MICROELECTROMECHANICAL DEVICE AND METHOD UTILIZING CONDUCTING LAYERS SEPARATED BY STOPS

• US 20080239455A1
• Filed: 03/28/2007
• Published: 10/02/2008
• Est. Priority Date: 03/28/2007
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Kogut, Lior, Tung, Ming-Hau
• Granted Patent: US 7,742,220 B2
• Time in Patent Office: Days
• US Class Current: 359/291
• CPC Class Codes: B81B 2201/047 Optical MEMS not provided for in B81B2201/042 - B81B2201/045
• CPC Class Codes: B81B 3/001 Structures having a reduced contact area, e.g. with bumps or with a textured surface
• 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: Y10T 29/49002 Electrical device making

Abstract

A microelectromechanical system (MEMS) device includes a reflective element that includes at least one stop member. The device also includes an electrode and an aperture that extends at least partially through the electrode. The aperture has a boundary. The device has an electrically nonconductive surface within the aperture or on a portion of the boundary of the aperture. A support structure separates the reflective element from the electrode. The reflective element can be moved between a first position and a second position. The stop member is spaced from the electrically nonconductive surface when the reflective element is in the first position. A portion of the stop member is in contact with the electrically nonconductive surface when the reflective element is in the second position. The reflective element and the electrode are electrically isolated from each other when the reflective element is in the second position.

Claims

1. A microelectromechanical system (MEMS) device comprising:

a reflective element comprising at least one stop member;

an electrode;

an aperture extending at least partially through the electrode and having a boundary;

an electrically nonconductive surface within the aperture or on a portion of the boundary; and

a support structure separating the reflective element from the electrode;

wherein the reflective element is movable between a first position and a second position, the stop member spaced from the electrically nonconductive surface when the reflective element is in the first position, and a portion of the stop member in contact with the electrically nonconductive surface when the reflective element is in the second position, and wherein the reflective element and the electrode are electrically isolated from each other when the reflective element is in the second position.

2. The MEMS device of claim 1, wherein the reflective element and the stop member are electrically conductive.

3. The MEMS device of claim 1, wherein the portion of the stop member has a width in a range from about 0.1 μ

m to about 4 μ

m.

4. The MEMS device of claim 1, wherein when the reflective element is in the second position, a gap between the electrode and the portion of the stop member is in a range from about 0.5 μ

m to about 2 μ

m.

5. The MEMS device of claim 1, wherein the aperture has a width in a range from about 0.1 μ

m to about 6 μ

m.

6. The MEMS device of claim 1, wherein a portion of the electrode is partially reflective and partially transmissive to light in a range of wavelengths.

7. The MEMS device of claim 1, wherein a portion of the electrode is covered with a partially reflective layer.

8. The MEMS device of claim 1, wherein a portion of the electrode is covered with a passivation layer.

9. The MEMS device of claim 1, wherein the reflective element comprises a reflective surface facing toward the electrode and the stop member comprises a stop surface facing toward the electrically nonconductive surface, the stop surface positioned closer to the electrically nonconductive surface than is the reflective surface.

10. The MEMS device of claim 9, wherein the stop member extends toward the aperture by a length in a range from about 500 Å

to about 2000 Å

.

11. The MEMS device of claim 1, wherein the electrode is on an electrically nonconductive substrate and the aperture extends completely through the electrode to expose the electrically nonconductive surface.

12. The MEMS device of claim 1, further comprising an electrically nonconductive substrate and wherein the electrically nonconductive surface of the aperture comprises a portion of the substrate.

13. The MEMS device of claim 12, wherein the substrate comprises a dielectric material.

14. The MEMS device of claim 1, wherein the reflective element comprises at least a first stop member and a second stop member, and the device comprises at least a first aperture and a second aperture, the first aperture extending at least partially through the electrode and having a first boundary and the second aperture extending at least partially through the electrode and having a second boundary, the device further comprising a first electrically nonconductive surface within the first aperture or on a first portion of the first boundary and a second electrically nonconductive surface within the second aperture or on a second portion of the second boundary, and wherein, when the reflective element is in the second position, at least a first portion of the first stop member is in contact with the first electrically nonconductive surface and at least a second portion of the second stop member is in contact with the second electrically nonconductive surface.

15. The MEMS device of claim 1, wherein the support structure comprises a mechanical layer and wherein the reflective element comprises a portion of the mechanical layer.

16. The MEMS device of claim 1, wherein the support structure comprises a mechanical layer and wherein the reflective element is mechanically coupled to the mechanical layer.

