Strain isolation structures for stretchable electronics

• US 9,408,305 B2
• Filed: 11/20/2015
• Issued: 08/02/2016
• 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
• Primary Examiner(s): Nguyen, Hoa C
• Assistant Examiner(s): TRAN, BINH BACH THANH
• Application Number:
  US14/947,558
• Publication Number:
  US 20160081192A1
• Time in Patent Office: 256 Days
• Field of Search: 361/748, 361/749, 361/750, 361/751, 361/760, 361/761, 361/762, 361/764, 361/765, 361/776, 361/783, 174/521, 174/251, 174/254, 174/255, 174/256
• US Class Current: 1/1
• 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
• 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
• 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 silicon-based semiconductor device component;

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

at least one conductive stretchable interconnect in electrical communication with the silicon-based semiconductor device component, the at least one conductive stretchable interconnect forming the electrical communication with the silicon-based semiconductor device component at a junction region;

a buffer structure having an annular shape with an inner edge surface defining an inner diameter of the annular shape and an outer edge surface defining an outer diameter of the annular shape, the inner edge surface of the buffer structure being horizontally offset from the junction region in a first direction and the outer edge surface of the buffer structure being horizontally offset from the junction region in a second opposing direction; and

an encapsulant encapsulating at least the silicon-based semiconductor 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.

2. The apparatus of claim 1, wherein the buffer structure includes a polymer.

3. The apparatus of claim 2, wherein the polymer includes a polyimide.

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

5. The apparatus of claim 1, wherein the buffer structure is sized, shaped, and positioned to redistribute strain imparted on the apparatus away from the junction region.

6. The apparatus of claim 1, wherein the buffer structure is more rigid than the encapsulant.

7. The apparatus of claim 1, wherein the buffer structure is thicker than the at least one conductive stretchable interconnect.

8. The apparatus of claim 1, wherein the at least one conductive stretchable interconnect is positioned in a first layer of the apparatus and wherein the buffer structure is positioned in a second layer of the apparatus that is spaced from the first layer of the apparatus.

9. The apparatus of claim 8, wherein the first layer is in a first X-Y plane and the second layer is in a second X-Y plane, the first and second X-Y planes being spaced from each other along a Z-axis that is perpendicular to both of the first and second X-Y planes.

10. The apparatus of claim 1, wherein the buffer structure is formed from a non-conductive material.

11. The apparatus of claim 1, wherein the encapsulant includes an elastomer.

12. The apparatus of claim 1, wherein the encapsulant includes a silicone polymer.

13. The apparatus of claim 1, wherein the encapsulant includes polyethylene terephthalate (PET).

14. The apparatus of claim 1, wherein the encapsulant includes polyurethane.

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

16. The apparatus of claim 1, wherein the encapsulant has a thickness of about 100 micrometers, about 125 micrometers, about 150 micrometers, about 175 micrometers, about 200 micrometers, about 225 micrometers, about 250 micrometers, about 300 micrometers, or greater.

17. The apparatus of claim 1, wherein the flexible base includes a polymeric material.

18. The apparatus of claim 1, wherein the flexible base includes a silicone polymer.

19. The apparatus of claim 1, wherein the flexible base is formed from a biodegradable material.

20. The apparatus of claim 1, wherein the flexible base has a thickness of about 5 micrometers, about 7.5 micrometers, about 9 micrometers, about 12 micrometers, or greater.