Multi-stage stopper system for MEMS devices

• US 8,516,891 B2
• Filed: 01/16/2008
• Issued: 08/27/2013
• Est. Priority Date: 01/16/2007
• Status: Active Grant

• Current Assignee: Analog Devices, Inc.
• Original Assignee: Analog Devices, Inc.
• Inventors: Zhang, Xin, Judy, Michael W.
• Primary Examiner(s): KWOK, HELEN C
• Application Number:
  US12/015,105
• Publication Number:
  US 20120228725A1
• Time in Patent Office: 2,050 Days
• Field of Search: 735/143.2, 735/143.6, 735/143.8, 735/142.9
• US Class Current: 73/514.38
• CPC Class Codes: B81B 2201/0235 Accelerometers
• CPC Class Codes: B81B 2201/0242 Gyroscopes
• CPC Class Codes: B81B 3/0051 For defining the movement, i.e. structures that guide or limit the movement of an element mechanical arrangements for preventing or damping vibration or shock H01H3/60

Abstract

A MEMS sensing system includes a movable mass having at least one contact surface, a stopper system for stopping the movement of the mass, the stopper system having at least one contact surface that contacts a corresponding contact surface of the mass if a sufficient movement of the mass occurs in a direction, at least one stopper gap formed between the at least one contact surface of the stopper system and the corresponding contact surface of the mass, and a spring system in communication with the at least one stopper gap.

Claims

1. A MEMS system comprising:

a movable mass having at least one contact surface;

a stopper for stopping a movement of the mass, the stopper having a first contact surface that contacts a corresponding first contact surface of the mass if a sufficient movement of the mass occurs in a first direction and a second contact surface that contacts a corresponding second contact surface of the mass if a sufficient movement of the mass occurs in a second direction wherein the second direction is opposite to the first direction;

a first stopper gap formed between the first contact surface of the stopper and the corresponding first contact surface of the mass and a second stopper gap formed between the second contact surface of the stopper and the corresponding second contact surface of the mass; and

a spring system in communication with and adjacent to at least one of the first and second stopper gaps wherein the spring system is formed as part of the moveable mass and wherein the spring system comprises at least two spring structures, each spring structure abutting a different stopper gap around the stopper.

2. The MEMS system of claim 1, wherein the stopper includes a third contact surface that contacts a corresponding third contact surface of the mass if a sufficient movement of the mass occurs in a third direction, where the third direction forms a ninety degree angle to the first direction.

3. The MEMS system of claim 1, wherein a portion of the spring system is serpentine shaped.

4. The MEMS system of claim 1, wherein the spring system comprises at least two spring structures in communication with the same stopper gap along one side of the stopper.

5. The MEMS system of claim 1, wherein the stopper and the mass are arranged to form at least one protrusion protruding into at least one stopper gap.

6. A MEMS system comprising:

a movable mass having at least one contact surface;

a plurality of stoppers for stopping a movement of the mass, each stopper having a first contact surface that contacts a corresponding first contact surface of the mass if a sufficient movement of the mass occurs in a first direction and a second contact surface that contacts a corresponding second contact surface of the mass if a sufficient movement of the mass occurs in a second direction wherein the second direction is opposite to the first direction;

stopper gaps between each of the contact surfaces of the stoppers and the corresponding contact surfaces of the mass; and

a spring system in communication with and adjacent to at least one of the stopper gaps wherein the spring system is formed as part of the moveable mass and wherein the spring system comprises at least two spring structures, each spring structure abutting a different stopper gap around a given stopper.

7. The MEMS system of claim 6, wherein each stopper includes a third contact surface that contacts a corresponding third contact surface of the mass if a sufficient movement of the mass occurs in a third direction, where the third direction forms a ninety degree angle to the first direction.

8. The MEMS system of claim 6, wherein a portion of the spring system is serpentine shaped.

9. A method of producing an impact resistant MEMS sensor, the method comprising:

providing a movable mass having at least one contact surface;

providing a stopper for stopping a movement of the mass, the stopper having a first contact surface that contacts a corresponding first contact surface of the mass if a sufficient movement of the mass occurs in a first direction and a second contact surface that contacts a corresponding second contact surface of the mass if a sufficient movement of the mass occurs in a second direction wherein the second direction is opposite to the first direction;

forming a first stopper gap between the first contact surface of the stopper and the corresponding first contact surface of the mass and a second stopper gap formed between the second contact surface of the stopper and the corresponding second contact surface of the mass; and

forming a spring system as part of the moveable mass that abuts the at least one stopper gap, wherein forming a spring system comprises forming at least two spring structures, each spring structure abutting a different stopper gap around the stopper.

10. The method of claim 9, wherein the stopper includes a third contact surface that contacts a corresponding third contact surface of the mass if a sufficient movement of the mass occurs in a third direction, where the third direction forms a ninety degree angle to the first direction.

11. The method of claim 9, wherein a portion of the spring system is serpentine shaped.

12. The method of claim 9, wherein forming a spring system comprises forming at least two spring structures abutting the stopper gap along one side of the stopper.

13. The method of claim 9, further comprising forming at least one protrusion protruding into the at least one stopper gap.