Dynamic Focusing Techniques for Enhancing SEM Images

1972 ◽  
Vol 30 ◽  
pp. 378-379
Author(s):  
Nelson C. Yew
Keyword(s):  
Electron Beam ◽  
Spherical Surface ◽  
Sem Images ◽  
Condenser Lens ◽  
Sem Image ◽  
Collector System ◽  
Electron Collection ◽  
Effective Depth ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes

There are two major areas where Dynamic Focusing techniques can be used to enhance SEM image qualify and micrograph information content. When used in conjunction with the final condenser lens in the electron-optical column, it increases the effective depth of focus associated with an inclined specimen in the SEM. When used with an ultra-high resolution recording cathode ray tube it provides exceptional corner-to-corner sharpness on the micrograph.Most commercial scanning electron microscopes use a tilted specimen positioned close to the final condenser lens with the secondary electron collector system located in the tilting direction to facilitate efficient electron collection. electron beam pivoting through the center of the principle plane of this lens to minimize distortion and off-axis aberration problems. As a result, the final electron beam is truly focused only along a portion of the spherical surface with its center located at the pivoting point.

Impact of secondary electron emission noise in SEM

Microscopy ◽  
2019 ◽  
Vol 68 (4) ◽  
pp. 279-288 ◽  
Author(s):  
Makoto Sakakibara ◽  
Makoto Suzuki ◽  
Kenji Tanimoto ◽  
Yasunari Sohda ◽  
Daisuke Bizen ◽  
...  
Keyword(s):  
Semiconductor Device ◽  
Secondary Electron Emission ◽  
Image Noise ◽  
Sem Images ◽  
Sem Image ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Primary Electrons ◽  
Imaging Conditions ◽  
Si Wafer

Abstract In semiconductor-device inspection using scanning electron microscopes (SEMs), the irradiation dose of the electron beam becomes lower because of increasing needs for higher throughput and lower damage to the samples. Therefore, it is necessary to form images using fewer primary electrons, making noise reduction of SEM images one of the main challenges. We have modeled the imaging process of SEMs, which consists of the generation of primary, secondary and tertiary electrons (PEs, SEs and TEs, respectively), and detection. Furthermore, a method to accurately evaluate the fluctuation in the number of SEs and TEs are proposed. We found that SEM-image noise can be minimized by directly detecting SEs generated in the sample, in which case the fluctuation in the number of SEs determines the image quality. The variance number of SEs emitted from a 500-eV PE irradiation onto a Si wafer is 1.9 times as large as the value derived assuming a Poisson process. A Monte-Carlo simulation result was used to explain the experimental results and predict that PE energy less than 1 keV suppresses the fluctuation in the number of SEs, and consequently, the SEM-image noise level. These findings provide a method for determining imaging conditions that improve the throughput of SEMs.

High-resolution observation of sintered alumina (Al2O3) using the specimen-heated and electron-beam-induced conductivity method in a UHR-SEM

1994 ◽  
Vol 52 ◽  
pp. 1046-1047
Author(s):  
K. Ogura ◽  
T. Suzuki ◽  
C. Nielsen
Keyword(s):  
Electron Beam ◽  
High Resolution ◽  
Specimen Preparation ◽  
Conductivity Method ◽  
Fine Grain ◽  
Grain Structures ◽  
Resolution Observation ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Charging Effect

In spite of the complicated specimen preparation, Transmission Electron Microscopes (TEM) have traditionally been used for the investigation of the fine grain structures of sintered ceramics. Scanning Electron Microscopes (SEM) have not been used much for the same purpose as TEM because of poor results caused by the specimen charging effect, and also the lack of sufficient resolution. Here, we are presenting a successful result of high resolution imaging of sintered alumina (pure Al2O3) using the Specimen Heated and Electron Beam Induced Conductivity (SHEBIC) method, which we recently reported, in an ultrahigh resolution SEM (UHR-SEM). The JSM-6000F, equipped with a Field Emission Gun (FEG) and an in-lens specimen position, was used for this application.After sintered Al2O3 was sliced into a piece approximately 0.5 mm in thickness, one side was mechanically polished to get a shiny plane for the observation. When the observation was started at 20 kV, an enormous charging effect occured, and it was impossible to obtain a clear Secondary Electron (SE) image (Fig.1).

Field of View and Image Distortion : A Review of Low Magnification Imaging In the Environmental and Conventional Scanning Electron Microscopes (SEM)

1997 ◽  
Vol 3 (S2) ◽  
pp. 1193-1194
Author(s):  
Brendan J. Griffin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Field Of View ◽  
Depth Of Field ◽  
Aperture Size ◽  
Sem Image ◽  
Electron Microscopes ◽  
Working Distance ◽  
Scanning Electron Microscopes ◽  
Scanning Electron

Most scanning electron microscopy is performed at low magnification; applications utilising the large depth of field nature of the SEM image rather than the high resolution aspect. Some environmental SEMs have a particular limitation in that the field of view is restricted by a pressure limiting aperture (PLA) at the beam entry point of the specimen chamber. With the original ElectroScan design, the E-3 model ESEM utilised a 500 urn aperture which gave a very limited field of view (∼550um diameter at a 10mm working distance [WD]). An increase of aperture size to ∼lmm provided an improved but still unsatisfactory field of view. The simplest option to increase the field of view in an ESEM was noted to be a movement of the pressure and field, limiting aperture back towards the scan coils1. This approach increased the field of view to ∼2mm, at a 10mm WD. A commercial low magnification device extended this concept and indicated the attainment of conventional fields of view.

