Patent ID: 8507172

Claim:
A positive resist composition comprising: (A) a compound capable of generating an acid upon irradiation with actinic rays or radiation; (B) a resin of which solubility in an alkali developer increases under action of an acid; (C) a compound capable of decomposing under action of an acid to generate an acid; and (HR) a hydrophobic resin, wherein the pKa of the acid generated from the compound (C) is less than or equal to 3; and the resin (B) comprises at least one of a repeating unit represented by formula (Ia) and a repeating unit represented by formula (Ib): wherein Xa 1 represents a hydrogen atom, an alkyl group, a cyano group or a halogen atom; Ry 1 to Ry 3 each independently represents an alkyl group or a cycloalkyl group, and at least two members out of Ry 1 to Ry 3 may combine to form a monocyclic or polycyclic cyclohydrocarbon structure; Z represents an (n+1)-valent linking group; Ry 4 represents a hydrogen atom, an alkyl group or a cycloalkyl group and Ry 5 represents an alkyl group or a cycloalkyl group, and Ry 4 and Ry 5 may combine to form a monocyclic or polycyclic cyclohydrocarbon structure; L 1 represents an (n+1)-valent linking group; and n represents an integer of 1 to 3.