Resist composition and pattern forming process

A resist composition comprising a sulfonium salt of a carboxylic acid having a benzene ring substituted with at least one nitro group, wherein the carboxylic acid is free of iodine and bromine,

• wherein the sulfonium salt has the formula (A):
• wherein R1 is each independently chlorine, hydroxy group, amino group, or a C1-C20 hydrocarbyl group, C1-C20 hydrocarbyloxy group, C2-C20 hydrocarbylcarbonyloxy group, C2-C20 hydrocarbyloxycarbonyl group, C2-C20 hydrocarbyloxycarbonyloxy group, or C1-C20 hydrocarbylsulfonyl group, which may contain chlorine, hydroxy, amino, ether bond or ester bond, or —N(R1A)(R1B), —N(R1C)—C(═O)—R1D, —N(R1C)—C(═O)—O—R1D, or —N(R1E)—S(═O)2—R1F, R1A and R1B are each independently hydrogen or a C1-C6 saturated hydrocarbyl group, R1C and RIE are each independently hydrogen or a C1-C6 saturated hydrocarbyl group which may contain halogen, hydroxy moiety, C1-C6 saturated hydrocarbyloxy moiety, C2-C6 saturated hydrocarbylcarbonyl moiety or C2-C6 saturated hydrocarbylcarbonyloxy moiety, R1D and R1F are each independently a C1-C16 aliphatic hydrocarbyl group, C6-C14 aryl group or C7-C15 aralkyl group, which may contain halogen, hydroxy moiety, C1-C6 saturated hydrocarbyloxy moiety, C2-C6 saturated hydrocarbylcarbonyl moiety or C2-C6 saturated hydrocarbylcarbonyloxy moiety,
• R2 is fluorine,
• R3 to R5 are each independently halogen or a C1-C20 hydrocarbyl group which may contain a heteroatom, R3 and R4 may bond together to form a ring with the sulfur atom to which they are attached,
• X is a single bond or a C1-C20 divalent linking group which may contain an ether bond, carbonyl moiety, ester bond, amide bond, sultone ring, lactam ring, carbonate bond, halogen, hydroxy moiety or carboxy moiety,
• m is an integer of 1 to 3, n1 is an integer of 0 to 3, n2 is 0, and 1≤m+n1+n2≤5.