Electric microcontact printing method and apparatus

• US 20030178316A1
• Filed: 12/11/2002
• Published: 09/25/2003
• Est. Priority Date: 06/30/2000
• Status: Active Grant

• Current Assignee: President and Fellows of Harvard College (Harvard Corporation)
• Original Assignee: President and Fellows of Harvard College (Harvard Corporation)
• Inventors: Whitesides, George M., Jacobs, Heiko O.
• Granted Patent: US 7,771,647 B2
• Time in Patent Office: Days
• US Class Current: 205/157
• 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 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• 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: G03G 5/02 Charge-receiving layers G03G5/153 takes precedence

Abstract

A method and apparatus for providing electric microcontact printing is provided. A stamp is brought into contact with the surface of a substrate to provide high resolution features. Aspects of the invention may be used for data storage, microcontact printing, and for other applications requiring high resolution pattern transfer.

Claims

1. A method comprising:

applying an electric potential simultaneously to at least 5000 discrete regions on a substrate while leaving intervening regions substantially free of applied potential.

2. The method of claim 1 wherein lack of the discrete regions is less than 1 μ

m in size.

3. The method of claim 2 wherein the applied electric potential is from 1 mV to 1 kV.

4. The method of claim 3 wherein the applied electric potential is from 100 mV to 20 V.

5. The method of claim 2 wherein the discrete regions are charged.

6. The method of claim 5 wherein the discrete regions received a charge 0.01 to 1 C/cm².

7. The method of claim 5 wherein the discrete regions are positively charged.

8. The method of claim 5 wherein the discrete regions are negatively charged.

9. The method of claim 2 wherein the electric potential is applied at a current of 10 to 100 mA/ cm².

10. The method of claim 1 wherein lack of the discrete regions is less than about 250 nm is size.

11. The method of claim 1 wherein the discrete regions are applied to the substrate at a density of at least 10⁹ per square inch.

12. The method of claim 1 comprising oxidizing material at each of the discrete regions.

13. The method of claim 1 comprising trapping charges at each of the discrete regions.

14. The method of claim 1 wherein the discrete regions comprise resist.

15. The method of claim 1 wherein the discrete regions are in a coating of PMMA.

16. The method of claim 15 wherein the PMMA is coated onto a silicon wafer.

17. A method of claim 1, wherein the discrete regions are chemically altered.

18. The method of claim 17, wherein the substrate is chemically altered by changing the oxidation state of a portion of the substrate.

19. An article comprising:

a stamping surface including at least one protrusion contiguous with at least one indentation and a stamping surface having a pattern, the pattern including at least one feature having a lateral dimension of less than 100 microns, at least a portion of the stamping surface being electrically conductive.

20. The article of claim 19 wherein the stamping surface is flexible.

21. The article of claim 20 wherein the stamp is flexible.

22. The article of claim 20 wherein the stamping surface is comprised of elastomeric material.

23. The article of claim 19 wherein the stamp is comprised of elastomeric material.

24. The article of claim 23 wherein the stamp is comprised of polydimethylsiloxane.

25. The article of claim 23 wherein the elastomeric compound is electrically conductive.

26. The article of claim 19, wherein the stamping surface comprises a conductive coating.

27. The article of claim 19, wherein the stamping surface comprises a metallic coating.

28. The article of claim 19 wherein at least one feature has a lateral dimension of less than 10 microns.

29. The article of claim 28 wherein at least one feature has a lateral dimension of less than 1 micron.

30. An article comprising:

a flexible stamp having a surface wherein at least a portion of the surface is electrically conductive.

31. The article of claim 30 wherein the stamp comprises a elastomeric compound.

32. The article of claim 31 wherein the stamp is comprised of polydimethylsiloxane.

33. The article of claim 30 further comprising a plurality of protrusions on the surface.

34. The article of claim 30 having a density of surface protrusion of at least 5,000 per cm².

35. The article of claim 34 wherein the stamp comprises a coating.

36. The article of claim 34 wherein the surface protrusions have an aspect ratio of at least 0.2:

1.

37. The article of claim 34 wherein the surface protrusions form a pattern.

38. The article of claim 34 wherein the density of surface protrusions is at least 10⁶/cm².

39. A method comprising:

contacting a substrate with a flexible stamp;

applying an electrical potential between the substrate and the stamp; and

forming discrete features in a coating on the substrate.

40. The method of claim 39 further including passing current between the substrate and the stamp.

41. The method of claim 39 wherein the discrete features are charged.

42. The method of claim 39 further comprising a step of growing oxides on the coating.

43. A data storage device fabricated by a process comprising:

contacting a substrate with a flexible stamp having a plurality of protrusions on an electrically conductive surface;

transferring a charge between the stamp and the substrate; and

forming a plurality of discrete charged regions on the substrate.

44. The data storage device of claim 43 wherein the substrate comprises a silicon wafer.

45. The data storage device of claim 44 wherein the substrate further comprises polymethylmethacrylate.

46. The data storage device of claim 43 wherein the regions are positively charged.

47. The data storage device of claim 43 wherein the regions are negatively charged.

48. The data storage device of claim 43 wherein the regions are charged at about 1 V.

49. The data storage device of claim 43 wherein the discrete charged regions are stable for at least 3 weeks.

50. A method of printing a surface comprising:

simultaneously forming a plurality of trapped charges on at least a portion of the surface, at least one of the trapped charges having a dimension of less than 1 um.

51. The method of claim 50 wherein at least a second portion of the surface is charged at less than ½

the voltage of the charged regions.

52. The method of claim 51 wherein the at least a second portion of the surface is charged at less than about 0.1×

the voltage of the charged particles.

53. The method of claim 50 wherein the surface is less than about 1 cm².