Novel Polymeric Sulfonium Photoacid Generator and Its Application for Chemically Amplified Photoresists

Abstract

The polymeric PAGs based resist systems which incorporated the PAG units into the main chain showed improved lithographic performance, such as faster photospeed and higher stability, lower outgassing, and lower LER than corresponding blend resists. In this paper, with poly (4-hydroxylstyrene) (PHS) as raw material, a new type of polymeric photoacid generators (PAGs) was synthesized with sulfonuium triflate groups bonded onto part of the benzene rings. The phenolic hydroxyl group was partly esterified to improve its solubility in common organic solvents for resists. Upon irradiation to light, the sulfonium units in the polymer effectively decomposed to generate sulfonic acid. The properties of the novel polymeric PAGs were investigated. Chemically amplified photorssists can be formed by the polymeric PAG and other film forming material containing acid labile groups.