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.

主权项

1. A chemically amplified positive resist composition for ArF immersion lithography, comprising
(A) a triarylsulfonium 2,3,3,3-tetrafluoro-2-(1,1,2,2,3,3,3-heptafluoropropoxy)propionate having the general formula (1-1):wherein Ar is a substituted or unsubstituted C6-C20 aryl group which may contain a heteroatom, or a plurality of Ar groups may bond together directly or via an oxygen atom, methylene, sulfone or carbonyl moiety,
(B) one or more acid generator having the general formula (1-2):wherein R1 is a C1-C30 alkyl, alkenyl or aralkyl group which may contain a heteroatom, R2 is hydrogen or trifluoromethyl, and Ar is a substituted or unsubstituted C6-C20 aryl group which may contain a heteroatom, or a plurality of Ar groups may bond together directly or via an oxygen atom, methylene, sulfone or carbonyl moiety,
(C) a base resin having an acidic functional group protected with an acid labile group, which is insoluble or substantially insoluble in alkaline developer, but turns soluble in alkaline developer upon deprotection of the acid labile group, and (D) an organic solvent.