BURIED TRACES FOR SEALED ELECTROSTATIC MEMBRANE ACTUATORS OR SENSORS

• US 20100077609A1
• Filed: 09/29/2008
• Published: 04/01/2010
• Est. Priority Date: 09/29/2008
• Status: Active Grant

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Nystrom, Peter J., GULVIN, Peter M.
• Granted Patent: US 8,358,047 B2
• Time in Patent Office: Days
• US Class Current: 29/846
• CPC Class Codes: B41J 2/14314 Structure of ink jet print heads with electrostatically actuated membrane
• CPC Class Codes: B41J 2/1621 Manufacturing processes
• CPC Class Codes: B41J 2/1629 wet etching
• CPC Class Codes: B41J 2/1639 sacrificial molding
• CPC Class Codes: Y10T 29/49155 Manufacturing circuit on or in base

Abstract

In accordance with the invention, there are micro-electromechanical devices and methods of fabricating them. An exemplary micro-electromechanical device can include a first dielectric layer; a buried conductive trace disposed over the first dielectric layer, such that the buried conductor trace is electrically connected to an outside power source; a second dielectric layer disposed over the buried conductive trace; at least one conductive electrode disposed over the second dielectric layer and electrically connected to the buried conductive trace; and at least one conductive membrane including membrane anchors disposed over the second dielectric layer, such that the at least one conductive membrane is electrically isolated from the at least one conductive electrode and the buried conductor trace, wherein the at least one conductive electrode is electrically connected to the power source through the buried conductive trace.

Claims

1. A method of fabricating a micro-electromechanical device, the method comprising:

providing a first dielectric layer;

depositing a buried conductor layer over the first dielectric layer;

patterning the buried conductor layer to form a buried conductive trace, such that the buried conductive trace is electrically connected to an outside power source;

depositing a second dielectric layer over the buried conductor layer;

patterning the second dielectric layer to create one or more vias that extend up to the buried conductive trace;

depositing a first conductor layer over the second dielectric layer;

patterning the first conductor layer to form at least one conductive electrode electrically connected to the buried conductive trace through the one or more vias; and

forming at least one conductive membrane comprising membrane anchors, the membrane anchors disposed over the second dielectric layer, such that the at least one conductive membrane is electrically isolated from the at least one conductive electrode and the buried conductive trace, wherein the at least one conductive electrode is electrically connected to a power source through the buried conductive trace.

2. The method of claim 1, wherein the step of providing a first dielectric layer comprises providing an insulator substrate.

3. The method of claim 1, wherein the step of providing a first dielectric layer comprises providing a first dielectric layer disposed over an electrically conductive substrate.

4. The method of claim 1, wherein the step of depositing a first dielectric layer over a substrate comprises depositing a field oxide layer over a substrate.

5. The method of claim 1, wherein the step of depositing a buried conductor layer over the first dielectric layer comprises depositing a polysilicon layer over the first dielectric layer.

6. The method of claim 1, wherein the step of depositing a second dielectric layer over the buried conductor layer comprises:

depositing a silicon oxide layer over the buried conductor layer; and

depositing a silicon nitride layer over the silicon oxide layer.

7. The method of claim 1, wherein the step of forming at least one conductive membrane comprising membrane anchors over the second dielectric layer comprises:

depositing a sacrificial layer over the first conductor layer;

patterning a plurality of holes in the sacrificial layer;

depositing a second conductor layer over the sacrificial layer and filling the plurality of holes, thereby forming a plurality of membrane anchors;

patterning a plurality of holes in the second conductor layer;

removing the sacrificial layer by etching through the plurality of holes; and

plugging the plurality of holes to form a seal that keeps air inside and ink outside, thereby forming at least one conductive membrane.

8. The method of claim 1 further comprising:

patterning the first conductor layer to form at least one conductive electrode electrically connected to the buried conductive trace and one or more first conductive layer regions electrically isolated from the conductive electrode; and

forming at least one conductive membrane comprising membrane anchors, wherein the membrane anchors are disposed over the one or more first conductive layer regions electrically isolated from the conductive electrode.

9. A micro-electromechanical device comprising:

a first dielectric layer;

a buried conductive trace disposed over the first dielectric layer, such that the buried conductor trace is electrically connected to a power source;

a second dielectric layer disposed over the buried conductive trace, the second dielectric layer comprising one or more vias that extend up to the buried conductive trace;

at least one conductive electrode disposed over the second dielectric layer and electrically connected to the buried conductive trace through the one or more vias; and

at least one conductive membrane comprising membrane anchors disposed over the second dielectric layer, such that the at least one conductive membrane is electrically isolated from the at least one conductive electrode and the buried conductor trace, wherein the at least one conductive electrode is electrically connected to the power source through the buried conductive trace.

