Positive resist composition and positive resist base material using the same

摘要

A positive resist composition comprising: (A) a compound which generates an acid upon irradiation with active light or radiant ray, and (B) a resin which exhibits increased solubility in an alkali by action of an acid and includes a copolymer including (b-1) 40% to 85% by mole of a unit having an alkali-soluble group, (b-2) 3% to 25% by mole of a unit having (i) an acid-decomposable dissolution-inhibiting group and (ii) a group which accelerates dry-etching resistance, and (b-3) 3% to 40% by mole of a unit having an acid-decomposable dissolution-inhibiting group and being other than the units (b-1) and (b-2). This composition is a chemically amplified positive resist composition that can be applied to a resist having a reduced thickness, is excellent in dry-etching resistance and definition and can form a patterned resist with a good sectional shape.