| abstract |
A polymer comprising recurring units of formula (2) is prepared by effecting deblocking reaction on a polymer comprising recurring units of formula (1) in the presence of an acid catalyst.In the formulae, R<1 >and R<4 >are H or methyl, R<2 >and R<3 >are C1-C10 alkyl, or R<2 >and R<3 >may form a ring, R<5 >is H, hydroxyl, alkyl, alkoxy or halogen, R<6 >and R<7 >are H, methyl, alkoxycarbonyl, cyano or halogen, R<8 >is C4-C20 tertiary alkyl, n is an integer of 0 to 4, p is a positive number, q and r each are 0 or a positive number, exclusive of q=r=0, p1 is a positive number, p2 is 0 or a positive number, and p1+p2=p. The polymer thus produced has a narrower molecular weight distribution than polymers produced by the prior art methods. A resist composition comprising the polymer as a base resin has advantages including a dissolution contrast of resist film, high resolution, exposure latitude, process flexibility, good pattern profile after exposure, and minimized line edge roughness. |