Sulfonium salt, resist composition and pattern forming process

A sulfonium salt having the formula (1):

• wherein p, q and r are each independently an integer of 0 to 3, s is 1 or 2, and r+s is from 1 to 3,
• R1 and R2 are each independently halogen, trifluoromethyl, trifluoromethoxy, trifluoromethylthio, nitro, cyano, —C(═O)—R4, —O—C(═O)—R5 or —O—R5,
• R3 is halogen, trifluoromethyl, trifluoromethoxy, trifluoromethylthio, nitro, cyano, —O—C(═O)—R5 or —O—R5,
• R4 is a C1-C10 hydrocarbyl group, C1-C10 hydrocarbyloxy group, or —O—R4A, the hydrocarbyl group and hydrocarbyloxy group may be substituted with fluorine or hydroxy, R4A is an acid labile group,
• R5 is a C1-C10 hydrocarbyl group,
• X1 is a single bond, ether bond, carbonyl group, —N(R)—, sulfide bond or sulfonyl group, R is hydrogen or a C1-C6 saturated hydrocarbyl group,
• Xq− is an anion having the formula (2):
• wherein R6 is a single bond or C1-C4 alkanediyl group,
• R7A and R7B are each independently hydrogen, fluorine, or trifluoromethyl, at least one thereof being fluorine or trifluoromethyl,
• R8 is a single bond or C1-C20 hydrocarbylene group which may contain a heteroatom,
• R9 is a C6-C20 straight or branched hydrocarbyl group which may contain a heteroatom or C3-C20 cyclic hydrocarbyl group which may contain a heteroatom, and
• L1 is an ether bond, ester bond, carbonate bond or urethane bond.