Positive resist composition and method of forming resist pattern

Abstract

A positive resist composition including a resin component (A) which exhibits increased solubility in an alkali developing solution under action of acid and has a structural unit (a1) represented by general formula (a1-0-2) shown below, and an acid-generator component (B) which generates acid upon exposure and includes an acid generator (B1) consisting of a compound represented by general formula (b1-12) shown below: wherein R represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group; X2 represents an acid dissociable, dissolution inhibiting group; and Y2 represents an alkylene group or a divalent aliphatic cyclic group; and R2—O—Y1—SO3−A+  (b1-12) wherein R2 represents a monovalent aromatic organic group; Y1 represents an alkylene group of 1 to 4 carbon atoms which may be substituted with a fluorine atom; and A+ represents a cation.

Dependencies are inferred from the claim text.