STRAIN ISOLATION STRUCTURES FOR STRETCHABLE ELECTRONICS

• US 20140240932A1
• Filed: 03/15/2013
• Published: 08/28/2014
• Est. Priority Date: 06/11/2012
• Status: Active Grant

• Current Assignee: Medidata Solutions Incorporated (Dassault Systemes SA)
• Original Assignee: MC10, Inc.
• Inventors: Hsu, Yung-Yu
• Granted Patent: US 9,226,402 B2
• Time in Patent Office: Days
• US Class Current: 361/749
• CPC Class Codes: H05K 1/0271 Arrangements for reducing stress or warp in rigid printed circuit boards, e.g. caused by loads, vibrations or differences in thermal expansion
• CPC Class Codes: H05K 1/028 Bending or folding regions of flexible printed circuits H05K1/0283 takes precedence
• CPC Class Codes: H05K 1/0283 Stretchable printed circuits
• CPC Class Codes: H05K 1/036 Multilayers with layers of different types
• CPC Class Codes: H05K 1/0393 Flexible materials H05K1/038 takes precedence; specific organic compositions are classified in H05K1/0313 and subgroups
• CPC Class Codes: H05K 1/09 Use of materials for the conductive, e.g. metallic pattern
• CPC Class Codes: H05K 1/118 specially for flexible printed circuits, e.g. using folded portions
• CPC Class Codes: H05K 1/147 at least one of the printed circuits being bent or folded, e.g. by using a flexible printed circuit H05K1/148 takes precedence
• CPC Class Codes: H05K 1/148 Arrangements of two or more hingeably connected rigid printed circuit boards, i.e. connected by flexible means
• CPC Class Codes: H05K 1/185 Components encapsulated in the insulating substrate of the printed circuit or incorporated in internal layers of a multilayer circuit semiconductor chips encapsulated by interconnect and support structures H01L23/5389, H01L24/00
• CPC Class Codes: H05K 1/189 characterised by the use of a flexible or folded printed circuit H05K3/326 takes precedence
• CPC Class Codes: H05K 2201/0133 Elastomeric or compliant polymer elastomeric conductor H05K2201/0314
• CPC Class Codes: H05K 2201/0154 Polyimide
• CPC Class Codes: H05K 2201/0187 with regions of different dielectrics in the same layer, e.g. in a printed capacitor for locally changing the dielectric properties
• CPC Class Codes: H05K 2201/09245 Crossing layout alternating conductors H05K2201/097
• CPC Class Codes: H05K 2201/1028 Thin metal strips as connectors or conductors
• CPC Class Codes: H05K 2201/10287 Metal wires as connectors or conductors
• CPC Class Codes: H05K 2201/2009 Reinforced areas, e.g. for a specific part of a flexible printed circuit
• CPC Class Codes: H05K 3/4691 Rigid-flexible multilayer circuits comprising rigid and flexible layers, e.g. having in the bending regions only flexible layers
• CPC Class Codes: H05K 3/4694 Partitioned multilayer circuits having adjacent regions with different properties, e.g. by adding or inserting locally circuit layers having a higher circuit density H05K3/4691 takes precedence

Abstract

Buffer structures are provided that can be used to reduce a strain in a conformable electronic system that includes compliant components in electrical communication with more rigid device components. The buffer structures are disposed on, or at least partially embedded in, the conformable electronic system such that the buffer structures overlap with at least a portion of a junction region between a compliant component and a more rigid device component. The buffer structure can have a higher value of Young'"'"'s modulus than an encapsulant of the conformable electronic system.

Claims

1. An apparatus comprising:

a device component;

at least one conductive stretchable and/or flexible interconnect in electrical communication with the device component, the at least one conductive stretchable and/or flexible interconnect forming the electrical communication with the device component at a junction region;

a buffer structure; and

an encapsulant encapsulating at least the device component and the junction region, wherein;

the buffer structure overlaps with at least a portion of the junction region; and

the buffer structure has a higher value of Young'"'"'s modulus than the encapsulant.

2. The apparatus of claim 1, wherein the buffer structure is an annular buffer structure having an inner diameter and an outer diameter.

3. The apparatus of claim 2, wherein the inner diameter of the annular buffer structure is positioned over a portion of the device component proximate the junction region, and wherein the outer diameter of the annular buffer structure is positioned over the junction region.

4. The apparatus of claim 3, wherein the device component is disposed on, or at least partially embedded in, a flexible base.

5. The apparatus of claim 4, wherein the inner diameter of the annular buffer structure is positioned over the flexible base, and wherein the outer diameter of the annular buffer structure is positioned over the junction region.

6. The apparatus of claim 1, wherein the buffer structure is a cylindrical buffer structure having an outer edge.

7. The apparatus of claim 6, wherein the cylindrical buffer structure is disposed over the device component such that the outer edge of the cylindrical buffer structure is positioned over the junction region.

8. The apparatus of claim 1, wherein the buffer structure comprises at least one projection portion that extends over a portion of the at least one conductive stretchable and/or flexible interconnect proximate to the junction region.

9. The apparatus of claim 1, wherein the buffer structure comprises at least one projection portion that extends to a side of a portion of the at least one conductive stretchable and/or flexible interconnect proximate to the junction region.

10. The apparatus of claim 1, wherein the least one conductive stretchable and/or flexible interconnect is embedded in a polymer, and wherein the encapsulant encapsulates the polymer.

