Composition for pattern formation, and pattern-forming method
A composition for pattern formation includes a first polymer, a second polymer and a solvent. The first polymer includes: a first block including a first structural unit derived from a substituted or unsubstituted styrene; and a second block including a second structural unit other than the first structural unit. The second polymer includes: the first structural unit; and a group bonding to at least one end of a main chain thereof and including a polar group. The polar group is preferably a hydroxy group or a carboxyl group. A number average molecular weight of the second polymer is preferably no greater than 6,000. A mass ratio of the second polymer to the first polymer is preferably no less than 0.15 and no greater than 0.4. The solvent preferably comprises a compound comprising a hydroxyl group and an alkyl ester group.
1. A composition for pattern formation, consisting of:
a first polymer comprising: a first block comprising a first structural unit derived from a substituted or unsubstituted styrene; and a second block comprising a second structural unit derived from a (meth)acrylic acid ester;
a second polymer consisting of:
a main chain which is a homopolymer of a third structural unit derived from a substituted or unsubstituted styrene; and
a terminal group which bonds to at least one end of the main chain and which comprises a polar group;
a solvent comprising a compound which comprises: a secondary hydroxy group; and an alkyl ester group; and
optionally, a surfactant.
2. The composition according to claim 1 , wherein the polar group is a hydroxy group or a carboxyl group.
3. The composition according to claim 1 , wherein a number average molecular weight of the second polymer is no greater than 6,000.
4. The composition according to claim 1 , wherein a mass ratio of the second polymer to the first polymer is no less than 0.15 and no greater than 0.4.
5. The composition according to claim 1 , wherein a content of the compound in the solvent is no less than 20% by mass and no greater than 50% by mass.
6. A pattern-forming method comprising:
applying the composition according to claim 1 on at least an upper face side of a substrate directly or via other layer to form a coating film;
carrying out phase separation of the coating film such that a plurality of phases of the coating film are formed;
removing a part of the plurality of phases of the coating film after the phase separation such that a resist pattern of the coating film is formed; and
etching the substrate using directly or indirectly the resist pattern as a mask.
7. The pattern-forming method according to claim 6 , wherein a hole pattern is formed by the etching.
8. The composition according to claim 1 , wherein the compound included in the solvent comprises a lactic acid alkyl ester.
9. The composition according to claim 1 , wherein the terminal group included in the second polymer is represented by formula (1):
wherein in the above formula (1), R 1 represents a single bond or a divalent organic group having 1 to 30 carbon atoms; and R 2 represents a hydrogen atom or a monovalent organic group having 1 to 30 carbon atoms.
10. The composition according to claim 1 , wherein a mass ratio of the second polymer to the first polymer is from 0.05 to 0.5.
11. The composition according to claim 1 , wherein a mass ratio of the second polymer to the first polymer is from 0.2 to 0.3.
12. The pattern-forming method according to claim 6 , wherein the compound included in the solvent comprises a lactic acid alkyl ester.
13. The pattern-forming method according to claim 6 , wherein the terminal group included in the second polymer is represented by formula (1):
wherein in the above formula (1), R 1 represents a single bond or a divalent organic group having 1 to 30 carbon atoms; and R 2 represents a hydrogen atom or a monovalent organic group having 1 to 30 carbon atoms.
14. The pattern-forming method according to claim 8 , wherein a mass ratio of the second polymer to the first polymer is from 0.05 to 0.5.
15. The pattern-forming method according to claim 8 , wherein a mass ratio of the second polymer to the first polymer is from 0.2 to 0.3.
16. The composition according to claim 1 , wherein the first polymer has a weight average molecular weight of from 30,000 to 150,000, and the second polymer has a weight average molecular weight of from 1,000 to 6,000.
17. The pattern-forming method according to claim 6 , wherein the first polymer has a weight average molecular weight of from 30,000 to 150,000, and the second polymer has a weight average molecular weight of from 1,000 to 6,000.
18. The composition according to claim 16 , wherein the first polymer has a number average molecular weight of 75,000 or more, and a ratio of the weight average molecular weight to the number average molecular weight is from 1.0 to 1.2.
19. The pattern-forming method according to claim 17 , wherein the first polymer has a number average molecular weight of 75,000 or more, and a ratio of the weight average molecular weight to the number average molecular weight is from 1.0 to 1.2.