Method of manufacturing MEMS devices providing air gap control

• US 8,102,590 B2
• Filed: 05/05/2009
• Issued: 01/24/2012
• 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): Mack, Ricky
• Assistant Examiner(s): Jones, James
• Application Number:
  US12/436,059
• Publication Number:
  US 20090213451A1
• Time in Patent Office: 994 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. An electromechanical device, comprising:

a substrate;

a moveable element over the substrate and separated from the substrate by a cavity, the movable element having a deformable layer configured to move through the cavity; and

one or more flexure controllers over the substrate configured so as to operably support the moveable element and to form the cavity between the substrate and the movable element, wherein at least a portion of at least one flexure controller is connected to and overlies a portion of the deformable layer of a movable element so that the portion of the deformable layer connected to the at least one flexure controller is between the at least one flexure controller and the substrate;

wherein the at least one flexure controller includes a movable wing portion that is connected to the deformable layer of a movable element, the wing portion positioned angled away from the substrate when the deformable layer is in an unactuated state such that wing portion holds the deformable layer further away from the substrate relative to the position of the deformable layer when the wing portion is positioned parallel to the substrate.

3. The device of claim 1, 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.

2. An electromechanical device, comprising:

a substrate;

a plurality of moveable elements over the substrate each movable 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, and

wherein the one or more flexure controllers includes 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.

4. An interferometric modulator, comprising:

first means for reflecting light;

second means for reflecting light separated from the first reflecting means by a cavity, the second reflecting means having a deformable layer, and

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

wherein at least a portion of the supporting means is connected to and overlies a portion the deformable layer of the second reflecting means so that the portion of the deformable layer connected to the supporting means is between the supporting means and the first means for reflecting light.

5. The interferometric modulator of claim 4, wherein the first reflecting means includes a partially reflective layer.

6. The interferometric modulator of claim 4, wherein the second reflecting means includes a movable reflective layer.

7. The interferometric modulator of claim 4, wherein the supporting means includes at least one of a post structure and a rivet structure.

8. An interferometric modulator, comprising:

first means for reflecting light;

second means for reflecting light separated from the reflecting means by a cavity, the second reflecting means having a deformable layer configured to move through the cavity; and

means for supporting the second reflecting means, wherein at least a portion of the supporting means is connected to and overlies a portion of the deformable layer of the second reflecting means so that the portion of the deformable layer connected to the supporting means is between the supporting means and the first reflecting means,

wherein the supporting means includes a moveable portion that is connected to the deformable layer of the second reflecting means, the moveable portion positioned angled away from the first reflecting means when the deformable layer is in an unactuated state such that the moveable portion holds the deformable layer further away from the first reflecting means relative to the position of the deformable layer when the moveable portion is positioned parallel to the first reflecting means.

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

10. The interferometric modulator of claim 8, wherein the second reflecting means includes a movable reflective layer.

11. The interferometric modulator of claim 8, wherein the supporting means includes at least one of a post structure and a rivet structure and wherein the post structure and the rivet structure include different sized members contacting the movable element.