scholarly journals Continuum models of focused electron beam induced processing

2015 ◽  
Vol 6 ◽  
pp. 1518-1540 ◽  
Author(s):  
Milos Toth ◽  
Charlene Lobo ◽  
Vinzenz Friedli ◽  
Aleksandra Szkudlarek ◽  
Ivo Utke
Keyword(s):  
Electron Beam ◽  
Substrate Surface ◽  
Input Parameter ◽  
Reaction Pathways ◽  
Continuum Models ◽  
Direct Write ◽  
Reaction Products ◽  
Wide Range ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes

Focused electron beam induced processing (FEBIP) is a suite of direct-write, high resolution techniques that enable fabrication and editing of nanostructured materials inside scanning electron microscopes and other focused electron beam (FEB) systems. Here we detail continuum techniques that are used to model FEBIP, and release software that can be used to simulate a wide range of processes reported in the FEBIP literature. These include: (i) etching and deposition performed using precursors that interact with a surface through physisorption and activated chemisorption, (ii) gas mixtures used to perform simultaneous focused electron beam induced etching and deposition (FEBIE and FEBID), and (iii) etch processes that proceed through multiple reaction pathways and generate a number of reaction products at the substrate surface. We also review and release software for Monte Carlo modeling of the precursor gas flux which is needed as an input parameter for continuum FEBIP models.

Stereological Analysis Of Sem Images

1977 ◽  
Vol 35 ◽  
pp. 212-213
Author(s):  
H. S Schmiβer ◽  
R. A. Swensson
Keyword(s):  
Image Analysis ◽  
Three Dimensional ◽  
Quantitative Information ◽  
Quantitative Image Analysis ◽  
Sem Images ◽  
Detection Systems ◽  
The Past ◽  
Quantitative Image ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes

Development of new signal detection systems for STEREOSCAN scanning electron microscopes has greatly increased the applicability of quantitative image analysis to pictures obtained with an s.e.m. While quantitative image analysis has proven to be a powerful technique to draw quantitative information from pictures obtained from light microscopes as well as various other sources of images, the field of scanninq electron microscopy has largely been uncovered in the past.This was mainly due to the particular appearance of “normal” s.e.m. pictures. Exactly those features which make s.e.m. pictures easy to interpret intuitively an aesthetically attractive i.e. the pseudo three dimensional appearance made it virtually impossible to treat these images with the well known methods of electronic image analysis.

Advances in Scanning Electron Microscopy

MRS Bulletin ◽  
1991 ◽  
Vol 16 (3) ◽  
pp. 41-45 ◽  
Author(s):  
K. Sujata ◽  
Hamlin M. Jennings
Keyword(s):  
Electron Beam ◽  
X Rays ◽  
Backscattered Electrons ◽  
Scanning Transmission ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Television Image ◽  
Focused Beam ◽  
Scanning Electron

Scanning electron microscopes offer several unique advantages and they have evolved into complex integrated instruments that often incorporate several important accessories. Their principle advantage stems from the method of constructing an image from a highly focused electron beam that scans across the surface of a specimen. The beam generates backscattered electrons and excites secondary electrons and x-rays in a highly localized “spot.” These signals can be detected, and the results of the analysis are displayed as a specific intensity on a screen at a position that represents the position of the electron spot. As with a television image, after a given period, information about the entire field of view is displayed on the screen, resulting in a complete image. If the specimen is thin, the same type of information can be gathered from the transmitted electrons, and a scanning transmission image is thus constructed.The scanning electron microscope is highly versatile and widely used. The quality of the image is related to its resolution and contrast, which, in turn, depend on the diameter of the focused beam as well as its energy and current. Because electron lenses have inherently high aberrations, the usable aperture angles are much smaller than in a light microscope and, therefore, the electron beam remains focused over a relatively large distance, giving these instruments a very large depth of focus.Scanning electron microscopes are versatile in their ability to detect and analyze a lot of information. As a result, modern versions of these instruments are equipped with a number of detectors. Developments are sometimes related to placing the detectors in a geometrically attractive position close to the specimen.

scholarly journals TEM Sample Preparation Using Focused Ion Beam - Capabilities And Limits

2003 ◽  
Vol 11 (2) ◽  
pp. 22-25 ◽  
Author(s):  
H.J. Engelmann ◽  
B. Volkmann ◽  
Y. Ritz ◽  
H. Saage ◽  
H Stegmann ◽  
...  
Keyword(s):  
Electron Beam ◽  
Sample Preparation ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Sample Handling ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Preparation Techniques ◽  
Scanning Electron

TEM sample preparation using Focused Ion Beam (FIB) methods becomes more and more interesting for microscopists because the technique allows for reliable and very efficient sample preparation. The first application of TEM sample preparation by FIB-cutting was reported more than 10 years ago. Meanwhile, a lot of experience has been gathered that allows one to discuss the capabilities and limits of the FIB technique in detail.Several TEM sample preparation techniques are known that all include FIB-cutting but differ in sample pre-preparation, sample handling,etc. This paper focuses on the actual FIB process, FIB tools are closely related to Scanning Electron Microscopes, but instead of an electron beam an ion beam (mostly Ga+ions) is used to remove and deposit material.

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