Resist composition and patterning process

A resist composition consisting of:

• (A) a photoacid generator in the form of a sulfonium salt having the formula (1):
• wherein R1 is hydrogen or a C1-C10 monovalent hydrocarbon group which may contain a heteroatom, R2 is a C1-C10 monovalent hydrocarbon group which may contain a heteroatom selected from the group consisting of oxygen, sulfur and nitrogen, L is a single bond, ether bond or thioether bond, and A is hydrogen or trifluormethyl,
• (B) a base polymer adapted to change its solubility in a developer under the action of an acid, and
• (C) an organic solvent, and
• optionally
• (D) a photoacid generator having the formula (2) or (3):
• wherein the sulfonium cation in formula (2) is selected from the group consisting of the following formulae;
• and X− is an anion having the formula (2A) or (2B):
• wherein Rfa is fluorine, a C1-C4 perfluoroalkyl group, or a C1-C40 monovalent hydrocarbon group which may contain a heteroatom, and Rfb is a C1-C40 monovalent hydrocarbon group which may contain a heteroatom,
• wherein R201 and R202 are each independently a C1-C30 monovalent hydrocarbon group which may contain a heteroatom, R203 is a C1-C30 divalent hydrocarbon group which may contain a heteroatom, any two of R201, R202 and R203 may bond together to form a ring with the sulfur atom to which they are attached, LA is a single bond, ether bond or a C1-C20 divalent hydrocarbon group which may contain a heteroatom, X1, X2, X3 and X4 are each independently hydrogen, fluorine or trifluoromethyl, at least one of X1, X2, X3 and X4 being fluorine or trifluoromethyl,
• (E) a quencher,
• (F) a surfactant which is insoluble in water and soluble in alkaline developer, and/or
• (G) other components selected from the group consisting of an acid amplifier compound, an organic acid derivative, a fluorinated alcohol, a crosslinker, a dissolution inhibitor and acetylene alcohol.