Method and structure reducing parasitic influences of deflection devices in an integrated spatial light modulator

• US 7,184,195 B2
• Filed: 06/15/2005
• Issued: 02/27/2007
• Est. Priority Date: 06/15/2005
• Status: Active Grant

• Current Assignee: Miradia Inc. (Walsin Lihwa Corporation)
• Original Assignee: Miradia Inc. (Walsin Lihwa Corporation)
• Inventors: Yang, Xiao
• Primary Examiner(s): Fourson; George
• Assistant Examiner(s): MANDALA, VICTOR A
• Application Number:
  US11/154,834
• Publication Number:
  US 20060285191A1
• Time in Patent Office: 622 Days
• Field of Search: 257/414, 359/223, 359/224, 359/291, 359/292, 359/295, 359/298
• US Class Current: 359/295
• CPC Class Codes: B81B 2201/047 Optical MEMS not provided for in B81B2201/042 - B81B2201/045
• CPC Class Codes: B81B 3/001 Structures having a reduced contact area, e.g. with bumps or with a textured surface
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means

Abstract

A method of fabricating an integrated spatial light modulator with contact structures. The method includes providing a first substrate having a bonding surface, providing a device substrate having a device surface, and depositing a first layer on the device surface, the first layer having an upper surface opposite the device surface. The method also includes patterning the first layer to define a plurality of contact structure openings, depositing a conductive layer on the upper surface of the first layer, reducing the thickness of the conductive layer, and removing at least a portion of the first layer to expose a plurality of contact structures. The method further includes depositing a standoff layer on the first layer, forming standoff structures from the standoff layer, and joining the bonding surface of the first substrate to the standoff structures to form a bonded substrate structure.

Claims

1. A spatial light modulator comprising:

a first substrate, the first substrate comprising a plurality of electrodes adapted to receive control signals;

a bias grid coupled to the first substrate and electrically isolated from the plurality of electrodes;

a standoff structure coupled to the first substrate;

a mirror plate bonded to the standoff structure, electrically coupled to the bias grid, and adapted to rotate from a first orientation to a second orientation in response to the control signals received by the plurality of electrodes;

a landing post support structure coupled to the first substrate and electrically coupled to the bias grid; and

a landing post coupled to the landing post support structure, electrically coupled to the bias grid, and adapted to make contact with the mirror plate positioned at the first orientation.

2. The spatial light modulator of claim 1 wherein the standoff structure is fabricated from a layer deposited at a temperature of less than 400°

C.

3. The spatial light modulator of claim 2 wherein the layer is selected from the group consisting of silicon oxide, silicon nitride, and silicon oxynitride.

4. The spatial light modulator of claim 2 wherein the layer is polished using a chemical mechanical polishing process after deposition.

5. The spatial light modulator of claim 1 wherein the landing post is fabricated from tungsten.

6. The spatial light modulator of claim 1 wherein the landing post is fabricated using a premetal contact hole or inter-metal dielectric via plug process.

7. The spatial light modulator of claim 1 wherein the mirror layer comprises a torsion spring hinge.

8. An array of integrated spatial light modulators comprising:

an electrode layer coupled to a device substrate, the electrode layer including a plurality of electrodes and at least one alignment mark;

a bias grid layer coupled to the device substrate and electrically isolated from the electrode layer;

a plurality of landing posts coupled to the device substrate and electrically coupled to the bias grid layer;

a three-dimensional standoff structure, the standoff structures having side regions defined in a plane perpendicular to the device substrate, a bottom region coupled to the device substrate, and a top region opposite the bottom region; and

a silicon layer coupled to the top region of the standoff structure, the silicon layer comprising;

a hinge support region coupled to the top region of the standoff structure;

a plurality of hinges coupled to the hinge support region; and

a plurality of moveable members aligned with respect to the at least one alignment mark by imaging the at least one alignment mark through the silicon layer.

9. The array of integrated spatial light modulators of claim 8 wherein the standoff structure is fabricated from a layer deposited at a temperature of less than 400°

C., the layer being selected from the group consisting of silicon oxide, silicon nitride, and silicon oxynitride.

10. The array of integrated spatial light modulators of claim 9 wherein the layer is polished using a chemical mechanical polishing process after deposition.

11. The array of integrated spatial light modulators of claim 8 wherein the landing posts are fabricated from tungsten.

12. The array of integrated spatial light modulators of claim 8 wherein the landing posts are fabricated using a premetal contact hole or inter-metal dielectric via plug process.

13. The array of integrated spatial light modulators of claim 8 wherein the silicon layer is semi-transparent during at least one stage of processing.