Multi-step bake apparatus and method for directed self-assembly lithography control

• US 9,136,110 B2
• Filed: 03/10/2014
• Issued: 09/15/2015
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Rathsack, Benjamen M.
• Primary Examiner(s): TRINH, MICHAEL MANH
• Application Number:
  US14/202,642
• Publication Number:
  US 20140273522A1
• Time in Patent Office: 554 Days
• Field of Search: 438/725, 438/781, 438/947, 427/379, 427/377
• US Class Current: 1/1
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: G03F 7/0002 Lithographic processes using patterning methods other than those involving the exposure to radiation, e.g. by stamping
• CPC Class Codes: G03F 7/40 Treatment after imagewise removal, e.g. baking
• CPC Class Codes: H01L 21/02269 deposition by thermal evaporation H01L21/02293 takes precedence
• CPC Class Codes: H01L 21/0271 comprising organic layers
• CPC Class Codes: H01L 21/0337 characterised by the process involved to create the mask, e.g. lift-off masks, sidewalls, or to modify the mask, e.g. pre-treatment, post-treatment

Abstract

A method of forming a patterned substrate includes casting a layer of a block copolymer having an intrinsic glass transition temperature T_g, on a substrate to form a layered substrate. The method also includes heating the layered substrate at an annealing temperature, which is greater than about 50° C. above the intrinsic glass transition temperature T_g of the block copolymer, in a first atmosphere. The method further includes thermally quenching the layered substrate to a quenching temperature lower than the intrinsic glass transition temperature T_g, at a rate of greater than about 50° C./minute in a second atmosphere. The method further includes controlling an oxygen content in the first and second atmospheres to a level equal to or less than about 8 ppm to maintain the annealing and quenching temperatures below a thermal degradation temperature T_d of the block copolymer.

Claims

1. A method of forming a patterned substrate, comprising:

casting a layer of a block copolymer on a substrate to form a layered substrate, wherein the block copolymer is polystyrene-b-polydimethylsiloxane, polystyrene-b- poly(ferrocenyldimethylsilane), or poly(2-vinylpyridine)-b-polydimethylsiloxane, and wherein the block copolymer has an intrinsic glass transition temperature T_g;

heating the layered substrate at an annealing temperature in a first atmosphere for a first time period, wherein the annealing temperature is greater than about 50°

C. above the intrinsic glass transition temperature T_g of the block copolymer;

thermally quenching the layered substrate to a quenching temperature at a rate of greater than about 50°

C/minute in a second atmosphere, wherein the quenching temperature is lower than the intrinsic glass transition temperature T_g; and

controlling an oxygen content in the first and second atmospheres to a level equal to or less than about 8 ppm to maintain the annealing temperature and the quenching temperature below a thermal degradation temperature T_d of the block copolymer.

2. The method of claim 1, wherein thermally quenching comprises:

reducing a pressure of the second atmosphere;

flowing a convective gas around the layered substrate;

contacting the layered substrate with a wafer chuck configured in fluid communication with a chiller unit;

contacting the layered substrate with cooling arms;

or

combinations thereof.

3. The method of claim 2, wherein the thermally quenching comprises flowing a convective gas comprising nitrogen.

4. The method of claim 1, wherein the thermally quenching lowers a temperature of the layered substrate from the annealing temperature to the quenching temperature over a duration of time equal to or less than about 5 minutes.

5. The method of claim 1, wherein the oxygen content is less than about 5 ppm of oxygen.

6. The method of claim 1, wherein the first atmosphere is defined by a heating chamber and the second atmosphere is defined by a cooling chamber, the method further comprising:

transferring the layered substrate to the heating chamber prior to heating the layered substrate at the annealing temperature; and

transferring the layered substrate to the cooling chamber prior to thermally quenching.

7. The method of claim 6, wherein the cooling chamber comprises at least one of a wafer chuck configured in fluid communication with a chiller unit, a thermoelectric device, or a gas inlet in fluid communication with a convective gas supply.

8. The method of claim 6, wherein the cooling chamber comprises a cooling front opening unified pod.

9. The method of claim 1, wherein the casting of the layer of the block copolymer comprises:

applying a solution comprising the block copolymer and an organic solvent to the substrate to form a solvated layer of the block copolymer; and

performing a post-application bake to reduce an amount of the organic solvent in the solvated layer prior to heating the layered substrate at the annealing temperature.

10. The method of claim 9, wherein performing the post-application bake is performed on a track.

11. The method of claim 9, further comprising transferring the layered substrate to a furnace prior to heating the layered substrate at the annealing temperature.

12. The method of claim 1, wherein the heating the layered substrate occurs on a track in an oven, the method further comprising:

transferring the layered substrate from the track to a cooling chamber prior to thermally quenching.

13. The method of claim 12, wherein the cooling chamber comprises at least one of a wafer chuck configured in fluid communication with a chiller unit, a nitrogen blanket, or cooling arm.

14. The method of claim 1, further comprising:

evacuating an environment surrounding the layered substrate to a pressure equal to or less than 100 torr prior to the heating the layered substrate at the annealing temperature; and

optionally introducing a processing gas having an oxygen content equal to or less than about 8 ppm to the environment surrounding the layered substrate to provide the first atmosphere, wherein the introducing the processing gas is performed after the evacuating and prior to the heating the layered substrate at the annealing temperature.

15. The method of claim 14, wherein the processing gas comprises an organic solvent in a gaseous phase to provide a partial pressure of the organic solvent in the first atmosphere at a level equal to or greater than about 100 torr thereby defining a solvent-rich environment.

16. The method of claim 15, further comprising:

maintaining the layered substrate at a temperature below the intrinsic glass transition temperature T_g after thermally quenching, while concurrently lowering the organic solvent content in the environment surrounding the layered substrate.

17. The method of claim 16, further comprising:

transferring the layered substrate to a post application bake plate; and

baking the layered substrate at the temperature below the intrinsic glass transition temperature T_g, wherein the baking removes an amount of the organic solvent from the layered substrate.

18. The method of claim 1, wherein the first time period is less than about four hours.

19. The method of claim 1, wherein the first time period is about one hour.

20. The method of claim 1, wherein the block copolymer is polystyrene-b-polydimethylsiloxane, and the annealing temperature is 340°

C.