EPL stencil mask defect inspection system using transmission electron beam

The morphology and composition of the fiber-matrix interface can best be studied by transmission electron microscopy and electron diffraction. For some composites satisfactory samples can be prepared by electropolishing. For others such as aluminum alloy-boron composites ion erosion is necessary.When one wishes to examine a specimen with the electron beam perpendicular to the fiber, preparation is as follows: A 1/8 in. disk is cut from the sample with a cylindrical tool by spark machining. Thin slices, 5 mils thick, containing one row of fibers, are then, spark-machined from the disk. After spark machining, the slice is carefully polished with diamond paste until the row of fibers is exposed on each side, as shown in Figure 1.In the case where examination is desired with the electron beam parallel to the fiber, preparation is as follows: Experimental composites are usually 50 mils or less in thickness so an auxiliary holder is necessary during ion milling and for easy transfer to the electron microscope. This holder is pure aluminum sheet, 3 mils thick.

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Domain Formation in Synthetic Quartz

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100064839 ◽

1971 ◽

Vol 29 ◽

pp. 156-157

Author(s):

Joseph J. Comer

Keyword(s):

Electron Beam ◽

Room Temperature ◽

Domain Formation ◽

Synthetic Quartz ◽

Transmission Electron ◽

Black Spots ◽

Diffraction Mode ◽

Domain Boundaries ◽

Kikuchi Lines ◽

Straight Lines

Domains visible by transmission electron microscopy, believed to be Dauphiné inversion twins, were found in some specimens of synthetic quartz heated to 680°C and cooled to room temperature. With the electron beam close to parallel to the [0001] direction the domain boundaries appeared as straight lines normal to <100> and <410> or <510> directions. In the selected area diffraction mode, a shift of the Kikuchi lines was observed when the electron beam was made to traverse the specimen across a boundary. This shift indicates a change in orientation which accounts for the visibility of the domain by diffraction contrast when the specimen is tilted. Upon exposure to a 100 KV electron beam with a flux of 5x 1018 electrons/cm2sec the boundaries are rapidly decorated by radiation damage centers appearing as black spots. Similar crystallographio boundaries were sometimes found in unannealed (0001) quartz damaged by electrons.

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Aspects of microanalysis in a transmission electron microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100109690 ◽

1978 ◽

Vol 36 (1) ◽

pp. 510-511

Author(s):

R. Sinclair ◽

B.E. Jacobson

Keyword(s):

Grain Size ◽

Electron Beam ◽

Electron Microscope ◽

Chemical Analysis ◽

Transmission Electron Microscope ◽

Vapor Deposition ◽

Critical Currents ◽

X Ray ◽

Fine Grain ◽

Transmission Electron

INTRODUCTIONThe prospect of performing chemical analysis of thin specimens at any desired level of resolution is particularly appealing to the materials scientist. Commercial TEM-based systems are now available which virtually provide this capability. The purpose of this contribution is to illustrate its application to problems which would have been intractable until recently, pointing out some current limitations.X-RAY ANALYSISIn an attempt to fabricate superconducting materials with high critical currents and temperature, thin Nb3Sn films have been prepared by electron beam vapor deposition [1]. Fine-grain size material is desirable which may be achieved by codeposition with small amounts of Al2O3 . Figure 1 shows the STEM microstructure, with large (∽ 200 Å dia) voids present at the grain boundaries. Higher quality TEM micrographs (e.g. fig. 2) reveal the presence of small voids within the grains which are absent in pure Nb3Sn prepared under identical conditions. The X-ray spectrum from large (∽ lμ dia) or small (∽100 Ǻ dia) areas within the grains indicates only small amounts of A1 (fig.3).

