Optical microelectromechanical device and fabrication method thereof

• US 7,164,524 B2
• Filed: 05/24/2005
• Issued: 01/16/2007
• Est. Priority Date: 12/30/2004
• Status: Active Grant

• Current Assignee: AU Optronics Corporation, Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: AU Optronics Corporation
• Inventors: Wong, Jia-Fam, Lin, Han-Tu, Lee, Chia-Sheng
• Primary Examiner(s): Ben; Loha
• Application Number:
  US11/135,900
• Publication Number:
  US 20060146391A1
• Time in Patent Office: 602 Days
• Field of Search: 359290-295, 359/298, 359/201, 359/224, 359/230, 359/231, 359/850, 359/245, 359/247, 359/321, 438/29, 438/57, 438/72, 438/73, 438/772, 430/311, 430313-318, 430/322, 430/394, 427/162, 427/163.1, 427/259, 353/99, 345/84, 345/85, 347/239, 216/58, 156/345.33
• US Class Current: 359/291
• 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: Y10S 359/904 Micromirror

Abstract

An optical microelectromechanical (MEMS) device includes a conductive layer, a dielectric layer, a reflective layer and a plurality of supporters between the dielectric layer and reflective layer. The supporters are tapers, or inversed tapers, having an acute angle, wherein a side surface of one of the supporters and the surface of the dielectric layer form the acute angle. Each supporter comprises a horizontal extending portion connecting to the reflective layer, such that the reflective layer is suspended from the dielectric layer by a predetermined gap.

Claims

1. An optical microelectromechanical device, comprising:

a conductive layer;

a dielectric layer disposed on the conductive layer;

a reflective layer disposed over the dielectric layer by a predetermined gap; and

a plurality of supporters disposed between the dielectric layer and the reflective layer, wherein a side surface of one of the supporters and the surface of the dielectric layer form an acute angle.

2. The optical microelectromechanical device as claimed in claim 1, wherein the acute angle is between about 15°

and 70°

.

3. The optical microelectromechanical device as claimed in claim 2, wherein the acute angle is about 45°

.

4. The optical microelectromechanical device as claimed in claim 1, wherein the conductive layer and the dielectric layer are made of transparent material.

5. The optical microelectromechanical device as claimed in claim 1, wherein the conductive layer comprises Indium Tin Oxide (ITO) or Chromium (Cr).

6. The optical microelectromechanical device as claimed in claim 1, wherein the dielectric layer comprises SiOx or SiNx.

7. The optical microelectromechanical device as claimed in claim 1, wherein the supporters comprise photoresists.

8. The optical microelectromechanical device as claimed in claim 1, wherein at least one of the supporters is formed as a taper.

9. The optical microelectromechanical device as claimed in claim 1, wherein at least one of the supports comprises a horizontal top portion contacting with the reflective layer.

10. The optical microelectromechanical device as claimed in claim 9, wherein the thickness of the top portion is between 300 Å

and 1500 Å

.

11. The optical microelectromechanical device as claimed in claim 9, wherein the top portion is in mushroom shape.

12. The optical microelectromechanical device as claimed in claim 11, wherein the thickness of the top portion is between 300 Å

and 1500 Å

.

13. The optical microelectromechanical device as claimed in claim 1, wherein the predetermined gap is between about 1000 Å

and 8000 Å

.

14. The microelectromechanical systems device as claimed in claim 1, wherein the reflective layer comprises Ag, Al, Rb(Al)x, Ni, or Cr.

15. A method for fabricating an optical microelectromechanical device, comprising:

forming a conductive layer, a dielectric layer, and a sacrificial layer sequentially on a substrate;

forming a plurality of openings through the sacrificial layer to expose the dielectric layer, wherein a side surface of one of the openings and the surface of the dielectric layer form an acute angle;

inserting fillers into the openings to form a plurality of supporters therein;

forming a reflective layer on the sacrificial layer and over the fillers; and

removing the sacrificial layer, such that the reflective layer is supported by the supporters, and that the reflective layer and the dielectric layer are separated by the supporters.

16. The method as claimed in claim 15, wherein the acute angle is between about 15°

and 70°

.

17. The method as claimed in claim 15, wherein the acute angle is about 45°

.

18. The method as claimed in claim 15, wherein the conductive layer comprises ITO or Cr.

19. The method as claimed in claim 15, wherein the dielectric layer comprises SiOx or SiNx.

20. The method as claimed in claim 15, wherein the fillers comprise photoresists.

21. The method as claimed in claim 15, further comprising hardening the supporters.

22. The method as claimed in claim 15, wherein the thickness of the sacrificial layer is between about 1000 Å

and 8000 Å

.

23. The method as claimed in claim 15, wherein the sacrificial layer comprises Mo, Ta, Si, or Ge.

24. The method as claimed in claim 15, wherein the reflective layer comprises Ag, Al, Rb(Al)x, Ni, or Cr.