by a low-coherence source and the reflected
intensity is acquired by an optical spectrum analyzer. The resonant behavior of the cavity enables to overcome the
conventional Rayleigh limit. For this system the transverse resolution is not defined by the NA of fiber but it is a
function of the transverse electromagnetic field inside the micro-cavity. The lens-free system paves the way towards
quantitative measurements in air and liquid environment.
A compact physical CD-SEM simulator for IC photolithography modeling applications
Author(s):
Chao Fang;
Mark D. Smith;
Alessandro Vaglio Pret;
John J. Biafore;
Stewart A. Robertson;
Joost Bekaert
Show Abstract
Scanning Electron Microscopy (SEM) is widely used to measure Critical Dimensions (CD) in semiconductor lithography
processes. As the size of transistors keeps shrinking, the uncertainty associated with CD-SEM accounts for a fast
growing contributor to the entire manufacturing error budget. Capability to predict the metrology results from a CDSEM
is highly desirable to quantify the uncertainty of metrology. Simulation has proven to be a valuable means of
studying both SEM metrology and photolithography. Monte-Carlo based simulators are generally used to model the
detailed image formation process of a CD-SEM, while physics-based photolithography simulations, such as PROLITH™
are commonly used for lithography modeling. However, the high computational cost limits the application of Monte-
Carlo based CD-SEM simulations in conjunction with lithography simulation. We present here a compact physical CDSEM
simulator which simplifies the image formation process while preserving many essential SEM imaging
mechanisms. Several applications of our CD-SEM simulator are presented to demonstrate the predicting capability
compared with experiments.
A tale of three trials: from science to junk science
Author(s):
Bryan R. Burnett
Show Abstract
The defendant had three trials. The first and second ended in mistrial; the third he was convicted. Examination of the
gunshot residue evidence presented in the first and third trials starkly define an extraordinary difference: science versus
junk science. The defendant was convicted on the junk science.
Do electron flux and solar x-ray in juxtaposition prior a seismic event make signature?
Author(s):
Umesh Prasad Verma;
Madhurendra Nath Sinha
Show Abstract
Variation in the trend of electron flux graph in the ionosphere on the global map is common with respect to proton
flux variation in inverse manner seen on diurnal basis. Continuous observation connected with the NOAA , IPS and
SOHO satellite respectively of USA, Australia ,Japan and India have revealed the facts remarkably peculiar and
interesting trend other than usual graph of Electron flux and solar x-ray decrease in peak level immediate prior a
seismic event. An observation recorded in juxtaposition the trend of correlation establishes this fact. This typify the
events like Iran 14th April, China 17th April 2013, with 7.8 and 7.3 MW, New Zealand 6.8 MW on 16th August 2013,
Pakistan 7.8 Mw and 6.8 Mw respectively on25th September, and 26th September’2013 are the supportive
illustrations to the concluding concepts. The trend is also observed during the solar coronal mass ejection event.
Events occur deceptively quite similar to the pre seismicity. Its diagnostic distinction can be made with the solar
data available by SWPC (Australia) forecasting for solar prominences data prediction and forecasting tool. Most of
the seismic phenomena are the diagnostic preseismic phenomena as the electron flux anomaly mechanism and
principle clarify on the basis of fundamental laws of electrostatics and Maxwell equation of electromagnetic wave
theory. This may prove a precursory tool in the seismic event forecasting and prediction technique.
Confirmatory analysis of field-presumptive GSR test sample using SEM/EDS
Author(s):
Sarah J. Toal;
Wayne D. Niemeyer;
Sean Conte;
Daniel D. Montgomery;
Gregory S. Erikson
Show Abstract
RedXDefense has developed an automated red-light/green-light field presumptive lead test using a sampling pad which
can be subsequently processed in a Scanning Electron Microscope for GSR confirmation. The XCAT’s sampling card is
used to acquire a sample from a suspect’s hands on the scene and give investigators an immediate presumptive as to the
presence of lead possibly from primer residue. Positive results can be obtained after firing as little as one shot. The
same sampling card can then be sent to a crime lab and processed on the SEM for GSR following ASTM E-1588-10
Standard Guide for Gunshot Residue Analysis by Scanning Electron Microscopy/Energy Dispersive X-Ray
Spectrometry, in the same manner as the existing tape lifts currently used in the field. Detection of GSR-characteristic
particles (fused lead, barium, and antimony) as small as 0.8 microns (0.5 micron resolution) has been achieved using a
JEOL JSM-6480LV SEM equipped with an Oxford Instruments INCA EDS system with a 50mm2 SDD detector, 350X
magnification, in low-vacuum mode and in high vacuum mode after coating with carbon in a sputter coater. GSR
particles remain stable on the sampling pad for a minimum of two months after chemical exposure (long term stability
tests are in progress). The presumptive result provided by the XCAT yields immediate actionable intelligence to law
enforcement to facilitate their investigation, without compromising the confirmatory test necessary to further support the
investigation and legal case.