Electron-beam lithography on M108Y and M35G chemically amplified DUV photoresists

Abstract

Despite the development of high-end optical lithography systems, electron-beam lithography (EBL) remains the preferred solution for rapid fabrication of deep sub-micrometric features. Although poly-methylmethacrylate (PMMA), HSQ and ZEP remain the most popular resists on the market, a variety of alternatives have emerged, including chemically amplified resists like CSAR. Here, we investigate the use of two resists initially intended for deep ultraviolet (DUV) lithography, namely M108Y and M35G from JSR, as EBL resists. Their chemically amplified nature involves high sensitivity, de facto increasing the throughput. The critical dimensions of each resist are studied, as well as the pattern transfer into the underlying silicon substrate. They yield similar CD performance as ZEP or CSAR; at the same time, they are more resistant than those resists with respect to different dry etching recipes. Overall, the two analyzed DUV photoresists are proven to be valid solutions as alternatives to standard EBL resists. • Electron-beam lithography on M108Y and M35G deep ultraviolet photoresists. • Chemically amplified nature of resists yields high sensitivity. • Critical dimensions performance are similar to ZEP and CSAR. • Resists are more resistant to dry etching than standard solutions. • Pronounced undercut in M35G allows single-layer lift-off.