MEMS devices having support structures

• US 7,936,031 B2
• Filed: 07/21/2006
• Issued: 05/03/2011
• 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: Chung, Wonsuk, Chui, Clarence, Miles, Mark W., Sampsell, Jeffrey B., Kothari, Manish, Sasagawa, Teruo, Tung, Ming-Hau
• Primary Examiner(s): Fulk; Steven J
• Application Number:
  US11/491,490
• Publication Number:
  US 20070047900A1
• Time in Patent Office: 1,747 Days
• Field of Search: 257/432, 257/E31.127, 359/247
• US Class Current: 257/432
• 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, both rivets and posts may be used. In certain embodiments, these support structures are formed from rigid inorganic materials, such as metals or oxides. In certain embodiments, etch barriers may also be deposited to facilitate the use of materials in the formation of support structures which are not selectively etchable with respect to other components within the MEMS device.

Claims

1. An electromechanical device formed by a method comprising:

providing a substrate;

depositing an electrode layer over the substrate;

depositing a sacrificial layer over the electrode layer;

patterning the sacrificial layer to form apertures;

forming support structures over the sacrificial layer, wherein the support structures are formed at least partially within the apertures in the sacrificial material, wherein the support structures comprise an inorganic material, wherein an upper surface of each support structure comprises a depression within an interior region of the support structure, and wherein the support structures comprise a substantially horizontal wing portion extending over a substantially flat portion of the sacrificial material; and

depositing a movable layer over the sacrificial layer and the support structures, wherein a portion of the movable layer extends between at least two of the support structures.

2. An electromechanical device, comprising:

a substrate;

an electrode layer located over the substrate;

a movable layer located over the electrode layer, wherein the movable layer is generally spaced apart from the electrode layer by a gap; and

support structures underlying at least a portion of the movable layer, wherein a portion of the movable layer extends between at least two of the support structures, wherein each of the support structures comprises a substantially horizontal wing portion, said substantially horizontal wing portion being spaced apart from the electrode layer by the gap, wherein an upper surface of each support structure comprises a depression within an interior region of the support structure, and wherein the support structures comprise an inorganic material.

3. The device of claim 2, wherein the movable layer comprises a reflective sublayer facing the electrode layer, and a mechanical sublayer located over the reflective sublayer.

4. The device of claim 3, wherein the mechanical sublayer is at least partially spaced apart from the reflective sublayer.

5. The device of claim 3, wherein the reflective sublayer comprises aluminum.

6. The device of claim 3, wherein the mechanical sublayer comprises at least one material selected from the group of:

nickel and chromium.

7. The device of claim 3, wherein the reflective sublayer extends underneath at least a portion of each support structure.

8. The device of claim 3, additionally comprising a partially reflective layer located on the opposite side of the gap as the reflective sublayer.

9. The device of claim 3, additionally comprising at least one stiffening structure formed on the opposite side of the reflective sublayer from the electrode layer.

10. The device of claim 9, wherein the stiffening structure comprises the same material as the support structure.

11. The device of claim 2, wherein a protective layer is located between at least a portion of each support structure and the air gap.

12. The device of claim 2, additionally comprising at least one support structure located over the movable layer, wherein the at least one overlying support structure at least partially overlies at least one support structure underlying the substrate.

13. The device of claim 2, additionally comprising an adhesion enhancement layer located between the support structures and the movable layer.

14. The device of claim 2, additionally comprising a partially reflective layer located over the substrate, wherein the partially reflective layer is located on the same side of the air gap as the electrode layer.

15. The device of claim 2, wherein said depression is at least partially filled by a planarization material.

16. The device of claim 2, wherein each support structure comprises a metallic material.

17. The device of claim 2, wherein each support structure comprises an anodized material.

18. The device of claim 2, wherein the device comprises an interferometric modulator.

19. The device of claim 2, 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.

20. The device of claim 19, further comprising a driver circuit configured to send at least one signal to at least one of said electrode layer and said movable layer.

21. The device of claim 20, further comprising a controller configured to send at least a portion of the image data to the driver circuit.

22. The device of claim 19, further comprising an image source module configured to send said image data to said processor.

23. The device of claim 22, wherein the image source module comprises at least one of a receiver, transceiver, and transmitter.

24. The device of claim 19, further comprising an input device configured to receive input data and to communicate said input data to said processor.

25. An electromechanical device, comprising:

first means for electrically conducting;

second means for electrically conducting; and

means for supporting said second conducting means over said first conducting means, wherein said second conducting means overlie the supporting means, and wherein said second conducting means is movable relative to said first conducting means in response to generating electrostatic potential between said first and second conducting means, wherein said supporting means comprise a substantially horizontal wing portion spaced apart from said first conducting means, wherein an upper surface of said supporting means comprises a depression within an interior region of the supporting means, and wherein said supporting means comprise an inorganic material.

26. The device of claim 25, wherein the first conducting means comprises an electrode layer supported by a substrate.

27. The device of claim 25, wherein the second conducting means comprises a movable layer, portions of which are spaced apart from said first conducting means by an interferometric gap.

28. The device of claim 25, wherein the supporting means comprise at least two support structures formed over said first conducting means and underlying said second conducting means, wherein a portion of the second conducting means extends between at least two of said supporting means.