Resist underlayer film-forming composition, pattern-forming method and resist underlayer film

1. A pattern-forming method comprising:

providing a resist underlayer film on a substrate using a resist underlayer film-forming composition, the resist underlayer film-forming composition comprising a polymer having a glass transition temperature (Tg) of 0 to 180° C.;

providing a silicon-containing oxide film on a surface of the resist underlayer film;

subjecting the silicon-containing oxide film to wet etching; and

subjecting the substrate to dry etching using the resist underlayer film as a mask, after the silicon-containing oxide film is subjected to wet etching.

2. The pattern-forming method according to claim 1 , further comprising:

applying a resist composition to the silicon-containing oxide film to form a resist pattern, after providing the silicon-containing oxide film and before subjecting the silicon-containing oxide film to wet etching; and

sequentially subjecting the silicon-containing oxide film and the resist underlayer film to dry etching using the resist pattern as a mask, after providing the silicon-containing oxide film and before subjecting the silicon-containing oxide film to wet etching.

3. The pattern-forming method according to claim 1 , wherein the resist underlayer film has a static contact angle with water of 70° or more.

4. The pattern-forming method according to claim 1 , wherein the polymer comprises a first structural unit represented by formula (1),

wherein

R 1 is a hydrogen atom, a fluorine atom, or a methyl group, wherein some or all of the hydrogen atoms of the methyl group represented by R 1 are substituted with a substituent, or unsubstituted,

E is an oxygen atom, —CO—O—*, or —CO—NH—*, wherein * is a bonding site to which R 2 is bonded, and

R 2 is a monovalent hydrocarbon group, wherein some or all of the hydrogen atoms of the hydrocarbon group represented by R 2 are substituted with a substituent, or unsubstituted.

5. The pattern-forming method according to claim 1 , wherein the polymer comprises a second structural unit represented by formula (2),

wherein

R 3 is a hydrogen atom, a fluorine atom, or a methyl group, wherein some or all of the hydrogen atoms of the methyl group represented R 3 are substituted with a substituent, or unsubstituted,

R 4 is a single bond or a chain hydrocarbon group having 1 to 4 carbon atoms, and

Ar is a monovalent aromatic hydrocarbon group, wherein some or all of the hydrogen atoms of the aromatic hydrocarbon group represented by Ar are substituted with a substituent, or unsubstituted.

6. The pattern-forming method according to claim 1 , wherein the polymer comprises a third structural unit, the third structural unit including a —CH 2 OH group and an aromatic group.

7. The pattern-forming method according to claim 1 , wherein the polymer comprises a fourth structural unit represented by formula (3),

wherein

Ar 2 is an aromatic group having a valency of (m11+m12+1),

R 10 is a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkoxycarbonyl group having 2 to 10 carbon atoms, an aryl group having 6 to 14 carbon atoms, a glycidyl ether group, an alkyl glycidyl ether group in which an alkyl moiety has 1 to 6 carbon atoms, or —OR in which R is a labile functional group, wherein some or all of the hydrogen atoms of the alkyl group, the alkoxy group, the alkoxycarbonyl group, the aryl group, the glycidyl ether group, and the alkyl glycidyl ether group represented by R 10 are substituted with a substituent, or unsubstituted,

Z 0 is a single bond, a methylene group, an alkylene group having 2 to 20 carbon atoms, an arylene group having 6 to 14 carbon atoms, or an alkylene ether group, wherein some or all of the hydrogen atoms of the methylene group, the alkylene group, the arylene group, and the alkylene ether group represented by Z 0 are substituted with a substituent, or unsubstituted,

* is a bonding site,

m11 is an integer from 1 to 6 that indicates the number of Z 0 bonded to Ar 2 , and

m12 is an integer from 1 to 6 that indicates the number of R 10 bonded to Ar 2 , wherein a plurality of Z 0 are each either identical or different in a case where m11 is an integer from 2 to 6, and a plurality of R 10 are each either identical or different in a case where m12 is an integer from 2 to 6.

8. The pattern-forming method according to claim 4 , wherein the polymer further comprises a second structural unit represented by formula (2),

wherein

R 3 is a hydrogen atom, a fluorine atom, or a methyl group, wherein some or all of the hydrogen atoms of the methyl group represented R 3 are substituted with a substituent, or unsubstituted,

R 4 is a single bond or a chain hydrocarbon group having 1 to 4 carbon atoms, and

Ar is a monovalent aromatic hydrocarbon group, wherein some or all of the hydrogen atoms of the aromatic hydrocarbon group represented by Ar are substituted with a substituent, or unsubstituted.

9. The pattern-forming method according to claim 4 , wherein the polymer further comprises a third structural unit, the third structural unit including a —CH 2 OH group and an aromatic group.

10. The pattern-forming method according to claim 5 , wherein the polymer further comprises a third structural unit, the third structural unit including a —CH 2 OH group and an aromatic group.

11. The pattern-forming method according to claim 8 , wherein the polymer further comprises a third structural unit, the third structural unit including a —CH 2 OH group and an aromatic group.

12. The pattern-forming method according to claim 1 , wherein the polymer has the glass transition temperature (Tg) of 160° C. or less.

13. The pattern-forming method according to claim 1 , wherein the polymer has the glass transition temperature (Tg) of 40° C. or more.

14. The pattern-forming method according to claim 4 , wherein a content of the first structural unit in the polymer is 1 to 50 mol %.

15. The pattern-forming method according to claim 5 , wherein a content of the second structural unit in the polymer is 1 to 80 mol %.

16. The pattern-forming method according to claim 6 , wherein a content of the third structural unit in the polymer is 1 to 50 mol %.