Non-chemically amplified resists for 193 nm lithography

Acid diffusion during the post-exposure bake of chemically amplified resists (CARs) is a major contributing factor to line width roughness (LWR) and resolution limits at the 32 nm node and beyond. To overcome these limitations, non-CAR materials are becoming more attractive because acid diffusion is eliminated. We have therefore focused our effort on the synthesis of copolymers that have both a diacyldiazo side chain unit as well as a hexafluoroalcohol unit. This copolymer shows better contrast than that of copolymers containing lactone units due to their inhibition behavior. Furthermore, polymer blends containing hexafluoroalcohol groups show good 100 nm line and space patterning property for 193 nm lithography. This paper describes the design, synthesis, and characterization of these non-CARs, and thier improvement to photolithography.