The repeating structural unit which one possesses the repeating structural unit and the

摘要

PROBLEM TO BE SOLVED: To improve the adhesion of an unexposed part and to suppress the reduction of film thickness without deteriorating dry etching resistance by incorporating a compd. that generates an acid when degraded by irradiation with active light, etc., and a resin contg. specified repeating structural units and having groups that increase solubility when decomposed by the action of the acid. SOLUTION: This photoresist compsn. contains a compd. that generates an acid when degraded by irradiation with active light or radiation and a resin contg. repeating structural units represented by the formula and having groups that increase solubility in an alkali developer when decomposed by the action of the acid. In the formula, R1 is H or alkyl, this alkyl is preferably methyl or ethyl, especially preferably methyl and A is a single group such as alkylene, ether, thio-ether or carbonyl or a group obtd. by combining two or more such groups. It is preferable that the resin further contains repeating structural units each having an alicyclic hydrocarbon part in the molecule.