Composition for forming liquid immersion upper layer film, resist pattern-forming method, polymer, and compound

1. A composition for forming a liquid immersion upper layer film, comprising:

a polymer component comprising:

a first polymer comprising a first structural unit represented by formula (1); and

a second polymer comprising a second structural unit that comprises a fluorinated alkyl group or a fluorinated cycloalkyl group, the second polymer being identical to or different from the first polymer; and

a solvent,

wherein, in the formula (1),

R 1 represents a carboxy group or a group represented by formula (2);

X represents a single bond, a divalent hydrocarbon group having 1 to 20 carbon atoms or a divalent fluorinated hydrocarbon group having 1 to 20 carbon atoms;

R 2 represents a hydrocarbon group having 1 to 20 carbon atoms and having a valency of (n+1), a fluorinated hydrocarbon group having 1 to 20 carbon atoms and having a valency of (n+1), a hydrocarbon group having 1 to 20 carbon atoms and having a valency of (n+1) that includes between adjacent two carbon atoms thereof —CO—, —COO—, —O—, —NR′—, —CS—, —S—, —SO—, —SO 2 — or a combination thereof, or a fluorinated hydrocarbon group having 1 to 20 carbon atoms and having a valency of (n+1) that includes between adjacent two carbon atoms thereof —CO—, —COO—, —O—, —NR′—, —CS—, —S—, —SO—, —SO 2 — or a combination thereof; R′ represents a monovalent hydrocarbon group having 1 to 10 carbon atoms; n is an integer of 1 to 4; and

R 3 represents a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms,

wherein, in the formula (2),

R 4 represents a hydrogen atom, a halogen atom, a nitro group, an alkyl group, a monovalent alicyclic hydrocarbon group, an alkoxy group, an acyl group, an aralkyl group or an aryl group, wherein a part or all of hydrogen atoms included in the alkyl group, the alicyclic hydrocarbon group, the alkoxy group, the acyl group, the aralkyl group and the aryl group represented by R 4 are not substituted or substituted;

R 5 represents —C(═O) —R 6 , —S(═O) 2 —R 7 , —R 8 —CN or —R 9 —NO 2 ;

R 6 represents a hydrogen atom, an alkyl group, a fluorinated alkyl group, a monovalent alicyclic hydrocarbon group, an alkoxy group, a cyano group, a cyanomethyl group, an aralkyl group or an aryl group, or R 4 and R 6 taken together represent a ring structure;

R 7 represents a hydrogen atom, an alkyl group, a fluorinated alkyl group, a monovalent alicyclic hydrocarbon group, an alkoxy group, a cyano group, a cyanomethyl group, an aralkyl group or an aryl group, or R 4 and R 7 taken together represent a ring structure; and

R 8 and R 9 each independently represent a single bond, a methylene group or an alkylene group having 2 to 5 carbon atoms.

2. The composition according to claim 1 , wherein the polymer component further comprises a third structural unit that comprises a sulfo group, the third structural unit being included in a third polymer which is identical to or different from the first polymer and which is identical to or different from the second polymer.

3. The composition according to claim 2 , wherein the polymer component further comprises a fourth structural unit which comprises a group represented by formula (5), a group represented by formula (6) or a combination thereof, the fourth structural unit being included in a fourth polymer which is identical to or different from the first polymer, which is identical to or different from the second polymer, and which is identical to or different from the third polymer,

wherein, in the formula (5), R 10 represents a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms; and

in the formula (6), R 11 represents a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms; and R 12 represents a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms.

4. The composition according to claim 1 , wherein the polymer component further comprises a fourth structural unit which comprises a group represented by formula (5), a group represented by formula (6) or a combination thereof, the fourth structural unit being included in a fourth polymer which is identical to or different from the first polymer and which is identical to or different from the second polymer,

wherein, in the formula (5), R 10 represents a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms; and

in the formula (6), R 11 represents a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms; and R 12 represents a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms.

5. The composition for forming a liquid immersion upper layer film according to claim 1 , wherein the solvent comprises an ether solvent.

6. A resist pattern-forming method comprising:

providing a resist film using a photoresist composition;

providing a liquid immersion upper layer film on the resist film using an upper layer film composition;

exposing the resist film having the liquid immersion upper layer film provided thereon to an exposure light through a liquid immersion medium; and

developing the resist film

wherein the upper layer film composition comprises:

a polymer component comprising a first polymer which comprises a first structural unit represented by formula (1); and

a solvent,

wherein, in the formula (1),

R 1 represents a carboxy group or a group represented by formula (2);

X represents a single bond, a divalent hydrocarbon group having 1 to 20 carbon atoms or a divalent fluorinated hydrocarbon group having 1 to 20 carbon atoms;

