Structures and methods for testing printable integrated circuits
View Patent ↗A substrate includes an anchor area physically secured to a surface of the substrate and at least one printable electronic component. The at least one printable electronic component includes an active layer having one or more active elements thereon, and is suspended over the surface of the substrate by electrically conductive breakable tethers. The electrically conductive breakable tethers include an insulating layer and a conductive layer thereon that physically secure and electrically connect the at least one printable electronic component to the anchor area, and are configured to be preferentially fractured responsive to pressure applied thereto. Related methods of fabrication and testing are also discussed.
1. A structure, comprising:
a substrate; and
a plurality of printable electronic components, each of the printable electronic components attached to the substrate by one or more breakable tethers that physically secure the printable electronic component to the substrate, wherein at least one of the one or more breakable tethers has a first end and a second end opposite the first end and comprises a stress-concentrating feature between the first end and the second end that causes the breakable tether to preferentially fracture at the stress-concentrating feature in response to pressure,
wherein, for each breakable tether of the at least one of the one or more breakable tethers, the stress-concentrating feature of the breakable tether has a feature cross section of smaller area than a tether cross section of the breakable tether.
2. The structure of claim 1 , wherein the stress-concentrating features comprise grooves.
3. The structure of claim 1 , wherein the stress-concentrating features comprise portions of the respective tethers having a reduced thickness relative to other portions thereof.
4. The structure of claim 1 , wherein the stress-concentrating features comprise a notch in each of the one or more breakable tethers.
5. The structure of claim 4 , wherein the stress-concentrating features comprise two notches in each of the one or more breakable tethers.
6. The structure of claim 1 , wherein the stress-concentrating features comprise one or more stress-concentrating features at a center of each of the one or more breakable tethers.
7. The structure of claim 1 , wherein the stress-concentrating features comprise one or more off-center stress-concentrating features.
8. The structure of claim 1 , wherein the one or more breakable tethers are z-shape breakable tethers.
9. The structure of claim 1 , wherein the stress concentrating features of the one or more breakable tethers are configured to be preferentially fractured responsive to pressure applied by a stamp to transfer the at least one electronic component to a target substrate.
10. The structure of claim 1 , further comprising an anchor physically secured to a surface of the substrate, wherein each of the printable electronic components is secured to the substrate via the anchor and a respective tether.
11. The structure of claim 10 , wherein the anchor comprises one or more electrical elements to conduct an electrical test signal.
12. The structure of claim 11 , wherein the one or more breakable tethers are electrically conductive breakable tethers.
13. The structure of claim 12 , wherein the electrically conductive breakable tethers electrically connect the plurality of printable electronic components to the one or more electrical elements of the anchor.
14. The structure of claim 13 , wherein the one or more electrical elements of the anchor area are electrically connected to the printable electronic components by the electrically conductive breakable tethers such that one or more test signals can be sent from the one or more electrical elements of the anchor area to the printable electronic components.
15. The structure of claim 14 , wherein at least one of the printable electronic components is defective.
16. The structure of claim 1 , wherein the printable electronic components are light-emitting diodes.
17. The structure of claim 16 , wherein the light-emitting diodes are inorganic light-emitting diodes.
18. The structure of claim 1 , wherein each of the printable electronic components comprises an active layer.
19. The structure of claim 18 , wherein the active layer is amorphous, polycrystalline, microcrystalline, or crystalline.
20. The structure of claim 18 , wherein the active layer comprises silicon, gallium arsenide (GaAs), and/or a III-V compound semiconductor.
21. The structure of claim 1 , wherein, for each breakable tether of the at least one of the one or more breakable tethers, at least a portion of the breakable tether has a substantially constant tether cross section and the stress-concentrating feature of the breakable tether has a feature cross section of smaller area than the substantially constant tether cross section.