17. The MEMS device of claim 1, wherein the support structure comprises a plurality of posts.

18. The MEMS device of claim 1, further comprising:

a display;

a processor that is configured to communicate with said display, said processor being configured to process image data; and

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

19. The MEMS device of claim 18, further comprising a driver circuit configured to send at least one signal to said display.

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

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

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

23. The MEMS device of claim 18, further comprising an input device configured to receive input data and to communicate said input data to said processor.

24. A microelectromechanical system (MEMS) device comprising:

means for reflecting light, the reflecting means comprising means for stopping movement of the reflecting means;

means for conducting electricity;

means for receiving the stopping means, the receiving means having a boundary, the receiving means having an electrically nonconductive portion within the receiving means or on the boundary; and

means for separating the reflecting means and the conducting means,

wherein the reflecting means is movable between a first position and a second position, the stopping means spaced from the electrically nonconductive portion when the reflecting means is in the first position, and a portion of the stopping means in contact with the electrically nonconductive portion when the reflecting means is in the second position, and wherein the reflecting means and the conducting means are electrically isolated from each other when the reflecting means is in the second position.

25. The MEMS device of claim 24, wherein the reflecting means comprises a reflective element.

26. The MEMS device of claim 24, wherein the stopping means comprises at least one stop member.

27. The MEMS device of claim 24, wherein the reflecting means comprises a surface facing toward the conducting means and the stopping means comprises one or more portions of the surface facing toward the electrically nonconductive portion, the stopping means extending toward the receiving means wherein at least a portion of the stopping means is closer to the electrically nonconductive portion than is the reflecting means.

28. The MEMS device of claim 24, wherein the conducting means comprises an electrode.

29. The MEMS device of claim 28, wherein the receiving means comprises at least one aperture extending at least partially through the electrode.

30. The MEMS device of claim 29, wherein the electrically nonconductive portion of the receiving means comprises an electrically nonconductive surface within the aperture or on a portion of the boundary.

31. The MEMS device of claim 24, wherein the separating means comprises a support structure.

32. The MEMS device of claim 31, wherein the support structure comprises a mechanical layer and one or more posts.

33. A method of manufacturing a microelectromechanical system (MEMS) device, the method comprising:

providing a substrate;

forming an electrode on the substrate;

removing a portion of the electrode to form an aperture;

forming a first sacrificial layer over the electrode and the aperture;

removing a portion of the first sacrificial layer over the aperture;

forming a second sacrificial layer over the first sacrificial layer;

forming a reflective element over the second sacrificial layer, the reflective element having at least one stop member extending toward the aperture; and

removing the first and the second sacrificial layers.

34. The method of claim 33, wherein the substrate comprises a dielectric material.

35. The method of claim 33, wherein the electrode has a thickness in a range from about 50 Å

to about 1000 Å

.

36. The method of claim 33, wherein the aperture has a width in a range from about 0.1 μ

m to about 6 μ

m.

37. The method of claim 33, wherein the first sacrificial layer has a thickness of about 795 Å

.

38. The method of claim 33, wherein the second sacrificial layer has a thickness of about 2000 Å

.

39. The method of claim 33, wherein the second sacrificial layer is conformal to the first sacrificial layer.

40. The method of claim 33, wherein forming a reflective element comprises depositing a reflective material as a conformal thin film over the second sacrificial layer.

41. The method of claim 40, wherein the conformal thin film has a thickness in a range from about 300 Å

to about 10,000 Å

.

42. The method of claim 33, wherein removing a portion of the first sacrificial layer over the aperture comprises removing the first sacrificial layer to expose a portion of the substrate.

43. The method of claim 33, further comprising forming a partially reflective layer on the electrode before removing the portion of the electrode to form the aperture.

44. The method of claim 33, wherein removing the first and the second sacrificial layers comprises etching with an etchant.

45. The method of claim 33 further comprising, after forming the second sacrificial layer:

removing a portion of the first and the second sacrificial layers to form a hole; and

filling the hole with a dielectric material to form a support post.

46. The method of claim 33, further comprising removing a portion of the reflective element to form a mirror before removing the first and the second sacrificial layers.

47. The method of claim 46, further comprising forming a third sacrificial layer over the mirror and portions of the second sacrificial layer.

48. The method of claim 47, further comprising forming a mechanical layer over the third sacrificial layer.

49. The method of claim 48, further comprising removing the third sacrificial layer.

50. A microelectromechanical system (MEMS) device manufactured with the method of claim 33.