Abstract: 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.

Abstract: 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.

Abstract: A negative pattern is formed by coating a resist composition comprising a polymer comprising recurring units having a tertiary ester type acid labile group having a plurality of methyl or ethyl groups on alicycle and an acid generator onto a substrate, prebaking, exposing to high-energy radiation, baking, and developing in an organic solvent developer so that the unexposed region of resist film is dissolved away and the exposed region of resist film is not dissolved. The resist composition exhibits a high dissolution contrast during organic solvent development and forms a fine hole or trench pattern of dimensional uniformity.

Abstract: A negative pattern is formed by applying a resist composition onto a substrate, exposing the resist film, and developing the exposed resist film in an organic solvent developer. The process further involves coating the negative pattern with a shrink agent solution of a copolymer comprising recurring units having an ?-trifluoromethylhydroxy or fluoroalkylsulfonamide group and recurring units having an acid labile group-substituted amino group in a C6-C12 ether, C4-C10 alcohol, C6-C12 hydrocarbon, C6-C16 ester or C7-C16 ketone solvent, baking the coating, and removing the excessive shrink agent for thereby shrinking the size of spaces in the pattern.

Abstract: 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.

Abstract: 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.

Abstract: A negative pattern is formed by coating a resist composition comprising a polymer comprising recurring units having a tertiary ester type acid labile group having a plurality of methyl or ethyl groups on alicycle and an acid generator onto a substrate, prebaking, exposing to high-energy radiation, baking, and developing in an organic solvent developer so that the unexposed region of resist film is dissolved away and the exposed region of resist film is not dissolved. The resist composition exhibits a high dissolution contrast during organic solvent development and forms a fine hole or trench pattern of dimensional uniformity.