Patent ID: 8822136

Claim:
A pattern forming process comprising the steps of: applying a resist composition onto a substrate, the resist composition comprising a polymer comprising recurring units having a hydroxyl group substituted with an acid labile group and an acid generator, or a polymer comprising recurring units having a hydroxyl group substituted with an acid labile group and recurring units capable of generating an acid upon exposure, a sulfonium or iodonium salt of perfluoroalkyl ether carboxylic acid, and an organic solvent, prebaking the composition to form a resist film, exposing the resist film to high-energy radiation, baking, and developing the exposed film in an organic solvent-based developer to form a negative pattern wherein the unexposed region of film is dissolved away and the exposed region of film is not dissolved, wherein said sulfonium or iodonium salt of perfluoroalkyl ether carboxylic acid is a salt (Q1) or Q2) having the general formula (2): wherein R 101a , R 101b and R 101c are each independently a straight, branched or cyclic C 1 -C 12 alkyl, alkenyl, oxoalkyl or oxoalkenyl group, C 6 -C 20 aryl group, or C 7 -C 12 aralkyl or aryloxoalkyl group, in which some or all hydrogen atoms may be substituted by ether, ester, carbonyl, carbonate, hydroxyl, carboxyl, halogen, cyano, amino, amide, nitro, sultone, sulfonic acid ester, sulfone groups, or substituent groups having sulfonium salt, or R 101b and R 101c may bond together to form a ring with the sulfur atom to which they are attached, R 101b and R 101c each are a C 1 -C 6 alkylene group when they form a ring, R 101d and R 101e each are a C 6 -C 20 aryl group which may contain a straight, branched or cyclic C 1 -C 6 alkyl or alkoxy radical, or R 101d and R 101e may bond together to form a ring with the iodine atom to which they are attached, and R 14 —COO − is selected from the group consisting of the following formulae: