Flexible, stretchable electronic devices
View Patent ↗Fabrication methods are disclosed that facilitate the production of electronic structures that are both flexible and stretchable to conform to non-planar (e.g. curved) surfaces without suffering functional damage due to excessive strain. Electronic structures including CMOS devices are provided that can be stretched or squeezed within acceptable limits without failing or breaking. The methods disclosed herein further facilitate the production of flexible, stretchable electronic structures having multiple levels of intra-chip connectors. Such connectors are formed through deposition and photolithographic patterning (back end of the line processing) and can be released following transfer of the electronic structures to flexible substrates.
1. A flexible electronic device comprising:
a structure including:
an electrically insulating layer having a first side and a second side;
a circuitry layer comprising first and second CMOS circuitry regions adjoining a first side of the electrically insulating layer;
a first layer comprising electrically insulating material on the circuitry layer;
a space extending within the first layer and between the first and second CMOS circuitry regions, and
an electrical connector layer electrically connecting the first and second circuitry regions, the electrical connector layer extending within the first layer and including a wire extending across the space, and
a flexible substrate attached to the structure on the second side of the electrically insulating layer.
2. The flexible electronic device of claim 1 , wherein the structure further includes first and second doped semiconductor regions adjoining the second side of the electrically insulating layer, the flexible substrate being attached to the first and second doped semiconductor regions, and the space extending between the first and second doped semiconductor regions.
3. The flexible electronic device of claim 2 , wherein the flexible substrate comprises an elastomeric sheet.
4. The flexible electronic device of claim 1 , further including a low-k dielectric layer having a low modulus of elasticity, the wire being embedded in the low-k dielectric layer.
5. The flexible electronic device of claim 4 , wherein the wire has a wave-like configuration.
6. The flexible electronic device of claim 1 , wherein the wire extending across the space is suspended in air.
7. The flexible electronic device of claim 6 , wherein the wire has a wave-like configuration.
8. The flexible electronic device of claim 1 , wherein the flexible substrate comprises an elastomeric sheet.
9. The flexible electronic device of claim 8 , wherein the wire has a wave-like configuration and is entirely in a plane that is parallel to the circuitry layer.
10. The flexible electronic device of claim 9 , wherein the wire adjoins a top surface of the structure and the flexible substrate adjoins a bottom surface of the structure.
11. The flexible electronic device of claim 10 , wherein the wire is embedded in a low-k dielectric layer having a low modulus of elasticity.
12. The flexible electronic device of claim 1 , wherein the electrical connector layer further includes a metal layer within the first layer and a solderless electrical connection between the wire and the metal layer.
13. A flexible electronic device comprising:
first and second semiconductor chips, each of the semiconductor chips including a CMOS device, an electrically conductive contact layer, an electrically insulating layer on the contact layer, and one or more metal layers electrically connected to the CMOS device;
a space separating the first and second semiconductor chips;
a flexible substrate attached to a bottom surface of each of the first and second semiconductor chips and spanning the space separating the first and second semiconductor chips, and
a wire electrically connecting the first and second chips and spanning the space separating the first and second semiconductor chips, the wire having a wave-like configuration for allowing relative movement between the first and second semiconductor chips without fracturing, the wire and flexible substrate being in opposing relation.
14. The flexible electronic device of claim 13 , wherein each chip further includes a plurality of metal layers, further including a solderless electrical connection between one of the metal layers of each chip and the wire.
15. The flexible electronic device of claim 13 , further including a solderless electrical connection between one of the one or more metal layers of each chip and the wire.
16. The flexible electronic device of claim 15 , further including a low-k dielectric layer having a low modulus of elasticity, the wire being embedded in the low-k dielectric layer.
17. The flexible electronic device of claim 15 , wherein the flexible substrate comprises an elastomeric sheet.
18. The flexible electronic device of claim 17 , wherein the space separating the first and second semiconductor chips adjoins the flexible substrate.
19. The flexible electronic device of claim 17 , wherein each chip further includes an oxide layer, the oxide layer spanning the space, the flexible substrate being attached to the oxide layer.
20. The flexible electronic device of claim 17 , wherein each chip further includes a doped semiconductor layer, the flexible substrate being attached to the doped semiconductor layer of each chip.