Liquid immersion lithography upper-layer film-forming composition and photoresist pattern-forming method
A liquid immersion lithography upper-layer film-forming composition includes (A) a polymer that includes a structural unit (I) shown by the following formula (1), and (S) a solvent. R 1 in the formula (1) represents a hydrogen atom, a methyl group, or a trifluoromethyl group. The polymer (A) preferably further includes a structural unit (II) that includes a sulfo group. The polymer (A) preferably further includes a structural unit (III) shown by the following formula (3). R 2 in the formula (3) represents a hydrogen atom, a methyl group, or a trifluoromethyl group. R 3 represents a linear or branched monovalent hydrocarbon group having 1 to 12 carbon atoms or a monovalent alicyclic group having 3 to 20 carbon atoms, provided that at least one hydrogen atom of the hydrocarbon group or the alicyclic group is substituted with a fluorine atom.
1. A photoresist pattern-forming method comprising:
applying a photoresist composition to a substrate to form a photoresist film;
applying a composition to the photoresist film to form a liquid immersion lithography upper-layer film;
exposing the photoresist film and the liquid immersion lithography upper-layer film via an immersion medium and a mask having a given pattern, the immersion medium being disposed between the liquid immersion lithography upper-layer film and a lens; and
developing the photoresist film and the liquid immersion lithography upper-layer film that have been exposed,
wherein the composition comprises:
(A) a polymer that comprises a structural unit (I) shown by formula (1), a structural unit (II) that comprises a sulfo group, and a structural unit (III) shown by formula (3)
(B) a polymer that comprises the structural unit (I) and a structural unit (III) shown by formula (3), and has a fluorine atom content higher than a fluorine atom content of the polymer (A); and
(S) a solvent,
wherein R 1 represents a hydrogen atom, a methyl group, or a trifluoromethyl group,
wherein R 2 represents a hydrogen atom, a methyl group, or a trifluoromethyl group, and R 3 represents a linear or branched monovalent hydrocarbon group having 1 to 12 carbon atoms or a monovalent alicyclic group having 3 to 20 carbon atoms, provided that at least one hydrogen atom of the hydrocarbon group or the alicyclic group is substituted with a fluorine atom.
2. The photoresist pattern-forming method according to claim 1 , wherein the polymer (A) further comprises a structural unit (IV) shown by formula (4),
wherein R 4 represents a hydrogen atom, a methyl group, or a trifluoromethyl group, and R 5 represents a linear or branched monovalent hydrocarbon group having 1 to 12 carbon atoms or a monovalent alicyclic group having 3 to 20 carbon atoms.
3. The photoresist pattern-forming method according to claim 1 , wherein the polymer (B) further comprises includes a structural unit (IV) shown by formula (4),
wherein R 4 represents a hydrogen atom, a methyl group, or a trifluoromethyl group, and R 5 represents a linear or branched monovalent hydrocarbon group having 1 to 12 carbon atoms or a monovalent alicyclic group having 3 to 20 carbon atoms.
4. The photoresist pattern-forming method according to claim 1 , wherein the structural unit (II) comprises a structural unit shown by formula (2-1), a structural unit shown by (2-2), or both,
wherein R 6 and R 7 individually represent a hydrogen atom, a methyl group, or a trifluoromethyl group, and R 8 and R 9 each individually represent a single bond, a linear or branched divalent hydrocarbon group having 1 to 6 carbon atoms, a divalent alicyclic group having 4 to 12 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 12 carbon atoms.
5. The photoresist pattern-forming method according to claim 1 , wherein a content of the structural unit (I) in the polymer (A) is 20 to 99 mol % based on a total of structural units included in the polymer (A).
6. The photoresist pattern-forming method according to claim 1 , wherein a content of the structural unit (II) in the polymer (A) is 1 to 20 mol % based on a total of structural units included in the polymer (A).
7. The photoresist pattern-forming method according to claim 1 , wherein a content of the structural unit (III) in the polymer (B) is 5 to 80 mol % based on a total of structural units included in the polymer (A).
8. The photoresist pattern-forming method according to claim 1 , wherein the polymer (A) further comprises a structural unit (V) which is shown by formula (5-1) or formula (5-2),
wherein R 10 and R 11 each represent a hydrogen atom, a methyl group, or a trifluoromethyl group, R 12 represents a single bond, a linear or branched alkanediyl group having 1 to 6 carbon atoms which is other than a 1,2-ethylene group, or a divalent alicyclic group having 4 to 12 carbon atoms, R 13 represents a single bond, a linear or branched alkanediyl group having 1 to 6 carbon atoms, or a divalent alicyclic group having 4 to 12 carbon atoms, and R 14 represents a linear or branched hydrocarbon group having 1 to 10 carbon atoms or a monovalent alicyclic group having 3 to 10 carbon atoms, provided that at least one hydrogen atom of the hydrocarbon group or the alicyclic group represented by R 14 is substituted with a fluorine atom.
9. The photoresist pattern-forming method according to claim 1 , wherein a content of the polymer (A) in the composition is 20 mass % or more based on a total of polymers included in the composition.
10. The photoresist pattern-forming method according to claim 1 , wherein a content of the polymer (A) in the composition is 40 mass % or more based on a total of polymers included in the composition.
11. The photoresist pattern-forming method according to claim 1 , wherein a content of the polymer (A) in the composition is 60 mass % or more based on a total of polymers included in the composition.
12. The photoresist pattern-forming method according to claim 1 , wherein the composition further comprises (C) a polymer that comprises a structural unit (V) which is shown by formula (5-1) or formula (5-2), and the structural unit (III), the polymer (C) having a fluorine atom content higher than a fluorine content of the polymer (A),
wherein R 10 and R 11 each represent a hydrogen atom, a methyl group, or a trifluoromethyl group, R 12 represents a single bond, a linear or branched alkanediyl group having 1 to 6 carbon atoms which is other than a 1,2-ethylene group, or a divalent alicyclic group having 4 to 12 carbon atoms, R 13 represents a single bond, a linear or branched alkanediyl group having 1 to 6 carbon atoms, or a divalent alicyclic group having 4 to 12 carbon atoms, and R 14 represents a linear or branched hydrocarbon group having 1 to 10 carbon atoms or a monovalent alicyclic group having 3 to 10 carbon atoms, provided that at least one hydrogen atom of the hydrocarbon group or the alicyclic group represented by R 14 is substituted with a fluorine atom.
13. The photoresist pattern-forming method according to claim 12 , wherein the polymer (C) further comprises a structural unit (IV) shown by formula (4),
wherein R 4 represents a hydrogen atom, a methyl group, or a trifluoromethyl group, and R 5 represents a linear or branched monovalent hydrocarbon group having 1 to 12 carbon atoms or a monovalent alicyclic group having 3 to 20 carbon atoms.