Method of fabricating micromirror device

• US 7,866,036 B2
• Filed: 10/14/2008
• Issued: 01/11/2011
• Est. Priority Date: 02/12/2003
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Duboc, Robert M. Jr., Patel, Satyadev R., Doan, Jonathan C.
• Primary Examiner(s): Nguyen; Donghai D.
• Application Number:
  US12/250,652
• Publication Number:
  US 20090039536A1
• Time in Patent Office: 819 Days
• Field of Search: 298/30, 298/46, 298/52, 216/24, 216/79, 359/198, 359/224.1, 359/291, 359/292, 359/295, 359/846, 438/29, 438/700
• US Class Current: 29/846
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: Y10T 29/49155 Manufacturing circuit on or in base

Abstract

A micromirror device and a method of making the same are disclosed herein. The micromirror device comprises a mirror plate, hinge, and post each having an electrically conductive layer. One of the hinge, mirror plate, and post further comprises an electrically insulating layer. To enable the electrical connections between the conducting layers of the hinge, mirror plate, and post, the insulating layer is patterned.

Claims

1. A method of fabricating a micromirror device, comprising:

depositing first and second sacrificial layers on a substrate;

forming a reflective mirror plate on one of the first or second sacrificial layers;

forming a deformable hinge on the other sacrificial layer, the hinge forming comprising;

forming the hinge that has a first hinge layer that is electrically insulating and a second hinge layer that is electrically conducting, wherein the first hinge layer is disposed between the second hinge layer and the reflective mirror plate; and

wherein the first hinge layer is patterned such that at least a portion of the second hinge layer is electrically connected to the reflective mirror plate; and

removing the first and second sacrificial layers so as to free the mirror plate.

2. The method of claim 1, wherein the first and second hinge layers have different shapes after patterning.

3. The method of claim 2, wherein the step of forming the deformable hinge further comprises:

forming a post for supporting the deformable hinge and mirror plate, comprising;

depositing a first post layer that is electrically conductive, wherein said first post layer is electrically connected to the electrically conductive layer of the deformable hinge.

4. The method of claim 3, further comprising:

depositing a second post layer that is electrically insulating; and

patterning the second post layer such that the first post layer which is electrically insulating is electrically connected to the electrically conductive layer of the hinge.

5. The method of claim 4, wherein the step of forming the deformable hinge further comprises:

depositing and patterning a third hinge layer.

6. The method of claim 5, wherein the third hinge layer is electrically conductive.

7. The method of claim 6, wherein the third hinge layer is electrically insulating.

8. The method of claim 4, wherein the first hinge layer comprises SiNx.

9. The method of claim 4, wherein the second hinge layer comprises TiNx.

10. The method of claim 2, wherein the first sacrificial layer is deposited on the substrate;

wherein the mirror plate is formed on the first sacrificial layer;

wherein the second sacrificial layer is deposited and patterned on the first sacrificial layer and the formed mirror plate; and

wherein the deformable hinge is formed on the second sacrificial layer.

11. The method of claim 2, wherein the first sacrificial layer is deposited on the substrate that is a semiconductor substrate;

wherein the deformable hinge is formed on the first sacrificial layer;

wherein the second sacrificial layer is deposited on the first sacrificial layer and the deformable hinge; and

wherein the mirror plate is formed on the second sacrificial layer.

12. The method of claim 2, wherein the step of forming the mirror plate further comprises:

depositing first and second mirror plate layers, wherein the first layer comprises a visible light reflective layer; and

wherein the second mirror plate layer comprises a mechanical enhancing layer for improving a mechanical property of the mirror plate.

13. The method of claim 12, wherein the first mirror plate is electrically conductive.

14. The method of claim 13, wherein the second mirror plate layer is electrically insulating.

15. The method of claim 14, wherein the first mirror plate is electrically connected to the second hinge layer.

16. The method of claim 14, further comprising:

depositing a third mirror plate layer such that the first mirror plate is laminated between two electrically insulting layers.

17. The method of claim 16, further comprising:

patterning the third mirror plate layer that is electrically insulting such that the electrically conductive first mirror plate layer is electrically connected to the first hinge layer that is electrically conductive.

18. The method of claim 1, wherein the substrate is transmissive to visible light.

19. The method of claim 1, wherein the substrate is a standard semiconductor substrate on which an integrated circuit can be fabricated.

20. The method of claim 1, wherein the first sacrificial layer comprises amorphous silicon.

21. The method of claim 1, wherein the second sacrificial layer comprises amorphous silicon.

22. The method of claim 21, wherein the first and second sacrificial layers are removed with a spontaneous vapor phase chemical etchant.

23. The method of claim 22, wherein the spontaneous vapor phase chemical etchant comprises an interhalogen.

24. The method of claim 23, wherein the spontaneous vapor phase chemical etchant comprises a noble gas halide.

25. The method of claim 24, wherein the noble gas halide is xenon difluoride.

26. The method of claim 22, wherein the etchant comprises a diluent gas.

27. The method of claim 26, wherein the diluent gas is an inert gas.