Fluorine-containing polymer, purification method, and radiation-sensitive resin composition
An object of the present invention is to provide a novel fluorine-containing polymer, a radiation-sensitive resin composition for liquid immersion lithography which contains the fluorine-containing polymer, which leads to a pattern having an excellent shape and excellent depth of focus, wherein the amount of an eluted component in a liquid for liquid immersion lithography such as water that comes in contact with the resist during exposure in liquid immersion lithography is little, and which provides a larger receding contact angle between the resist film and the liquid for liquid immersion lithography such as water, and a method for purifying the fluorine-containing polymer. The present resin composition comprises a novel fluorine-containing polymer (A) containing repeating units represented by the general formulae (1) and (2) and having Mw of 1,000-50,000, a resin (B) having an acid-unstable group, a radiation-sensitive acid generator (C), a nitrogen-containing compound (D) and a solvent (E).
1. A radiation-sensitive resin composition comprising:
a fluorine-containing polymer;
a resin comprising an acid-unstable group;
a first radiation-sensitive acid generator comprising a first cation and a first anion which comprises a partial structure represented by —SO 2 —N − —;
a second radiation-sensitive acid generator comprising a second cation and a second anion which comprises a partial structure represented by —SO 3 − ; and
a solvent,
wherein the fluorine-containing polymer comprises:
a first repeating unit represented by formula (1); and
a second repeating unit represented by formula (2);
wherein
R 1 represents a hydrogen atom, a methyl group or a trifluoromethyl group;
A represents a single bond, an oxygen atom, a sulfur atom, a carbonyloxy group, an oxycarbonyl group, an amide group, a sulfonylamide group, or a urethane group; and
R 2 represents a linear or branched alkyl group having 1 to 6 carbon atoms or a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, the linear or branched alkyl group and the monovalent alicyclic hydrocarbon group represented by R 2 comprising at least one fluorine atom, or a derivative thereof,
wherein
R 3 represents a hydrogen atom, a methyl group or a trifluoromethyl group; and
R 4 individually represents a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof, or a linear or branched alkyl group having 1 to 4 carbon atoms, and
wherein the fluorine-containing polymer has a weight average molecular weight determined by get permeation chromagraphy in a range from 1,000 to 9,100.
2. The radiation-sensitive resin composition according to claim 1 , wherein the first anion comprises a partial structure represented by R 18 —SO 2 —N − —, wherein R 18 represents a linear or branched alkyl group having fluorine atom and 1 to 10 carbon atoms.
3. The radiation-sensitive resin composition according to claim 1 , wherein the second anion is an anion represented by R 17 C n F 2n SO 3 − , an anion represented by R 17 SO 3 − , or both thereof, wherein R 17 represents a fluorine atom or a substituted or unsubstituted hydrocarbon group having 1 to 12 carbon atoms, and n is an integer of 1 to 10.
4. The radiation-sensitive resin composition according to claim 3 , wherein the second anion is represented by R 17 C n F 2n SO 3 − .
5. The radiation-sensitive resin composition according to claim 1 , further comprising a nitrogen-containing compound.
6. The radiation-sensitive resin composition according to claim 5 , wherein the nitrogen-containing compound comprises at least one of an amine compound, an amide group-containing compound, a urea compound, or a nitrogen-containing heterocyclic compound.
7. The radiation-sensitive resin composition according to claim 1 , wherein the resin comprises a repeating unit comprising a lactone structure.
8. The radiation-sensitive resin composition according to claim 1 , wherein the acid-unstable group of the resin comprises a monocyclic structure or a polycyclic structure.
9. The radiation-sensitive resin composition according to claim 1 , wherein a content of the fluorine-containing polymer is 0.1% or more by weight based on 100% by weight of the radiation-sensitive resin composition.
10. The radiation-sensitive resin composition according to claim 1 , wherein at least one of the first cation and the second cation is represented by formula (7-1),
wherein
R 14 represents a hydrogen atom, a fluorine atom, a hydroxyl group, a linear or branched alkyl group having 1 to 10 carbon atoms, a linear or branched alkoxyl group having 1 to 10 carbon atoms, or a linear or branched alkoxycarbonyl group having 2 to 11 carbon atoms;
R 15 represents a linear or branched alkyl group having 1 to 10 carbon atoms, an alkoxyl group, or a linear, branched or cyclic alkanesulfonyl group having 1 to 10 carbon atoms;
each R 16 individually represents a linear or branched alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted phenyl group, or a substituted or unsubstituted naphthyl group, or two R 16 s taken together represent a substituted or unsubstituted divalent group which has 2 to 10 carbon atoms;
k is an integer of 0 to 2; and
r is an integer of 0 to 10.
11. The radiation-sensitive resin composition according to claim 10 , wherein each R 16 individually represents a substituted or unsubstituted phenyl group or a substituted or unsubstituted naphthyl group.
12. The radiation-sensitive resin composition according to claim 1 , wherein a content of the fluorine-containing polymer in the radiation-sensitive resin composition is from 0.5% to 35% by weight based on 100% by weight of the radiation-sensitive resin composition.
13. The radiation-sensitive resin composition according to claim 1 , wherein an amount of the first and second radiation-sensitive acid generators is from 0.5 to 10 parts by weight based on 100 parts by weight of a total of the fluorine-containing polymer and the resin.