POSITIVE RESIST COMPOSITION AND METHOD OF FORMING RESIST PATTERN

摘要

A positive resist composition from which a resist pattern of a satisfactory shape is obtained. It is a positive resist composition obtained by dissolving in an organic solvent (S) a resin ingredient (A) whose alkali solubility increases by the action of an acid and an acid generator ingredient (B) which generates an acid upon irradiation with a radiation, the resin ingredient (A) comprising a copolymer (A1) which comprises a constituent unit (a1) having an acetal-type protective group, a constituent unit (a2) represented by the general formula (a2-1) and derived from an acrylic ester having a lactone-containing polycyclic group, and a constituent unit (a3) derived from an acrylic ester having a polar-group-containing aliphatic hydrocarbon group. [Chemical formula 1] (a2-1) [In the formula, R represents hydrogen, fluorine, lower alkyl, or lower fluoroalkyl; R' represents hydrogen, lower alkyl, or C_1-5 alkoxy; and m is 0 or 1.]