Method and structure for adding mass with stress isolation to MEMS structures

• US 8,710,597 B1
• Filed: 04/19/2011
• Issued: 04/29/2014
• Est. Priority Date: 04/21/2010
• Status: Active Grant

• Current Assignee: Movella Incorporated (Movella Holdings, Inc.)
• Original Assignee: mCube, Inc.
• Inventors: Koury, Daniel N. Jr.
• Primary Examiner(s): Nguyen, Thinh T
• Application Number:
  US13/090,228
• Time in Patent Office: 1,106 Days
• Field of Search: 257/414, 257/252, 257/254, 257/419, 735/143.2, 735/040.3, 438/48, 438/49
• US Class Current: 257/414
• CPC Class Codes: B81C 1/00134 comprising flexible or deformable structures manufacture of MEMS devices for specific applications, see relevant places, e.g. gyroscopes G01C19/5719, pressure sensors G01L9/0042, accelerometers G01P15/0802, acoustic transducers or diaphragms therefor H04R31/00
• CPC Class Codes: B81C 1/00142 Bridges deformable micromirrors G02B26/0841
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: H01L 27/14609 Pixel-elements with integrated switching, control, storage or amplification elements scanning details of imagers (circuitry of solid-state image sensors H04N25/00); circuitry of imagers H04N25/70
• CPC Class Codes: H01L 27/14643 Photodiode arrays; MOS imagers
• CPC Class Codes: H01L 2924/01013 Aluminum [Al]

Abstract

A method and structure for adding mass with stress isolation to MEMS. The structure has a thickness of silicon material coupled to at least one flexible element. The thickness of silicon material can be configured to move in one or more spatial directions about the flexible element(s) according to a specific embodiment. The apparatus also includes a plurality of recessed regions formed in respective spatial regions of the thickness of silicon material. Additionally, the apparatus includes a glue material within each of the recessed regions and a plug material formed overlying each of the recessed regions.

Claims

1. An apparatus disposed upon a substrate having a surface region, the apparatus comprising:

a thickness of silicon material coupled to at least one flexible element, the thickness of silicon material being configured to move in one or more spatial directions about the flexible element, the thickness of silicon material having at least one intermediate cavity having a cavity surface region, the at least one flexible element being coupled to at least one portion of the surface region and at least one portion of the cavity surface region, the at least one flexible element being spatially oriented to be substantially 45 degrees or substantially (pi/4) radians to the edges of a die;

a plurality of recessed regions formed in respective spatial regions of the thickness of silicon material; and

a plug material formed overlying each of the recessed regions.

2. The apparatus of claim 1 further comprising a glue material provided within each of the recessed regions.

3. The apparatus of claim 1 wherein the plurality of recessed regions are configured as an array.

4. The apparatus of claim 1 wherein each of the recessed regions is characterized by an aspect ratio of greater than five to one.

5. The apparatus of claim 1 wherein the glue material comprises a titanium nitride material.

6. The apparatus of claim 1 wherein the glue material includes at least a titanium material, a platinum material, a cobalt material, a tantalum material, a tungsten material, or a nitride material.

7. The apparatus of claim 1 wherein the plug material comprises a tungsten material.

8. The apparatus of claim 1 wherein the thickness of silicon material comprises a proof mass configured from at least the plug material provided in each of the recessed regions.

9. The apparatus of claim 1 further comprising at least one stress isolation region configured within a vicinity of the flexible element(s).

10. An apparatus disposed upon a substrate having a surface region, the apparatus comprising:

at least one intermediate anchor structure;

at least one intermediate spring structure coupled to the at least one intermediate anchor structure;

a movable base having a thickness of silicon material coupled to the at least one intermediate spring structure, the thickness of silicon material being configured to move in one or more spatial directions about the intermediate spring structure(s), the movable base having at least one intermediate cavity disposed in an intermediate portion of the movable base, the at least one intermediate cavity having a cavity surface region;

wherein the at least one intermediate anchor structure is disposed within the at least one intermediate cavity, the intermediate anchor structure(s) being coupled to at least one portion of the surface region;

wherein the at least one intermediate spring structure is coupled to at least one portion of the cavity surface region, the intermediate spring structure(s) being oriented to be substantially 45 degrees or substantially (pi/4) radians to the edges of a die;

a plurality of recessed regions formed in respective spatial regions of the thickness of silicon material of the movable base, the plurality of recessed regions being formed as an array;

a glue material provided within each of the recessed regions; and

a plug material formed overlying each of the recessed regions;

the plug material comprising a tungsten material.