Dynamics of Radical Cation of Poly(4-hydroxystyrene) and Its Copolymer for Extreme Ultraviolet and Electron Beam Resists

摘要

The use of ionizing radiation such as extreme ultraviolet (EUV) radiation is expected in next-generation lithography. Poly(4-hydroxystyrene) (PHS), which has been used in KrF excimer laser (248 nm) lithography as a backbone polymer, is a promising material for chemically amplified EUV and electron beam resists. In this study, the dynamics of the radical cation of poly(styrene-ran-4-hydroxystyrene) [P(S-HS)] was investigated. It was found that the hole transfer reaction in the matrix plays an important role in the sensitization of the resist. The hole transfer range is estimated to be ～2.5 units (～1.0nm).