Sulfonium salt, polymer, polymer making method, resist composition, and patterning process

摘要

A sulfonium salt having formula (1a) is provided wherein R1 is H, F, CH3 or CF3, R1a to R1m are each independently H or a monovalent hydrocarbon group, L is a single bond or divalent hydrocarbon group, X is a divalent alkylene group optionally substituted with fluorine, and n is 0 or 1. The sulfonium salt having a polymerizable anion provides for efficient scission of acid labile groups in a chemically amplified resist composition, and it is a very useful monomer from which a base resin for resist use is prepared.;

主权项

1. A sulfonium salt having the general formula (1b): wherein R1 is hydrogen, fluorine, methyl or trifluoromethyl, R1a to R1m are each independently hydrogen, fluorine, or a C1-C20 straight or branched, monovalent hydrocarbon group which may be substituted with or separated by a heteroatom, L1 is a single bond or a C1-C20 straight, branched or cyclic, divalent hydrocarbon group which may be substituted with or separated by a heteroatom, A is trifluoromethyl, and n is 0 or 1, with the proviso that n is 0 when L1 is a single bond.