Patent ID: 8389201

Claim:
A positive resist composition comprising at least: (A) a base resin, which has acidic functional groups protected by acid labile groups, respectively, and is insoluble or hardly soluble in alkali, and which is turned to be soluble in alkali upon elimination of the acid labile groups; (B) an acid generator; and (C) a nitrogen-containing compound as a basic component; wherein the base resin is a polymer consisting of repeating units selected from repeating units represented by the following general formulae (1), (2), (3), (4), (6), (6)′, and (9); further wherein the polymer contains repeating units each represented by the general formula (1) and, as the repeating units having the acidic functional groups protected by the acid labile groups, respectively, at least one or more repeating units each represented by the general formulae (2), (4), and (6), and when the polymer does not contain the repeating unit represented by the general formula (2), the polymer contains at least the repeating unit represented by the general formula (3); and wherein the base resin contains the repeating units represented by the general formulae (1), (2), and (3), respectively, at a sum ratio of 70 mole % or more relative to a total amount of all repeating units constituting the base resin: wherein, X represents an acid labile group; and R 1 represents a hydrogen atom, a halogen atom, a linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms, a linear, branched, or cyclic alkoxy group having 1 to 10 carbon atoms and being uneliminatable by an acid, or a linear, branched, or cyclic acyl group having 1 to 10 carbon atoms and being uneliminatable by an acid; wherein X and R 1 may be selected in multiple kinds, respectively; Y represents an acid labile group; and R represents a hydrogen atom or a methyl group; wherein Y and R may be selected in multiple kinds, respectively; R 2 represents a hydrogen atom, a hydroxyl group, a linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms, a linear, branched, or cyclic alkoxy group having 1 to 10 carbon atoms and being uneliminatable by an acid, or a linear, branched, or cyclic acyl group having 1 to 10 carbon atoms and being uneliminatable by an acid; and wherein R 2 may be selected in multiple kinds.