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 consisting of: at least one first repeating unit represented by formula (1); and at least one second repeating unit represented by formula (2);
an acid-unstable resin having an acid-unstable group, comprising a third repeating unit represented by formula (2);
a radiation-sensitive acid generator;
a nitrogen-containing compound; and
a solvent,
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, partially or fully fluorinated alkyl group having 1 to 6 carbon atoms or a monovalent partially or fully fluorinated alicyclic hydrocarbon group having 4 to 20 carbon atoms,
wherein:
R 3 represents a hydrogen atom, a methyl group or a trifluoromethyl group; and
each 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 optionally two of R 4 s taken together represent a divalent alicyclic hydrocarbon group or a derivative thereof together with the carbon atom to which the two of R 4 s bond,
wherein an amount of the third repeating unit in the acid-unstable resin is from 53.8 to 69.6 mol % with respect to an amount of all repeating units in the acid-unstable resin.
2. The radiation-sensitive resin composition according to claim 1 , wherein the acid-unstable resin further comprises a repeating unit comprising a lactone structure.
3. The radiation-sensitive resin composition according to claim 1 , wherein the radiation-sensitive acid generator comprises an onium ion, the onium ion comprising:
a cation; and
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, a cycloalkyl group, or a bridge alicyclic hydrocarbon group, the cycloalkyl group and the bridge alicyclic hydrocarbon group having no more than 12 carbon atoms and optionally being substituted, and n is an integer of 1 to 10.
4. The radiation-sensitive resin composition according to claim 3 , wherein the anion is represented by R 17 C n F 2n SO 3 − .
5. The radiation-sensitive resin composition according to claim 3 , wherein R 17 is the bridge alicyclic hydrocarbon group.
6. The radiation-sensitive resin composition according to claim 3 , wherein the anion is represented by R 17 C n F 2n SO 3 − , and R 17 is the bridge alicyclic hydrocarbon group.
7. The radiation-sensitive resin composition according to claim 3 , wherein the 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, or an alkoxyl group;
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 comprises 2 to 10 carbon atoms;
k is an integer of 0 to 2; and
r is an integer of 0 to 10.
8. The radiation-sensitive resin composition according to claim 7 , wherein R 16 individually represents a substituted or unsubstituted phenyl group or a substituted or unsubstituted naphthyl group.
9. The radiation-sensitive resin composition according to claim 1 , wherein an amount of the radiation-sensitive acid generator 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 acid-unstable resin.
10. The radiation-sensitive resin composition according to claim 1 , wherein a content of the fluorine-containing polymer in the radiation-sensitive resin composition is 0.1% or more by weight based on 100% by weight of the radiation-sensitive resin composition.
11. 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.
12. The radiation-sensitive resin composition according to claim 1 , wherein the fluorine-containing polymer has a weight average molecular weight determined by gel permeation chromatography in a range from 1,000 to 50,000.
13. The radiation-sensitive resin composition according to claim 1 , 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.
14. The radiation-sensitive resin composition according to claim 1 , wherein an amount of the radiation-sensitive acid generator is from 7 to 9.5 parts by weight based on 100 parts by weight of the acid-unstable resin.