Patent ID: 8574809

Claim:
A positive resist composition comprising a resin component (A) which exhibits increased solubility in an alkali developing solution under action of acid, and an acid-generator component (B) which generates acid upon irradiation, said resin component (A) containing a polymer comprising: a core portion represented by formula (1) shown below; and arm portions that are bonded to the core portion and are also composed of a polymer chain obtained by an anionic polymerization method, wherein said arm portions have a structural unit derived from a hydroxystyrene derivative, P X—Y) a (1) wherein P represents an a-valent organic group; a represents an integer of 3 to 20; Y represents an arylene group or an alkylene group of 1 to 12 carbon atoms; and X represents any one of the linking groups represented by formulas (2) to (5) shown below which can be cleaved under action of acid, wherein R 1 and R 2 each independently represents a linear, branched or cyclic alkyl group of 1 to 12 carbon atoms which may be substituted with alkoxy group, hydroxyl group, a halogen atom or an epoxy group, an aryl group which may be substituted with alkoxy group, hydroxyl group, a halogen atom or an epoxy group, alkoxy group or a hydrogen atom; R 3 and R 4 each independently represents a linear, branched or cyclic alkyl group of 1 to 12 carbon atoms which may be substituted with alkoxy group, hydroxyl group, a halogen atom or an epoxy group, an aryl group which may be substituted with alkoxy group, hydroxyl group, a halogen atom or an epoxy group, or an alkoxy group; and R 5 represents a linear, branched or cyclic alkylene group of 1 to 12 carbon atoms which may be substituted with alkoxy group, hydroxyl group, a halogen atom or an epoxy group, an arylene group which may be substituted with alkoxy group, hydroxyl group, a halogen atom or an epoxy group, or a single bond.