Effects of Electrons Ejected from the Substrate on PGMA Negative Resist Cross-Linking in X-Ray Lithography

Abstract

Effects of electrons ejected from the substrate on poly (glycidyl methacrylate) (PGMA) cross-linking have been experimentally studied by comparing sensitivity characteristics obtained using Pd, Mo, Si and Al X-ray sources. In the Al, Si or SiO₂ substrate, remaining PGMA film thicknesses, measured at the gel-point X-ray dose obtained with the AZ-1450 J substrate, have been compared for the above 4 X-ray sources. It was found that the remaining film thicknesses were in the 100–500 A range. It was also found that fairly close correlation exists between the remaining film thickness and the absorption coefficient for the substrate.