Electron Beam Machining

Machining ◽  
1989 ◽  
pp. 568-571
Keyword(s):  
Electron Beam

Techniques for Transmission Electron Microscopy of Fiber-Matrix Interfaces in Aluminum Alloy-Boron Composites by Ion Erosio

1971 ◽  
Vol 29 ◽  
pp. 204-205
Author(s):  
G. G. Shaw
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Aluminum Alloy ◽  
Electron Beam ◽  
Pure Aluminum ◽  
Ion Milling ◽  
Transmission Electron ◽  
Fiber Matrix ◽  
Ion Erosion ◽  
Row Of Fibers

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.

Temperature Dependence of the Critical Electron Dose for Fatty Acid Monolayers

1982 ◽  
Vol 40 ◽  
pp. 78-79
Author(s):  
Kenneth H. Downing ◽  
Robert M. Glaeser
Keyword(s):  
Electron Beam ◽  
Fatty Acid ◽  
Inelastic Scattering ◽  
Temperature Dependence ◽  
Structural Damage ◽  
Direct Result ◽  
Second Step ◽  
Strong Temperature Dependence ◽  
Electron Dose ◽  
Covalent Bonds

The structural damage of molecules irradiated by electrons is generally considered to occur in two steps. The direct result of inelastic scattering events is the disruption of covalent bonds. Following changes in bond structure, movement of the constituent atoms produces permanent distortions of the molecules. Since at least the second step should show a strong temperature dependence, it was to be expected that cooling a specimen should extend its lifetime in the electron beam. This result has been found in a large number of experiments, but the degree to which cooling the specimen enhances its resistance to radiation damage has been found to vary widely with specimen types.

Lithography below 100 nm

1983 ◽  
Vol 41 ◽  
pp. 96-99
Author(s):  
L. D. Jackel
Keyword(s):  
Spatial Distribution ◽  
Electron Beam ◽  
Electron Scattering ◽  
Electron Beam Lithography ◽  
Substrate Material ◽  
Local Electron ◽  
Electron Dose ◽  
Positive Resist ◽  
Exposure Process

Most production electron beam lithography systems can pattern minimum features a few tenths of a micron across. Linewidth in these systems is usually limited by the quality of the exposing beam and by electron scattering in the resist and substrate. By using a smaller spot along with exposure techniques that minimize scattering and its effects, laboratory e-beam lithography systems can now make features hundredths of a micron wide on standard substrate material. This talk will outline sane of these high- resolution e-beam lithography techniques.We first consider parameters of the exposure process that limit resolution in organic resists. For concreteness suppose that we have a “positive” resist in which exposing electrons break bonds in the resist molecules thus increasing the exposed resist's solubility in a developer. Ihe attainable resolution is obviously limited by the overall width of the exposing beam, but the spatial distribution of the beam intensity, the beam “profile” , also contributes to the resolution. Depending on the local electron dose, more or less resist bonds are broken resulting in slower or faster dissolution in the developer.

Domain Formation in Synthetic Quartz

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.

Materials for Electron Beam Information Storage

1969 ◽  
Vol 27 ◽  
pp. 152-153 ◽  
Author(s):  
D. E. Speliotis
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Recent Literature ◽  
Electron Beams ◽  
Information Storage ◽  
The Subject ◽  
The Magnetic Field

The interaction of electron beams with a large variety of materials for information storage has been the subject of numerous proposals and studies in the recent literature. The materials range from photographic to thermoplastic and magnetic, and the interactions with the electron beam for writing and reading the information utilize the energy, or the current, or even the magnetic field associated with the electron beam.

Application of Improved Voltage Compensation in the SEM to Imaging of Organic Materials

1973 ◽  
Vol 31 ◽  
pp. 444-445
Author(s):  
P.J. Killingworth ◽  
M. Warren
Keyword(s):  
Electron Beam ◽  
Organic Materials ◽  
Operating Parameters ◽  
Low Density ◽  
Beam Diameter ◽  
Incident Electron Beam ◽  
Specimen Material ◽  
Voltage Compensation ◽  
Selection Of ◽  
Scanning Electron

Ultimate resolution in the scanning electron microscope is determined not only by the diameter of the incident electron beam, but by interaction of that beam with the specimen material. Generally, while minimum beam diameter diminishes with increasing voltage, due to the reduced effect of aberration component and magnetic interference, the excited volume within the sample increases with electron energy. Thus, for any given material and imaging signal, there is an optimum volt age to achieve best resolution.In the case of organic materials, which are in general of low density and electric ally non-conducting; and may in addition be susceptible to radiation and heat damage, the selection of correct operating parameters is extremely critical and is achiev ed by interative adjustment.

