Diphenyliodonium salts with pyranine conk as an environment-friendly photo-acid generator and their applications to chemically amplified resists

Abstract

A diphenyliodonium salt with an environment-friendly dye as anion was designed. This salt was shown to possess photosensitivity suitable for use as a chemically amplified resist at both 365 and 405 nm. PAG of tris(diphenyliodonium) 9-hydroxy-pyrene-1,4,6-trisulfonate had a negative Ames test, showed good thermal stability, and had a decomposition temperature of 199.9°C. The quantum yield of acid generation upon irradiation was 0.63. The mechanism of acid generation was intramoleculor electron transfer from the excited dye moiety to the iodonium structure. The photosensitivities of PAG in a polymer with a t-butoxycarbonyl protecting group were 31 and 58 mJ/cm 2 for 365 and 405 nm light, respectively.