Resist composition and patterning process

A resist composition comprising a base polymer and an acid generator containing a sulfonium salt having the formula (1-1) or an iodonium salt having the formula (1-2):

• wherein R1 is each independently a hydroxyl, C1-C20 straight, branched or cyclic alkyl or alkoxy group, C2-C20 straight, branched or cyclic acyl or acyloxy group, fluorine, chlorine, bromine, amino, or alkoxycarbonyl-substituted amino group,
• R2 is each independently a single bond or C1-C4 alkylene group,
• R3 is a single bond or C1-C20 divalent linking group when p=1, or a C1-C20 tri- or tetravalent linking group when p=2 or 3, the linking group optionally containing an oxygen, sulfur or nitrogen atom,
• Rf1 to Rf4 are each independently hydrogen, fluorine or trifluoromethyl, at least one of Rf1 to Rf4 being fluorine or trifluoromethyl, or Rf1 and Rf2, taken together, may form a carbonyl group,
• R4, R5, R6, R7 and R8 are each independently a C1-C12 straight, branched or cyclic alkyl group, C2-C12 straight, branched or cyclic alkenyl group, C6-C20 aryl group or C7-C12 aralkyl or aryloxyalkyl group, in which at least one hydrogen may be substituted by a hydroxyl, carboxyl, halogen, cyano, oxo, amide, nitro, sultone, sulfone, or sulfonium salt-containing moiety, or in which an ether, ester, carbonyl, carbonate or sulfonic acid ester moiety may intervene in a carbon-carbon bond, or R4 and R5 may bond together to form a ring with the sulfur atom to which they are attached,
• m is an integer of 1 to 5, n is an integer of 0 to 3, and p is an integer of 1 to 3.