Methods of fabricating MEMS with spacers between plates and devices formed by same

• US 8,830,557 B2
• Filed: 09/10/2012
• Issued: 09/09/2014
• Est. Priority Date: 05/11/2007
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Sampsell, Jeffrey Brian, Gally, Brian James, Floyd, Philip Don
• Primary Examiner(s): Choi, William
• Application Number:
  US13/608,949
• Publication Number:
  US 20130003160A1
• Time in Patent Office: 729 Days
• Field of Search: 359/230, 359/231, 359290-292
• US Class Current: 359/290
• CPC Class Codes: B81B 2201/042 Micromirrors, not used as optical switches
• CPC Class Codes: B81B 2207/07 Interconnects
• CPC Class Codes: B81B 2207/092 Buried interconnects in the substrate or in the lid
• 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
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G02B 5/284 of etalon type comprising a resonant cavity other than a thin solid film, e.g. gas, air, solid plates etalons for fibre optic multiplexing G02B6/29358; etalons for spectral measurement G01J3/26
• CPC Class Codes: H01L 31/04 adapted as photovoltaic [PV] conversion devices testing thereof during manufacture H01L22/00; testing thereof after manufacture H02S50/10
• CPC Class Codes: Y10T 29/49126 Assembling bases

Abstract

Methods of fabricating an electromechanical systems (EMS) device with spacers between plates and EMS devices formed by the same are disclosed. In one embodiment, a EMS device is fabricated by laminating a front substrate and a carrier, each of which has components preformed thereon. The front substrate is provided with stationary electrodes formed thereover. A carrier including movable electrodes formed thereover is attached to the front substrate. The carrier may be released after transferring the movable electrodes to the front substrate. In other embodiments, the carrier stays over the front substrate, and serves as a backplate for the EMS device. Features are formed by deposition and patterning, by embossing, or by patterning and etching. Spacers are provided between the front substrate and the backplate to maintain a gap therebetween. The resulting EMS devices can trap smaller volumes between laminated substrates and are less susceptible to pressure variations and moisture leakage.

Claims

1. An electromechanical system device, comprising:

a front substrate having a first surface, the front substrate including an optical stack formed over the first surface;

a backplate opposing the front substrate, the backplate having a second surface facing the first surface, the backplate including;

supports extending from the second surface toward the first surface such that the height of the supports defines a distance between the first surface and the second surface; and

a plurality of posts projecting from the backplate towards the front substrate; and

a plurality of movable electrode strips extending substantially parallel to one another, the strips being suspended from the plurality of posts, spaced apart from the front substrate and the backplate, and interposed between the first surface and the second surface.

2. The device of claim 1, wherein the first surface of the front substrate includes an array region within which the movable electrode strips are positioned, and wherein the array region of the first surface is devoid of posts.

3. The device of claim 1, wherein the optical stack over the first surface is discontinuous.

4. The device of claim 1, wherein the optical stack includes a partially reflective layer.

5. The device of claim 4, wherein the optical stack further includes an electrode layer.

6. The device of claim 4, wherein the optical stack and at least one of the movable electrode strips constitute an interferometric modulator.

7. The device of claim 1, wherein the front substrate includes a peripheral region including a land, wherein the land supports portions of the movable electrode strips.

8. The device of claim 1, wherein the front substrate includes a plurality of stationary electrodes separated by a gap from the movable electrode strips.

9. An electromechanical system device, comprising:

a front substrate;

a backplate opposing the front substrate, the backplate having a surface facing the front substrate;

a plurality of movable electrode strips extending substantially parallel to one another, the strips being interposed between the front substrate and the backplate, portions of the strips being movable toward the front substrate; and

a plurality of spacers extending from the surface of the backplate such that the spacers are arranged to limit movement of the portions of the strips toward the surface of the backplate.

10. The device of claim 9, wherein the plurality of movable electrode strips are suspended from the plurality of spacers.

11. The device of claim 9, further comprising a plurality of first supports extending from the front substrate toward the backplate, each of the first supports including at least one of a post and a rail.

12. The device of claim 11, wherein portions of the movable electrode strips are interposed between the first supports and the spacers of the backplate.

13. The device of claim 11, wherein the front substrate includes an optical stack between the front substrate and the backplate.

14. The device of claim 13, wherein the electromechanical system device includes an interferometric modulator including a reflective layer and at least one of the movable electrode strips.

15. The device of claim 13, wherein portions of the optical stack are between the first supports and the movable electrode strips.

16. The device of claim 11, wherein the movable electrode strips include openings and wherein the spacers extend through the openings.

17. The device of claim 9, wherein the backplate includes a plurality of stop posts configured to prevent overshoot of the movable electrode strips towards the backplate.

18. The device of claim 17, wherein the movable electrode strips are suspended from the stop posts.

19. The device of claim 17, wherein the movable electrode strips do not contact the stop posts.

20. An electromechanical system device, comprising:

a front substrate having a first surface, the front substrate including an optical stack formed over the first surface;

a backplate opposing the front substrate, the backplate having a second surface facing the first surface, the backplate including supports extending from the second surface toward the first surface such that the height of the supports defines a distance between the first surface and the second surface; and

a plurality of movable electrode strips extending substantially parallel to one another, the strips being interposed between the first surface and the second surface,

wherein the optical stack includes a partially reflective layer.

21. The device of claim 20, wherein the first surface of the front substrate includes an array region within which the movable electrode strips are positioned, and wherein the array region of the first surface is devoid of posts.

22. The device of claim 20, wherein the optical stack over the first surface is discontinuous.

23. The device of claim 20, wherein the optical stack further includes an electrode layer.

24. The device of claim 20, wherein the optical stack and at least one of the movable electrode strips constitute an interferometric modulator.

25. The device of claim 20, wherein the front substrate includes a peripheral region including a land, wherein the land supports portions of the movable electrode strips.

26. The device of claim 20, wherein the front substrate includes a plurality of stationary electrodes separated by a gap from the movable electrode strips.