Pattern forming process and shrink agent

A shrink agent comprising a block copolymer and a solvent,

• wherein the block copolymer comprising recurring units having an α-trifluoromethylhydroxy and/or fluoroalkylsulfonamide group and recurring units having an acid labile group-substituted amino group has the general formula (1):
• wherein R1, R3, and R6 each are hydrogen or methyl, m is 1 or 2, X1 in case that m is 1 and X2 each are phenylene or —C(═O)—O—R9—, R9 is a straight, branched or cyclic C1-C10 alkylene group which may contain an ether or ester moiety, C6-C10 arylene group, or C2-C10 alkenylene group, or X1 in case that m is 2 is a trivalent group in which one hydrogen atom is eliminated from X1 in case that m is 1, R2 is hydrogen, fluorine, methyl, trifluoromethyl, or difluoromethyl, R2 may bond with X1 to form a C1-C6 ring which may contain a fluorine atom or ether moiety, R4 is hydrogen or a C1-C4 alkyl group, R5 is a straight, branched or cyclic C1-C10 alkyl group or C6-C10 aryl group which has at least one fluorine atom, n is 1 or 2, Y in case that n is 1 is a single bond, —C(═O)—O—R10— or —C(═O)—NH—, R10 is a single bond, a straight, branched or cyclic C1-C10 alkylene group which may contain an ether moiety, ester moiety, —N═ or —S—, or a phenylene group or naphthylene group, or Y in case that n is 2 is a trivalent group in which one hydrogen atom is eliminated from Y in case that n is 1, R7 is an acid labile group, R8 is hydrogen, C1-C4 alkyl group or acid labile group, R8 may bond with Y to form a C3-C10 ring, 0≦a1<1.0, 0≦a2<1.0, 0<a1+a2<1.0, and 0<b<1.0, and
• wherein the solvent is selected from the group consisting of di-n-butyl ether, diisobutyl ether, di-sec-butyl ether, di-n-pentyl ether, diisopentyl ether, di-sec-pentyl ether, di-tert-amyl ether, di-n-hexyl ether, methyl cyclopentyl ether, methyl cyclohexyl ether, methyl phenyl ether, methyl benzyl ether, ethyl cyclopentyl ether, ethyl cyclohexyl ether, ethyl phenyl ether, ethyl benzyl ether, 1-butyl alcohol, 2-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, tert-amyl alcohol, neopentyl alcohol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol, 3-hexanol, 2,3-dimethyl-2-butanol, 3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol, 2,2-diethyl-1-butanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pentanol, cyclohexanol, 1-octanol, benzene, toluene, xylene, mesitylene, ethylbezene, n-propylbenzene, cumene, n-butylbenzene, cymene, amylbenzene, diethylbenzene, octane, nonane, decane, turpentine oil, pinene, 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methylacetophenone, ethyl n-butyl ketone, di-n-butyl ketone, diisobutyl ketone, amyl phoronate, amyl acetate, isoamyl acetate, 2-ethylhexyl acetate, cyclohexyl acetate, methylcyclohexyl acetate, hexyl formate, ethyl valerate, propyl valerate, isopropyl valerate, butyl valerate, isobutyl valerate, tert-butyl valerate, amyl valerate, isoamyl valerate, ethyl isovalerate, propyl isovalerate, isopropyl isovalerate, butyl isovalerate, isobutyl isovalerate, tert-butyl isovalerate, isoamyl isovalerate, ethyl pivalate, propyl pivalate, isopropyl pivalate, butyl pivalate, tert-butyl pivalate, ethyl pentenoate, propyl pentenoate, isopropyl pentenoate, butyl pentenoate, tert-butyl pentenoate, propyl crotonate, isopropyl crotonate, butyl crotonate, tert-butyl crotonate, butyl propionate, isobutyl propionate, tert-butyl propionate, benzyl propionate, propyl butyrate, butyl butyrate, isobutyl butyrate, tert-butyl butyrate, methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, ethyl phenylacetate, 2-phenylethyl acetate, and a mixture thereof.