Controlled buckling structures in semiconductor interconnects and nanomembranes for stretchable electronics

• US 8,217,381 B2
• Filed: 09/06/2007
• Issued: 07/10/2012
• Est. Priority Date: 06/04/2004
• Status: Active Grant

• Current Assignee: Board of Trustees of The University of Illinois
• Original Assignee: Board of Trustees of The University of Illinois
• Inventors: Rogers, John A., Meitl, Matthew, Sun, Yugang, Ko, Heung Cho, Carlson, Andrew, Choi, Won Mook, Stoykovich, Mark, Jiang, Hanqing, Huang, Yonggang, Nuzzo, Ralph G., Lee, Keon Jae, Zhu, Zhengtao, Menard, Etienne, Khang, Dahl-Young, Kim, Hoon-sik, Kang, Seong Jun, Ahn, Jong Hyun
• Primary Examiner(s): WOJCIECHOWICZ, EDWARD JOSEPH
• Application Number:
  US11/851,182
• Publication Number:
  US 20080157235A1
• Time in Patent Office: 1,769 Days
• Field of Search: 257/9, 257/40, 257/619, 439/67
• US Class Current: 257/9
• CPC Class Codes: H01L 21/02422 Non-crystalline insulating materials, e.g. glass, polymers
• CPC Class Codes: H01L 21/02628 using solutions
• CPC Class Codes: H01L 21/4846 Leads on or in insulating or insulated substrates, e.g. metallisation H01L21/4821 takes precedence; metallisation of ceramics in general C04B41/51; printed circuits H05K3/00
• CPC Class Codes: H01L 21/8258 the substrate being a semiconductor, using a combination of technologies covered by H01L21/8206, H01L21/8213 , H01L21/822, H01L21/8252, H01L21/8254 or H01L21/8256
• CPC Class Codes: H01L 23/5387 Flexible insulating substrates H01L23/5388 takes precedence
• CPC Class Codes: H01L 27/12 the substrate being other than a semiconductor body, e.g. an insulating body
• CPC Class Codes: H01L 29/0657 characterised by the shape of the body
• CPC Class Codes: H01L 29/72 Transistor-type devices, i.e. able to continuously respond to applied control signals
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/12041 LED
• CPC Class Codes: H01L 2924/13091 Metal-Oxide-Semiconductor Field-Effect Transistor [MOSFET]
• CPC Class Codes: H05K 1/0283 Stretchable printed circuits
• CPC Class Codes: H05K 2201/0133 Elastomeric or compliant polymer
• CPC Class Codes: H05K 2201/09045 Locally raised area or protrusion of insulating substrate
• CPC Class Codes: H05K 2203/0271 Mechanical force other than pressure, e.g. shearing or pulling
• CPC Class Codes: H05K 3/20 by affixing prefabricated conductor pattern H05K1/187, H05K3/046, H05K3/4658, H05K3/4682 takes precedence
• CPC Class Codes: H05K 3/22 Secondary treatment of printed circuits H05K3/1283 takes precedence; embedding circuits in grooves by pressure H05K3/107
• CPC Class Codes: Y10T 29/4913 Assembling to base an electrical component, e.g., capacitor, etc.

Abstract

In an aspect, the present invention provides stretchable, and optionally printable, components such as semiconductors and electronic circuits capable of providing good performance when stretched, compressed, flexed or otherwise deformed, and related methods of making or tuning such stretchable components. Stretchable semiconductors and electronic circuits preferred for some applications are flexible, in addition to being stretchable, and thus are capable of significant elongation, flexing, bending or other deformation along one or more axes. Further, stretchable semiconductors and electronic circuits of the present invention are adapted to a wide range of device configurations to provide fully flexible electronic and optoelectronic devices.

Claims

1. A two-dimensional stretchable and bendable device comprising:

a. an elastomeric substrate having a contact surface;

b. an interconnect having a first end bonded to said elastomeric substrate contact surface and a second end bonded to said elastomeric substrate contact surface, and a central portion between said first and second ends;

wherein movement of said first end and said second ends toward each other generates a curve and physical separation between said elastomeric substrate contact surface and interconnect central portion with a maximum physical separation distance between said central portion and said elastomeric substrate contact surface that is greater than or equal to 100 nm and less than or equal to 1 mm;

said first end connected to a first contact pad and said second end connected to a second contact pad, wherein said contact pads are substantially flat for receiving a device component and said contact pads are bonded to said substrate;

wherein said interconnect electrically connects said first contact pad and said second contact pad, and said curved central portion provides said device stretching and bending while maintaining electrical connectivity when said contact pads move relative to one another.

