Patent ID: 7455952

Claim:
A resist overcoat material for use in an immersion lithography process for forming a pattern, comprising the steps of forming a photoresist layer on a wafer, forming a protective coating on the photoresist layer from a resist overcoat material, exposing the layer structure to light in water, and developing, the resist overcoat material comprising a polymer having copolymerized recurring units containing fluorine and recurring units having sulfo groups, said recurring units containing fluorine being recurring units selected from the following general formulae (1) and (2), and said recurring units having sulfo groups being recurring units selected from the following general formulae (3) to (7): wherein R 1 to R 4 are independently selected from the class consisting of hydrogen atoms, fluorine atoms, C 1 -C 10 alkyl groups, at least partially fluorine-substituted C 1 -C 10 alkyl groups, and at least partially fluorine-substituted C 1 -C 10 alkyl ether groups, which may have hydroxyl groups, or R 3 and R 4 may bond together to form a ring with the carbon atoms to which they are attached, either one of R 1 to R 4 should contain at least one fluorine atom; R 5 is hydrogen, fluorine, methyl, trifluoromethyl or —CH 2 C(═O)OH; R 6 is a straight, branched or cyclic C 1 -C 20 alkyl group which may have an ester, ether, hydroxy or amide group and which should contain at least one fluorine atom; R 9 and R 11 each are hydrogen or methyl; R 10 is a C 1 -C 10 alkylene group; R 12 is a single bond or a straight, branched or cyclic C 1 -C 4 alkylene group; X is a sulfo group; Y is —O— or —NH— ; m is an integer of 0 to 10; and n is an integer of 1 to 10.