MEMS microphone

• US 7,301,212 B1
• Filed: 07/30/2004
• Issued: 11/27/2007
• Est. Priority Date: 07/30/2004
• Status: Active Grant

• Current Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Original Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Inventors: Hopper, Peter J., Drury, Robert, Mian, Michael
• Primary Examiner(s): Huynh; Andy
• Assistant Examiner(s): Nguyen; Thinh T
• Application Number:
  US10/909,190
• Time in Patent Office: 1,215 Days
• Field of Search: 257/415, 257/416, 257/418, 257/419
• US Class Current: 257/415
• CPC Class Codes: H04R 19/016 for microphones

Abstract

The sensitivity of a MEMS microphone is substantially increased by using a portion of the package that holds the MEMS microphone as the diaphragm or a part of the diaphragm. As a result, the diaphragm of the present invention is substantially larger, and thus more sensitive, than the diaphragm in a comparably-sized MEMS microphone die.

Claims

1. A micro-electromechanical system (MEMS) microphone comprising:

a package base;

a MEMS semiconductor die that is bonded to the package base, the MEMS semiconductor die having a semiconductor substrate and a top layer of isolation material that overlies the semiconductor substrate;

a connector that contacts the top layer of isolation material, the connector being flexible, and including a piezoresistive material and a spring; and

a package top that has a bottom side connected to the connector.

2. The MEMS microphone of claim 1 wherein the package top includes a plurality of conductive strips that contact a bottom side of the package top.

3. The MEMS microphone of claim 1 wherein the package top includes:

a top surface; and

side wall surfaces that extend away from the top surface, the side wall surfaces contacting the package bottom.

4. The MEMS microphone of claim 3 wherein a side wall surface includes a pressure equalization port.

5. A micro-electromechanical system (MEMS) microphone comprising:

a base having a top surface, the top surface having a first region and a second region;

a semiconductor die attached to the top surface of the base, the semiconductor die lying vertically over the first region of the top surface of the base, and not lying vertically over the second region of the top surface of the base;

a connector that contacts the semiconductor die; and

a member that contacts the connector, the member lying over both the first region and the second region of the top surface of the base.

6. The MEMS microphone of claim 5 wherein the member has a substantially planar top surface.

7. The MEMS microphone of claim 5 wherein the member is spaced apart from the base.

8. The MEMS microphone of claim 5 wherein the member includes a plurality of conductive strips that contact a bottom side of the member.

9. The MEMS microphone of claim 8 wherein the connector includes a number of elastically deformable piezo-responsive structures that contact the plurality of conductive strips.

10. The MEMS microphone of claim 5 wherein the connector includes a layer of piezo-responsive material that contacts the semiconductor die.

11. The MEMS microphone of claim 10 wherein the connector further includes a number of elastically deformable structures that contact the layer of piezo-responsive material and the bottom side of the member.

12. The MEMS microphone of claim 5 wherein the member includes a conductive region that contacts a bottom side of the member.

13. The MEMS microphone of claim 12 wherein the connector includes a number of elastically deformable structures that contact the conductive region.

14. The MEMS microphone of claim 5 wherein the connector includes a piezoelectric material.

15. A micro-electromechanical system (MEMS) microphone comprising:

a semiconductor die having a top surface, the top surface having an area;

a connector that contacts the semiconductor die, the connector being elastically deformable; and

a member that contacts the connector, the member having a top surface, the top surface of the member having an area, the area of the top surface of the member being substantially larger than the area of the top surface of the semiconductor die.

16. The MEMS microphone of claim 15 wherein the member elastically deforms the connector in response to an external force applied to the member.

17. The MEMS microphone of claim 15 wherein the member is conductive.

18. The MEMS microphone of claim 15 wherein the member includes a plurality of conductive strips that contact a bottom side of the member.

19. The MEMS microphone of claim 15 wherein the member includes a conductive region that contacts a bottom side of the member.