Block copolymers for directed self-assembly applications

Patent metadata

Field	Value
Publication number	US-9879152-B2
Application number	US-201514919070-A
Country	US
Kind code	B2
Filing date	Oct 21, 2015
Priority date	Oct 21, 2015
Publication date	Jan 30, 2018
Grant date	Jan 30, 2018

Abstract

Block copolymers (BCPs) for self-assembly applications comprise a linear fluorinated linking group L′ joining a pair of adjacent blocks. A film layer comprising a BCP, which is disposed on an underlayer and in contact with an atmosphere, is capable of forming a perpendicularly oriented domain pattern when the underlayer is preferentially wetted by one domain of an otherwise identical self-assembled BCP in which all fluorines of L′ are replaced by hydrogen. The BCP can be a low-chi or high-chi BCP. In a preferred embodiment, the BCP comprises a styrene-based first block, and a second block comprises a carbonate and/or ester repeat unit formed by ring opening polymerization of a cyclic carbonate and/or cyclic ester monomer. The linking group L′ has a lower surface energy than each of the polymer blocks.

First claim

What is claimed is:

1. A block copolymer, comprising:
a first polymer block (block A), wherein block A comprises an ethylenic repeat unit of formula (A-1):

wherein i) backbone carbons of the block copolymer are numbered 1 and 2 in (A-1), ii) R w is a monovalent radical selected from the group consisting of H, F, methyl, ethyl, and trifluoromethyl (*—CF 3 ), and iii) R d is a monovalent radical comprising an aromatic ring linked to carbon 1;
a second polymer block (block B) having a chemical structure different from block A and capable of phase-segregating from block A; and
a divalent linking group L′ covalently linking an end repeat unit of block A to an end repeat unit of block B, wherein L′ comprises 1-24 fluorines, wherein each of the fluorines of L′ is linked to a backbone carbon of the block copolymer.

2. The block copolymer of claim 1 , wherein a film layer comprising the block copolymer is capable of self-assembling spontaneously and/or when thermally treated, thereby forming a pattern of phase-segregated alternating domains comprising respective chemically distinct blocks of the block copolymer.

3. The block copolymer of claim 1 , wherein R w is H.

4. The block copolymer of claim 1 , wherein L′ has a lower surface energy than block A and a lower surface energy than block B.

5. The block polymer of claim 1 , wherein L′ has a surface energy between 0 and 30 mN/m.

6. The block polymer of claim 1 , wherein L′ comprises a fluorinated alkylene group of formula (C-1):

wherein
backbone carbons of the block copolymer are numbered 1, 2, and 3 in (C-1),
each carbon linked to a fluorine is a backbone carbon of the block copolymer,
n′ is an integer having a value of 2-12,
m′ is an integer having a value of 1-5, and
k′ is an integer having a value of 1-5.

7. The block copolymer of claim 1 , wherein L′ comprises a divalent linear fluorinated ethylene oxide group in accordance with formula (C-2):

wherein
backbone atoms of the block copolymer are numbered 1, 2, 3, 4, 5, 6, 7, and 8 in (C-2)
each carbon linked to a fluorine is a backbone carbon of the block copolymer, and
n″ is an integer having a value of 1-5.

8. The block copolymer of claim 1 , wherein block B comprises an aliphatic carbonate repeat unit.

9. The block copolymer of claim 8 , wherein the aliphatic carbonate repeat unit comprises a pendent ester group.

10. The block copolymer of claim 9 , wherein the aliphatic carbonate repeat unit has a structure according to formula (B-4):

wherein R g is a monovalent hydrocarbyl group comprising 1-20 carbons.

11. The block copolymer of claim 10 , wherein R g is selected from the group consisting of methyl, ethyl, propyl, butyl, pentyl, hexyl, and benzyl.

12. The block copolymer of claim 1 , wherein the block B comprises an aliphatic ester repeat unit.

13. The block copolymer of claim 12 , wherein the aliphatic ester repeat unit has a structure selected from the group consisting of

wherein j′ is an integer having a value of 0-4, and

14. The block copolymer of claim 1 , wherein block B comprises an aliphatic ether repeat unit.

15. The block copolymer of claim 14 , wherein the aliphatic ether repeat unit is selected from the group consisting of ethylene oxide, propylene oxide, ring opened glycidyl ethers, and combinations thereof.

16. The block copolymer of claim 1 , wherein block A comprises an ethylenic repeat unit selected from the group consisting of

and combinations thereof.

17. The block copolymer of claim 1 , wherein block B is a homopolymer comprising a repeat unit selected from the group consisting of

18. A composition, comprising:
a solvent; and
the block copolymer of claim 1 ;

wherein
the composition is capable of forming a film layer comprising the block copolymer, wherein the film layer is capable of self-assembling spontaneously and/or when thermally treated, thereby forming a pattern of phase-segregated alternating domains comprising respective chemically distinct blocks of the block copolymer.

19. A method, comprising:
providing a substrate which is a first layered structure comprising a top layer (underlayer);
forming a film layer comprising the block copolymer of claim 1 disposed on the underlayer, wherein the film layer has a top surface in contact with an atmosphere interface; and
allowing or inducing the block copolymer of the film layer to self-assemble using a thermal treatment, thereby forming a second layered structure comprising a phase-segregated domain pattern having a characteristic pitch (Lo), the domain pattern comprising perpendicularly oriented alternating domains comprising respective chemically distinct blocks of the block copolymer.

20. The method of claim 19 , wherein the domain pattern comprises lamellar domains.

21. The method of claim 19 , wherein the domain pattern comprises cylindrical domains.

22. The method of claim 19 , wherein the characteristic pitch (Lo) is about 4 nm to about 80 nm.

23. The method of claim 19 , wherein the underlayer is preferentially wetted by one of the domains of an otherwise identical self-assembled block copolymer in which all fluorines of L′ are replaced by hydrogen.

24. The method of claim 19 , wherein the atmosphere interface is preferentially wetted by one of the domains of an otherwise identical self-assembled block copolymer in which all fluorines of L′ are replaced by hydrogen.

25. The method of claim 19 , comprising selectively etching one of the domains, thereby forming a third layered structure comprising an etched domain pattern comprising one or more remaining domains of the self-assembled block copolymer.

26. The method of claim 25 , comprising transferring the etched domain pattern to the substrate.

27. The method of claim 26 , wherein said transferring the etched domain pattern to the substrate is performed using a tone inversion process with respect to the etched domain pattern.

28. The method of claim 19 , wherein said inducing the block copolymer of the film layer to self-assemble using a thermal treatment comprises baking the film layer at a temperature between about 80° C. and about 250° C. for between about 1 second and about 24 hours.

29. The method of claim 19 , wherein the method comprises forming a topographic resist pattern disposed on the underlayer before said disposing the composition of claim 15 , wherein the film layer comprising the block copolymer for self-assembly is substantially confined to recessed regions of the topographic resist pattern.

Assignees

• IBM

Inventors

• Arellano Noel
• Cheng Joy
• Magbitang Teddie P
• Pitera Jed W
• Sanders Daniel P
• Schmidt Kristin
• Truong Hoa D
• Vora Ankit

Classifications

• C08J2467/04

  Polyesters derived from hydroxy carboxylic acids, e.g. lactones (C08J2467/06 takes precedence) · CPC title

• C08J2469/00

  Characterised by the use of polycarbonates; Derivatives of polycarbonates · CPC title

• C08G64/18

  Block or graft polymers · CPC title

• C08J2333/12

  Homopolymers or copolymers of methyl methacrylate · CPC title

• C08F212/08

  Styrene · CPC title