Chemically amplified positive resist composition for ArF immersion lithography and pattern forming process

摘要

A chemically amplified positive resist composition comprising (A) a triarylsulfonium salt of 2,3,3,3-tetrafluoro-2-(1,1,2,2,3,3,3-heptafluoropropoxy)propionic acid, (B) an acid generator, (C) a base resin, and (D) an organic solvent is suited for ArF immersion lithography. The sulfonium salt is highly hydrophobic and little leached out in immersion water. By virtue of controlled acid diffusion, a pattern profile with high resolution can be constructed.