Sulfonium salts, radiation- sensitive acid generators, and positive radiator-sensitive resin compositions

摘要

A sulfonium salt compound excelling in transparency to deep ultraviolet rays at a wavelength of 220 nm or less, exhibiting well-balanced excellent performance such as sensitivity, resolution, pattern form, LER, and storage stability when used as a photoacid generator, a photoacid generator comprising the sulfonium salt compound, and a positive-tone radiation-sensitive resin composition containing the photoacid generator. The sulfonium salt compound is shown by the following formula (I), wherein R¹ represents a halogen atom, an alkyl group, a monovalent alicyclic hydrocarbon group, an alkoxyl group, or -OR³ group, wherein R³ is a monovalent alicyclic hydrocarbon group, R² represents a (substituted)-alkyl group or two or more R² groups form a cyclic structure, p is 0-7, q is 0-6, n is 0-3, and X^- indicates a sulfonic acid anion. The positive-tone radiation-sensitive resin composition comprises (A) a photoacid generator of the sulfonium-salt compound and (B) an acid-dissociable group-containing resin.