Methods of reducing defects in directed self-assembled structures

• US 9,159,558 B2
• Filed: 03/15/2013
• Issued: 10/13/2015
• Est. Priority Date: 03/15/2013
• Status: Expired due to Fees

• Current Assignee: Elpis Technologies Inc. (Wi-LAN Inc.)
• Original Assignee: International Business Machines Corporation
• Inventors: Cheng, Joy, Sanders, Daniel P., Tjio, Melia
• Primary Examiner(s): Mellott, James M
• Application Number:
  US13/840,880
• Publication Number:
  US 20140273476A1
• Time in Patent Office: 942 Days
• US Class Current: 1/1
• CPC Class Codes: B05D 1/32 using means for protecting parts of a surface not to be coated, e.g. using stencils, resists
• CPC Class Codes: B05D 1/38 with intermediate treatment intermediate treatment per se B05D3/00
• CPC Class Codes: B05D 3/107 Post-treatment of applied coatings
• CPC Class Codes: B81C 1/00031 Regular or irregular arrays of nanoscale structures, e.g. etch mask layer photomechanical, e.g. photolithographic, production of textured or patterned surfaces G03F7/00; lithographic processes for making patterned surfaces using printing and stamping G03F7/0002
• CPC Class Codes: B81C 2201/0149 Forming nanoscale microstructures using auto-arranging or self-assembling material
• 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 7/0035 Multiple processes, e.g. applying a further resist layer on an already in a previously step, processed pattern or textured surface
• CPC Class Codes: H01L 21/0273 characterised by the treatment of photoresist 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
• CPC Class Codes: H01L 21/31058 of organic layers

Abstract

Methods are disclosed for reducing the number of defects in a directed self-assembled structure formed on a guiding pre-pattern (e.g., a chemical pre-pattern) on a substrate. A first layer comprising a first self-assembly material is applied onto the guiding pre-pattern, with the first self-assembly material forming domains whose alignment and orientation are directed by the guiding pre-pattern; as a result, a first self-assembled structure is formed. The first self-assembled structure is washed away, and a second layer comprising a second self-assembly material is then applied. The second self-assembly material forms a second self-assembled structure having fewer defects than the first self-assembled structure.

Claims

1. A method of reducing the number of defects in a directed self-assembled structure formed on a guiding pre-pattern on a substrate, the method comprising:

(a) applying a first layer comprising a first self-assembly material onto the guiding pre-pattern, the first self-assembly material forming domains whose alignment and orientation are directed by the guiding pre-pattern, thereby creating a first self-assembled structure;

(b) optionally annealing the first self-assembled structure;

(c) directly following step (b), or if step (b) is not performed then directly following step (a);

washing away the first self-assembled structure, without removing the guiding pre-pattern; and

(d) after said washing, applying a second layer comprising a second self-assembly material over the substrate, wherein the second layer occupies space previously occupied by the first layer, the second self-assembly material forming a second self-assembled structure having fewer defects than the first self-assembled structure.

2. The method of claim 1, wherein no etch process is performed between (i) the step of applying the first layer and (ii) the step of applying the second layer.

3. The method of claim 1, comprising:

washing away the second self-assembled structure; and

after said washing away of the second self-assembled structure, applying a third layer comprising a third self-assembly material over the substrate, wherein the third layer occupies space previously occupied by the first layer, the third self-assembly material forming a third self-assembled structure having fewer defects than the second self-assembled structure.

4. The method of claim 1, comprising:

annealing the first layer, prior to said washing.

5. The method of claim 1, comprising:

after the step of washing but before the step of applying the second layer, baking the substrate, thereby removing any residual solvent.

6. The method of claim 1, comprising:

annealing the second layer.

7. The method of claim 1, wherein the first self-assembly material and the second self-assembly material are the same kind of material.

8. The method of claim 1, wherein the first material and the second material both include PS-b-PMMA.

9. The method of claim 1, wherein the thickness of the second layer is at least about 55 nm.

10. The method of claim 1, wherein the thickness of the second layer is greater than two times that of a characteristic pitch of the second self-assembled structure.

11. The method of claim 1, wherein the second self-assembled structure has a pitch that is less than 50 nm.

12. The method of claim 1, wherein the second self-assembled structure has a pitch that is no greater than about 25 nm.

13. The method of claim 1, wherein the method of claim 1 is part of an in-line process.

14. The method of claim 13, wherein the in-line process is a 300 mm wafer process.

15. The method of claim 1, wherein the thickness of the first layer is less than the thickness of the second layer.

16. The method of claim 1, wherein the pre-pattern is a chemical pre-pattern.

17. The method of claim 1, comprising etching the second self-assembled structure.

18. The method of claim 1, comprising:

annealing the first layer, prior to said washing; and

annealing the second layer.

19. The method of claim 18, wherein the second self-assembled structure has a pitch that is less than 50 nm.

20. The method of claim 19, comprising etching the second self-assembled structure.

21. The method of claim 1, wherein the second self-assembled structure has fewer dislocation defects than the first self-assembled structure.

22. The method of claim 1, wherein the second self-assembled structure has a dislocation defect density less than or equal to about 25 per square centimeter.

23. A method of reducing the number of defects in a directed self-assembled structure formed on a guiding pre-pattern on a substrate, the method comprising:

(a) applying a first layer comprising a first self-assembly material onto the guiding pre-pattern, the first self-assembly material forming domains whose alignment and orientation are directed by the guiding pre-pattern, thereby creating a first self-assembled structure;

(b) optionally annealing the first self-assembled structure;

(c) directly following step (b), or if step (b) is not performed then directly following step (a);

washing away the first self-assembled structure, and leaving behind a modified guiding pre-pattern; and

(d) after said washing, applying a second layer comprising a second self-assembly material onto the modified guiding pre-pattern, the second self-assembly material forming domains whose alignment and orientation are directed by the modified guiding pre-pattern, thereby creating a second self-assembled structure having fewer defects than the first self-assembled structure.

24. The method of claim 23, wherein no etch process is performed between (i) the step of applying the first layer and (ii) the step of applying the second layer.

25. The method of claim 23, comprising:

annealing the first layer, prior to said washing.

26. The method of claim 23, comprising:

annealing the second layer.

27. The method of claim 23, wherein the first material and the second material both include PS-b-PMMA.

28. The method of claim 23, wherein the method of claim 23 is part of an in-line process.

29. The method of claim 28, wherein the in-line process is a 300 mm wafer process.

30. The method of claim 23, wherein the thickness of the first layer is less than the thickness of the second layer.

31. The method of claim 23, wherein the pre-pattern is a chemical pre-pattern.

32. The method of claim 23, comprising etching the second self-assembled structure.

33. The method of claim 23, wherein the second self-assembled structure has fewer dislocation defects than the first self-assembled structure.

34. The method of claim 23, wherein the second self-assembled structure has a dislocation defect density less than or equal to about 25 per square centimeter.