2. The device of claim 1, wherein said curved central portion has a plurality of contact regions bonded to said substrate contact surface, to form a plurality of curved regions.

3. The device of claim 1, wherein said first end, said second end, said first contact pad and said second contact pad bonded to said elastomeric substrate correspond to active substrate regions.

4. The device of claim 3, wherein said active substrate regions correspond to:

a. a pattern of adhesive sites on said substrate contact surface or said interconnect;

b. a selected pattern of substrate or interconnect physical parameters, said parameters selected from one or more of;

i. substrate or interconnect thickness having a spatial thickness variation;

ii. substrate or interconnect modulus having a spatial modulus variation;

iii. substrate or interconnect temperature having a spatial temperature variation; and

iv. substrate or interconnect composition;

having a spatial composition variation;

c. chemical modification of said substrate surface;

or

d. regions adjacent to free edges of said interconnect on said substrate contact surface.

5. The device of claim 1, wherein said interconnect comprises a material selected from the group consisting of one or more of:

a metal, a semiconductor, a piezoelectric, a ferroelectric, a magnetostrictive material, an electrostrictive material, a superconductor, a ferromagnetic material, and a thermoelectric material.

6. The device of claim 1 selected from the group consisting of an electronic device, an optical device, an opto-electronic device, mechanical device, a microfluidic device, a microelectromechanical system, a nanoelectromechanical system, and a thermal device.

7. The device of claim 1 wherein said substrate contact surface is substantially flat.

8. The device of claim 1, wherein said substrate contact surface has one or more relief features.

9. The device of claim 8, wherein said substrate contact surface has a portion that is curved or wavy.

10. The device of claim 1, wherein said elastomeric substrate comprises poly(dimethylsiloxane).

49. The device of claim 1, further comprising an encapsulation layer that embeds said interconnect, wherein said encapsulation layer is supported by said substrate contact surface.

50. The device of claim 49, wherein said encapsulation layer is an elastomer.

51. The device of claim 50, wherein said elastomer is poly(d imethylsiloxane).

53. The device of claim 1, wherein said movement of said first and second interconnect ends toward each other is from said elastomeric substrate relaxing from an elongated state to a relaxed state.

54. The device of claim 1, wherein said movement of said first and second interconnect ends toward each other is from said elastomeric substrate in a compressed state.

55. The device of claim 1, wherein said movement of said first and second ends toward each other correspond to a strain between said interconnect first end and second end greater than or equal to 20% and less than or equal to 100%.

11. A stretchable interconnect for establishing electrical contact with device components supported by an elastomeric substrate, said interconnect comprising:

a first end bonded to said elastomeric substrate;

a second end bonded to said elastomeric substrate; and

a central portion disposed between the first and second ends, wherein movement of said interconnect first end and said interconnect second end toward each other generates a bend in said central portion and separation between said elastomeric substrate and said interconnect central portion, with a maximum separation distance between said central portion and said elastomeric substrate that is greater than or equal to 100 nm and less than or equal to 1 mm;

wherein the device components are supported by said elastomeric substrate and the interconnect electrically connects a first device component with a second device component, wherein said bent central portion not in physical contact with the elastomeric substrate provides said interconnect stretching while maintaining electrical connectivity when said device components move relative to one another.

12. The interconnect of claim 11, wherein the interconnect central portion comprises one or more bond regions to form a plurality of distinct curved portion regions not in physical contact with the substrate.

13. The interconnect of claim 12, wherein the separation distance from said elastomeric substrate of at least one of the distinct curved portion regions is different than the separation distance from said elastomeric substrate of another curved portion region.

14. The interconnect of claim 11, wherein the interconnect comprises a ribbon.

15. The interconnect of claim 14, wherein the ribbon has a thickness that is greater than 100 nm.

16. The interconnect of claim 15, wherein the ribbon has a thickness that is between about 300 nm and 1 mm.

17. The interconnect of claim 11, wherein the interconnect central portion has a bridge configuration comprising a central portion peak from which three or more interconnects extend therefrom.

