Method of transferring a micro device
A micro device transfer head and head array are disclosed. In an embodiment, the micro device transfer head includes a base substrate, a mesa structure with sidewalls, an electrode formed over the mesa structure, and a dielectric layer covering the electrode. A voltage can be applied to the micro device transfer head and head array to pick up a micro device from a carrier substrate and release the micro device onto a receiving substrate.
1. A method of transferring a micro device comprising:
positioning a transfer head over a micro device of 1 to 100 μm scale connected to a carrier substrate, the transfer head comprising:
a mesa structure;
an electrode over the mesa structure; and
a dielectric layer covering the electrode;
contacting the micro device with the transfer head;
applying a voltage to the electrode to create a grip pressure on the micro device;
picking up the micro device with the transfer head; and
releasing the micro device onto a receiving substrate.
2. The method of claim 1 , further comprising performing an operation to create a phase change in a bonding layer connecting the micro device to the carrier substrate prior to picking up the micro device.
3. The method of claim 2 , wherein performing the operation to create the phase change in the bonding layer comprises changing the bonding layer from solid to liquid state.
4. The method of claim 3 , further comprising changing the bonding layer from solid to liquid state prior to contacting the micro device with the transfer head.
5. The method of claim 3 , further comprising changing the bonding layer from solid to liquid state after contacting the micro device with the transfer head.
6. The method of claim 3 , further comprising contacting the receiving substrate with the micro device and a substantial portion of the bonding layer, with the substantial portion of the bonding layer in the liquid state.
7. The method of claim 1 , wherein applying the voltage to the electrode comprises applying a constant voltage to the electrode.
8. The method of claim 1 , wherein the transfer head includes a pair of electrodes over the mesa structure, and further comprising applying the voltage across the pair of electrodes to create the grip pressure on the micro device.
9. The method of claim 8 , wherein applying the voltage to pair of electrodes comprises applying an alternating voltage across the pair of electrodes.
10. The method of claim 1 , further comprising applying the voltage to the electrode prior to contacting the micro device with the transfer head.
11. The method of claim 1 , further comprising applying the voltage to the electrode while contacting the micro device with the transfer head.
12. The method of claim 1 , further comprising applying the voltage to the electrode after contacting the micro device with the transfer head.
13. A method of transferring an array of micro devices comprising:
positioning an array of transfer heads over an array of micro devices, wherein each micro device is of 1 to 100 μm scale and each transfer head comprises:
a mesa structure;
an electrode over the mesa structure; and
a dielectric layer covering the electrode;
contacting the array of micro devices with the array of transfer heads;
selectively applying a voltage to a portion of the array of transfer heads;
picking up a corresponding portion of the array of micro devices with the portion of the array of transfer heads; and
selectively releasing the portion of array of micro devices onto at least one receiving substrate.
14. The method of claim 13 , further comprising performing an operation to create a phase change in a plurality of locations of a bonding layer connecting the array of micro devices to the carrier substrate prior to picking up the array of micro devices.
15. The method of claim 14 , wherein performing the operation to create the phase change in the plurality of locations of the bonding layer comprises changing the bonding layer from solid to liquid state.
16. The method of claim 15 , further comprising changing the bonding layer from solid to liquid state prior to contacting the micro device with the transfer head.
17. The method of claim 15 , further comprising changing the bonding layer from solid to liquid state after contacting the micro device with the transfer head.
18. The method of claim 15 , wherein the plurality of locations of the bonding layer are a plurality of laterally separate locations of the bonding layer.
19. The method of claim 13 , further comprising rubbing the array of transfer heads on the array of micro devices after contacting the array of micro devices with the array of transfer heads.
20. The method of claim 13 , wherein selectively applying the voltage to the portion of the array of transfer heads comprises applying the voltage to every transfer head in the array of transfer heads.
21. The method of claim 13 , wherein selectively applying the voltage to the portion of the array of transfer heads comprises applying the voltage to less than every transfer head in the array of transfer heads.
22. A method of transferring a micro device comprising:
positioning a transfer head over a micro device of 1 to 100 μm scale on a carrier substrate;
contacting the micro device with the transfer head;
applying a voltage to the transfer head to create an electrostatic grip pressure on the micro device;
picking up the micro device with the transfer head; and
releasing the micro device onto a receiving substrate.
23. The method of claim 22 , further comprising applying the voltage to the transfer head while contacting the micro device with the transfer head or after contacting the micro device with the transfer head.
24. The method of claim 22 , further comprising performing an operation to create a phase change in a bonding layer connecting the micro device to the carrier substrate.
25. The method of claim 24 , further comprising changing the bonding layer from solid to liquid state prior to contacting the micro device with the transfer head.
26. A method of transferring an array of micro devices comprising:
positioning an array of transfer heads over an array of micro devices, wherein each micro device is of 1 to 100 μm scale;
contacting the array of micro devices with the array of transfer heads;
applying a voltage to the array of transfer heads to create an electrostatic grip pressure on the array of micro devices;
picking up the array of micro devices with the array of transfer heads; and
releasing the array of micro devices onto a receiving substrate.
27. The method of claim 26 , further comprising performing an operation to create a phase change in a plurality of locations of a bonding layer connecting the array of micro devices to a carrier substrate.
28. The method of claim 27 , wherein performing the operation to create the phase change in the plurality of locations of the bonding layer comprises changing the bonding layer from solid to liquid state.
29. The method of claim 27 , wherein the plurality of locations of the bonding layer are a plurality of laterally separate locations of the bonding layer.
30. The method of claim 26 , further comprising applying the voltage to the array of transfer heads while contacting the array of micro devices with the array of transfer heads or after contacting the array of micro devices with the array of transfer heads.