Stretchable and foldable electronic devices
Disclosed herein are stretchable, foldable and optionally printable, processes for making devices and devices such as semiconductors, electronic circuits and components thereof that are capable of providing good performance when stretched, compressed, flexed or otherwise deformed. Strain isolation layers provide good strain isolation to functional device layers. Multilayer devices are constructed to position a neutral mechanical surface coincident or proximate to a functional layer having a material that is susceptible to strain-induced failure. Neutral mechanical surfaces are positioned by one or more layers having a property that is spatially inhomogeneous, such as by patterning any of the layers of the multilayer device.
1. An electronic device comprising: a flexible or stretchable substrate; a plurality of device islands supported by said flexible or stretchable substrate; a serpentine electrical interconnect having a first end electrically connected to a first device island and a second end electrically connected to a second device island; and an encapsulation layer positioned over said serpentine electrical interconnect and said flexible or stretchable substrate to embed said serpentine electrical interconnect and wherein the encapsulation layer comprises a polymer and wherein for an applied strain of up to 70% a peak strain in said serpentine electrical interconnect is less than or equal to 0.2%.
2. The electronic device of claim 1 , wherein adjacent device islands are electrically interconnected by one or more serpentine interconnects.
3. The electronic device of claim 1 , wherein said serpentine electrical interconnect is non-coplanar relative to a substrate surface of the flexible or stretchable substrate.
4. The electronic device of claim 1 , wherein said serpentine electrical interconnect is coplanar relative to a substrate surface of the flexible or stretchable substrate.
5. The electronic device of claim 4 , wherein said coplanar serpentine electrical interconnect is bonded to said flexible or stretchable substrate and maintains a coplanar alignment with said substrate surface under an applied force.
6. The electronic device of claim 1 , comprising a second serpentine electrical interconnect that electrically connects said first device island and said second device island.
7. The electronic device of claim 1 , wherein said serpentine electrical interconnect has at least three distinct curved portions between said first end and said second end.
8. The electronic device of claim 7 having a distinct curved portion that is opposibly positioned relative to at least one other distinct curved portion.
9. The electronic device of claim 7 , wherein at least one distinct curved portion is in physical contact with at least one other distinct curved portion in a relaxed state electronic device.
10. The electronic device of claim 1 , wherein said serpentine electrical interconnect has an in-plane amplitude and a wavelength, wherein said in-plane amplitude is greater than said wavelength.
11. The electronic device of claim 1 , wherein said serpentine electrical interconnect accommodates an applied strain by a change in a separation distance from said flexible or stretchable substrate, a change in a shape of said serpentine electrical interconnect, or both.
12. The electronic device of claim 1 , wherein a peak strain in said serpentine electrical interconnect is at least 200 times less than an applied strain to the electronic device.
13. The electronic device of claim 1 , wherein upon electronic device stretching, compressing or bending at least a portion of said serpentine electrical interconnect adopts a non-coplanar geometry.
14. The electronic device of claim 13 , wherein said non-coplanar geometry corresponds to at least partial lift-off from said flexible or stretchable substrate or a deformation of said serpentine electrical interconnect.
15. The electronic device of claim 1 , wherein said serpentine electrical interconnect accommodates an electronic device bending radius of up to 5 mm without impacting electronic device performance.
16. The electronic device of claim 1 , wherein said serpentine electrical interconnect is coiled or twisted.
17. The electronic device of claim 1 , wherein said serpentine electrical interconnect is not bonded to said flexible or stretchable substrate and said serpentine electrical interconnect accommodates an applied force by movement of a portion of said serpentine electrical interconnect relative to said flexible or stretchable substrate.
18. The electronic device of claim 1 , wherein said electronic device has an electrical property that is stable over at least 1000 cycles of stretching.
19. The electronic device of claim 1 , comprising a second serpentine electrical interconnect electrically connected to said first device island, wherein said second serpentine interconnect extends in a different lateral direction relative to said serpentine interconnect to electrically connect said first device island to a third device island that is not aligned with said first and second device islands.
20. The electronic device of claim 19 , comprising an array of device islands, wherein device islands of said array are electrically connected to a plurality of adjacent device islands by said serpentine electrical interconnects.
21. The electronic device of claim 1 , comprising an array of device islands, wherein adjacent device islands are electrically interconnected by one or more of said serpentine electrical interconnects.
22. The electronic device of claim 21 that accommodates a device stretching strain of up to 70% with a peak strain in the serpentine interconnect that is less than or equal to 0.2%.
23. The electronic device of claim 22 , wherein said encapsulation layer comprises a liquid covered by a solid polymer layer.
24. The electronic device of claim 23 , wherein said liquid comprises a liquid polymer.
25. The electronic device of claim 24 , wherein said liquid polymer comprises pre-polymerized PDMS and said solid polymer layer comprises PDMS.
26. The electronic device of claim 1 , wherein said device islands are bonded to said flexible or stretchable substrate.
27. The electronic device of claim 26 , wherein said serpentine electrical interconnect region between said first and second ends is not bonded to said flexible or stretchable substrate.
28. The electronic device of claim 1 , wherein said serpentine electrical interconnect comprises a bent region that is not in physical contact with said flexible or stretchable substrate.
29. The electronic device of claim 1 , wherein at least a portion of said serpentine electrical interconnect is bonded to said substrate.
30. The electronic device of claim 1 , wherein said first end is bonded to said first device island and said second end is bonded to said second device island.
31. The electronic device of claim 1 , wherein a central portion of the serpentine interconnect between the first and second ends is separated from the flexible or stretchable substrate.
32. The electronic device of claim 1 , wherein said substrate is flexible and stretchable, and the electronic device is flexible and stretchable.
33. An electronic device comprising: an array of device islands supported by a flexible or stretchable substrate; an array of serpentine electrical interconnects, each serpentine electrical interconnect having a first end electrically connected to a device island and a second end electrically connected to a different device island that is adjacent to said device island; wherein said array of serpentine electrical interconnects form two alignment directions that are orthogonal to each other; and an encapsulation layer positioned over said serpentine electrical interconnect and said flexible or stretchable substrate to embed said serpentine electrical interconnect and wherein the encapsulation layer comprises a polymer and wherein for an applied strain of up to 70% a peak strain in said serpentine electrical interconnect is less than or equal to 0.2%.
34. The electronic device of claim 33 , wherein the array of serpentine electrical interconnects have a portion that is physically separated from the flexible or stretchable substrate.
35. The electronic device of claim 33 , wherein said substrate is flexible and stretchable, and the electronic device is flexible and stretchable.