High-chi block copolymers for interconnect structures by directed self-assembly

1. A method, comprising:

providing a substrate having a top surface comprising a topographic pre-pattern of discrete initial openings, the initial openings comprising respective sidewalls and bottom surfaces, the initial openings having a critical dimension CD Init ;

forming a film layer disposed within each of the initial openings, the film layer having a top surface in contact with an atmosphere, the film layer comprising a linear diblock copolymer (BCP) comprising a block A and a block B, wherein

i) block A comprises a styrene repeat unit (A-2a):

ii) block B is an aliphatic polycarbonate or an aliphatic polyester,

iii) block A and block B are covalently linked by respective end repeat units to a divalent linking group L′, wherein L′ is a single bond or a group comprising at least one carbon,

iv) the BCP is capable of self-assembling to form a phase-segregated domain pattern comprising alternating domains of respective chemically distinct blocks of the block copolymer, and

v) the sidewalls of the initial openings are preferentially wetted by block B;

allowing or inducing the BCP disposed in the initial openings to self-assemble, thereby forming the domain pattern within each of the initial openings, the domain pattern comprising: a) a central block B domain comprising block B which is centrally located within the initial openings and b) a peripheral block B domain comprising block B which is in contact with the sidewalls, wherein the central block B domain and the peripheral block B domain are separated by, and in contact with, a block A domain comprising block A, and wherein the domain pattern within the initial openings has a top surface in contact with the atmosphere; and

selectively removing the central block B domain without substantially removing the block A domain and without substantially removing the peripheral block B domain, thereby forming an etched domain pattern comprising second openings, the second openings centrally located within the initial openings and having sidewalls comprising the block A domain, the second openings having a critical dimension CD 2nd corresponding to CD Init and smaller than CD Init ;

wherein

the method is suitable for forming openings for conductive interconnects that contact two or more layers of a multi-layered structure.

2. The method of claim 1 , comprising transferring the etched domain pattern to the substrate, thereby forming the openings for the conductive interconnects.

3. The method of claim 1 , wherein the domain pattern has a bulk periodicity Lo, and CD Init is about 2Lo.

4. The method of claim 1 , wherein the bulk periodicity Lo has a value in the range of 4 nm to 100 nm.

5. The method of claim 1 , wherein the initial openings include circular openings having a diameter of length d′, and CD Init is d′.

6. The method of claim 1 , wherein the initial openings include bar-shaped openings having a long axis of length 1′, a short axis of length w′, and an aspect ratio of l′:w′ between 1:1 and 100:1, and wherein CD Init is w′.

7. The method of claim 1 , wherein the block copolymer is capable of forming a lamellar domain pattern.

8. The method of claim 1 , wherein block A is a homopolymer of styrene.

9. The method of claim 1 , wherein block B is a polycarbonate comprising the carbonate repeat unit (A-4):

10. The method of claim 9 , wherein block B is a homopolymer of the carbonate repeat unit (A-4).

11. The method of claim 1 , wherein block B is a polyester comprising the ester repeat unit (A-8):

12. The method of claim 11 , wherein block B is a homopolymer of the ester repeat unit (A-8).

13. The method of claim 1 , wherein block A comprises a 4-(trimethylsilyl)styrene (TMSS) repeat unit (A-3):

14. The method of claim 1 , wherein L′ comprises 1-25 fluorine atoms.

15. The method of claim 1 , wherein the block copolymer has a block A:block B volume ratio in the range of 45:55 to 55:45.

16. A method, comprising:

providing a substrate having a top surface comprising a topographic pre-pattern of discrete initial openings, the initial openings comprising respective sidewalls and bottom surfaces, the initial openings having a critical dimension CD Init ;

forming a film layer disposed within each of the initial openings, the film layer having a top surface in contact with an atmosphere, the film layer comprising a linear diblock copolymer (BCP) comprising a block A, a block B, and a divalent linking group L′, wherein

i) block A comprises a styrene repeat unit (A-2a):

ii) block B comprises a repeat unit selected from the group consisting of carbonate repeat unit (A-4):

and

ester repeat unit (A-8):

iii) L′ comprises at least one carbon and 1-25 fluorine atoms,

iv) block A and block B are covalently linked by respective end repeat units to L′,

v) the BCP is capable of self-assembling to form a phase-segregated domain pattern comprising alternating domains of respective chemically distinct blocks of the block copolymer, and

vi) the sidewalls of the initial openings are preferentially wetted by block B;

allowing or inducing the BCP disposed in the initial openings to self-assemble, thereby forming the domain pattern within each of the initial openings, the domain pattern comprising: a) a central block B domain comprising block B which is centrally located within the initial openings and b) a peripheral block B domain comprising block B which is in contact with the sidewalls, wherein the central block B domain and the peripheral block B domain are separated by, and in contact with, a block A domain comprising block A, and wherein the domain pattern within the initial openings has a top surface in contact with the atmosphere; and

selectively removing the central block B domain without substantially removing the block A domain and without substantially removing the peripheral block B domain, thereby forming an etched domain pattern comprising second openings, the second openings centrally located within the initial openings and having sidewalls comprising the block A domain, the second openings having a critical dimension CD 2nd corresponding to CD Init and smaller than CD Init ;

wherein

the method is suitable for forming openings for conductive interconnects that contact two or more layers of a multi-layered structure.

