Resist composition and patterning process

A resist composition comprising as a base resin a hydrogenated product of a ring-opening metathesis polymer, said product comprising at least one structural unit [A] of the following formula (1) and at least one or both of a structural unit [B] of the following formula (3) and a structural unit [C] of the following formula (4), and having a constitutional molar ratio defined as [A]:([B]+[C]) of from 20:80 to 99:1 and a dispersity defined as a weight average molecular weight (Mw) divided by a number average molecular weight (Mn) of 1.0 to 2.0,

• wherein at least one of R1 to R4 is a functional group having a tertiary ester group of cyclic alkyl of the following formula (2):
• wherein the broken line denotes a valence bond, R5 is selected from the group consisting of hydrogen, straight, branched or cyclic alkyl groups of 1 to 10 carbon atoms, straight, branched or cyclic alkoxyalkyl groups of 2 to 10 carbon atoms, and straight, branched or cyclic acyl groups of 1 to 10 carbon atoms, R6 is a straight, branched or cyclic alkyl group of 1 to 10 carbon atoms, W1 is a single bond or (k+2)-valent hydrocarbon group of 1 to 10 carbon atoms, Z is a divalent hydrocarbon group of 2 to 15 carbon atoms which forms a single ring or bridged ring with the carbon atom, and k is 0 or 1;
• the remainders of R1 to R4 are independently selected from the group consisting of hydrogen, straight, branched or cyclic alkyl groups of 1 to 20 carbon atoms, halogen atoms, straight, branched or cyclic haloalkyl groups of 1 to 20 carbon atoms, straight, branched or cyclic alkoxy groups of 1 to 20 carbon atoms, straight, branched or cyclic alkoxyalkyl groups of 2 to 20 carbon atoms, straight, branched or cyclic alkylcarbonyloxy groups of 2 to 20 carbon atoms, arylcarbonyloxy groups of 6 to 20 carbon atoms, straight, branched or cyclic alkylsulfonyloxy groups of 1 to 20 carbon atoms, arylsulfonyloxy groups of 6 to 20 carbon atoms, straight, branched or cyclic alkoxycarbonyl groups of 2 to 20 carbon atoms, and straight, branched or cyclic alkoxycarbonylalkyl groups of 3 to 20 carbon atoms;
• X1, which may be the same or different, is —O— or —CR72—wherein R7 is hydrogen or a straight or branched alkyl group of 1 to 10 carbon atoms;
• and
• j is 0 or an integer of 1 to 3;
• wherein R8 to R11 each are independently hydrogen or a straight, branched or cyclic alkyl group of 1 to 10 carbon atoms, X2, which may be the same or different, is —O— or —CR122—wherein R12 is hydrogen or a straight or branched alkyl group of 1 to 10 carbon atoms, and m is 0 or an integer of 1 to 3;
• wherein R13 to R16 each are independently hydrogen or a straight, branched or cyclic alkyl group of 1 to 10 carbon atoms, X3, which may be the same or different, is —O— or —CR172—wherein R17 is hydrogen or a straight or branched alkyl group of 1 to 10 carbon atoms, one of Y1 and Y2 is —(C═O)— and the other is —CR182— wherein R18 is hydrogen or a straight or branched alkyl group of 1 to 10 carbon atoms, and n is 0 or an integer of 1 to 3;
• provided that the product contains:
• at least one structural unit [A] of the formula (1) where X1 is O,
• at least one structural unit [B] of the formula (3) where X2 is O, or
• at least one structural unit [C] of the formula (4) where X3 is O.