SELECTIVE TRANSFER OF MICRO DEVICES
What is disclosed is a method of selectively transferring micro devices from a donor substrate to contact pads on a receiver substrate. Micro devices being attached to a donor substrate with a donor force. The donor substrate and receiver substrate are aligned and brought together so that selected micro devices meet corresponding contact pads. A receiver force is generated to hold selected micro devices to the contact pads on the receiver substrate. The donor force is weakened and the substrates are moved apart leaving selected micro devices on the receiver substrate. Several methods of generating the receiver force are disclosed, including adhesive, mechanical and electrostatic techniques.
1 . A method of transferring a micro device, the method comprising:
positioning a donor substrate comprising the micro device proximal to a receiver substrate, wherein the micro device is affixed to the donor substrate by a donor force; and
transferring the micro device from the donor substrate to the receiver substrate responsive to selectively reducing the donor force affixing the micro device to the donor substrate.
2 . The method of claim 1 , wherein selectively reducing the donor force comprises physically shielding the micro device from the donor force.
3 . The method of claim 1 , wherein selectively reducing the donor force comprises changing the bias condition of donor force.
4 . The method of claim 1 , wherein selectively reducing the donor force comprises selectively applying a form of light to the micro device using a shadow mask.
5 . The method of claim 1 , wherein selectively reducing the donor force comprises changing a distance between the micro device and a source of the donor force.
6 . A method of transferring a micro device, the method comprising:
positioning a donor substrate comprising the micro device proximal to a receiver substrate, wherein the receiver substrate comprises a force modulator element; and
transferring the micro device from the donor substrate to the receiver substrate responsive to selectively reducing the distance between the micro device and the force modulator element.
7 . The method of claim 6 , wherein reducing the distance between the micro device and the force modulator element comprises moving the micro device toward the force modulator element using a membrane.
8 . A method of transferring a micro device, the method comprising:
positioning a donor substrate comprising the micro device proximal to a receiver substrate, wherein the receiver substrate comprises a force modulator element creating transfer force for transferring the selected micro devices; and
reducing the effect of said force generated by the force modulator element on unwanted micro devices.
9 . The method of claim 8 , wherein selectively reducing the effect of a force generated by the force modulator element comprises generating a reverse polarity of force surrounding the force modulating element.
10 . A method of transferring micro devices, the method comprising:
positioning a donor substrate comprising micro devices proximal to a receiver substrate, wherein the receiver substrate comprises a current curable bonding layer; and
transferring the micro devices by applying current to the bonding layer of selected micro devices.
11 . The method of claim 10 , wherein the current is applied using a circuit in the receiver substrate.
12 . The method of claim 10 , wherein the circuit in the receiver substrate is shared with a circuit associated the driving or controlling the selected micro devices.
13 . The method of claim 10 , wherein the bonding layer comprises one or more contact pads and selectively curing a portion of the bonding layer comprises curing a portion of the bonding layer between one or more contact pads.
14 . A receiver substrate used to receive a micro device from a donor substrate, the receiver substrate comprising:
an array of one or more pad structures, wherein each pad structure comprises a conductive layer and a dielectric layer.
15 . The receiver substrate of claim 14 , wherein the dielectric layer can be modulated to be a conductive layer.
16 . The receiver substrate of claim 15 , wherein the dielectric layer is modulated to the conductive layer during operation to couple a circuit in the receiver substrate to the micro device.
17 . The receiver substrate of claim 15 , wherein the dielectric layer is modulated to the conductive layer using a doped layer.
18 . The receiver substrate of claim 15 , wherein the dielectric layer is modulated to the conductive layer using a laser to induce dielectric breakdown.
19 . The receiver substrate of claim 14 , wherein the dielectric layer creates electrostatic force that attracts the micro device from the donor substrate.
20 . A method of transferring a micro device, the method comprising:
positioning a donor substrate comprising a micro device proximal to a receiver substrate, wherein the receiver substrate comprises a pad structure having a dielectric layer and a conductive layer;
transferring the micro device from the donor substrate to the pad structure; and
coupling the first micro device and the conductive layer by removing the dielectric layer.
21 . The method of claim 20 , wherein the dielectric layer is removed by the means of mechanical force.
22 . The method of claim 20 , wherein the dielectric layer is removed by the means of thermal force.
23 . The method of using a deformable layer on top of the receiver pad or landing or the micro device to adjust for different height in the micro devices.
24 . The method of claim 23 , where the deformable layer consists of either conductive layer, high resistive layer, or a dielectric layer.