Chemically amplified positive resist composition

A chemical amplification type positive resist composition comprising a resin which has the following polymeric units (A), (B) and (C), and is insoluble itself in an alkali, but becomes alkali-soluble by the action of an acid;

• and an acid generating agent,
• (A) At least one polymeric unit of an alicyclic lactone selected from polymeric units represented by the following formulae (Ia) and (Ib):
• 9
• wherein, each of R1 and R2 independently represents hydrogen or methyl, and n represents a number of 1 to 3.
• (B):
• At least one polymeric unit selected fromapolymeric unit of 3-hydroxy-1-adamantyl (meth)acrylate represented by the following formula (II), a polymeric unit of a combination of a unit represented by the following formula (III) and a unit derived from unsaturated dicarboxylic acid anhydride selected from maleic anhydride and itaconic anhydride and a polymeric unit of (α)β-(meth)acryloyloxy-γbutyrolactone represented by the following formula (IV):
• 10
• wherein, R3 and R7 represent hydrogen or methyl, R4represents hydrogen or hydroxyl group, each of R5 and R6 independently represents hydrogen, alkyl having 1 to 3 carbon atom, hydroxyalkyl having 1 to 3 carbon atoms, carboxyl, cyano or group —COOR7 wherein R7 is an alcohol residue, or R5 and R6 together form a carboxylic anhydride residue represented by —C(═O)OC(═O)—.
• (C) A polymeric unit which becomes alkali-soluble by cleavage of a part of groups by the action of an acid.