Chemical amplification type positive resist composition and a resin therefor

摘要

A resin which comprises (1) at least one structural unit selected from the group consisting of a structural unit derived from 3-hydroxy-1-adamantyl(meth)acrylate, a structural unit derived from 3,5-dihydroxy-1-adamantyl(meth)acrylate, a structural unit derived from (meth)acryloyloxy-gamma-butyrolactone having a lactone ring optionally substituted by alkyl, a structural unit of the formula (Ia) and a structural unit of the formula (Ib) and (2) a structural unit of the formula (II) and which itself is insoluble or poorly soluble in an alkali aqueous solution but becomes soluble in an alkali aqueous solution by the action of an acid; and also provides a chemical amplification type positive resist composition comprising a resin defined above and an acid generator.