Patent ID: 8722321

Claim:
A pattern forming process comprising the steps of applying a resist composition onto a substrate, post-applied baking the composition to form a resist film, exposing the resist film to high-energy radiation, post-exposure baking the resist film, and developing the exposed resist film in an organic solvent-based developer to selectively dissolve the unexposed region of the resist film to form a negative pattern, the resist composition comprising a base resin, an acid generator, and an organic solvent, the base resin being a hydrogenated product of a ring-opening metathesis polymerization polymer comprising recurring units (A) including a partial structure having a carboxyl group protected with an acid labile group, represented by the general formula (1), and recurring units (B) having a lactone structure, represented by the general formula (3) or (4), the recurring units (A) and (B) each being of at least one type, wherein at least one of R 1 to R 4 is a functional group having the general formula (2): wherein the broken line denotes a valence bond, R 5 is hydrogen, C 1 -C 10 straight, branched or cyclic alkyl, C 2 -C 10 straight, branched or cyclic alkoxyalkyl, or C 1 -C 10 straight, branched or cyclic acyl, R 6 is an acid labile group, W 1 is a single bond or a (k+2)-valent C 1 -C 10 hydrocarbon group, and k is 0 or 1, the remains of R 1 to R 4 are each independently hydrogen, C 1 -C 20 straight, branched or cyclic alkyl, halogen, C 1 -C 20 straight, branched or cyclic haloalkyl, C 1 -C 20 straight, branched or cyclic alkoxy, C 2 -C 20 straight, branched or cyclic alkoxyalkyl, or C 2 -C 20 straight, branched or cyclic alkylcarbonyloxy, C 6 -C 20 arylcarbonyloxy, C 1 -C 20 straight, branched or cyclic alkylsulfonyloxy, C 6 -C 20 arylsulfonyloxy, C 2 -C 20 straight, branched or cyclic alkoxycarbonyl, or C 3 -C 20 straight, branched or cyclic alkoxycarbonylalkyl, X 11 and X 12 are each independently —O— or —CR 7 2 —, R 7 is hydrogen or C 1 -C 10 straight or branched alkyl, and j is 0 or an integer of 1 to 3, wherein R 8 to R 11 are each independently hydrogen or C 1 -C 10 straight, branched or cyclic alkyl, X 21 and X 22 are each independently —O— or —CR 12 2 —, R 12 is hydrogen or C 1 -C 10 straight or branched alkyl, m is 0 or an integer of 1 to 3, R 13 to R 16 are each independently hydrogen or C 1 -C 10 straight, branched or cyclic alkyl, X 31 and X 32 are each independently —O— or —CR 17 2 —, R 17 is hydrogen or C 1 -C 10 straight or branched alkyl, one of Y 1 and Y 2 is —(C═O)— and the other is —CR 18 2 —, R 18 is hydrogen or C 1 -C 10 straight or branched alkyl, and n is 0 or an integer of 1 to 3, at least one of X 11 , X 12 , X 21 , X 22 , X 31 , X 32 in the formulae is —O—.