Stretchable and elastic interconnects

• US 20040192082A1
• Filed: 03/28/2003
• Published: 09/30/2004
• Est. Priority Date: 03/28/2003
• Status: Active Grant

• Current Assignee: Princeton University
• Original Assignee: Princeton University
• Inventors: Wagner, Sigurd, Lacour, Stephanie Perichon, Suo, Zhigang
• Granted Patent: US 7,491,892 B2
• Time in Patent Office: Days
• US Class Current: 439/67
• CPC Class Codes: H05K 1/0283 Stretchable printed circuits
• CPC Class Codes: H05K 1/11 Printed elements for providing electric connections to or between printed circuits
• CPC Class Codes: H05K 2201/0133 Elastomeric or compliant polymer
• CPC Class Codes: H05K 2201/091 Locally and permanently deformed areas including dielectric material
• CPC Class Codes: H05K 2203/0271 Mechanical force other than pressure, e.g. shearing or pulling

Abstract

The present invention relates to stretchable interconnects which can be made in various geometric configurations, depending on the intended application. The stretchable interconnects can be formed of an electrically conducting film or an elastomer material to provide elastic properties in which the interconnects can be reversibly stretched in order to stretch and relax the elastomer material to its original configuration. Alternatively, stretchable interconnects can be formed of an electrically conducting film or a plastic material to provide stretching of the material to a stretched position and retaining the stretched configuration. The stretchable interconnect can be formed of a flat 2-dimensional conductive film covering an elastomeric or plastic substrate. When this structure is stretched in one or two dimensions, it retains electrical conduction in both dimensions. Alternatively, the stretchable and/or elastic interconnects can be formed of a film or stripe that is formed on an elastomeric or plastic substrate such that it is buckled randomly, or organized in waves with long-range periodicity. The buckling or waves can be induced by various techniques, including: release of built-in stress of the conductive film or conductive stripe; pre-stretching the substrate prior to the fabrication of the conductive film or conductive stripe; and patterning of the surface of the substrate prior to the fabrication of the metal film. The stretchable interconnect can be formed of a plurality of conductive films or conductive stripes embedded between a plurality of layers of a substrate formed of an elastomer or plastic.

Claims

1. A stretchable interconnect for electronically connecting electronic components comprising:

a stretchable substrate, said substrate being substantially flat; and

a conductive material formed on or embedded within said substrate,

wherein said conductive material extends between two of said devices for electronically coupling a contact of one device to a contact of another device and said stretchable interconnect is capable of being stretched up to a predetermined percentage and retain electrical conductivity.

2. The stretchable interconnect of claim 1 wherein said conductive material comprises a conductive film.

3. The stretchable interconnect of claim 1 wherein said stretchable interconnect can be stretched along its length, width or Z direction and retain electrical conduction in respective length, width or Z directions.

4. The stretchable interconnect of claim 2 wherein said conductive film is a metallic material.

5. The stretchable interconnect of claim 4 wherein said conductive film is formed of a first metallic material adhering to said substrate and a second metallic material adhering to said first metallic material.

6. The stretchable interconnect of claim 2 wherein said conductive film is an organic conducting material or an inorganic material.

7. The stretchable interconnect of claim 2 wherein said substrate can be stretched reversibly.

8. The stretchable interconnect of claim 7 wherein said substrate is an elastomeric material.

9. The stretchable interconnect of claim 8 wherein said substrate is selected from the group consisting of:

silicone rubber such as polydimethyl siloxane (PDMS) and acrylic rubber.

10. The stretchable interconnect of claim 2 wherein said substrate can be stretched non-reversibly.

11. The stretchable interconnect of claim 10 wherein said substrate is formed of a polymeric or plastic material.

12. The stretchable interconnect of claim 1 wherein said conductive material comprises a conductive stripe.

13. The stretchable interconnect of claim 12 wherein said conductive stripe is a metallic material.

14. The stretchable interconnect of claim 12 wherein said substrate is formed of a first metallic material adhering to said substrate and a second metallic material adhering to said first metallic material.

15. The stretchable interconnect of claim 12 wherein said conductive stripe is an organic conducting material or an inorganic material.

16. The stretchable interconnect of claim 12 wherein said substrate can be stretched reversibly.

17. The stretchable interconnect of claim 16 wherein said substrate is an elastomeric material.

18. The stretchable interconnect of claim 17 wherein said substrate is selected from the group consisting of silicone rubber and acrylic rubber.

19. The stretchable interconnect of claim 12 wherein said substrate can be stretched non-reversibly.

20. The stretchable interconnect of claim 19 wherein said substrate is formed of a plastic material.

21. The stretchable interconnect of claim 12 wherein said conductive stripe has a width in the range of about 1 nm to about 1 m.

22. The stretchable interconnect of claim 1 wherein upon forming said conductive material on said stretchable substrate, a wavy or buckled profile is formed in said stretchable interconnect.

23. The stretchable interconnect of claim 2 wherein upon forming said conductive film on said stretchable substrate, a wavy or buckled profile is formed in said stretchable interconnect.

24. The stretchable interconnect of claim 12 wherein upon forming said conductive stripe on said stretchable substrate, a wavy or buckled profile is formed in said stretchable interconnect.

