Jr. Maldonado et al., EFFECT OF ABSORBER THICKNESS ON IMAGE SHORTENING IN X-RAY-LITHOGRAPHY, Journal of vacuum science & technology. B, Microelectronics and nanometer structures processing, measurement and phenomena, 13(6), 1995, pp. 3094-3098
Image shortening effects have been shown to be a problem for pattern r
eplication using current optical tools. However a previous study [R. D
ellaGuardia, J. R. Maldonado, and H. Oertel., J. Vac. Sci. Technol. B
12, 3936 (1994)] indicated that image shortening is less pronounced wh
en pattern replication is performed using x-ray lithography. This arti
cle describes the effect of absorber thickness on the Image shortening
observed in x-ray lithography. The goal is to determine the optimum a
bsorber thickness that minimizes Image shortening when replicating com
plex patterns with the x-ray spectrum from the HELIOS storage ring ins
talled at the IBM Advanced Lithography Facility. To study these effect
s, an x-ray mask with four quadrants, each having different gold thick
ness, was fabricated using the IBM vector scan (VS-5) electron-beam sy
stem. The mask contains challenging patterns used in IBM devices with
ground rules from 0.4 mu m down to 0.15 mu m, The image shortening eff
ects for different mask/wafer gaps, various fine shapes, and feature s
izes will be presented in this article. In addition, experimental resu
lts with conventional and chemically amplified resists will be present
ed ta shed light on the rob of resist in image shortening. (C) 1995 Am
erican Vacuum Society.