Compound, polymer, and resin composition
A radiation-sensitive resin composition which has high transparency to radiation, excelling in basic properties as a resist such as sensitivity, resolution, and pattern shape, and, in particular, exhibiting high resolution performance, excellent DOF and LER, and high resistance to a liquid medium used in liquid immersion lithography is provided. Also provided are a polymer which can be used in the composition, a novel compound useful for synthesizing the polymer, and a method of producing the composition. A radiation-sensitive resin composition having an excellent resistance to a liquid medium can be obtained by using the novel compound shown by the following formula (1), wherein R 1 represents a methyl group or a hydrogen atom, R 2 , R 3 and R 4 individually represent a substituted or unsubstituted monovalent organic group having 1 to 10 carbon atoms, n is an integer from 0 to 3, A represents a methylene group, a linear or branched alkylene group having 2 to 10 carbon atoms, or an arylene group, and X − represents a counter ion of S + .
1. A polymer comprising a first repeating unit derived from a compound shown by the following formula (1),
wherein R 1 represents a methyl group or a hydrogen atom, R 2 individually represents a substituted or unsubstituted monovalent organic group having 1 to 10 carbon atoms, n is an integer from 0 to 3, R 3 and R 4 individually represent a substituted or unsubstituted monovalent aryl group, A represents a methylene group, a linear or branched alkylene group having 2 to 10 carbon atoms, or an arylene group, and X − represents a sulfonate ion, a BF 4− ion, a PF 6− ion, or a tetraarylboronium ion, and a second repeating unit having an acid-dissociable group, and
wherein the polymer has a polystyrene-reduced weight average molecular weight measured by gel permeation chromatography (GPC) of 1,000 to 100,000.
2. A polymer according to claim 1 , wherein the substituted or unsubstituted monovalent aryl group is a phenyl group.
3. A polymer according to claim 1 , wherein the X − is the sulfonate ion.
4. A radiation-sensitive resin composition comprising a resin containing an acid-dissociable group which is insoluble or scarcely-soluble in alkali and becomes readily-soluble in alkali by the action of an acid, wherein the resin containing an acid-dissociable group is the polymer according to claim 1 .
5. A radiation-sensitive resin composition for liquid immersion lithography used in a system or a method of liquid immersion lithography which comprises irradiation through a liquid between a lens and a photoresist film, wherein the radiation-sensitive resin composition is applied onto the photoresist film to form an upper layer film covering the photoresist film, and wherein the radiation-sensitive resin composition is the resin composition according to claim 4 .