Patterning of mechanical layer in MEMS to reduce stresses at supports

• US 7,405,863 B2
• Filed: 06/01/2006
• Issued: 07/29/2008
• Est. Priority Date: 06/01/2006
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Chung, Wonsuk, Tung, Ming-Hau
• Primary Examiner(s): Schwartz; Jordan M.
• Assistant Examiner(s): JONES, JAMES
• Application Number:
  US11/445,529
• Publication Number:
  US 20070279753A1
• Time in Patent Office: 789 Days
• Field of Search: 359/291
• US Class Current: 359/291
• CPC Class Codes: B81B 2201/047 Optical MEMS not provided for in B81B2201/042 - B81B2201/045
• CPC Class Codes: B81C 1/00666 Treatments for controlling internal stress or strain in MEMS structures
• CPC Class Codes: B81C 2201/0109 Sacrificial layers not provided for in B81C2201/0107 - B81C2201/0108
• CPC Class Codes: G02B 26/001 based on interference in an adjustable optical cavity interference filters G02B5/28; devices or arrangements using multiple reflections in spectrometry or monochromators G01J3/26

Abstract

A method of fabricating a MEMS device includes the formation of support posts having horizontal wing portions at the edges of the post. A mechanical layer is deposited over the support posts and portions of the mechanical layer overlying portions of the support post other than the horizontal wing portions are etched away. A resultant MEMS device includes a mechanical layer overlying at least a portion of the horizontal wing portions of the underlying support structures.

Claims

1. A MEMS device, comprising:

an electrode layer located over a substrate;

at least one support structure; and

a mechanical layer located over said support structure and spaced apart from the electrode layer by a cavity, the mechanical layer comprising an aperture extending through said mechanical layer and overlying a central portion of the support structure, the aperture being surrounded by an annular section of the mechanical layer which extends about the periphery of the support structure and overlies the support structure.

2. The device of claim 1, wherein the support structure comprises a substantially horizontal wing portion extending around the periphery of the support structure.

3. The device of claim 2, wherein the mechanical layer overlies only the substantially horizontal wing portion of the support structures.

4. The MEMS device of claim 1, additionally comprising a reflective layer located under the mechanical layer.

5. The MEMS device of claim 2, wherein the reflective layer extends underneath a portion of the support structure.

6. The MEMS device of claim 4, wherein the reflective layer extends over a portion of the support structure.

7. The MEMS device of claim 4, wherein the reflective layer comprises Al.

10. The MEMS device of claim 1, additionally comprising a dielectric layer located over the electrode layer.

11. The MEMS device of claim 2, wherein the support structure comprises a sloped sidewall portion located in the interior of the support structure, and a transition between said sloped sidewall portion and the horizontal wing portion.

12. The MEMS device of claim 11, wherein the mechanical layer does not overlie the transition between the sloped sidewall portion and the horizontal wing portion.

13. The MEMS device of claim 11, wherein the mechanical layer overlies the transition between the sloped sidewall portion and the horizontal wing portion.

14. The MEMS device of claim 11, wherein the support structure comprises a substantially flat base portion, and wherein the aperture in the mechanical layer exposes the transition between the sloped sidewall portion and the substantially flat base portion.

15. The MEMS device of claim 1, additionally comprising:

a processor that is configured to communicate with at least one of said electrode layer and said mechanical layer, said processor being configured to process image data; and

a memory device that is configured to communicate with said processor.

16. The MEMS device of claim 15, further comprising a driver circuit configured to send at least one signal to at least one of said electrode layer and said mechanical layer.

17. The MEMS device of claim 16, further comprising a controller configured to send at least a portion of the image data to the driver circuit.

18. The MEMS device of claim 15, further comprising an image source module configured to send said image data to said processor.

19. The MEMS device of claim 18, wherein the image source module comprises at least one of a receiver, transceiver, and transmitter.

20. The MEMS device of claim 15, further comprising an input device configured to receive input data and to communicate said input data to said processor.

8. The MEMS device of 2, additionally comprising a partially reflective layer located over the substrate.

9. The MEMS device of claim 8, wherein the partially reflective layer is located over the electrode layer.

21. An MEMS device, comprising:

an electrode layer located over a substrate;

at least one support structure;

a mechanical layer located over said support structure and spaced apart from the electrode layer by a cavity, the mechanical layer comprising an aperture overlying at least a portion of the support structure, wherein an annular section of the mechanical layer that is defined by the aperture extends about the periphery of the support structure and overlies the support structure; and

a reflective layer located under the mechanical layer, wherein the reflective layer extends underneath a portion of the support structures.

22. An MEMS device, comprising:

an electrode layer located over a substrate;

at least one support structure, wherein the support structure comprises a substantially horizontal wing portion extending wound the periphery of the support structure, a sloped sidewall portion located in the interior of the support structure and a transition between said sloped sidewall portion and the horizontal wing portion, and a substantially flat base portion; and

a mechanical layer located over said support structure and spaced apart from the electrode layer by a cavity, the mechanical layer comprising an aperture overlying at least a portion of the support structure, wherein an annular section of the mechanical layer that is defined by the aperture extends about the periphery of the support structure and overlies the support structure, and wherein the aperture in the mechanical layer exposes the transition between the sloped sidewall portion and the substantially flat base portion.