| abstract |
A sulfonium salt of formula (1) is provided wherein A 1 is a divalent hydrocarbon group, A 2 is a divalent hydrocarbon group, A 3 is hydrogen or a monovalent hydrocarbon group, B 1 is an alkylene or arylene group, k is 0 or 1, R 1 , R 2 and R 3 are alkyl, alkenyl, oxoalkyl, aryl, aralkyl or aryloxoalkyl. A resist composition comprising the sulfonium salt as PAG exhibits a very high resolution when processed by EB and EUV lithography. A pattern with minimal LER is obtainable. |