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Reduction of Specimen Contamination in Electron-Beam Instruments

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100092840 ◽

1976 ◽

Vol 34 ◽

pp. 576-577

Author(s):

G. Lehmpfuhl ◽

P. J. Smith

Keyword(s):

Electron Beam ◽

Cold Trap ◽

Beam Diameter ◽

Transmission Electron ◽

Scanning Transmission ◽

Hydrocarbon Molecules ◽

Electron Microscopes ◽

Combination Of Methods ◽

Convergent Beam ◽

Very High

Specimens being observed with electron-beam instruments are subject to contamination, which is due to polymerization of hydrocarbon molecules by the beam. This effect becomes more important as the size of the beam is reduced. In convergent-beam studies with a beam diameter of 100 Å, contamination was observed to grow on samples at very high rates. Within a few seconds needles began forming under the beam on both the top and the underside of the sample, at growth rates of 400-500 Å/s, severely limiting the time available for observation. Such contamination could cause serious difficulty in examining a sample with the new scanning transmission electron microscopes, in which the beam is focused to a few angstroms.We have been able to reduce the rate of contamination buildup by a combination of methods: placing an anticontamination cold trap in the sample region, preheating the sample before observation, and irradiating the sample with a large beam before observing it with a small beam.

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Effects of High-Energy Ions on Synthetic Quartz

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100095972 ◽

1972 ◽

Vol 30 ◽

pp. 544-545

Author(s):

Joseph J. Comer ◽

Charles Bergeron ◽

Lester F. Lowe

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Electron Beam ◽

High Energy ◽

Transmission Electron ◽

Kikuchi Lines ◽

High Energy Ions ◽

Diffraction Patterns ◽

Dauphiné Twinning ◽

Beam Damage

Using a Van De Graaff Accelerator thinned specimens were subjected to bombardment by 3 MeV N+ ions to fluences ranging from 4x1013 to 2x1016 ions/cm2. They were then examined by transmission electron microscopy and reflection electron diffraction using a 100 KV electron beam.At the lowest fluence of 4x1013 ions/cm2 diffraction patterns of the specimens contained Kikuchi lines which appeared somewhat broader and more diffuse than those obtained on unirradiated material. No damage could be detected by transmission electron microscopy in unannealed specimens. However, Dauphiné twinning was particularly pronounced after heating to 665°C for one hour and cooling to room temperature. The twins, seen in Fig. 1, were often less than .25 μm in size, smaller than those formed in unirradiated material and present in greater number. The results are in agreement with earlier observations on the effect of electron beam damage on Dauphiné twinning.

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Enhanced information from biological materials through technological improvements in cryo-electron microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100124343 ◽

1992 ◽

Vol 50 (1) ◽

pp. 788-789

Author(s):

Marc J.C. de Jong ◽

Wim M. Busing ◽

Max T. Otten

Keyword(s):

Electron Microscopy ◽

Electron Beam ◽

Biological Materials ◽

Electron Crystallography ◽

Cryo Electron Microscopy ◽

Transmission Electron ◽

The Many ◽

Technological Improvements ◽

Beam Damage

Biological materials damage rapidly in the electron beam, limiting the amount of information that can be obtained in the transmission electron microscope. The discovery that observation at cryo temperatures strongly reduces beam damage (in addition to making it unnecessaiy to use chemical fixatives, dehydration agents and stains, which introduce artefacts) has given an important step forward to preserving the ‘live’ situation and makes it possible to study the relation between function, chemical composition and morphology.Among the many cryo-applications, the most challenging is perhaps the determination of the atomic structure. Henderson and co-workers were able to determine the structure of the purple membrane by electron crystallography, providing an understanding of the membrane's working as a proton pump. As far as understood at present, the main stumbling block in achieving high resolution appears to be a random movement of atoms or molecules in the specimen within a fraction of a second after exposure to the electron beam, which destroys the highest-resolution detail sought.

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The use of an energy-filtering electron microscope to reduce chromatic aberration in images of thick biological specimens

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100142116 ◽

1986 ◽

Vol 44 ◽

pp. 88-91

Author(s):

L. D. Peachey ◽

J. P. Heath ◽

G. Lamprecht

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Electron Beam ◽

Cross Section ◽

Electron Scattering ◽

Chromatic Aberration ◽

Image Resolution ◽

Incident Electron Energy ◽

Energy Filtering ◽

Transmission Electron

Biological specimens of cells and tissues generally are considerably thicker than ideal for high resolution transmission electron microscopy. Actual image resolution achieved is limited by chromatic aberration in the image forming electron lenses combined with significant energy loss in the electron beam due to inelastic scattering in the specimen. Increased accelerating voltages (HVEM, IVEM) have been used to reduce the adverse effects of chromatic aberration by decreasing the electron scattering cross-section of the elements in the specimen and by increasing the incident electron energy.

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