Photoacid generator and photoreactive composition

摘要

A photoacid generator, which shows very high sensitivity in the near ultraviolet range of about 300 to 400 nm, and also can remarkably increase a reaction rate of a photoreactive composition using the same, and a photoreactive composition which can initiate the reaction even by irradiation with near ultraviolet light within a short time and also can obtain a desired reaction product. A dithienyl sulfide disulfonium salt represented by the formula (A1): a dithienyl sulfide sulfonium salt represented by the formula (B1): and a phenylthiothiophene sulfonium salt represented by the formula (C1):