Electromechanical devices having overlying support structures

• US 7,566,940 B2
• Filed: 07/21/2006
• Issued: 07/28/2009
• Est. Priority Date: 07/22/2005
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Ganti, SuryaPrakash, Chui, Clarence, Miles, Mark W., Kothari, Manish, Sasagawa, Teruo, Tung, Ming-Hau
• Primary Examiner(s): LE, DUNG ANH
• Application Number:
  US11/490,880
• Publication Number:
  US 20070019280A1
• Time in Patent Office: 1,103 Days
• Field of Search: 438 48- 52, 257414-420, 257/190, 257/528, 359/94, 359/224
• US Class Current: 257/419
• CPC Class Codes: B81B 2201/047 Optical MEMS not provided for in B81B2201/042 - B81B2201/045
• CPC Class Codes: B81B 2203/0307 Anchors
• CPC Class Codes: B81B 2203/053 Translation according to an axis perpendicular to the substrate
• CPC Class Codes: B81B 3/007 For controlling stiffness, e.g. ribs
• 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

Embodiments of MEMS devices comprise a conductive movable layer spaced apart from a conductive fixed layer by a gap, and supported by rigid support structures, or rivets, overlying depressions in the conductive movable layer, or by posts underlying depressions in the conductive movable layer. In certain embodiments, portions of the rivet structures extend through the movable layer and contact underlying layers. In other embodiments, the material used to form the rigid support structures may also be used to passivate otherwise exposed electrical leads in electrical connection with the MEMS devices, protecting the electrical leads from damage or other interference.

Claims

1. An electromechanical device, comprising:

a substrate;

an electrode layer located over the substrate;

a conductive movable layer located over the electrode layer, wherein the movable layer is generally spaced apart from the electrode layer by an air gap, and wherein the movable layer comprises depressions in support regions; and

rigid support structures formed over the movable layer and at least partially within the depressions in the movable layer, wherein the rigid support structures extend over only a portion of the movable layer.

2. The device of claim 1, wherein the rigid support structures extend outside the depressions over an upper surface of the movable layer.

3. The device of claim 1, wherein the support structure extends through an aperture in the movable layer to an underlying layer.

4. The device of claim 3, wherein the depressions in the movable layer comprise a substantially flat base portion, and wherein the aperture in the movable layer extends through the substantially flat base portion.

5. The device of claim 3, wherein the depressions in the movable layer comprise sidewalls, and wherein the aperture in the movable layer extends through a sidewall of the movable layer.

6. The device of claim 1, additionally comprising columns of additional material located underneath the movable layer and extending about the depressions in the movable layer, wherein said columns of additional material provide additional support for the overlying support structure.

7. The device of claim 1, additionally comprising:

a first lead located on said substrate, wherein said first lead is in electrical communication with the movable layer;

a second lead located on said substrate, wherein said second lead is in electrical communication with the electrode layer.

8. The device of claim 7, additionally comprising a passivation material patch formed over at least a portion of one of said first or second leads, wherein the passivation material patch and the rigid support structures are formed from the same material.

9. The device of claim 7, wherein the movable layer comprises a mechanical sublayer, and wherein the first lead is formed from the same material as the mechanical sublayer.

10. The device of claim 7, wherein the second lead comprises a layer of ITO in direct contact with a layer of nickel.

11. The device of claim 1, additionally comprising a dielectric layer located between the electrode layer and the air gap.

12. The device of claim 11, wherein the support structures comprise at least one material selected from the group of:

aluminum, AlO_x, silicon oxide, SiNx, nickel, and chromium.

13. The device of claim 11, additionally comprising at least one rib structure located over the movable layer and away from the depressions in the movable layer, wherein the rib structure is formed from the same material as the support structures.

14. The device of claim 1, wherein the movable layer comprises a reflective sublayer and a mechanical sublayer, and wherein the depressions in the mechanical layer comprise depressions in at least the mechanical sublayer in the support regions.

15. The device of claim 1, additionally comprising a protective layer located over the support structures.

16. The device of claim 15, wherein the protective layer comprises one or more areas of protective material which cover one or more of the rigid support structures while leaving at least a portion of the movable layer exposed.

17. The device of claim 1, additionally comprising:

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

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

18. The MEMS device of claim 17, further comprising a driver circuit configured to send at least one signal to at least one of said electrode layer and said movable layer.

19. The MEMS device of claim 18, further comprising a controller configured to send at least a portion of the image data to the driver circuit.

20. The MEMS device of claim 17, further comprising an image source module configured to send said image data to said processor.

21. The MEMS device of claim 20, wherein the image source module comprises at least one of a receiver, transceiver, and transmitter.

22. The MEMS device of claim 17, further comprising an input device configured to receive input data and to communicate said input data to said processor.

23. The device of claim 1, wherein the movable layer comprises a mechanical sublayer and a reflective sublayer suspended beneath a portion of the mechanical sublayer, wherein the reflective sublayer is partially detached from the mechanical sublayer.

24. An electromechanical device, comprising:

a substrate;

an electrode layer located over the substrate;

a movable layer located over the electrode layer, the movable layer comprising a reflective sublayer and a mechanical sublayer overlying and at least partially spaced apart from the reflective sublayer, wherein the reflective sublayer is spaced apart from the electrode layer by an air gap, and wherein the mechanical sublayer comprises depressions in support regions; and

rigid support structures formed over the mechanical sublayer and at least partially within the depressions in the mechanical sublayer.

25. The device of claim 24, wherein the rigid support structures extend outside the depressions over an upper surface of the mechanical layer.

26. The device of claim 24, wherein the support structure extends through an aperture in the movable layer to an underlying layer.

27. The device of claim 24, additionally comprising a partially reflective layer located adjacent to the electrode layer.

28. The device of claim 24, additionally comprising a dielectric layer located between the electrode layer and the air gap.

29. The device of claim 24, wherein the support structures comprise a dielectric layer.

30. The device of claim 24, wherein the mechanical sublayer comprises a conductive material.