The optical proximity effect becomes significant near the practical resolution limit of photolithography, depending on the wavelength and numerical aperture of the stepper. Recently, VLSI design rules have almost reached their limits. Larger ICs cannot be designed and be manufactured without using a lithographic DRC (design rule check) tool or an OPC (optical proximity correction) tool. Therefore, it has become necessary to develop a technology which can accurately predict resist features from the designed circuit layout. We studied deviation in both the line width and the length due to proximity effect and investigated the phenomena. Also we developed a technology which can accurately predict the behavior of the proximity effect from an aerial image. This technology is based on a simple threshold model. We optimized the calculations for an aerial image and the threshold of intensity in order to predict deviations in the line width and length. We also considered the profile of an aerial image to predict the critical point. The calculations for an aerial image and threshold which we optimized in this manner can be used to predict 2D patterns.

Date Published: 7 July 1997
PDF: 10 pages
Proc. SPIE 3051, Optical Microlithography X, (7 July 1997); doi: 10.1117/12.275985

Published in SPIE Proceedings Vol. 3051:
Optical Microlithography X
Gene E. Fuller, Editor(s)