Polymer Compound, Positive Resist Composition and Process for Forming Resist Pattern

摘要

The positive resist composition of the present invention is a polymer compound comprising at least one constituent unit (a1) selected from the group consisting of constituent units represented by the following general formulas (1) and (1)', a constituent unit (a2) derived from an (alpha-lower alkyl)acrylate ester having a lactone-containing monocycle or a polycyclic group, and a constituent unit (a3) which is a constituent unit other than the constituent unit (a1) and the constituent unit (a2) and is derived from an (alpha-lower alkyl)acrylate ester which has an aliphatic cyclic group-containing non-acid dissociable dissolution inhibiting group and does not have a polar group: wherein R represents a hydrogen atom, a fluorine atom, a lower alkyl group having 20 or less carbon atoms, or a fluorinated lower alkyl group having 20 or less carbon atoms, R¹ represents at most 20-membered cyclic group which may have a substituent, n represents 0 or an integer of 1 to 5, and m represents 0 or 1.