Composition and pattern-forming method

1. A composition comprising:

a block copolymer comprising:

a polystyrene block comprising a styrene unit; and

a polyalkyl (meth)acrylate block comprising an alkyl (meth)acrylate unit; and

a solvent,

the block copolymer comprising an organic group that is bound to at least one end of a main chain of the block copolymer and that comprises a hetero atom,

wherein the organic group included in the block copolymer comprises a phosphorus atom, a tin atom, or a combination thereof, or is represented by formula (1):

wherein, in the formula (1), R 1 represents a divalent organic group having 1 to 30 carbon atoms; and R 2 represents a hydrogen atom, an aliphatic linear hydrocarbon group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 30 carbon atoms, or a group in which the aliphatic linear hydrocarbon group having 1 to 30 carbon atoms or the alicyclic hydrocarbon group having 3 to 30 carbon atoms comprises a hetero atom between adjacent two carbon atoms, and

wherein condition (a), condition (b), or both is satisfied:

(a) the group represented by the formula (1) is directly connected to the polystyrene block or the polyalkyl (meth)acrylate block;

(b) R 1 represents a group in which at least one group selected from the group consisting of —CO, —COO, and —OCO is inserted between two carbon atoms of a divalent hydrocarbon group having 2 to 30 carbon atoms.

2. The composition of claim 1 , wherein the block copolymer is a diblock copolymer or a triblock copolymer.

3. The composition of claim 1 , wherein the block copolymer is a diblock copolymer.

4. The composition of claim 1 , wherein the organic group is bound to an end of the main chain of the polyalkyl (meth)acrylate block.

5. The composition of claim 1 , wherein the block copolymer is a diblock copolymer and the organic group is bound to an end of the main chain of the polyalkyl (meth)acrylate block.

6. The composition of claim 1 , wherein the alkyl (meth)acrylate unit is a methyl methacrylate unit.

7. The composition of claim 1 , wherein a molar ratio of styrene units to alkyl (meth)acrylate units in the block copolymer is no less than 10/90 and no greater than 90/10.

8. The composition of claim 1 , wherein the organic group included in the block copolymer is derived from an epoxy compound.

9. The composition of claim 1 , wherein the condition (b) is satisfied and the divalent hydrocarbon group having 2 to 30 carbon atoms is an aliphatic linear hydrocarbon group having 2 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 30 carbon atoms, or an aromatic hydrocarbon group having 6 to 30 carbon atoms.

10. The composition of claim 1 , wherein the organic group included in the block copolymer is represented by the formula (1).

11. The composition of claim 1 , further comprising a surfactant.

12. A pattern-forming method comprising:

providing a directed self-assembling film having a phase separation structure on a substrate using the composition according to claim 1 ; and

removing a part of phases of the directed self-assembling film.

13. The pattern-forming method according to claim 12 ,

wherein the method further comprises before providing the directed self-assembling film:

providing an underlayer film on the substrate; and

forming a prepattern on the underlayer film,

wherein the directed self-assembling film is provided in a region compartmentalized by the prepattern on the underlayer film, and

wherein the method further comprises after providing the directed self-assembling film,

removing the prepattern.

14. The pattern-forming method according to claim 12 , wherein

the pattern obtained is a line-and-space pattern or a hole pattern.

15. The pattern-forming method according to claim 12 , wherein the block copolymer is a diblock copolymer.

16. The pattern-forming method according to claim 12 , wherein the organic group is bound to an end of the main chain of the polyalkyl (meth)acrylate block.

17. The pattern-forming method according to claim 12 , wherein the block copolymer is a diblock copolymer and the organic group is bound to an end of the main chain of the polyalkyl (meth)acrylate block.

18. The pattern-forming method according to claim 12 , wherein the alkyl (meth)acrylate unit is a methyl methacrylate unit.

19. The pattern-forming method according to claim 12 , wherein a molar ratio of styrene units to alkyl (meth)acrylate units in the block copolymer is no less than 10/90 and no greater than 90/10.

20. The pattern-forming method according to claim 12 , wherein the organic group included in the block copolymer is derived from an epoxy compound.