Patent ID: 7279265

Claim:
A positive resist composition comprising: (A) a resin capable of increasing its solubility in an alkali developer under action of an acid, wherein the resin contains a repeating unit originated in an acrylic acid ester derivative in an amount of 50 to 100 mol % based on all repeating units and wherein the resin has repeating units of at least one kind selected from repeating units represented by the following formula (IV) and repeating units having groups represented by the following formula (V-1), (V-2), (V-3) and (V-4); and repeating units represented by the following formula (AII), (B) a compound capable of generating an acid upon irradiation with actinic rays or radiation, wherein the compound (B) contains a triaryl-sulfonium salt compound and a phenacylsulfonium salt compound, and (C) a mixed organic solvent comprising at least one solvent selected from the group consisting of a propylene glycol monoalkyl ether carboxylate, an alkyl lactate and a linear ketone; and a cyclic ketone: wherein R 1a represents a hydrogen atom or a methyl group, W 1 represents a single bond or a divalent linking group, Ra 1 , Rb 1 , Rc 1 , Rd 1 and Re 1 each independently represents a hydrogen atom or an alkyl group, m and n each independently represents an integer of 0 to 3, and m+n is from 2 to 6; wherein R 1b to R 5b each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group or an alkenyl group, and two of R 1b to R 5b may be combined with each other to form a ring; wherein R 1c represents a hydrogen atom or a methyl group, and R 2c to R 4c each independently represents a hydrogen atom, a hydroxyl group, an alkoxy group, an acyloxy group or an alkyloxycarbonyloxy group, provided that one or two of R 2c to R 4c represents a hydroxyl group.