MEMS device and deformation protection structure therefor and method for making same

• US 8,479,576 B2
• Filed: 03/08/2011
• Issued: 07/09/2013
• Est. Priority Date: 12/30/2010
• Status: Active Grant

• Current Assignee: PixArt Imaging Incorporated
• Original Assignee: PixArt Imaging Incorporated
• Inventors: Wang, Chuan-Wei
• Primary Examiner(s): KWOK, HELEN C
• Application Number:
  US12/932,869
• Publication Number:
  US 20120167683A1
• Time in Patent Office: 854 Days
• Field of Search: 735/143.2, 735/143.3, 735/143.4, 735/143.8, 438/48, 438 50- 53, 257414-418, 295/921, 295/95
• US Class Current: 73/514.32
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: Y10T 29/49002 Electrical device making
• CPC Class Codes: Y10T 29/49007 Indicating transducer
• CPC Class Codes: Y10T 29/49155 Manufacturing circuit on or in base

Abstract

The present invention discloses a MEMS (Micro-Electro-Mechanical System, MEMS) device with a deformation protection structure. The MEMS device is located on a substrate, and it includes: a movable part; and a deformation protection structure, which has: a fixed plug, which is fixed on the substrate; multiple metal layers, including a top metal layer; and multiple plugs connecting the multiple metal layers. From top view, the top metal layer overlaps a portion of the movable part, and from cross section view, the bottom surface of the top metal layer is higher than the top surface of the movable part by a predetermined distance.

Claims

1. A MEMS device on a substrate, the MEMS device comprising:

a movable part; and

a deformation protection structure including;

a fixed plug fixed on the substrate;

multiple metal layers including a top metal layer and a bottom metal layer, wherein the bottom metal layer is connected with the fixed plug; and

multiple plugs connecting the multiple metal layers;

wherein from top view, the top metal layer overlaps a portion of the movable part, and from cross section view, a bottom surface of the top metal layer is higher than a top surface of the movable part by a predetermined distance.

2. The MEMS device of claim 1, wherein from top view, the deformation protection structure is located inside of the MEMS device.

3. The MEMS device of claim 1, wherein the MEMS device comprises:

at least one spring;

a proof mass connected with the spring; and

at least one sense electrode connected with the proof mass;

wherein the movable part includes one or more of the followings;

the spring, the proof mass and the sense electrode.

4. The MEMS device of claim 3, wherein the sense electrode includes one or both of an in-plane sense electrode and an out-of-plane sense electrode.

5. The MEMS device of claim 1, wherein the top metal layer overlaps the portion of the movable part by a width of at least 1 μ

m.

6. A deformation protection structure located on a substrate for a MEMS device having a movable part, the deformation protection structure comprising:

a fixed plug fixed on the substrate;

multiple metal layers including a top metal layer and a bottom metal layer, wherein the bottom metal layer is connected with the fixed plug; and

multiple plugs connecting the multiple metal layers;

wherein from top view, the top metal layer overlaps a portion of the movable part, and from cross section view, a bottom surface of the top metal layer is higher than a top surface of the movable part by a predetermined distance.

7. The deformation protection structure of claim 6, wherein from cross section view, the top metal layer and an uppermost one of the multiple plugs, in combination, form an approximately L-shape or T-shape.

8. The deformation protection structure of claim 6, wherein from top view, the deformation protection structure is located inside of the MEMS device.

9. A method for manufacturing a MEMS device, comprising:

providing a substrate;

forming a fixed plug fixed on the substrate;

forming multiple metal layers and multiple plugs connecting the multiple metal layers, and defining patterns of the multiple metal layers and the multiple plugs to form a movable part and a fixed structure which are separated from each other, wherein the fixed structure is connected with the fixed plug; and

forming a metal plug and a top metal layer on the fixed structure, wherein from top view, the top metal layer overlaps a portion of the movable part, and from cross section view, a bottom surface of the top metal layer is higher than a top surface of the movable part by a predetermined distance.

10. The method of claim 9, wherein from top view, the fixed structure is located inside of the MEMS device.

11. The method of claim 9, further comprising;

forming a sacrificial layer surrounding the multiple metal layers, the multiple plugs, and the metal plug and the top metal layer on the fixed structure; and

etching to remove the sacrificial layer.