17. The method of claim 16 , comprising transferring the etched domain pattern to the substrate, thereby forming the openings for the conductive interconnects.

18. The method of claim 16 , wherein L′ comprises a fluorinated alkyl group of formula (A-9):

wherein

n′ is an integer having a value of 0-11, and

m′ is an integer having a value of 1-5.

19. The method of claim 16 , wherein L′ comprises a fluorinated alkylene group of formula (A-10):

wherein

n′ is an integer having a value of 1-12,

m′ is an integer having a value of 1-5, and

k′ is an integer having a value of 1-5.

20. The method of claim 16 , wherein L′ comprises a divalent linear fluorinated ethylene oxide group in accordance with formula (A-10):

wherein

n″ is an integer having a value of 1-5.

21. A method, comprising:

providing a substrate having a top surface comprising a topographic pre-pattern of discrete initial openings, the initial openings comprising respective sidewalls and bottom surfaces, the initial openings having a critical dimension CD Init ;

forming a film layer disposed within each of the initial openings, the film layer having a top surface in contact with an atmosphere, the film layer comprising a linear diblock copolymer (BCP) comprising a block A, a block B, and a divalent linking group L′, wherein

i) block A comprises an styrene repeat unit (A-2a):

and

ii) block B comprises a repeat unit selected from the group consisting of carbonate repeat unit (A-4):

and

ester repeat unit (A-8):

iii) L′ comprises at least one carbon and 1-25 fluorine atoms,

iv) block A and block B are covalently linked by respective end repeat units to L′,

v) the BCP is capable of self-assembling to form a phase-segregated domain pattern comprising alternating domains of respective chemically distinct blocks of the block copolymer, and

vi) the sidewalls of the initial openings are preferentially wetted by block A;

allowing or inducing the BCP disposed in the initial openings to self-assemble, thereby forming the domain pattern within each of the initial openings, the domain pattern comprising a central block B domain which is centrally located within the initial openings and a peripheral block A domain which is in contact with the sidewalls and the central block B domain, wherein the central block B domain and the peripheral block A domain have respective top surfaces in contact with the atmosphere; and

selectively removing the central block B domain without substantially removing the peripheral block A domain, thereby forming an etched domain pattern comprising second openings, the second openings centrally located within the initial openings and having sidewalls comprising the block A domain, the second openings having a critical dimension CD 2nd corresponding to CD Init and smaller than CD Init ;

wherein

the method is suitable for forming openings for conductive interconnects that contact two or more layers of a multi-layered structure.

22. The method of claim 21 , wherein block B comprises a repeat unit selected from the group consisting of carbonate repeat unit (A-4):

and

ester repeat unit (A-8):

23. The method of claim 21 , comprising transferring the etched domain pattern to the substrate, thereby forming the openings for the conductive interconnects.

24. The method of claim 21 , wherein the domain pattern has a bulk periodicity Lo, and CD Init is about 1Lo.

25. The method of claim 21 , wherein the initial openings include circular openings having a diameter of length d′, and CD Init is d′.

26. The method of claim 21 , wherein the initial openings include bar-shaped openings having a long axis of length 1′ and a short axis of length w′, wherein the bar-shaped openings have an aspect ratio of l′:w′ between 1:1 and 100:1, and CD Init is w′.

27. The method of claim 21 , wherein the substrate includes at least one of: a resist layer, a hardmask layer, and an antireflection layer (ARC).

28. The method of claim 21 , wherein L′ comprises 1-25 fluorine atoms.

29. A method, comprising:

providing a substrate having a top surface comprising a topographic pre-pattern of discrete initial openings, the initial openings comprising respective sidewalls and bottom surfaces, the initial openings having a critical dimension CD Init ;

forming a film layer disposed within each of the initial openings, the film layer having a top surface in contact with an atmosphere, the film layer comprising a linear block copolymer (BCP) comprising a block A and a block B, wherein

i) block A and block B are covalently linked by respective end repeat units to a divalent linking group L′, wherein L′ is a single bond or a group comprising at least one carbon,

ii) the BCP is capable of self-assembling to form a phase-segregated domain pattern comprising alternating domains of respective chemically distinct blocks of the block copolymer, and

iii) the sidewalls of the initial openings are preferentially wetted by block B;

allowing or inducing the BCP disposed in the initial openings to self-assemble, thereby forming the domain pattern within each of the initial openings, the domain pattern comprising: a) a central block B domain comprising block B which is centrally located within the initial openings and b) a peripheral block B domain comprising block B which is in contact with the sidewalls, wherein the central block B domain and the peripheral block B domain are separated by, and in contact with, a block A domain comprising block A, and wherein the domain pattern within the initial openings has a top surface in contact with the atmosphere; and

selectively removing the central block B domain without substantially removing the block A domain and without substantially removing the peripheral block B domain, thereby forming an etched domain pattern comprising second openings, the second openings centrally located within the initial openings and having sidewalls comprising the block A domain, the second openings having a critical dimension CD 2nd corresponding to CD Init and smaller than CD Init ;

wherein

the method is suitable for forming openings for conductive interconnects that contact two or more layers of a multi-layered structure.

30. The method of claim 29 , wherein the BCP is a diblock copolymer.

31. The method of claim 29 , wherein block A comprises a styrenic repeat unit.

32. The method of claim 29 , wherein block B is an aliphatic polycarbonate or an aliphatic polyester.