25. The stretchable interconnect of claim 1 wherein said predetermined percentage up to about 500 percent.

26. The stretchable interconnect of claim 22 wherein said predetermined percentage is determined by said stretchable interconnect being first stretched flat up to about 0.5% and second stretched to an amount up to about 500% percent.

27. The stretchable interconnect of claim 2 wherein said conductive film is formed on said substrate.

28. The stretchable interconnect of claim 2 wherein said conductive film is embedded within said substrate.

29. The stretchable interconnect of claim 28 further comprising openings formed in said substrate, wherein said contact of said device and said contact of another device access said stretchable interconnect through said openings.

30. The stretchable interconnect of claim 12 wherein said conductive stripe is formed on said substrate.

31. The stretchable interconnect of claim 12 wherein said conductive stripe is embedded within said substrate.

32. The stretchable interconnect of claim 31 further comprising openings formed in said substrate, wherein said contact of said device and said contact of another device access said stretchable interconnect through said openings.

33. The stretchable interconnect of claim 1 wherein said stretchable substrate is pre-stretched to a predetermined pre-stretched percentage before said conductive material is formed on said substrate.

34. The stretchable interconnect of claim 33 wherein said conductive material comprises a conductive film.

35. The stretchable interconnect of claim 33 wherein said conductive material comprises a conductive stripe.

36. The stretchable interconnect of claim 33 wherein said conductive material is a metallic material.

37. The stretchable interconnect of claim 36 wherein said conductive material is formed of a first metallic material adhering to said substrate and a second metallic material adhering to said first metallic material.

38. The stretchable interconnect of claim 37 wherein said conductive material is selected from the group consisting of copper, silver, gold and aluminum.

39. The stretchable interconnect of claim 33 wherein said substrate can be stretched reversibly.

40. The stretchable interconnect of claim 39 wherein said substrate is an elastomeric material.

41. The stretchable interconnect of claim 40 wherein said substrate is selected from the group consisting of:

silicone rubber and acrylic rubber.

42. The stretchable interconnect of claim 33 wherein the predetermined pre-stretched percentage is in the range of about 0.5% to about 500%.

43. The stretchable interconnect of claim 42 wherein said predetermined percentage is determined by said stretchable interconnect being first stretched to said pre-stretched percentage and second stretched to an amount up to about 500%.

44. The stretchable interconnect of claim 1 further comprising a plurality of layers of said conductive material formed on or embedded between a plurality of layers of said stretchable substrate.

45. The stretchable interconnect of claim 44 wherein each layer of said stretchable substrate is pre-stretched to a predetermined pre-stretched percentage before said conductive material is formed on said substrate.

46. The stretchable interconnect of claim 44 wherein upon forming each layer of said conductive material on each layer of said substrate, a wavy or buckled profile is formed in said stretchable interconnect.

63. The stretchable interconnect of claim 2 wherein the conductive film is a mono atomic layer.

47. A method for forming a stretchable interconnect comprising the steps of:

pre-stretching a stretchable substrate to a predetermined pre-stretch percentage;

forming one or more layers of a conductive material on said pre-stretched substrate; and

relaxing said stretchable substrate,

wherein said formed stretchable interconnect is capable of being stretched up to a predetermined percentage and retain electrical conduction.

48. The method of claim 47 wherein said conductive material comprises a conductive film.

49. The method of claim 47 wherein said conductive material is a conductive film of a metallic material.

50. The method of claim 48 wherein said step of forming one or more layers of conductive material comprises:

forming a first layer of a first metallic material for adhering to said substrate; and

forming a second layer of a second metallic material for adhering to said first metallic material.

51. The method of claim 47 wherein said substrate can be stretched reversibly.

52. The method of claim 51 wherein said substrate is an elastomeric material.

53. The method of claim 52 wherein said substrate is selected from the group consisting of:

silicone rubber and acrylic rubber.

54. The method of claim 47 wherein said step of forming one or more layers of a conductive material further comprises the steps of:

associating a shadow mask with said substrate; and

evaporating said conductive film through a shadow mask,

wherein said layer of conductive material is formed as a conductive stripe.

55. The method of claim 54 wherein said shadow mask is a compliant material and said step of associating a shadow mask with said substrate comprises:

applying said shadow mask to said substrate.

56. The method of claim 54 wherein said shadow mask is formed of a rigid material and said step of associating a shadow mask with said substrate comprises:

mounting said shadow mask to said substrate.

57. The method of claim 47 wherein said step of forming one or more layers of a conductive material further comprises the step of photolithography patterning said conductive material onto said substrate for forming a conductive stripe.

58. A device formed by the method of claim 47.

59. A device comprising at least two electronic devices and at least one stretchable interconnect for connecting said electronic devices, said stretchable interconnect comprising:

a stretchable substrate; and

a conductive material formed on or embedded within said substrate,

wherein said conductive material extends between two of said devices for electronically coupling a contact of one device to a contact of another device and said stretchable interconnect is capable of being stretched up to a predetermined percentage and retain electroconductivity.

60. The device of claim 59 wherein said at least one stretchable interconnect is formed of a stack of stretchable interconnects for connecting a plurality of said electronic devices.

61. The device of claim 59 wherein said stretchable interconnects are formed or embedded with said stretchable substrate as a conductive stripe in a direction for connecting said electronic devices.

62. The device of claim 61 wherein said stretchable interconnects are oriented in one or more of an X, Y or Z direction.