Compliant micro device transfer head
A compliant monopolar micro device transfer head array and method of forming a compliant monopolar micro device transfer array from an SOI substrate are described. In an embodiment, the micro device transfer head array including a base substrate and a patterned silicon layer over the base substrate. The patterned silicon layer may include a silicon interconnect and an array of silicon electrodes electrically connected with the silicon interconnect. Each silicon electrode includes a mesa structure protruding above the silicon interconnect, and each silicon electrode is deflectable into a cavity between the base substrate and the silicon electrode. A dielectric layer covers a top surface of each mesa structure.
1. A compliant transfer head array comprising:
a base substrate;
an insulating layer on the base substrate;
a patterned device layer on the insulating layer, the patterned device layer comprising:
a trace interconnect integrally formed with an array of electrodes;
wherein each electrode includes a mesa structure protruding above the trace interconnect, and each electrode is deflectable toward the base substrate; and
a dielectric layer covering a top surface of each mesa structure.
2. The compliant transfer head array of claim 1 , wherein the trace interconnect runs through a working area of the compliant transfer head array including the array of electrodes.
3. The compliant transfer head array of claim 1 , wherein each electrode is deflectable into a cavity in the base substrate.
4. The compliant transfer head array of claim 3 , wherein each electrode is deflectable into the same cavity in the base substrate.
5. The compliant transfer head array of claim 3 , wherein the cavity wraps around an end of the trace interconnect.
6. The compliant transfer head array of claim 3 , wherein each electrode is deflectable into a separate cavity in the base substrate.
7. The compliant transfer head array of claim 1 , further comprising a first dielectric layer covering a top surface of the trace interconnect.
8. The compliant transfer head array of claim 7 , wherein the dielectric layer overlaps a top surface of the first dielectric layer.
9. The compliant transfer head array of claim 8 , wherein the dielectric layer has a higher dielectric constant or dielectric breakdown strength than the first dielectric layer.
10. The compliant transfer head array of claim 1 , wherein each electrode further comprises an electrode lead spanning between a corresponding mesa structure and the trace interconnect.
11. The compliant transfer head array of claim 10 , wherein the electrode lead for each electrode runs perpendicular to trace interconnect.
12. The compliant transfer head array of claim 10 , wherein each electrode extends from the trace interconnect in a single sided clamped cantilever beam configuration.
13. The compliant transfer head array of claim 12 , wherein the patterned device layer further comprises a second trace interconnect, and each electrode further comprises a second electrode lead spanning between a corresponding mesa structure and the second trace interconnect.
14. The compliant transfer head array of claim 13 , wherein each electrode extends between the trace interconnect and the second trace interconnect in a double sided clamped cantilever beam configuration.
15. The compliant transfer head array of claim 12 , wherein the patterned device layer further comprise a second array of second electrodes integrally formed with the trace interconnect, wherein each second electrode includes a second mesa structure protruding above the trace interconnect, and each second electrode is deflectable toward the base substrate.
16. The compliant transfer head array of claim 15 , wherein the array of electrodes and second array of second electrodes extend in opposite directions from the trace interconnect.
17. The compliant transfer head array of claim 16 , wherein the array of electrodes and second array of electrodes are deflectable into a cavity in the base substrate.
18. The compliant transfer head array of claim 17 , wherein the array of electrodes and second array of electrodes are deflectable into the same cavity in the base substrate.
19. The compliant transfer head array of claim 17 , wherein the array of electrodes and second array of electrodes are deflectable into different cavities in the base substrate.