Patent ID: 7598015

Claim:
A polymer consisting of recurring units having the general formulae (1), (2), (4) and (5), the recurring units being of at least one type for each formula, and having a weight average molecular weight of 1,000 to 50,000, wherein R 1 , R 10 and R 13 are independently hydrogen or methyl, R 2 is an acid labile group selected from the general formulae (R 2 -1) to (R 2 -7): wherein the broken line indicates a bonding site and direction, R 5 is each independently a straight, branched or cyclic alkyl group of 1 to 10 carbon atoms, R 6 and R 7 are each independently a straight, branched or cyclic alkyl group of 1 to 10 carbon atoms, or R 6 and R 7 , taken together, may form a ring with the carbon atom to which they are attached, Z is a divalent hydrocarbon group of 2 to 20 carbon atoms which forms a single ring or bridged ring with the carbon atom to which it is attached and which may contain an oxygen atom, and m is 0 or 1, R 11 and R 12 are independently hydrogen or hydroxyl, and R 14 is a lactone structure-containing group selected from the general formulae (R 14 -1) to (R 14 -5): wherein the broken line indicates a bonding site, R 15 is a straight, branched or cyclic alkyl group of 1 to 10 carbon atoms, R 16 and R 17 are each independently hydrogen or a straight, branched or cyclic alkyl group of 1 to 10 carbon atoms, or R 16 and R 17 , taken together, may form a ring with the carbon atom to which they are attached, and the recurring unit having the general formula (2) is selected from the group consisting of the units represented by the following formulae: