Selective micro device transfer to receiver substrate
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 receiver substrate structure comprising:
an array of landing areas for holding micro devices from a donor substrate selectively, each landing area comprising:
at least one contact pad for coupling a micro device to a circuit or a potential in the receiver substrate; and
at least one force modulation element for creating a receiver force for holding micro devices on the receiver substrate, wherein the force modulation is an adhesive layer formed at least on one side of the contact pad holding selected micro devices that adhere to the adhesive layer and contact to the contact pad,
wherein the adhesive layer is made of a non-conductive material and not covering at least part of a conductive pad.
2. The receiver substrate structure of claim 1 , wherein for each landing area, a same element acts as the force modulation element and the contact pad.
3. The receiver substrate structure of claim 1 , wherein the adhesive layer is conductive.
4. The receiver substrate structure of claim 1 , wherein the adhesive layer is applied selectively.
5. A method to hold micro devices on a receiver substrate, the method comprising:
having an array an array of landing areas for holding micro devices from a donor substrate selectively, each landing area comprising:
at least one contact pad for coupling a micro device to a circuit or a potential in the receiver substrate;
at least one force modulation element for creating a receiver force for holding micro devices on the receiver substrate, wherein the force modulation is an adhesive layer formed at least on one side of the contact pad holding selected micro devices that adhere to the adhesive layer and contact to the contact pad,
wherein a transferred micro device bonding is cured after a transfer into the receiver substrate.
6. The method of claim 5 , wherein the adhesive layer is cured selectively.
7. The method of claim 5 , wherein the adhesive layer is applied by printing or stamping.