Method of manufacturing MEMS devices providing air gap control

• US 8,964,280 B2
• Filed: 01/23/2012
• Issued: 02/24/2015
• Est. Priority Date: 06/30/2006
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Tung, Ming-Hau, Kogut, Lior
• Primary Examiner(s): Jones, James
• Application Number:
  US13/356,447
• Publication Number:
  US 20120122259A1
• Time in Patent Office: 1,128 Days
• Field of Search: 359/290, 359/291
• US Class Current: 359/290
• CPC Class Codes: B81B 2201/042 Micromirrors, not used as optical switches
• CPC Class Codes: B81B 3/0072 For controlling internal stress or strain in moving or flexible elements, e.g. stress compensating layers
• CPC Class Codes: B81C 1/00047 Cavities
• CPC Class Codes: B81C 2201/0167 by adding further layers of materials having complementary strains, i.e. compressive or tensile strain

Abstract

Methods and apparatus are provided for controlling a depth of a cavity between two layers of a light modulating device. A method of making a light modulating device includes providing a substrate, forming a sacrificial layer over at least a portion of the substrate, forming a reflective layer over at least a portion of the sacrificial layer, and forming one or more flexure controllers over the substrate, the flexure controllers configured so as to operably support the reflective layer and to form cavities, upon removal of the sacrificial layer, of a depth measurably different than the thickness of the sacrificial layer, wherein the depth is measured perpendicular to the substrate.

Claims

1. A method of making an electromechanical systems device, the method comprising:

providing a substrate;

forming a plurality of movable elements over the substrate, wherein each movable element is separated from the substrate; and

forming a plurality of flexure controllers over the substrate that are configured to operably support the movable elements, wherein the flexure controllers include wing portions, each wing portion being connected to a portion of a movable element which it supports, and wherein the plurality of flexure controllers include at least two flexure controllers having wing portions of differing length.

2. The method of claim 1, further including forming an electrically conductive layer over at least a portion of the substrate.

3. The method of claim 1, wherein at least a portion of each movable element is electrically conductive.

4. The method of claim 1, wherein at least a portion of each movable element includes a reflective surface.

5. The method of claim 1, wherein each of the plurality of movable elements are configured such that at least a portion of a movable element deforms in response to a deflection of a flexure controller supporting the movable element.

6. The method of claim 1, further comprising forming the plurality of flexure controllers from one or more of silicon nitride (SiN) and silicon dioxide (SiO₂).

7. The method of claim 1, wherein the plurality of flexure controllers are selected from post structures and rivet structures.

8. The method of claim 1, wherein the wing portions of the plurality of flexure controllers contacting respective movable elements overlap the movable elements by a distance between 1 μ

m to 6 μ

m.

9. The method of claim 1, further comprising forming a sacrificial layer upon at least a portion of the substrate.

10. The method of claim 9, further comprising removing the sacrificial layer, wherein each movable element is separated from the substrate by a cavity formed after removal of the sacrificial layer, and wherein the plurality of flexure controllers operably support the movable elements after removal of the sacrificial layer.

11. A method of making an electromechanical systems device, the method comprising:

providing a substrate;

forming a plurality of movable elements over the substrate, wherein each movable element is separated from the substrate; and

forming a plurality of flexure controllers over the substrate that are configured to operably support the movable elements, wherein the flexure controllers include wing portions, each wing portion being connected to a portion of a movable element which it supports, and wherein at least a portion of at least two of the plurality of flexure controllers include wing portions of differing thickness.

12. The method of claim 11, further comprising forming an electrically conductive layer over at least a portion of the substrate.

13. The method of claim 11, wherein at least a portion of each movable element is electrically conductive.

14. The method of claim 11, wherein at least a portion of the plurality of movable elements include a reflective surface.

15. The method of claim 11, wherein each of the plurality of movable elements are configured such that at least a portion of a movable element deforms in response to a deflection of a flexure controller supporting the movable element.

16. The method of claim 11, further including forming the plurality of flexure controllers from one or more of silicon nitride (SiN) and silicon dioxide (SiO₂).

17. The method of claim 11, wherein the plurality of flexure controllers are selected from post structures and rivet structures.

18. The method of claim 11, wherein the thickness of the plurality of flexure controllers is selected between 1000 μ

m to 2000 μ

m.

19. The method of claim 11, further comprising forming a sacrificial layer upon at least a portion of the substrate.

20. The method of claim 19, further comprising removing the sacrificial layer, wherein each movable element is separated from the substrate by a cavity formed after removal of the sacrificial layer, and wherein the plurality of flexure controllers operably support the movable elements after removal of the sacrificial layer.

21. A method of making an electromechanical systems device, the method comprising:

providing a substrate;

forming a plurality of movable elements over the substrate, each movable element is separated from the substrate; and

forming a plurality of flexure controllers over the substrate configured so as to operably support the movable elements, wherein the flexure controllers include wing portions, each wing portion being connected to a portion of a movable element which it supports, and wherein at least two of the plurality of flexure controllers include different materials.

22. The method of claim 21, further comprising forming an electrically conductive layer over at least a portion of the substrate.

23. The method of claim 21, wherein at least a portion of each movable element is electrically conductive.

24. The method of claim 21, wherein at least a portion of the plurality of movable elements include a reflective surface.

25. The method of claim 21, wherein each of the plurality of movable elements are configured such that at least a portion of a movable element deforms in response to a deflection of a flexure controller supporting the movable element.

26. The method of claim 21, further comprising forming the plurality of flexure controllers from one or more of silicon nitride (SiN) and silicon dioxide (SiO₂).

27. The method of claim 21, wherein the plurality of flexure controllers are selected from post structures and rivet structures.

28. The method of claim 21, further comprising forming a sacrificial layer upon at least a portion of the substrate.

29. The method of claim 28, further comprising removing the sacrificial layer, wherein each movable element is separated from the substrate by a cavity formed after removal of the sacrificial layer, and wherein the plurality of flexure controllers operably support the movable elements after removal of the sacrificial layer.

30. A method of forming an electromechanical systems device, the method comprising:

providing a substrate;

forming a plurality of movable elements over the substrate, each movable element separated from the substrate; and

forming a plurality of flexure controllers over the substrate configured so as to operably support the movable elements, wherein the flexure controllers include wing portions, each wing portion being connected to a portion of a movable element which it supports, and wherein the flexure controllers further include tapered edges connected to the wing portions, and a base which operably supports the edges and separates the edges by a selected distance.

31. The method of claim 30, further comprising forming an electrically conductive layer over at least a portion of the substrate.

32. The method of claim 30, wherein at least a portion of each movable element is electrically conductive.

33. The method of claim 30, wherein at least a portion of the plurality of movable elements include a reflective surface.

34. The method of claim 30, wherein each of the plurality of movable elements are configured such that at least a portion of a movable element deforms in response to a deflection of a flexure controller supporting the movable element.

35. The device of claim 30, further comprising forming the plurality of flexure controllers from one or more of silicon nitride (SiN) and silicon dioxide (SiO₂).

36. The method of claim 30, wherein the plurality of flexure controllers are selected from post structures and rivet structures.

37. The method of claim 30, further comprising forming a sacrificial layer upon at least a portion of the substrate.

38. The method of claim 37, further comprising removing the sacrificial layer, wherein each movable element is separated from the substrate by a cavity formed after removal of the sacrificial layer, and wherein the plurality of flexure controllers operably support the movable elements after removal of the sacrificial layer.