Compliant bipolar micro device transfer head with silicon electrodes
A compliant bipolar micro device transfer head array and method of forming a compliant bipolar micro device transfer array from an SOI substrate are described. In an embodiment, a compliant bipolar micro device transfer head array includes a base substrate and a patterned silicon layer over the base substrate. The patterned silicon layer may include first and second silicon interconnects, and first and second arrays of silicon electrodes electrically connected with the first and second silicon interconnects and deflectable into one or more cavities between the base substrate and the silicon electrodes.
1. An electrostatic transfer head array comprising:
a base substrate;
an insulating layer on the base substrate:
a device layer on the insulating layer, the device layer comprising:
a first trace interconnect integrally formed with a first array of electrodes; and
a second trace interconnect integrally formed with a second array of electrodes;
wherein the first array of electrodes is electrically insulated from the second array of electrodes;
an array of dielectric joints between the first array of electrodes and the second array of electrodes;
wherein the first trace interconnect and the second trace interconnect are parallel to one another, and the dielectric joints are perpendicular to the first trace interconnect and the second trace interconnect.
2. The electrostatic transfer head array of claim 1 , wherein each electrode of the first array of electrodes and the second array of electrodes is deflectable toward the base substrate.
3. The electrostatic transfer head array of claim 2 , further comprising a cavity in the base substrate, and the first array of electrodes and the second array of electrodes are deflectable into the cavity.
4. The electrostatic transfer head array of claim 2 , further comprising an array of cavities in the base substrate, and the first array of electrodes and the second array of electrodes are deflectable into the array of cavities.
5. The electrostatic transfer head array of claim 1 :
wherein the first array of electrodes comprises a first array of electrode leads and a first array of mesa structures; and
wherein the second array of electrodes comprises a second array of electrode leads and a second array of mesa structures.
6. The electrostatic transfer head array of claim 5 , wherein the array of dielectric joints joins the first array of mesa structures to the second array of mesa structures.
7. The electrostatic transfer head array of claim 1 , further comprising a first voltage source connection electrically connected with the first trace interconnect and a second voltage source connection electrically connected with the second trace interconnect.
8. The electrostatic transfer head array of claim 7 , wherein the first voltage source connection comprises a first via opening extending though the base substrate, and the second voltage source connection comprises a second via opening extending though the base substrate.
9. The electrostatic transfer head array of claim 8 , wherein the first voltage source connection comprises a third via opening extending through the device layer, and the second voltage source connection comprises a fourth via opening extending through the device layer.
10. The electrostatic transfer head array of claim 9 , further comprising a dielectric layer on the device layer.
11. The electrostatic transfer head array of claim 10 , further comprising a first conductive layer within the third via opening, and a second conductive layer within the fourth via opening.
12. The electrostatic transfer head array of claim 11 , wherein the first conductive layer is directly on the device layer, and the second conductive layer is directly on the device layer.
13. The electrostatic transfer head array of claim 12 , wherein the first conductive layer is directly on a top surface of the device layer, and the second conductive layer is directly on the top surface of device layer.
14. The electrostatic transfer head array of claim 12 , wherein the first conductive layer is directly on the dielectric layer, and the second conductive layer is directly on the dielectric layer.
15. The electrostatic transfer head array of claim 1 , wherein the base substrate comprises silicon.
16. The electrostatic transfer head array of claim 15 , wherein the device layer comprises silicon.