METHOD OF MANUFACTURING MEMS DEVICES PROVIDING AIR GAP CONTROL

• US 20090213451A1
• Filed: 05/05/2009
• Published: 08/27/2009
• Est. Priority Date: 06/30/2006
• 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 8,102,590 B2
• Time in Patent Office: Days
• US Class Current: 359/291
• 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 at least a portion of at least one flexure controller of the plurality of flexure controllers is overlying and operably supporting at least one moveable element of the plurality of moveable elements,

wherein the plurality of flexure controllers control selected flexures of the plurality of moveable elements to form a plurality of cavities having different depths between the substrate and the plurality of movable elements.

2. The device of claim 1, wherein the plurality of flexure controllers comprise portions of different dimensions to control the selected flexures.

3. The device of claim 2, wherein the portions of different dimensions of the plurality of flexure controllers comprise portions having different thicknesses.

4. An electromechanical device, comprising:

a substrate;

a moveable element over the substrate; and

one or more flexure controllers over the substrate configured so as to operably support the moveable element and to form a cavity between the substrate and the movable element,

wherein the one or more flexure controllers are operative to increase the depth of the cavity by about 30 percent greater or more as compared to the depth of a cavity formed when the moveable element extends approximately parallel to the substrate, wherein depth is measured perpendicular to the substrate, and

wherein at least a portion of at least one of the flexure controllers is overlying and operably supporting at least a portion of the moveable element.

5. The device of claim 4, wherein the one or more flexure controllers comprise one or more post structures and one or more rivet structures, and wherein the post structure and the rivet structure comprise different sized members contacting the movable element.

6. The device of claim 4, wherein the one or more flexure controllers are formed with tensile or compressive stresses, wherein the combined stresses of the flexure controllers cause a deflection of the movable element that increases the cavity depth by about 30 percent greater or more as compared to the depth of a cavity formed when the moveable element extends approximately parallel to the substrate.

7. An interferometric modulator, comprising:

first means for reflecting light;

second means for reflecting light; and

means for supporting the second reflecting means and for forming a cavity between the first reflecting means and the second reflecting means,

wherein the depth of the cavity may be increased by the supporting means to a depth about 30 percent greater or more than the depth of a cavity formed when the second means for reflecting light extends approximately parallel to the first means for reflecting light, wherein depth is measured perpendicular to the first reflecting means, and

wherein at least a portion of the supporting means is overlying and operably supporting at least a portion of the second reflecting means.

8. The interferometric modulator of claim 7, wherein the first reflecting means comprises a partially reflective layer.

9. The interferometric modulator of claim 7, wherein the second reflecting means comprises a movable reflective layer.

10. The interferometric modulator of claim 7, wherein the supporting means comprises at least one of a post structure and a rivet structure.

11. An electromechanical device, comprising:

a substrate;

a moveable element over the substrate; and

one or more flexure controllers over the substrate configured so as to operably support the moveable element and to displace the movable element towards the substrate,

wherein at least a portion of at least one of the flexure controllers is overlying and operably supporting at least a portion of the moveable element.

12. An interferometric modulator, comprising:

first means for reflecting light;

second means for reflecting light; and

means for supporting the second reflecting means and for effecting a displacement of the second reflecting means towards the first reflecting means upon removal of the first supporting means, wherein at least a portion of the second supporting means is overlying and operably supporting at least a portion of the second reflecting means.

13. The interferometric modulator of claim 12, wherein the first reflecting means comprises a partially reflective layer.

14. The interferometric modulator of claim 12, wherein the second reflecting means comprises a movable reflective layer.

15. The interferometric modulator of claim 12, wherein the supporting means comprises at least one of a post structure and a rivet structure.