11. The apparatus of claim 10, wherein the polymer is a polyimide.

12. The apparatus of claim 1, wherein the buffer structure is formed from a polymer.

13. The apparatus of claim 12, wherein the polymer is a polyimide.

14. The apparatus of claim 1, wherein the at least one conductive stretchable and/or flexible interconnect comprises gold, copper, aluminum, stainless steel, silver, a doped semiconductor, a conductive polymer, or any combination thereof.

15. The apparatus of claim 1, wherein the encapsulant is an elastomer.

16. The apparatus of claim 1, wherein the device component is disposed on a flexible base.

17. An apparatus comprising:

a device component;

at least one conductive stretchable and/or flexible interconnect in electrical communication with the device component, the at least one conductive stretchable and/or flexible interconnect forming the electrical communication with the device component at a junction region;

a first buffer structure disposed over the device component;

a second buffer structure disposed below the device component; and

an encapsulant encapsulating at least the device component and the junction region, wherein;

the first buffer structure and the second buffer structure overlap with at least a portion of the junction region; and

the first buffer structure and the second buffer structure have a higher value of Young'"'"'s modulus than the encapsulant.

18. The apparatus of claim 17, wherein the first buffer structure or the second buffer structure is an annular buffer structure having an inner diameter and an outer diameter.

19. The apparatus of claim 18, wherein the inner diameter of the annular buffer structure overlaps a portion of the device component proximate the junction region, and wherein the outer diameter of the annular buffer structure overlaps the junction region.

20. The apparatus of claim 18, wherein the device component is disposed on, or at least partially embedded in, a flexible base.

21. The apparatus of claim 20, wherein the inner diameter of the annular buffer structure overlaps the flexible base, and wherein the outer diameter of the annular buffer structure is positioned over the junction region.

22. The apparatus of claim 17, wherein the first buffer structure or the second buffer structure is a cylindrical buffer structure having an outer edge.

23. The apparatus of claim 22, wherein the cylindrical buffer structure overlaps the device component such that the outer edge of the cylindrical buffer structure overlaps the junction region.

24. The apparatus of claim 17, wherein the first buffer structure or the second buffer structure comprises at least one projection portion that extends over a portion of the at least one conductive stretchable and/or flexible interconnect proximate to the junction region.

25. The apparatus of claim 17, wherein the first buffer structure or the second buffer structure comprises at least one projection portion that extends to a side of a portion of the at least one conductive stretchable and/or flexible interconnect proximate to the junction region.

26. The apparatus of claim 17, wherein the least one conductive stretchable and/or flexible interconnect is embedded in a polymer, and wherein the encapsulant encapsulates the polymer.

27. The apparatus of claim 17, wherein the first buffer structure or the second buffer structure is formed from a polymer.

28. The apparatus of claim 27, wherein the polymer is a polyimide.

29. The apparatus of claim 17, wherein the at least one conductive stretchable and/or flexible interconnect comprises gold, copper, aluminum, stainless steel, silver, a doped semiconductor, a conductive polymer, or any combination thereof.

30. The apparatus of claim 17, wherein the encapsulant is an elastomer.

31. The apparatus of claim 17, further comprising a third buffer structure proximate to the device component;

wherein the third buffer structure has a higher value of Young'"'"'s modulus than the encapsulant.

32. The apparatus of claim 17, wherein the second buffer structure is disposed below the device component such that the second buffer structure is concentric with the second buffer structure.

33. The apparatus of claim 17, wherein the second buffer structure is disposed below the device component such that a central axis of the second buffer structure is not coincident with a central axis of the second buffer structure.

34. An apparatus comprising:

a device component;

a flexible base, the device component being disposed on, or at least partially embedded in, the flexible base;

at least one conductive stretchable and/or flexible interconnect in electrical communication with the device component, the at least one conductive stretchable and/or flexible interconnect forming the electrical communication with the device component at a junction region;

a buffer structure; and

an encapsulant encapsulating at least the device component and the junction region, wherein;

the buffer structure overlaps with at least a portion of the flexible base;

the flexible base has a higher value of Young'"'"'s modulus than the encapsulant; and

the buffer structure has a higher value of Young'"'"'s modulus than the encapsulant.

35. The apparatus of claim 34, wherein the buffer structure is an annular buffer structure having an inner diameter and an outer diameter.

36. The apparatus of claim 35, wherein the inner diameter of the annular buffer structure is positioned over a portion of the flexible base, and wherein the outer diameter of the annular buffer structure is positioned over a portion of the at least one conductive stretchable and/or flexible interconnect.

37. The apparatus of claim 34, wherein the buffer structure is a cylindrical buffer structure having an outer edge.

38. The apparatus of claim 37, wherein the cylindrical buffer structure is disposed over the flexible base such that the outer edge of the cylindrical buffer structure is positioned over the at least one conductive stretchable and/or flexible interconnect.

39. The apparatus of claim 34, wherein the buffer structure comprises at least one projection portion that extends over a portion of the at least one conductive stretchable and/or flexible interconnect proximate to an edge of the flexible base.

40. The apparatus of claim 34, wherein the buffer structure comprises at least one projection portion that extends to a side of a portion of the at least one conductive stretchable and/or flexible interconnect proximate to an edge of the flexible base.

41. The apparatus of claim 40, wherein the buffer structure is formed from a polymer.

42. The apparatus of claim 41, wherein the polymer is a polyimide.

43. The apparatus of claim 34, wherein the at least one conductive stretchable and/or flexible interconnect comprises gold, copper, aluminum, stainless steel, silver, a doped semiconductor, a conductive polymer, or any combination thereof.

44. The apparatus of claim 34, wherein the encapsulant is an elastomer.