Replication and transfer of microstructures and nanostructures

• US 6,849,558 B2
• Filed: 09/17/2002
• Issued: 02/01/2005
• Est. Priority Date: 05/22/2002
• Status: Expired due to Term

• Current Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford University)
• Original Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford University)
• Inventors: Schaper, Charles Daniel
• Primary Examiner(s): Nhu, David
• Application Number:
  US10/246,379
• Publication Number:
  US 20030219992A1
• Time in Patent Office: 868 Days
• Field of Search: 438/758, 438/1, 438/311, 438/680, 438/681, 438/700, 438/736, 438/738, 438/789, 438/790, 438/793, 438/794, 438/933, 438/942, 438/947, 438/948, 438/949
• US Class Current: 438/758
• CPC Class Codes: B29C 33/52 soluble or fusible in particular used in injection moulding B29C45/4457
• CPC Class Codes: B81C 1/0046 using stamping, e.g. imprinting nanoimprinting for making etch masks G03F7/0002
• 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 7/091 characterised by antireflection means or light filtering or absorbing means, e.g. anti-halation, contrast enhancement
• CPC Class Codes: Y10S 438/942 Masking

Abstract

A method for the duplication of microscopic patterns from a master to a substrate is disclosed, in which a replica of a topographic structure on a master is formed and transferred when needed onto a receiving substrate using one of a variety of printing or imprint techniques, and then dissolved. Additional processing steps can also be carried out using the replica before transfer, including the formation of nanostructures, microdevices, or portions thereof. These structures are then also transferred onto the substrate when the replica is transferred, and remain on the substrate when the replica is dissolved. This is a technique that can be applied as a complementary process or a replacement for various lithographic processing steps in the fabrication of integrated circuits and other microdevices.

Claims

1. A method for pattern formation comprising:

creating a replica of a master pattern;

transferring the replica onto a substrate comprising material to be patterned; and

destroying the replica while it is in contact with the substrate.

2. The method of claim 1, in which

the replica can be dissolved in a solvent, and

the step of destroying comprises dissolving the replica in said solvent.

3. The method of claim 2, in which

the replica is fabricated from polyvinyl alcohol (PVA), and

the solvent is an aqueous solution.

4. The method of claim 1, in which

the step of destroying comprises etching the replica.

5. The method of claim 1, in which

the step of creating the replica comprises spin coating of the replica material from a solution onto the master.

6. The method of claim 1, in which

the step of creating the replica comprises casting a liquid polymer on the master.

7. The method of claim 5 or 6, in which

the step of creating the replica also comprises drying the liquid polymer.

8. The method of claim 5 or 6, in which

the step of creating the replica also comprises UV curing of the polymer.

9. The method of claim 5 or 6, in which

the step of creating the replica also comprises heating the polymer.

10. The method of claim 1, comprising an additional step of

removing the replica from the master, and

attaching the replica to a carrier.

11. The method of claim 10, in which

the carrier is coated with a material to promote adhesion to the replica.

12. The method of claim 10, in which

the replica is coated with a material to promote adhesion to the carrier.

13. The method of claim 11 or 12, in which

the adhesion promotion material comprises polyvinyl alcohol (PVA).

14. The method of claim 11 or 12, in which

the adhesion promotion material comprises the same material as the replica.

15. The method of claim 10, further comprising the additional step of

storing the replica and carrier.

16. The method of claim 15, in which

the storage environment is controlled for temperature.

17. The method of claim 15, in which

the storage environment is controlled for humidity.

18. The method of claim 15, in which

the storage environment is controlled for pressure.

19. The method of claim 15, in which

the atmosphere of the storage environment is controlled for chemical composition.

20. The method of claim 15, in which

the replica is inserted into a protective package during storage.

21. The method of claim 10, in which

the step of transferring comprises aligning the carrier to the substrate.

22. The method of claim 10, in which

the step of transferring comprises touching the replica against the substrate.

23. The method of claim 22, in which

the step of transferring comprises pressing the replica against the substrate.

24. The method of claim 22, in which

the substrate is coated with a material to promote adhesion of the replica.

25. The method of claim 24, in which the adhesion promotion material comprises a cyanoacrylate ester.

26. The method of claim 22, in which

the substrate is coated with a deformable material.

27. The method of claim 26, in which

the deformable material is a polymer.

28. The method of claim 26, in which

the deformable material is a photoresist.

29. The method of claim 26, in which

the deformable polymer is the material to be patterned.

33. The method of claim 10, comprising additional steps of

forming a barrier layer on the replica after the replica is removed from the master.

34. The method of claim 33, in which

the material for the barrier layer comprises gold.

35. The method of claim 34, in which

the step of forming the barrier layer comprises deposition of gold on the replica using a sputtering process.

36. The method of claim 33 or 35, comprising an additional step of

forming an additional barrier layer of polymer on the replica.

37. The method of claim 36, in which

the polymer barrier layer is subsequently etched.

30. A method for forming a pattern on a substrate, comprising:

spin coating a polymer film onto a master comprising topographic patterns, such that the polymer film replicates the topographic structures of the master;

transferring the polymer film to a carrier;

aligning the carrier carrying the polymer film to a substrate which comprises a material to be patterned;

transferring the polymer film to the substrate, in a manner such that the polymer film transfers the topographic pattern of the polymer film to the material to be patterned; and

dissolving the polymer film while it is attached to the substrate.

31. The method of claim 30, in which

the polymer used to form the polymer film is polyvinyl alcohol.

32. The method of claim 30, comprising an additional step of

storing the carrier with polymer film for some time before transferring the replica to the substrate.

38. A method for forming a patterned layer of material on a substrate, comprising

preparation of a master with topographic structures in a layout that corresponds to a desired pattern;

coating the master with a polymer film;

curing the polymer film in a manner that forms topographic structures in the film that replicate at least a portion of the topographic patterns of the master;

transferring the polymer film from the master to a carrier;

processing the polymer film with a sequence of steps that leave solid materials on certain portions of the topographic structures of the polymer film that correspond to the desired pattern;

aligning the polymer film with solid materials to a substrate;

bringing the polymer film with solid materials and the substrate into close proximity; and

transferring the solid materials from said certain portions on the polymer film to the substrate.

39. The method of claim 38, in which

the sequence of steps that leave solid materials comprises sputtering a material.

40. The method of claim 39, in which the composition of the material to be sputtered is selected from the group containing gold, platinum, palladium, copper, aluminum, chromium, nickel, silicon, germanium, tungsten, silver, yttrium, barium, cobalt, and carbon.

41. The method of claim 38, in which

the sequence of steps that leave solid materials comprises electroplating.

42. The method of claim 41, in which

the sequence of steps that leave solid materials comprises sputtering a layer of material,

followed by a step of electroplating using additional material of similar composition as said layer of material,

such that the dimensions of the layer of material increase.

43. The method of claim 38, in which

the sequence of steps that leave solid materials comprises spin coating a second polymer.

44. The method of claim 43, in which

the second polymer is a photoresist.

45. The method of claim 44, in which

the sequence of steps that leave solid materials additionally comprises exposure to ultraviolet light.

46. The method of claim 45, in which

the sequence of steps that leave solid materials additionally comprises developing the photoresist.

47. The method of claim 38, in which

the sequence of steps that leave solid materials comprises an etch process.