Patent ID: 7361446

Claim:
A positive resist composition comprising (a) a resin that is decomposed by the action of an acid to increase solubility in an alkali developing solution, contains a structural unit having a group represented by formula (X) shown below, has a weight average molecular weight of not more than 5,000, and contains an acid decomposable group in an amount of not more than 40% based on the sum total of a number of the acid decomposable group and a number of an alkali-soluble group not protected with the acid decomposable group, and (b) a compound that generates an acid upon irradiation of an actinic ray or radiation: in formula (X), R1 and R2, which may be the same or different, each represent a hydrogen atom or an alkyl group having from 1 to 4 carbon atoms; R3 and R4, which may be the same or different, each represent a hydrogen atom or an alkyl group; Z represents a phenyl group or an alicyclic group; and m represents an integer of from 1 to 20.