Cross-linked polymers for nanofabrication of high-resolution zone plates in nickel and germanium

A high resolution cross-linked PMMA resist has been synthesized and optimized for the generation of zone plate patterns down to 19 nm linewidth with e-beam lithography. This resist shows an increased resolution compared to PMMA for generating periodic structures with a line to space ratio of 1:1. Furthermore, we developed a cross-linked copolymer based on styrene and divinylbenzene, which is used in a new trilevel reactive ion etching ~RIE! process. In this process a resist pattern of low aspect ratio can be transferred into a copolymer galvanoform with high aspect ratios for the electrodeposition of nickel. The copolymer has also been used as a highly selective etching mask for zone plate pattern transfer into germanium by RIE. © 1995 American Vacuum Society.