New approaches to production-worthy 193-nm photoresists based on acrylic copolymers

We describe a series of improvements to the 'v2' etch- resistant methacrylate 193 nm photoresist platform. 'V2' itself possesses many desirable characteristics, but requires weak developers and lacks ultimate etch resistance for production processes. Modifications to address these challenges include incorporation of polar modifier monomers which provide improved developer compatibility, and use of alternative etch-resistant monomers which ameliorate the excessive hydrophobicity of isobornyl methacrylate. Specifically, we explore the use of methacrylonitrile as a polar modifier which simultaneously imparts strong-developer compatibility and improves RIE performance. Integration of these improvements results in methacrylate resists displaying strong-developer compatibility, sub-0.15 micrometers resolution, and etch rates equivalent to current 248 nm photoresists in prototype materials. ©2003 Copyright SPIE - The International Society for Optical Engineering.