Electrical contact method and structure for deflection devices formed in an array configuration

• US 20060152795A1
• Filed: 01/07/2005
• Published: 07/13/2006
• Est. Priority Date: 01/07/2005
• Status: Active Grant

• Current Assignee: Miradia Inc. (Walsin Lihwa Corporation)
• Original Assignee: Miradia Inc. (Walsin Lihwa Corporation)
• Inventors: Yang, Xiao
• Granted Patent: US 7,199,918 B2
• Time in Patent Office: Days
• US Class Current: 359/295
• CPC Class Codes: G02B 26/0816 by means of one or more reflecting elements

Abstract

A method of fabricating an electrical connection for a spatial light modulator includes providing a first substrate including a plurality of bias electrodes and a plurality of dielectric bond pads. The method also includes providing a second substrate of a predetermined thickness, the second substrate including a plurality of recessed regions within the predetermined thickness and arranged in a spatial manner as a second array, each of the recessed regions being bordered by a standoff region, and joining the dielectric bond pads of the first substrate to the standoff region of the second substrate. The method further includes forming mirror structures from a first portion of the second substrate, exposing a portion of the upper surface of the plurality of bias electrodes, and depositing a conductive layer on the mirror structures and the exposed portion of the upper surface of the plurality of bias electrodes.

Claims

1. A method of fabricating an electrical connection for a spatial light modulator, the method comprising:

providing a first substrate, the first substrate comprising;

a plurality of bias electrodes coupled to the first substrate, the plurality of bias electrodes having an upper surface and a lower surface and arranged in a spatial manner as a first array; and

a plurality of dielectric bond pads coupled to the plurality of bias electrodes;

providing a second substrate of a predetermined thickness, the second substrate including a plurality of recessed regions within the predetermined thickness and arranged in a spatial manner as a second array, each of the recessed regions being bordered by a standoff region, the standoff region having a thickness defined by a portion of the predetermined thickness;

joining the dielectric bond pads of the first substrate to the standoff region of the second substrate;

forming mirror structures from a first portion of the second substrate;

exposing a portion of the upper surface of the plurality of bias electrodes; and

depositing a conductive layer on the mirror structures and the exposed portion of the upper surface of the plurality of bias electrodes to provide an electrical connection between the plurality of bias electrodes and the mirror structures.

2. The method of claim 1 wherein the dielectric bond pads are fabricated from materials selected from the group consisting of silicon dioxide, silicon nitride, and silicon oxynitride.

3. The method of claim 1 wherein the bias electrodes are formed as a multilayer stack comprising layers of titanium nitride, aluminum, and titanium nitride.

4. The method of claim 1 wherein the conductive layer is formed as a multilayer stack comprising layers of titanium nitride and aluminum.

5. The method of claim 1 wherein the second substrate comprises a layer of single crystal silicon.

6. The method of claim 1 wherein the step of exposing a portion of the upper surface of the plurality of bias electrodes comprises etching a second portion of the second substrate and the dielectric bond pads to open contact vias passing through at least the standoff region and the dielectric bond pads.

7. A method of fabricating an electrical connection for a spatial light modulator, the method comprising:

providing a first substrate, the first substrate comprising;

a bias electrode array coupled to the first substrate, the bias electrode array having an upper surface and a lower surface; and

a dielectric standoff array coupled to the upper surface of the bias electrode array;

providing a second substrate having an upper surface and a bonding surface;

joining the dielectric standoff array to the bonding surface;

forming mirror structures from a portion of the second substrate;

exposing at least an upper surface of the conductive connector array; and

depositing a conductive layer on the mirror structures and the upper surface of the conductive connector array.

8. The method of claim 7 wherein the first substrate further comprises a conductive connector array coupled to the upper surface of the bias electrodes and partially surrounded by the dielectric standoff array.

9. The method of claim 8 wherein the first substrate further comprises an additional dielectric layer coupled to the dielectric standoff array and the conductive connector array and wherein the step of exposing at least an upper surface of the conductive connector array further comprises etching a portion of the additional dielectric layer to expose the upper surface of the conductive connector array.

10. The method of claim 8 wherein the conductive connector array is fabricated from tungsten.

11. The method of claim 9 wherein the conductive connector array comprises a plurality of tungsten plugs formed in the dielectric standoff array.

12. The method of claim 7 wherein the dielectric standoff regions are fabricated from materials selected from the group consisting of silicon dioxide, silicon nitride, and silicon oxynitride.

13. The method of claim 7 wherein the conductive layer is formed as a multilayer stack comprising layers of titanium nitride and aluminum.

14. A spatial light modulator adapted to reflect incident light, the spatial light modulator comprising:

a first substrate comprising a bias grid;

a bias electrode array coupled to the first substrate and electrically coupled to the bias grid;

a dielectric bond pad array coupled to the bias electrode array;

a standoff region array coupled to the dielectric bond pad array;

a plurality of mirror plates having an upper surface, the plurality of mirror plates flexibly coupled to the standoff region array; and

an electrically conductive layer deposited on the upper surface of the plurality of mirror plates and a portion of the bias electrode array to electrically couple the plurality of mirror plates to the bias electrode array.

15. The spatial light modulator of claim 14 further comprising a second reflective layer deposited on the electrically conductive layer.

16. The spatial light modulator of claim 14 wherein the electrically conductive layer is deposited on an internal surface of the standoff regions.

17. The spatial light modulator of claim 16 wherein the first and second electrically conductive layers are deposited sequentially.

18. The spatial light modulator of claim 14 wherein the standoff regions are formed from a single crystal silicon substrate.

19. The spatial light modulator of claim 14 wherein the standoff regions are formed from one or more deposited dielectric layers.

20. The spatial light modulator of claim 19 further comprising a plurality of tungsten connectors partially surrounded by portions of the standoff region array and electrically coupled to the bias electrode array.