Compliant electrostatic transfer head with spring support layer
A compliant electrostatic transfer head and method of forming a compliant electrostatic transfer head are described. In an embodiment, a compliant electrostatic transfer head includes a cavity in a base substrate, a spring support layer on the base substrate, and a patterned device layer on the spring support layer. The spring support layer includes a spring support layer beam profile that extends over and is deflectable toward the cavity, and the patterned device layer includes an electrode beam profile that is supported by the spring support layer beam profile and extends over and is deflectable toward the cavity.
1. A compliant electrostatic transfer head structure comprising:
a base substrate;
a cavity completely in the base substrate;
a spring support layer on the base substrate, wherein the spring support layer includes a spring support layer beam profile that extends over the cavity from a first side of the cavity to a second side of the cavity and is deflectable toward the cavity;
a first insulating layer on the spring support layer; and
a patterned device layer on the spring support layer, wherein the patterned device layer includes an electrode beam profile that is supported by the spring support layer beam profile and extends over the cavity from the first side of the cavity to the second side of the cavity and is deflectable toward the cavity.
2. The compliant electrostatic transfer head structure of claim 1 , wherein the first insulating layer electrically insulates the patterned device layer from the spring support layer.
3. The compliant electrostatic transfer head structure of claim 1 , wherein the electrode beam profile of the patterned device layer comprises a pair of electrodes, and the pair of electrodes includes a first electrode lead integrally formed with a first mesa structure protruding above the first electrode lead, and a second electrode lead integrally formed with a second mesa structure protruding above the second electrode lead.
4. The compliant electrostatic transfer head structure of claim 3 , further comprising a second insulating layer between the base substrate and the spring support layer, wherein the second insulating layer electrically insulates the spring support layer from the base substrate.
5. The compliant electrostatic transfer head structure of claim 4 , wherein the second insulating layer spans along a top surface of the base substrate, sidewalls of the cavity, and a bottom surface of the cavity.
6. The compliant electrostatic transfer head structure of claim 3 , wherein the patterned device layer further comprises a first trace interconnect integrally formed with the first electrode, and a second trace interconnect integrally formed with the second electrode.
7. The compliant electrostatic transfer head structure of claim 6 , wherein the patterned device layer is formed of silicon.
8. The compliant electrostatic transfer head structure of claim 6 , further comprising:
a first via in the base substrate and a first plug within the first via, the first plug electrically coupled to the first trace interconnect and the first electrode lead; and
a second via in the base substrate and a second plug within the second via, the second plug electrically coupled to the second trace interconnect and the second electrode lead.
9. The compliant electrostatic transfer head structure of claim 6 , wherein the electrode beam profile extends between the first and second trace interconnects.
10. The compliant electrostatic transfer head structure of claim 9 , wherein the spring support layer beam profile extends between the first and second trace interconnects, and the spring support layer beam profile is wider than the electrode beam profile.
11. The compliant electrostatic transfer head structure claim 9 , wherein the each of the first and second electrodes comprises a double bend.
12. The compliant electrostatic transfer head structure of claim 11 , wherein the electrode beam profile is characterized by an S-shape configuration.
13. The compliant electrostatic transfer head structure claim 3 , wherein the first and second mesa structures are separated by trench characterized by a width of 1.0 μm or less.
14. The compliant electrostatic transfer head structure of claim 13 , wherein the trench is filled with a dielectric material.
15. The compliant electrostatic transfer head structure of claim 1 , further comprising a second insulating layer directly on and spanning along a top surface of the base substrate, sidewalls of the cavity, and a bottom surface of the cavity, wherein the second insulating layer electrically insulates the spring support layer from the base substrate.
16. The compliant electrostatic transfer head of claim 15 , wherein the electrode beam profile of the patterned device layer comprises a pair of electrodes, and the pair of electrodes includes a first electrode lead integrally formed with a first mesa structure protruding above the first electrode lead, and a second electrode lead integrally formed with a second mesa structure protruding above the second electrode lead.
17. The compliant electrostatic transfer head of claim 16 , wherein the patterned device layer further comprises a first trace interconnect integrally formed with the first electrode lead, and a second trace interconnect integrally formed with the second electrode lead.
18. The compliant electrostatic transfer head of claim 15 , wherein the base substrate comprises silicon, and the second insulating layer comprises silicon oxide.
19. The compliant electrostatic transfer head of claim 18 , wherein the spring layer comprises silicon.
20. The compliant electrostatic transfer head of claim 18 , wherein the first insulating layer comprises silicon oxide, and the patterned device layer comprises silicon.