Fabrication of a high fill ratio reflective spatial light modulator with hidden hinge

• US 7,428,094 B2
• Filed: 07/03/2007
• Issued: 09/23/2008
• Est. Priority Date: 06/19/2002
• Status: Expired due to Term

• Current Assignee: Miradia Inc. (Walsin Lihwa Corporation)
• Original Assignee: Miradia Inc. (Walsin Lihwa Corporation)
• Inventors: Yang, Xiao, Pan, Shaoher X
• Primary Examiner(s): Choi; William C.
• Assistant Examiner(s): Dinh; Jack
• Application Number:
  US11/825,316
• Publication Number:
  US 20080062503A1
• Time in Patent Office: 448 Days
• Field of Search: 359/237, 359/291, 359/900, 216/2
• US Class Current: 359/291
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: Y10S 359/90 Methods

Abstract

A method of fabricating a spatial light modulator. The method includes forming cavities in a first substrate and fabricating electrodes on a second substrate. The method also includes bonding the first substrate to the second substrate and forming a mirror plate from a portion of the first substrate. The mirror plate has an upper surface and a lower surface. The method further includes forming a hinge coupled to the mirror plate and forming a reflective surface coupled to the upper surface of the mirror plate.

Claims

1. A method of fabricating a spatial light modulator having a silicon-bearing standoff structure, the method comprising:

providing a first substrate including a mirror plate layer;

forming a dielectric layer on the mirror plate layer;

removing a first portion of the dielectric layer to provide standoff cavities disposed in the dielectric layer;

filling the first portion of the standoff cavities with a silicon-bearing material, thereby forming a standoff structure;

removing a second portion of the dielectric layer;

providing a second substrate having one or more electrodes;

bonding the first substrate to the second substrate;

forming a hinge and mirror plate from the mirror plate layer; and

applying a reflective surface coupled to the mirror plate and above a portion of the hinge.

2. The method of claim 1 wherein removing the second portion of the dielectric layer includes removing a remainder of the dielectric layer.

3. The method of claim 1 wherein the standoff structure and mirror plate layer are formed from a same material.

4. The method of claim 1 wherein at least one of the mirror plate layer or the standoff structure comprises at least one of a single crystal silicon material or a polysilicon material.

5. The method of claim 1 wherein the mirror plate layer and the standoff structure have a same crystal orientation.

6. The method of claim 1 further comprising forming a motion stop structure coupled to the mirror plate layer.

7. The method of claim 6 wherein the motion stop structure comprises a silicon bearing material.

8. The method of claim 6 wherein forming the motion stop structure comprises performing an etching process and performing an epitaxial process.

9. The method of claim 1 wherein filling the first portion of the standoff cavities comprises performing an epitaxial process.

10. The method of claim 1 wherein removing the first portion of the dielectric layer comprises performing an etching process.

11. The method of claim 1 wherein the dielectric layer comprises a deposited layer.

12. A method of fabricating an array of micro-mirrors for a spatial light modulator having a silicon-bearing standoff structure, the method comprising:

providing a first substrate including a mirror plate layer;

forming a dielectric layer on the mirror plate layer;

removing a first portion of the dielectric layer to provide an array of standoff cavities disposed in the dielectric layer;

filling some of the first portion of the array of standoff cavities with a silicon-bearing material, thereby forming an array of standoff structures;

removing a second portion of the dielectric layer;

providing a second substrate having one or more electrodes;

bonding the first substrate to the second substrate; and

forming an array of micro-mirrors, wherein each of the micro-mirrors comprises;

a mirror plate and a hinge formed from the mirror plate layer, and

a reflective surface coupled to the top surface of the mirror plate and above a portion of the hinge.

13. The method of claim 12 wherein removing the second portion of the dielectric layer includes removing a remainder of the dielectric layer.

14. The method of claim 12 wherein the standoff structure comprises a polysilicon material.

15. The method of claim 12 further comprising forming a motion stop structure coupled to the mirror plate layer.

16. The method of claim 15 wherein the motion stop structure comprises a polysilicon material.

17. The method of claim 12 wherein the dielectric layer comprises a deposited layer.

18. A method of fabricating a spatial light modulator array, the method comprising:

providing a first substrate including a mirror plate layer;

forming a dielectric layer on the mirror plate layer;

removing a first portion of the dielectric layer to provide an array of standoff cavities disposed in the dielectric layer, wherein the standoff cavities are provided in a spatial manner as an array including a plurality of first standoff cavities arranged in strips and a plurality of second standoff cavities arranged in strips, the second standoff cavities intersecting the first standoff cavities to form the array;

filling at least a portion of the first portion of the array of standoff cavities with a silicon-bearing material, thereby forming an array of standoff structures;

removing a second portion of the dielectric layer;

providing a second substrate having one or more electrodes;

bonding the first substrate to the second substrate;

forming an array of micro-mirrors, wherein each of the micro-mirrors comprises;

a mirror plate and a hinge formed from the mirror plate layer, and

a reflective surface coupled to the top surface of the mirror plate and above a portion of the hinge.

19. The method of claim 18 further comprising forming a plurality of motion stop structures coupled to the mirror plate layer.

20. The method of claim 19 wherein the plurality of motion stop structures comprise a silicon bearing material.