18. The interconnect of claim 11, wherein the device component comprises a contact pad in electrical contact with one of the interconnect ends.

19. The interconnect of claim 18 wherein an additional device component is in electrical contact with the contact pad.

20. The interconnect of claim 11, wherein the elastomeric substrate comprises PDMS.

21. The interconnect of claim 20 capable of accommodating a substrate strain of up to 25% while maintaining electrical conductivity and electrical contact with the device component.

22. A device array comprising a plurality of interconnects of claim 11, wherein each interconnect provides electrical contact between a pair of device components.

23. The device array of claim 22, wherein the array has a grid configuration, floral configuration, bridge configuration, or any combination thereof.

24. The device array of claim 22, wherein each device component is connected to an adjacent device component by a plurality of interconnects.

25. The device array of claim 24, wherein at least one device component is connected to eight interconnects.

26. The device array of claim 22, wherein at least one interconnect is oriented in a direction that is different from another interconnect.

27. The device array of claim 22, wherein at least a portion of the array comprises a plurality of interconnects aligned in a direction parallel to each other.

28. The device array of claim 27, wherein at least one of the plurality of parallel interconnects is out of phase with at least one other of the interconnects.

29. The device array of claim 22, wherein the plurality of interconnects are oriented in two or more directions.

30. The device array of claim 29, wherein the orientation is in two directions that are perpendicular to each other.

31. The device array of claim 22, wherein the device comprises two or more adjacent layers, with each layer comprising a plurality of interconnects.

32. The device array of claim 22 capable of undergoing a strain of up to about 150% without fracturing.

33. The device array of claim 22, wherein the substrate has a surface with at least a portion that is curved.

34. The device array of claim 33, wherein the surface has at least a portion that is concave or convex.

35. The device array of claim 34, wherein the surface is hemispherical.

36. The device array of claim 22, wherein the device is one or more of a stretchable:

photodetector, display, light emitter, photovoltaic, sheet scanner, LED display, semiconductor laser, optical system, large-area electronics, transistor, or an integrated circuit.

37. A tunable device component of an electronic device comprising the interconnect of claim 11, said electronic device having at least one electronic property that changes selectively with the level of strain of said central portion provided by said bent configuration.

38. The tunable device component of claim 37 wherein said at least one electronic property is selected from the group consisting of electron mobility, resonance frequency, conductance, and resistance.

39. The tunable device component of claim 37 wherein said tunable device component comprises the semiconductor channel of a transistor.

40. A tunable device component of an optical device comprising the interconnect of claim 11, said tunable device component having at least one optical property that changes selectively with the level of strain of said central portion provided by said bent configuration.

41. The tunable device component of claim 40 wherein said at least one optical property is the refractive index of the tunable device component or the angle of incidence of an incident beam of electromagnetic radiation relative to a surface of the central portion of said stretchable interconnect.

42. The tunable device component of claim 40 wherein said tunable device component comprises a waveguide, an optical modulator, an optical switch, or an optical filter.

43. A tunable device component comprising the interconnect of claim 11, said tunable device component having a thermal conductivity that changes selectively with the level of strain of said central portion provided by said bent configuration.

44. The stretchable interconnect of claim 11 wherein said stretchable interconnect is a thermal isolation component of a device.

45. The stretchable interconnect of claim 44 wherein said central portion is not in thermal contact with said substrate, wherein said central portion supports one or more device components, thereby providing thermal isolation of said one or more device components supported by said central portion from said substrate.

46. The stretchable interconnect of claim 44 wherein said device is a long wavelength imaging system.

47. The stretchable interconnect of claim 11 wherein said stretchable interconnect is an actuator of a mechanical device, wherein the central portion is curved and has an amplitude that is capable of modulation by compressing or elongating said stretchable interconnect or by applying an electric potential to said central portion.

48. The stretchable interconnect of claim 47 wherein said mechanical device is selected from the group consisting of a microelectromechanical device, a nanoelectromechanical device, and a microfluidic device.

52. The stretchable interconnect of claim 11, further comprising an encapsulation layer that embeds said interconnect, wherein said encapsulation layer is an elastomer that is supported by said substrate.

56. The interconnect of claim 11, wherein movement of said first and second ends toward each other correspond to a strain between said interconnect first end and second end greater than or equal to 20% and less than or equal to 100%.