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

• US 9,321,629 B2
• Filed: 03/17/2014
• Issued: 04/26/2016
• Est. Priority Date: 06/23/2009
• 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:
  US14/217,376
• Publication Number:
  US 20140199799A1
• Time in Patent Office: 771 Days
• Field of Search: 438/48, 438/50, 438/51, 257/252, 257/414, 257/419, 257/E21.002
• US Class Current: 1/1
• 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. A method for fabricating a MEMS (micro-electro-mechanical-system) structure including a proof mass apparatus, the method comprising:

providing 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(s);

forming one or more stress isolation regions in thickness of silicon material in a vicinity of the flexible element;

forming a plurality of recessed regions in respective spatial regions of the thickness of silicon material adjacent the stress isolation regions;

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

forming a plug material overlying each of the recessed regions;

wherein a proof mass is configured from at least the plug material provided in each of the plug regions in the thickness of silicon material.

2. The method of claim 1 wherein the plurality of recessed regions are configured as an array.

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

4. The method of claim 1 wherein the glue material comprises titanium nitride material.

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

6. The method of claim 1 wherein the plug material comprises tungsten material.

7. The method of claim 1 wherein the proof mass is an inertial weight.

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

9. The method of claim 1 wherein the thickness of silicon material and the flexible element(s) are provided on a thickness of silicon material.

10. The method of claim 1 further comprising at least one stress isolation region pattern from at least one portion of the thickness of silicon material.

11. The method of claim 10 wherein the stress isolation region pattern comprises one or more isolation cavity regions.

12. A method for adding mass with stress isolation to a MEMS (micro-electro-mechanical-system) structure, the method comprising:

providing 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(s);

forming one or more stress isolation regions in a vicinity of the flexible element(s);

forming a plurality of recessed regions in respective spatial regions of the thickness of silicon material adjacent to the stress isolation regions;

forming a glue material within one or more of the recessed regions; and

forming a plug material overlying one or more of the recessed regions;

wherein a proof mass is configured from at least the plug material provided in each of the plug regions.

13. The method of claim 12 wherein the stress isolation region comprises one or more isolation cavity regions.

14. A method for adding mass with stress isolation to a MEMS (micro-electro-mechanical-system) structure, the method comprising:

providing a thickness of silicon material coupled to at least one flexible element which is attached to a MEMS structure, the thickness of silicon material being configured to move in one or more spatial directions about the flexible element(s);

forming one or more stress isolation regions in a vicinity of the flexible element(s);

forming a plurality of recessed regions in respective spatial regions of the thickness of silicon material adjacent to the stress isolation regions;

forming a glue material within one or more of the recessed regions; and

forming a plug material overlying one or more of the recessed regions;

wherein a proof mass is configured from at least the plug material provided in each of the plug regions.

15. The method of claim 14 wherein the stress isolation region comprises one or more isolation cavity regions.