Decal transfer lithography

• US 7,662,545 B2
• Filed: 10/14/2004
• Issued: 02/16/2010
• Est. Priority Date: 10/14/2004
• Status: Active Grant

• Current Assignee: Board of Trustees of The University of Illinois
• Original Assignee: Board of Trustees of The University of Illinois
• Inventors: Lee, Keon Jae, Motala, Michael J., Childs, William R., Nuzzo, Ralph G.
• Primary Examiner(s): Huff; Mark F
• Assistant Examiner(s): Sullivan; Caleen O
• Application Number:
  US10/965,279
• Publication Number:
  US 20060084012A1
• Time in Patent Office: 1,951 Days
• Field of Search: 430/322, 430/324, 430/394, 430/311, 430/256, 430/258, 430/253, 430/323, 430/254, 430/260
• US Class Current: 430/322
• CPC Class Codes: B81C 1/0038 Processes for creating layers of materials not provided for in groups B81C1/00357 - B81C1/00373
• CPC Class Codes: B81C 2201/0159 Lithographic techniques not provided for in B81C2201/0157
• CPC Class Codes: B81C 2201/0191 Transfer of a layer from a carrier wafer to a device wafer
• CPC Class Codes: B81C 2203/038 Bonding techniques not provided for in B81C2203/031 - B81C2203/037
• 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 7/34 Imagewise removal by selective transfer, e.g. peeling away
• CPC Class Codes: G03F 7/346 using photosensitive materials other than non-macromolecular photopolymerisable compounds having carbon-to-carbon double bonds

Abstract

A method of making a microstructure includes selectively activating a portion of a surface of a silicon-containing elastomer, contacting the activated portion with a substance, and bonding the activated portion and the substance, such that the activated portion of the surface and the substance in contact with the activated portion are irreversibly attached. The selective activation may be accomplished by positioning a mask on the surface of the silicon-containing elastomer, and irradiating the exposed portion with UV radiation.

Claims

1. A method of making a microstructure, comprising:

selectively activating an exposed portion of a surface of a silicon-containing elastomer by irradiating the exposed portion with UV radiation through a mask, while covering a protected portion of the surface with the mask,

where during the irradiating the exposed portion is in contact with an atmosphere containing oxygen, and the mask is in contact with the protected portion;

removing the mask from the surface of the silicon-containing elastomer;

contacting the surface of the silicon-containing elastomer with a substrate; and

bonding the activated portion and the substrate, such that the activated portion and a portion of the substrate in contact with the activated portion are irreversibly attached.

2. The method of claim 1, wherein the mask comprises a hard mask on the protected portion of the surface.

3. The method of claim 1, wherein the mask comprises a free-standing mask comprising a pattern of UV-opaque portions and UV-transparent portions, and comprising a spacer material under the UV-opaque portions;

and

exposed portion of the surface is below and spaced apart from the UV-transparent portions.

4. The method of claim 1, wherein at least the exposed portion is in contact with an atmosphere enriched in molecular oxygen during the irradiation.

5. The method of claim 1, wherein at least the exposed portion is in contact with an atmosphere enriched in ozone during the irradiation.

6. The method of claim 1, wherein the bonding comprises heating the silicon-containing elastomer and the substrate.

7. The method of claim 1, wherein the surface of the silicon-containing elastomer is planar.

8. The method of claim 1, wherein the surface of the silicon containing elastomer comprises a pattern of raised areas and lowered areas.

9. The method of claim 1, further comprising separating the silicon-containing elastomer and the substrate.

10. The method of claim 9, wherein the substrate and the activated portion of the surface remain in contact.

11. The method of claim 9, wherein the silicon-containing elastomer and the portion of the substrate in contact with the activated portion of the surface remain in contact.

13. The method of claim 10, wherein the separating comprises inducing cohesive failure within the silicon-containing elastomer.

14. The method of claim 10, wherein a layer of silicon- containing elastomer remains connected to the activated portion of the surface after the separating.

15. The method of claim 14, further comprising controlling the thickness of the layer by adjusting the duration of the irradiating.

16. The method of claim 10, wherein a minimum feature size of the activated portion of the surface on the substrate after the separating is less than 1 micrometer.

17. The method of claim 10, further comprising, after the separating,

applying an etching agent to the substrate to remove a portion of the substrate which is not in contact with the activated portion of the surface;

and

removing the silicon-containing elastomer from the substrate.

18. The method of claim 10, further comprising, after the separating,

depositing a material on the substrate;

and

removing the silicon-containing elastomer from the substrate to provide a pattern of the deposited material.

19. The method of claim 1, wherein the substrate is non-planar.

20. The method of claim 8, wherein the pattern of raised and lowered areas is configured as an array.

21. The method of claim 1, wherein the silicon-containing elastomer comprises a member selected from the group consisting of polysiloxanes;

block copolymers comprising segments of a polysiloxane; and

silicon-modified elastomers.

22. The method of claim 1, wherein the substrate comprises a member selected from the group consisting of silicon, silicon oxide, quartz, glass, a polymer, and a metal.

30. The method of claim 3, wherein the spacer material has a thickness of at least 100 nanometers.

31. The method of claim 3, wherein the spacer material has a thickness of at least 0.5 micrometers.

32. The method of claim 3, wherein the spacer material has a thickness of at least 3 micrometers.

33. The method of claim 3, wherein the spacer material comprises a photoresist.

12. A method of selectively activating a surface, comprising:

positioning a mask on a surface of a silicon-containing elastomer;

the mask comprising a pattern of UV-opaque portions and UV-transparent portions, and comprising a spacer material under the UV-opaque portions;

the surface comprising an exposed portion below and spaced apart from the UV-transparent portions, and a protected portion covered with the mask;

irradiating the exposed portion of the surface with UV radiation; and

contacting the exposed portion with an atmosphere enriched in molecular oxygen or ozone during the irradiation;

where the mask is in contact with the protected portion during the irradiating.

23. The method of claim 12, wherein the spacer material has a thickness of at least 100 nanometers.

24. The method of claim 12, wherein the spacer material has a thickness of at least 0.5 micrometers.

25. The method of claim 12, wherein the spacer material has a thickness of at least 3 micrometers.

26. The method of claim 12, wherein the spacer material comprises a photoresist.

27. The method of claim 12, wherein the silicon-containing elastomer comprises a member selected from the group consisting of polysiloxanes;

block copolymers comprising segments of a polysiloxane; and

silicon-modified elastomers.

28. The method of claim 12, wherein the silicon-containing elastomer comprises a polysiloxane.

29. The method of claim 12, wherein the silicon-containing elastomer comprises poly(dimethyl siloxane).