Method of manufacturing MEMS devices providing air gap control

• US 7,952,787 B2
• Filed: 05/05/2009
• Issued: 05/31/2011
• 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: Kogut, Lior, Tung, Ming-Hau
• Primary Examiner(s): Choi; William C
• Application Number:
  US12/436,064
• Publication Number:
  US 20090273823A1
• Time in Patent Office: 756 Days
• Field of Search: 359/198.1, 359/200.6, 359/200.7, 359/200.8, 359/224.1, 359/247, 359/290, 359/291, 359/302
• 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. An electromechanical device, comprising:

a substrate;

a plurality of moveable elements over the substrate, each moveable element separated from the substrate by a cavity; and

a plurality of flexure controllers over the substrate configured so as to operably support the moveable elements, wherein the flexure controllers comprise wing portions, each wing portion being connected to a portion of a movable element which it supports, and wherein the wing portions of at least one of the plurality of flexure controllers underlies the portion of the moveable elements that it is connected to and supports.

2. The device of claim 1, further comprising an electrically conductive layer over at least a portion of the substrate.

3. The device of claim 1, wherein at least a portion of the plurality of moveable elements are electrically conductive.

4. The device of claim 1, wherein at least a portion of the plurality of moveable elements comprise a reflective surface.

5. The device of claim 1, wherein the plurality of flexure controllers are formed from one or more of silicon nitride (SiN) and silicon dioxide (SiO₂).

6. An electromechanical device, comprising:

a substrate;

a plurality of moveable elements over the substrate, each moveable element separated from the substrate by a cavity; and

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

7. The device of claim 6, wherein the plurality of flexure controllers are formed from one or more of silicon nitride (SiN) and silicon dioxide (SiO₂).

8. The device of claim 6, wherein at least a portion of the plurality of moveable elements comprise a reflective surface.

9. An electromechanical device, comprising:

a substrate;

a plurality of moveable elements over the substrate, each moveable element separated from the substrate by a cavity; and

a plurality of flexure controllers over the substrate configured so as to operably support the moveable elements, wherein the flexure controllers comprise 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 comprise wing portions of differing thickness.

10. The device of claim 9, wherein the plurality of flexure controllers are formed from one or more of silicon nitride (SiN) and silicon dioxide (SiO₂).

11. The device of claim 9, wherein at least a portion of the plurality of moveable elements comprise a reflective surface.

12. An electromechanical device, comprising:

a substrate;

a plurality of moveable elements over the substrate, each moveable element separated from the substrate by a cavity; and

a plurality of flexure controllers over the substrate configured so as to operably support the moveable elements, wherein the flexure controllers comprise 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 comprise different materials.

13. The device of claim 12, wherein the plurality of flexure controllers are formed from one or more of silicon nitride (SiN) and silicon dioxide (SiO₂).

14. The device of claim 12, wherein at least a portion of the plurality of moveable elements comprise a reflective surface.

15. An electromechanical device, comprising:

a substrate;

a plurality of moveable elements over the substrate, each moveable element separated from the substrate by a cavity; and

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

16. The device of claim 15, wherein the plurality of flexure controllers are formed from one or more of silicon nitride (SiN) and silicon dioxide (SiO₂).

17. The device of claim 15, wherein at least a portion of the plurality of moveable elements comprise a reflective surface.

18. An electromechanical device, comprising:

a substrate;

a film layer over at least a portion of the substrate layer;

one or more flexure controllers over the substrate operably supporting the film layer and separating the film layer from the substrate, the flexure controllers comprising wing portions that contact the film layer;

one or more cavities defined between the substrate and the film layer; and

wherein the plurality of flexure controllers induce displacement of the film layer such that when the flexure controller is in a relaxed position, at least one cavity has a first depth which is about 30 percent or more greater than the depth of the cavity when the flexure controllers are positioned approximately parallel to the substrate in a non-released position, and wherein at least one of the plurality of flexure controllers is formed underlying the film layer.

19. The device of claim 18, wherein at least two of the plurality of flexure controllers comprise different materials.

20. An electromechanical device, comprising:

a substrate;

a film layer over at least a portion of the substrate layer;

one or more flexure controllers over the substrate operably supporting the film layer and separating the film layer from the substrate, the flexure controllers comprising wing portions that contact the film layer;

one or more cavities defined between the substrate and the film layer; and

wherein the plurality of flexure controllers induce displacement of the film layer such that when the flexure controller is in a relaxed position, at least one cavity has a first depth which is about 30 percent or more greater than the depth of the cavity when the flexure controllers are positioned approximately parallel to the substrate in a non-released position, and wherein the wing portions of at least two of the plurality of flexure controllers have wing portions of different lengths.

21. An electromechanical device, comprising:

a substrate;

a film layer over at least a portion of the substrate layer;

one or more flexure controllers over the substrate operably supporting the film layer and separating the film layer from the substrate, the flexure controllers comprising wing portions that contact the film layer;

one or more cavities defined between the substrate and the film layer; and

wherein the plurality of flexure controllers induce displacement of the film layer such that when the flexure controller is in a relaxed position, at least one cavity has a first depth which is about 30 percent or more greater than the depth of the cavity when the flexure controllers are positioned approximately parallel to the substrate in a non-released position, and wherein at least a portion of at least two of the plurality of flexure controllers have different thickness.

22. An electromechanical device, comprising:

a substrate;

a film layer over at least a portion of the substrate layer;

one or more flexure controllers over the substrate operably supporting the film layer and separating the film layer from the substrate, the flexure controllers comprising wing portions that contact the film layer;

one or more cavities defined between the substrate and the film layer; and

wherein the plurality of flexure controllers induce displacement of the film layer such that when the flexure controller is in a relaxed position, at least one cavity has a first depth which is about 30 percent or more greater than the depth of the cavity when the flexure controllers are positioned approximately parallel to the substrate in a non-released position, and wherein the plurality of flexure controllers are formed from one or more of silicon nitride (SiN), and silicon dioxide (SiO₂).

23. An electromechanical device, comprising:

a substrate;

a film layer over at least a portion of the substrate layer;

one or more flexure controllers over the substrate operably supporting the film layer and separating the film layer from the substrate, the flexure controllers comprising wing portions that contact the film layer;

one or more cavities defined between the substrate and the film layer; and

wherein the plurality of flexure controllers induce displacement of the film layer such that when the flexure controller is in a relaxed position, at least one cavity has a first depth which is about 30 percent or more greater than the depth of the cavity when the flexure controllers are positioned approximately parallel to the substrate in a non-released position, and wherein the flexure controllers further comprise tapered edges connected to the wing portions, and a base which operably supports the edges and separates the edges of the flexure controllers by a selected distance.