R 2 represents a hydrocarbon group having 1 to 20 carbon atoms and having a valency of (n+1), a fluorinated hydrocarbon group having 1 to 20 carbon atoms and having a valency of (n+1), a hydrocarbon group having 1 to 20 carbon atoms and having a valency of (n+1) that includes between adjacent two carbon atoms thereof —CO—, —COO—, —O—, —NR′—, —CS—, —S—, —SO—, —SO 2 — or a combination thereof, or a fluorinated hydrocarbon group having 1 to 20 carbon atoms and having a valency of (n+1) that includes between adjacent two carbon atoms thereof —CO—, —COO—, —O—, —NR′—, —CS—, —S—, —SO—, —SO 2 — or a combination thereof; R′ represents a monovalent hydrocarbon group having 1 to 10 carbon atoms; n is an integer of 1 to 4; and

R 3 represents a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms

wherein, in the formula (2),

R 4 represents a hydrogen atom, a halogen atom, a nitro group, an alkyl group, a monovalent alicyclic hydrocarbon group, an alkoxy group, an acyl group, an aralkyl group or an aryl group, wherein a part or all of hydrogen atoms included in the alkyl group, the alicyclic hydrocarbon group, the alkoxy group, the acyl group, the aralkyl group and the aryl group represented by R 4 are not substituted or substituted;

R 5 represents —C(═O) —R 6 , —S(═O) 2 —R 7 , —R 8 —CN or —R 9 —NO 2 ;

R 6 represents a hydrogen atom, an alkyl group, a fluorinated alkyl group, a monovalent alicyclic hydrocarbon group, an alkoxy group, a cyano group, a cyanomethyl group, an aralkyl group or an aryl group, or R 4 and R 6 taken together represent a ring structure;

R 7 represents a hydrogen atom, an alkyl group, a fluorinated alkyl group, a monovalent alicclic h drocarbon group, an alkoxy group,a cyano group, a cyanomethyl group, an aralkyl group or an aryl group, or R 4 and R 7 taken together represent a ring structure; and

R 8 and R 9 each independently represent a single bond, a methylene group or an alkylene group having 2 to 5 carbon atoms.

7. The resist pattern-forming method according to claim 6 , wherein the polymer component further comprises a second structural unit that comprises a fluorinated alkyl group or a fluorinated cycloalkyl group, the second structural unit being included in a second polymer which is identical to or different from the first polymer.

8. The resist pattern-forming method according to claim 6 , wherein the polymer component further comprises a third structural unit that comprises a sulfo group, the third structural unit being included in a third polymer which is identical to or different from the first polymer.

9. The resist pattern-forming method according to claim 6 , wherein the polymer component further comprises a fourth structural unit which comprises a group represented by formula (5), a group represented by formula (6) or a combination thereof, the fourth structural unit being included in a fourth polymer which is identical to or different from the first polymer,

wherein, in the formula (5), R 10 represents a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms; and

in the formula (6), R 11 represents a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms; and R 12 represents a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms.

10. A polymer comprising:

a first structural unit represented by formula (1); and

a second structural unit that comprises a fluorinated alkyl group or a fluorinated cycloalkyl group:

wherein, in the formula (1),

R 1 represents a carboxy group or a group represented by formula (2);

X represents a single bond, a divalent hydrocarbon group having 1 to 20 carbon atoms or a divalent fluorinated hydrocarbon group having 1 to 20 carbon atoms;

R 2 represents a hydrocarbon group having 1 to 20 carbon atoms and having a valency of (n+1), a fluorinated hydrocarbon group having 1 to 20 carbon atoms and having a valency of (n+1), a hydrocarbon group having 1 to 20 carbon atoms and having a valency of (n+1) that includes between adjacent two carbon atoms thereof —CO—, —COO—, —O—, —NR′—, —CS—, —S—, —SO—, —SO 2 — or a combination thereof, or a fluorinated hydrocarbon group having 1 to 20 carbon atoms and having a valency of (n+1) that includes between adjacent two carbon atoms thereof —CO—, —COO—, —O—, —NR′—, —CS—, —S—, —SO—, —SO 2 —or a combination thereof; R′ represents a monovalent hydrocarbon group having 1 to 10 carbon atoms; and n is an integer of 1 to 4; and

R 3 represents a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms,

wherein, in the formula (2),

R 4 represents a hydrogen atom, a halogen atom, a nitro group, an alkyl group, a monovalent alicyclic hydrocarbon group, an alkoxy group, an acyl group, an aralkyl group or an aryl group, wherein a part or all of hydrogen atoms included in the alkyl group, the alicyclic hydrocarbon group, the alkoxy group, the acyl group, the aralkyl group and the aryl group represented by R 4 are not substituted or substituted;

R 5 represents —C(═O) —R 6 , —S(═O) 2 —R 7 , —R 8 —CN or —R 9 —NO 2 ;

R 6 represents a hydrogen atom, an alkyl group, a fluorinated alkyl group, a monovalent alicyclic hydrocarbon group, an alkoxy group, a cyano group, a cyanomethyl group, an aralkyl group or an aryl group, or R 4 and R 6 taken together represent a ring structure;

R 7 represents a hydrogen atom, an alkyl group, a fluorinated alkyl group, a monovalent alicyclic hydrocarbon group, an alkoxy group, a cyano group, a cyanomethyl group, an aralkyl group or an aryl group, or R 4 and R 7 taken together represent a ring structure; and

R 8 and R 9 each independently represent a single bond, a methylene group or an alkylene group having 2 to 5 carbon atoms.