10. The micro-electromechanical device of claim 9, wherein the first dielectric layer comprises an insulator substrate.

11. The micro-electromechanical device of claim 9, wherein the first dielectric layer comprises a first dielectric layer disposed over an electrically conductive substrate.

12. The micro-electromechanical device of claim 9, wherein the first dielectric layer comprises a field oxide layer.

13. The micro-electromechanical device of claim 9, wherein the buried conductive trace comprises doped polysilicon.

14. The micro-electromechanical device of claim 9, wherein the second dielectric layer disposed over the buried conductor layer comprises:

a silicon oxide layer disposed over the buried conductor layer; and

a silicon nitride layer disposed over the silicon oxide layer.

15. The micro-electromechanical device of claim 9, wherein the membrane anchors are disposed over one or more first conductive layer regions electrically isolated from the conductive electrode.

16. The micro-electromechanical device of claim 9, wherein the device is at least one of an actuator and a sensor.

17. A method of fabricating a micro-electromechanical device, the method comprising:

forming a first dopant-well in a second dopant-doped substrate;

depositing a first dielectric layer over the substrate;

depositing a second dielectric layer over the first dielectric layer;

forming at least one via through the first and the second dielectric layer to form an electrical contact between the first dopant-well and a trace, wherein the trace is electrically connected to an outside power source;

depositing a first conductor layer over the second dielectric layer;

patterning the first conductor layer to form at least one conductive electrode electrically connected to the first dopant-well; and

forming at least one conductive membrane comprising membrane anchors, the membrane anchors disposed over the second dielectric layer, such that the at least one conductive membrane is electrically isolated from the conductive electrodes and the substrate, wherein the at least one conductive electrode is electrically connected to the power source through the first dopant-well.

18. The method of claim 17, wherein the first dopant and the second dopant are selected from the group consisting of nitrogen, phosphorus, arsenic, antimony, bismuth, boron, aluminum, gallium, indium, and thalium.

19. The method of claim 17, wherein the step of depositing a first dielectric layer over a substrate comprises depositing a field oxide layer over a substrate.

20. The method of claim 17, wherein the step of depositing a second dielectric layer over the first dielectric layer comprises depositing a silicon nitride layer over a field oxide layer.

21. The method of claim 17, wherein the step of forming at least one conductive membrane comprising membrane anchors over the second dielectric layer comprises:

depositing a sacrificial layer over the first conductor layer;

patterning a plurality of holes in the sacrificial layer;

depositing a second conductor layer over the sacrificial layer and filling the plurality of holes, thereby forming a plurality of membrane anchors;

patterning a plurality of holes in the second conductor layer;

removing the sacrificial layer by etching through the plurality of holes; and

plugging the plurality of holes to form a seal that keeps air inside and ink outside, thereby forming at least one conductive membrane.

22. The method of claim 17 further comprising:

patterning the first conductor layer and the second dielectric layer to form at least one conductive electrode electrically connected to the first dopant-well and one or more first conductive layer regions electrically isolated from the conductive electrode; and

forming at least one conductive membrane comprising membrane anchors, wherein the membrane anchors are disposed over the one or more first conductive layer regions electrically isolated from the conductive electrode.

23. A micro-electromechanical device comprising:

a first dielectric layer disposed over a second dopant-doped substrate, the second dopant-doped substrate comprising a first dopant-well;

a second dielectric layer disposed over the first dielectric layer;

at least one via through the first and the second dielectric layer to form an electrical contact between the first dopant-well and a trace, wherein the trace is electrically connected to an outside power source;

at least one conductive electrode electrically connected to the first dopant-well; and

at least one conductive membrane comprising membrane anchors, the membrane anchors disposed over the second dielectric layer, such that the at least one conductive membrane is electrically isolated from the conductive electrodes and the substrate, wherein the at least one conductive electrode is electrically connected to the power source through the first dopant-well.

24. The micro-electromechanical device of claim 23, wherein the first dielectric layer comprises a field oxide layer.

25. The micro-electromechanical device of claim 23, wherein the second dielectric layer disposed over the buried conductive trace comprises a silicon nitride layer disposed over a field oxide layer.

26. The micro-electromechanical device of claim 23, wherein the membrane anchors are disposed over one or more first conductive layer regions electrically isolated from the conductive electrode.

27. The micro-electromechanical device of claim 23, wherein the device is at least one of an actuator and a sensor.