Micro-LED transfer method and manufacturing method
A micro-LED transfer method and manufacturing method. The micro-LED ( 303 ) transfer method comprises: bringing pickup units ( 305 ) of a transfer head in contact with micro-LEDs ( 303 ) on a carrier substrate ( 301 ), wherein the pickup units ( 305 ) are able to apply current to the micro-LEDs ( 303 ); applying current to the micro-LEDs ( 303 ) via the pickup units ( 305 ) to heat up bonding layers ( 302 ) between the micro-LEDs ( 303 ) and the carrier substrate ( 301 ) to be melted; picking up the micro-LEDs ( 303 ) from the carrier substrate ( 301 ) with the transfer head; bonding the micro-LEDs ( 303 ) onto a receiving substrate ( 307 ); and removing the transfer head from the micro-LEDs.
1. A micro-LED transfer method, comprising:
bringing pickup units of a transfer head in contact with micro-LEDs on a carrier substrate, wherein the pickup units are able to apply current to the micro-LEDs;
applying current to the micro-LEDs via the pickup units to obtain I-V characteristics of the micro-LEDs;
determining known-good-die micro-LEDs on the carrier substrate based on the I-V characteristics;
applying current selectively to the known-good-die micro-LEDs via the pickup units to heat up bonding layers between the known-good-die micro-LEDs and the carrier substrate to be melted, wherein the melting of the bonding layers between the known-good-die micro-LEDs and the carrier substrate is determined by monitoring the I-V characteristics of the known-good-die micro-LEDs;
picking up the known-good-die micro-LEDs from the carrier substrate with the transfer head;
bonding the known-good-die micro-LEDs onto a receiving substrate; and
removing the transfer head from the known-good-die micro-LEDs.
2. The method according to claim 1 , wherein the pickup units include electrodes on a transfer substrate of the transfer head and a conductive adhesive layer on the electrodes;
wherein the current is applied via the electrodes and the conductive adhesive layer;
wherein the known-good-die micro-LEDs are picked up by means of the conductive adhesive layer; and
wherein the conductive adhesive layer is removed after the known-good-die micro-LEDs are bonded onto the receiving substrate.
3. The method according to claim 2 , wherein the conductive adhesive layer is blank.
4. The method according to claim 2 , wherein the conductive adhesive layer is a conductive photoresist layer,
wherein the conductive photoresist layer is cured during heating up the bonding layers between the known-good-die micro-LEDs and the carrier substrate, and
wherein the conductive photoresist layer is chemically removed after the known-good-die micro-LEDs are bonded onto the receiving substrate.
5. The method according to claim 1 , wherein the pickup units of the transfer head are in flexible contact with the known-good-die micro-LEDs on the carrier substrate.
6. The method according to claim 1 , wherein the pickup units of the transfer head pick up the known-good-die micro-LEDs from the carrier substrate by electrostatic force or electromagnetic force.
7. The method according to claim 1 , wherein each of the pickup units of the transfer head includes at least one picking up electrode and at least one current-applying electrode,
wherein the picking up electrode is covered with a dielectric layer,
wherein a metal probe is mounted on the current-applying electrode for applying current to the known-good-die micro-LEDs on the carrier substrate.
8. The method according to claim 1 , wherein current is applied to the known-good-die micro-LEDs at selective sites via the pickup units.
9. A method for manufacturing a micro-LED device, comprising transferring micro-LEDs onto a receiving substrate of the micro-LED device by using the micro-LED transfer method according to claim 1 .