Photobleaching photoacid generator

Abstract

A cyclopropyl group was introduced into the photoacid generator in order to give the photobleaching property at 193 nm. Cyclopropyldiphenylsulfonium trifluoromethanesulfonate (CpDP-Tf) was synthesized for this photobleaching effect. This compound is stable up to 165°C. The absorbance of CpDP-Tf at 193 nm decreases upon exposure. The resist containing CpDP-Tf gave the higher resolution comparing with that containing triphenyl-sulfonium trifluoromethanesulfonate.