Patent ID: 8097396

Claim:
A positive resist composition, consisting of: a resin component (A) that exhibits increased alkali solubility under action of acid; an acid generator component (B) that generates acid on exposure; a nitrogen-containing organic compound (D); and an organic solvent, wherein said component (A) is a copolymer (A1) that consists of a structural unit (a1) derived from an acrylate that contains an acid dissociable, dissolution inhibiting group; a structural unit (a2) derived from a methacrylate that contains a lactone ring; and a structural unit (a3) derived from an acrylate that contains a polar group-containing polycyclic group, wherein the structural unit (a1) is a structural unit represented by the general formula (I) shown below: [wherein, R 1 represents a lower alkyl group], the structural unit (a2) is a structural unit represented by the general formula (IV) shown below: [wherein, R′ represents a methyl group, and R 5 and R 6 represent hydrogen atoms], and the structural unit (a3) is a structural unit represented by the general formula (VIII) shown below: [wherein, R represents a hydrogen atom, n is 1, and the hydroxyl group is bonded to position 3 of the adamantyl group], and wherein the proportion of the structural unit (a1), relative to the combined total of all the structural units that constitute the component (A1), is within a range from 30 to 50 mol %, the proportion of the structural unit (a2), relative to the combined total of all the structural units that constitute the component (A1), is within a range from 20 to 60 mol % and the proportion of the structural unit (a3), relative to the combined total of all the structural units that constitute the component (A1), is within a range from 10 to 50 mol %.