Nucleation and Early Growth of Sputtered thin Films

1970 ◽  
Vol 28 ◽  
pp. 516-517
Author(s):  
Dudley M. Sherman ◽  
Thos. E. Hutchinson
Keyword(s):  
Thin Films ◽  
Electron Beam ◽  
Ion Beam ◽  
Ion Source ◽  
Water Cooling ◽  
Stages Of Growth ◽  
Lens Assembly ◽  
Microscope Technique ◽  
Ion Beam Sputter Deposition

The in situ electron microscope technique has been shown to be a powerful method for investigating the nucleation and growth of thin films formed by vacuum vapor deposition. The nucleation and early stages of growth of metal deposits formed by ion beam sputter-deposition are now being studied by the in situ technique.A duoplasmatron ion source and lens assembly has been attached to one side of the universal chamber of an RCA EMU-4 microscope and a sputtering target inserted into the chamber from the opposite side. The material to be deposited, in disc form, is bonded to the end of an electrically isolated copper rod that has provisions for target water cooling. The ion beam is normal to the microscope electron beam and the target is placed adjacent to the electron beam above the specimen hot stage, as shown in Figure 1.

Residual Gas Reaction in the Electron Microscope: II The Design of a Gas-Control Chamber for Quantitative Observations

1969 ◽  
Vol 27 ◽  
pp. 82-83
Author(s):  
Chester J. Calbick ◽  
Richard E. Hartman
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Local Environment ◽  
Chamber Pressure ◽  
Objective Lens ◽  
Ion Pump ◽  
Quantitative Studies ◽  
Precise Knowledge ◽  
Differential Pumping ◽  
And Control

Quantitative studies of the phenomenon associated with reactions induced by the electron beam between specimens and gases present in the electron microscope require precise knowledge and control of the local environment experienced by the portion of the specimen in the electron beam. Because of outgassing phenomena, the environment at the irradiated portion of the specimen is very different from that in any place where gas pressures and compositions can be measured. We have found that differential pumping of the specimen chamber by a 4" Orb-Ion pump, following roughing by a zeolite sorption pump, can produce a specimen-chamber pressure 100- to 1000-fold less than that in the region below the objective lens.

A controller for safe, convenient operation of LaB6 emitters on electron-beam instruments

1983 ◽  
Vol 41 ◽  
pp. 408-409
Author(s):  
W. J. Abramson ◽  
H. W. Estry ◽  
L. F. Allard
Keyword(s):  
Electron Beam ◽  
Control System ◽  
Thermal Shock ◽  
Appropriate Care ◽  
Electron Guns ◽  
Tungsten Filaments ◽  
Order Of Magnitude ◽  
Main Components

LaB6 emitters are becoming increasingly popular as direct replacements for tungsten filaments in the electron guns of modern electron-beam instruments. These emitters offer order of magnitude increases in beam brightness, and, with appropriate care in operation, a corresponding increase in source lifetime. They are, however, an order of magnitude more expensive, and may be easily damaged (by improper vacuum conditions and thermal shock) during saturation/desaturation operations. These operations typically require several minutes of an operator's attention, which becomes tedious and subject to error, particularly since the emitter must be cooled during sample exchanges to minimize damage from random vacuum excursions. We have designed a control system for LaBg emitters which relieves the operator of the necessity for manually controlling the emitter power, minimizes the danger of accidental improper operation, and makes the use of these emitters routine on multi-user instruments.Figure 1 is a block schematic of the main components of the control system, and Figure 2 shows the control box.

Modification of the Electron Microscope for Investigation of Fully Hydrated Biological Specimens

1969 ◽  
Vol 27 ◽  
pp. 418-419 ◽  
Author(s):  
R. C. Moretz ◽  
D. F. Parsons
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Structural Damage ◽  
Lower Percentage ◽  
Vacuum Drying ◽  
Total Removal ◽  
Total Absence ◽  
Biological Studies ◽  
Electron Microscopes ◽  
Beam Damage

Short lifetime or total absence of electron diffraction of ordered biological specimens is an indication that the specimen undergoes extensive molecular structural damage in the electron microscope. The specimen damage is due to the interaction of the electron beam (40-100 kV) with the specimen and the total removal of water from the structure by vacuum drying. The lower percentage of inelastic scattering at 1 MeV makes it possible to minimize the beam damage to the specimen. The elimination of vacuum drying by modification of the electron microscope is expected to allow more meaningful investigations of biological specimens at 100 kV until 1 MeV electron microscopes become more readily available. One modification, two-film microchambers, has been explored for both biological and non-biological studies.

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