Electron-beam lithography to improve quality of computer-generated hologram

2002 ◽  
Vol 61-62 ◽  
pp. 363-369 ◽  
Author(s):  
Feng Gao ◽  
Jianhua Zhu ◽  
Qizhong Huang ◽  
Yixiao Zhang ◽  
Yangsu Zeng ◽  
...  
Author(s):  
L. D. Jackel

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.


Author(s):  
B. L. Armbruster ◽  
B. Kraus ◽  
M. Pan

One goal in electron microscopy of biological specimens is to improve the quality of data to equal the resolution capabilities of modem transmission electron microscopes. Radiation damage and beam- induced movement caused by charging of the sample, low image contrast at high resolution, and sensitivity to external vibration and drift in side entry specimen holders limit the effective resolution one can achieve. Several methods have been developed to address these limitations: cryomethods are widely employed to preserve and stabilize specimens against some of the adverse effects of the vacuum and electron beam irradiation, spot-scan imaging reduces charging and associated beam-induced movement, and energy-filtered imaging removes the “fog” caused by inelastic scattering of electrons which is particularly pronounced in thick specimens.Although most cryoholders can easily achieve a 3.4Å resolution specification, information perpendicular to the goniometer axis may be degraded due to vibration. Absolute drift after mechanical and thermal equilibration as well as drift after movement of a holder may cause loss of resolution in any direction.


Author(s):  
E. V. Shevchuk ◽  
A. V. Shpak

The article describes experience of creating and implementing information-managing educational environment at university. The model of creating information-managing educational environment of university with elements of artificial intelligence and indicative management is described. This environment contributes to improve quality of training and management of educational processes and resources. The stages of creating and implementing information-managing educational environment are considered systemically, as continuous process focused on a consumer. The inhibitory and facilitating conditions for introduction of the model at university are described. To provide subject-oriented approach to the use of information resources of environment, recommended clusters of information subsystems for each category of users are described.Practically implemented scientific and methodological recommendations for subjects of educational process to overcome resistance to innovations introduced in educational organizations are proposed.Features of adaptation of the developed information-managing educational environment for schools are presented.


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