Resist composition and patterning process

A resist composition comprising a base polymer, an organic solvent and a sulfonium salt having the formula (A):

• wherein R1 and R2 are each independently hydrogen or a C1-C6 straight, branched or cyclic alkyl group, R1 and R2 may bond together to form a ring with the nitrogen atom to which they are attached, the ring optionally containing an ether bond, R3 is fluorine or trifluoromethyl, R4 is hydrogen, methyl, nitro or cyano, m is an integer of 1 to 4, n is an integer of 1 to 3,
• R5, R6 and R7 are each independently a C1-C12 straight, branched or cyclic alkyl or oxoalkyl group, C2-C12 straight, branched or cyclic alkenyl or oxoalkenyl group, C6-C20 aryl group, or C7-C12 aralkyl or aryloxoalkyl group, in which an ether, ester, carbonyl or carbonate moiety may intervene between carbon atoms, or at least one hydrogen may be substituted by an ether, ester, carbonyl, carbonate, hydroxyl, carboxyl, halogen, cyano, amide, nitro, sultone, sulfonic acid ester, sulfone moiety or sulfonium salt-containing substituent, or R5 and R6 may bond together to form a ring with the sulfur atom to which they are attached.