Method of manufacturing switching filters and design structures
Switchable and/or tunable filters, methods of manufacture and design structures are provided herein. The method of forming the filters includes forming at least one piezoelectric filter structure comprising a plurality of electrodes formed on a piezoelectric substrate. The method further includes forming a fixed electrode with a plurality of fingers on the piezoelectric substrate. The method further includes forming a moveable electrode with a plurality of fingers over the piezoelectric substrate. The method further includes forming actuators aligned with one or more of the plurality of fingers of the moveable electrode.
1. A method comprising:
forming at least one piezoelectric filter structure comprising a plurality of electrodes formed on a piezoelectric substrate, comprising:
forming a fixed electrode with a plurality of fingers on the piezoelectric substrate;
forming a moveable electrode with a plurality of fingers over the piezoelectric substrate; and
forming actuators aligned with one or more of the plurality of fingers of the moveable electrode,
wherein forming the actuators comprises etching a trench in the piezoelectric substrate and depositing a metal or metal alloy in the trench.
2. The method of claim 1 , wherein the moveable electrode is formed as a ground electrode, which, upon actuation, the plurality of fingers of the moveable electrode become interleaved with the plurality of fingers of the fixed electrode.
3. The method of claim 1 , wherein the moveable electrode is formed as a Vin electrode, which, upon actuation, the plurality of fingers of the Vin electrode become interleaved with the plurality of fingers of the ground electrode.
4. The method of claim 1 , wherein forming the actuators comprises aligning the actuators with the plurality of fingers of the moveable electrode.
5. The method of claim 1 , wherein forming the actuators comprises forming less than a number of the plurality of fingers of the moveable electrode.
6. The method of claim 1 , wherein the at least one piezoelectric filter structure is a surface acoustic wave (SAW) filter.
7. The method of claim 6 , wherein forming the SAW filter comprises:
forming a Vin interdigital transducer (IDT) comprising interleaved signal and ground electrodes; and
forming a Vout IDT comprising interleaved signal and ground electrodes.
8. The method of claim 7 , wherein forming the moveable electrode comprises positioning the moveable electrode above the signal electrode of the Vin IDT or the Vout IDT.
9. The method of claim 7 , wherein forming the moveable electrode comprises positioning the moveable electrode above a ground electrode of the Vin IDT or the Vout IDT.
10. The method of claim 1 , wherein the actuators are formed above and below the moveable electrode.
11. The method of claim 1 , wherein the plurality of fingers of the moveable electrode are connected together with a single wiring structure on a same plane.
12. The method of claim 11 , wherein the plurality of fingers of the fixed electrode are connected together with a single wiring structure on a same plane.
13. The method of claim 12 , wherein the moveable electrode with the plurality of fingers and the fixed electrode with the plurality of fingers are formed such that in a pull-in position, the plurality of fingers of the fixed electrode and the plurality of fingers of the moveable electrode are in a same plane.
14. The method of claim 13 , wherein the actuators aligned with one or more of the plurality of fingers of the moveable electrode are formed below each of the plurality of fingers of the moveable electrode on the piezoelectric substrate.
15. A method comprising:
forming at least one piezoelectric filter structure comprising a plurality of electrodes formed on a piezoelectric substrate, comprising:
forming a fixed electrode with a plurality of fingers on the piezoelectric substrate;
forming a moveable electrode with a plurality of fingers over the piezoelectric substrate; and
forming actuators aligned with one or more of the plurality of fingers of the moveable electrode,
wherein forming the moveable electrode comprises:
forming an insulator layer over the fixed electrode and the actuators;
patterning the insulator layer to expose the fixed electrode;
depositing a sacrificial material in the pattern of the insulator layer and over the fixed electrode;
forming the moveable electrode on the sacrificial material, which is positioned to have its plurality of fingers interleaved with the plurality of fingers of the fixed electrode;
forming an additional sacrificial material over the moveable electrode;
forming at least one actuator over the additional sacrificial material and in alignment with at least one of the plurality of fingers of the moveable electrode;
forming a capping layer over the additional sacrificial material;
forming at least one vent hole in the capping layer;
venting the sacrificial material and the additional sacrificial material through the at least one vent hole to form an upper cavity and a lower cavity about the moveable electrode; and
closing the at least one vent hole with material.
16. The method of claim 15 , wherein forming the additional sacrificial material comprises:
depositing an insulator material on the sacrificial material;
patterning the insulator material; and
depositing the additional sacrificial material within the pattern of the insulator material.
17. The method of claim 15 , wherein forming the additional sacrificial material comprises:
depositing the additional sacrificial material on the sacrificial material; and
patterning the additional sacrificial material.
18. A method comprising:
forming at least one piezoelectric filter structure comprising a plurality of electrodes formed on a piezoelectric substrate, comprising:
forming a fixed electrode with a plurality of fingers on the piezoelectric substrate;
forming a moveable electrode with a plurality of fingers over the piezoelectric substrate;
forming actuators aligned with one or more of the plurality of fingers of the moveable electrode; and
forming the actuators aligned with the one or more of the plurality of fingers of the moveable electrode in a dielectric material above the moveable electrode, and the moveable electrode with the plurality of fingers are within in a chamber formed by venting of sacrificial material between the piezoelectric substrate and the dielectric material.