Patent ID: 8828647

Claim:
A negative pattern-forming resist composition comprising a polymer, an acid generator, and an organic solvent, said polymer comprising recurring units (a2) having a hydroxyl group substituted with an acid labile group and recurring units (b) having an oxirane or oxetane ring as represented by the general formula (1): wherein R 1 and R 6 are each independently hydrogen or methyl, R 2 is a C 1 -C 16 straight, branched or cyclic aliphatic hydrocarbon group having a valence of 2 to 4 which may contain an ether or ester radical, R 3 is an acid labile group, m is an integer of 1 to 3, R 7 is a single bond or a C 1 -C 6 straight, branched or cyclic alkylene group, which may bond with R 8 to form a ring, R 8 , R 9 and R 10 are each independently hydrogen or a C 1 -C 6 straight, branched or cyclic alkyl group, p is 0 or 1, a2 and b indicative of a copolymerization ratio are in the range: 0<a2<1.0, 0<b<1.0, and 0<a2+b≦1.0, said polymer being dissolvable in a developer selected from the group consisting of 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate, amyl acetate, isoamyl acetate, butenyl acetate, phenyl acetate, propyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl valerate, methyl pentenoate, methyl crotonate, ethyl crotonate, methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, amyl lactate, isoamyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, benzyl acetate, methyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenylacetate, and 2-phenylethyl acetate wherein a monomer from which the recurring units (a2) are derived is one selected from the group consisting of the following formulae: wherein R 1 and R 3 are as defined above.