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Proceedings Paper

Two-Dimensional Modeling Of Contrast-Enhanced Lithography
Author(s): B. F. Griffing; W. E. Lorensen
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Paper Abstract

The aerial image produced by projection mask aligners can be readily visualized using high resolution computer graphics. This paper describes a computer model that calculates the aerial image using a mask pattern and the optical system characteristics as input. The program converts the digital result into a grey scale image. This image is an accu-rate representation of the image the photoresist actually "sees." The model is applied to contrast-enhanced lithography (CEL).1120 By combining the aerial image model with the known bleaching behavior of CEL materials it is possible to calculate the image intensity transmitted by the bleachable layer as a function of time. This result is presented in the form a computer-generated movie, which makes apparent the high contrast of the transmitted image. A second application of the aerial image model is to two-dimensional resist pattern modeling. Although not as sophisticated as SAMPLE4 this model is capable of modeling com-plete structures, such as a dynamic RAM cell. The output of the model is a three-dimensional surface which is displayed using a computer-generated, shaded surface. Linewidth variation with exposure is easily explored with this model. It is a best case model in that it assumes ideal optics and resist development conditions. Resist thickness is calculated using an experimentally determined thickness transfer function. These assumptions are necessary in order to minimize the time necessary for performing the calculations. The model calculates a pattern on a 512 X 512 point array from an image in 1-2 min. on a VAX-780. Since ideal conditions are assumed, the utility of the model is primarily in its ability to predict when a structure is beyond the limits of a given optical system. Applications of the model to CEL will be presented.

Paper Details

Date Published: 21 May 1984
PDF: 6 pages
Proc. SPIE 0469, Advances in Resist Technology I, (21 May 1984); doi: 10.1117/12.941783
Show Author Affiliations
B. F. Griffing, General Electric Corporate Research and Development Center (United States)
W. E. Lorensen, General Electric Corporate Research and Development Center (United States)


Published in SPIE Proceedings Vol. 0469:
Advances in Resist Technology I
C. Grant Willson, Editor(s)

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