Copolymer useful for positive photoresist and chemical amplification

Abstract

A copolymer having a repeating unit represented by the following general formula I and a chemical amplification positive photoresist composition having the copolymer and a photoacid generator. The photoresist can allow for a good pattern shape even though a post-baking is taken in a somewhat delayed time and for a use of any radiation, such as uv light, deep uv light and charged particle beam. Also, it is superior in storage stability and resolution so that it is useful for the high integration of semiconductor devices. The polymer ranges, in polystyrene-reduced average molecular weight, from 1,000 to 1,000,000. The polymer is represented by the following repeating pattern: ##STR1## wherein, R.sub.1, R.sub.2 and R.sub.3 independently represent a hydrogen atom or a methyl; R.sub.4, R.sub.5 and R.sub.6 independently represent a hydrogen atom, an alkyl group, an alkoxy group or a halogen; 1, m, n each is a repeating number satisfying the condition that 0.3<1/(m+n)<0.9, 0.1<m/(1+n)<0.6 and 0.01<n/(1+m)<0.5; h and g, which may be different and the same, each are an integer of 0-8; and Am represents NR.sub.7 R.sub.8, a cyclic secondary amine, or a heterocyclic secondary amine containing an oxygen or sulfur atom, wherein R.sub.7 and R.sub.8 independently represent a hydrogen atom, an alkyl group, an aryl group or a phenyl group.