Integration of microdevices into system substrate
In a micro-device integration process, a donor substrate is provided on which to conduct the initial manufacturing and pixelation steps to define the micro devices, including functional, e.g. light emitting layers, sandwiched between top and bottom conductive layers. The microdevices are then transferred to a system substrate for finalizing and electronic control integration. The transfer may be facilitated by various means, including providing a continuous light emitting functional layer, breakable anchors on the donor substrates, temporary intermediate substrates enabling a thermal transfer technique, or temporary intermediate substrates with a breakable substrate bonding layer.
1. A bonding structure comprising:
a plurality of microdevices on a donor substrate, each microdevice comprises one or more conductive pads formed on a surface of the microdevice; and
a temporary material to cover at least a part of each micro device or the one or more conductive pads, wherein the temporary material is coupled to a current/voltage source to redirect current to the one or more conductive pads through the temporary material.
2. The bonding structure of claim 1 , wherein the temporary material comprises conductive material or non-conductive material.
3. The bonding structure of claim 2 , wherein the temporary conductive material further covers fully or partially the one or more conductive pads.
4. The bonding structure of claim 1 , further comprising:
a conductive layer at the donor substrate to couple the temporary conductive material to the current/voltage source.
5. The bonding structure of claim 1 , further comprising:
a housing structure to cover at least a part of each microdevice on the donor substrate.
6. The bonding structure of claim 5 , wherein the temporary material act as an anchor holding the plurality of microdevices inside the housing structure in the donor substrate.
7. The bonding structure of claim 1 , further comprising:
at least one sacrificial layer between the housing structure and each microdevice.
8. The bonding structure of claim 1 , wherein the temporary material is patterned to create an opening on a top surface of the donor substrate.
9. The bonding structure of claim 8 , wherein the opening at the top surface of the donor substrate is used to release the micro device from sidewalls of the housing structure by removing the sacrificial layer.
10. The bonding structure of claim 9 , wherein the temporary material holds each microdevice in place after removal of the sacrificial layer and wherein the sacrificial layer is removed by using a chemical etch process or electromagnetic signals.
11. The bonding structure of claim 8 , wherein the temporary material is separated from the housing structure after transferring each microdevice to a receiver substrate by one of: a mechanical process, an optical process, a thermal process and a chemical process.
12. The bonding structure of claim 11 , wherein conductive traces on the top surface of the donor substrate are connected as one of: a mesh, rows or columns.
13. The bonding structure of claim 11 , wherein a plurality of access point on the top surface of the donor substrate is used for biasing the temporary material through the conductive traces.
14. The bonding structure of claim 1 , wherein the temporary material creates a passage between a surface facing the donor substrate and a surface facing away from the donor substrate.