Patent ID: 6872502

Claim:
A polymer for a chemically amplified negative photoresist, comprising up to four units and represented by formula: wherein each of the up to four monomer units present is different from the other monomer units present; R 1 is H or CH 3 ; R 2 and R 4 are each independently selected from (R) α (CH 2 ) β R′ and (R) α [(CH 2 ) γ O] δ R′, wherein, R is CO, CO 2 , O, OCO, or OCO 2 , R′ is O, CO 2 , or OCO 2 , α is 0 or 1, β is 0 to 5, γ is 1 or 2, and δ is 1 to 5; R 3 is represented by one of the formulae: wherein R 6 , which combines an acetal compound and a vinyl compound, is a C 1 -C 5 saturated alkyl, a C 1 -C 5 ether, or a C 1 -C 5 carbonyl; R 7 to R 11 are each independently selected from H, C 1 -C 5 saturated alkyls, C 1 -C 5 ethers, C 1 -C 5 carbonyl groups, C 1 -C 5 alcohol groups; and m is a number ranging from 1-5; and R 5 is represented by formula: wherein R 12 and R 13 are each independently selected from H and OH, and * represents the bonding site at which the R 4 group is bonded; R 14 and R 16 are each independently selected from a single bond, (R) α (CH 2 ) β R′ and (R) α [(CH 2 ) γ O] δ R′, wherein R is CO, CO 2 , O, OCO, or OCO 2 , R′ is O, CO 2 , or OCO 2 , α is 0 or 1, β is 0 to 5, γ is 1 or 2, and δ is 1 to 5; R 15 is a hydroxyl group; R 17 is a carboxyl group; a, b, c, and d represent mole ratios of each monomer, a has a value of 0-0.5, b has a value of 0-0.9, c has a value of 0-0.3, and d has a value of 0-0.3, provided that a+b+c+d=1; and n represents the degree of polymerization of each polymer, and has a value of at least 2.