Miniature Silicon Condenser Microphone

• US 20070082421A1
• Filed: 10/03/2006
• Published: 04/12/2007
• Est. Priority Date: 11/28/2000
• Status: Active Grant

• Current Assignee: Knowles Electronics Llc (Knowles Corporation)
• Original Assignee: Knowles Electronics Llc (Knowles Corporation)
• Inventors: Minervini, Anthony
• Granted Patent: US 7,537,964 B2
• Time in Patent Office: Days
• US Class Current: 438/50
• CPC Class Codes: B81B 2201/0257 Microphones or microspeakers
• CPC Class Codes: B81B 7/0064 for protecting against electromagnetic or electrostatic interferences
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H04R 19/016 for microphones
• CPC Class Codes: H04R 31/006 Interconnection of transducer parts of diaphragm and outer suspension by moulding H04R31/003
• CPC Class Codes: Y10T 29/49005 Acoustic transducer
• CPC Class Codes: Y10T 29/4908 Acoustic transducer

Abstract

A silicon condenser microphone package includes a transducer unit, a substrate, and a cover. The substrate includes an upper surface transducer unit is attached to the upper surface of the substrate and overlaps at least a portion of the recess wherein a back volume of the transducer unit is formed between the transducer unit and the substrate. The cover is placed over the transducer unit and either the cover or the substrate includes an aperture.

Claims

1. A method for producing a MEMS transducer, the method comprising:

providing a spacer;

providing and attaching a cover to the spacer;

joining a printed circuit board to the cover and the spacer to form a housing with a chamber;

providing an aperture within the housing, the aperture adapted to acoustically couple a signal external to the housing into the chamber; and

disposing a transducer within the chamber.

2. The method of claim 1, wherein:

the printed circuit board comprises at least one layer of a conductive material and at least one layer of an insulating material;

the spacer and the cover each comprise a conductive portion; and

the method further comprises electrically coupling the conductive layer and the conductive portions to form a shield against electromagnetic interference.

3. The method of claim 1, further comprising:

the printed circuit board comprises at least one layer of a conductive material and at least one layer of an insulating material;

the spacer and the cover each comprise a conductive portion; and

the method further comprises providing a conductive adhesive to electrically couple the conductive layer and the conductive portions to form a shield against electromagnetic interference.

4. The method of claim 1, providing an environmental barrier, the environmental barrier being disposed within the aperture.

5. The method of claim 4, the environmental barrier comprising a nonconductive material.

6. The method of claim 1, wherein providing the aperture comprises providing the aperture in the cover or the substrate or both the cover and the substrate.

7. The method of claim 1, further comprising:

forming a recess within the chamber; and

coupling the transducer to the recess to form a cavity.

8. The method of claim 7, wherein the cavity comprises a back volume.

9. The method of claim 1, further comprising:

forming a passage through the housing; and

coupling the transducer to the passage to form at least a portion of a cavity.

10. The method of claim 9, wherein the cavity comprises a back volume.

11. The method of claim 1, wherein each of the cover and the spacer comprise an inner surface, a portion of the cover inner surface and a portion of the spacer inner surface comprising a conductive material for shielding the transducer from an interference.

12. The method of claim 1, comprising:

providing an inner lining for the chamber, the inner lining providing a shield from an electromagnetic interference;

the printed circuit board comprises at least one layer of a conductive material and at least one layer of an insulating material, the conductive layers forming a portion of the inner lining; and

the spacer and the cover each comprise a conductive portion, the conductive portions forming a portion of the inner lining.

13. The method of claim 1, comprising providing the printed circuit board or the cover with one or more lead pads and electrically coupling the lead pads to the transducer.

14. The method of claim 13, further comprising:

providing the printed circuit board or the cover with an electrical ground plane and, the electrical ground plane being electrically coupled to at least one of the lead pads.

40. The method of claim 1, providing a sealing ring, the sealing ring being attached to the housing adjacent the aperture.

15. A method for producing a MEMS transducer, the method comprising:

providing a substrate, the substrate comprising a first insulating layer, a first conductive layer, and an aperture;

coupling a transducer to the substrate overlapping the aperture to form at least a portion of a cavity for the transducer;

providing and attaching a cover to the substrate to enclose and protect the transducer, the cover comprising a second insulating layer and a second conductive layer; and

joining the first conductive layer and the second conductive layer to form a shield against electromagnetic interference.

16. The method of claim 15, wherein the cavity comprises a back volume or an acoustic port.

17. The method of claim 16, wherein one of the first conductive layer and the second conductive layer comprises lead pads electrically coupled to the transducer.

18. The method of claim 16, wherein one of the first conductive layer and the second conductive layer comprises an electrical ground plane coupled to at least one of the lead pads.

41. The method of claim 15, providing a sealing ring, the sealing ring being attached to the substrate adjacent the cavity.

19. A method for producing a MEMS transducer, the method comprising:

providing a housing, the housing being an assembly of at least a substrate portion and a cover portion, the housing defining a sealed chamber;

forming an aperture within the housing acoustically coupling the chamber to an exterior portion of the housing for receiving a signal;

providing a transducer within the chamber; and

electrically shielding the transducer from electromagnetic interference.

20. The method of claim 19, wherein the housing comprises a spacer member formed as a portion of the assembly.

21. The method of claim 19, wherein electrically shielding the transducer comprises associating with the housing a conductive material such that the conductive material provides an effective shield against electromagnetic interference.

22. The method of claim 21, wherein the conductive material comprises one or more conductive layers formed within the housing.

23. The method of claim 21, wherein the conductive material comprises a inner lining a surface of the chamber.

24. The method of claim 19, wherein the substrate comprises a printed circuit board;

the printed circuit board comprises at least one layer of a conductive material and at least one layer of an insulating material;

the cover comprises a conductive portion;

providing a spacer, the spacer comprises a conductive portion, disposing the spacer between the printed circuit board and the cover; and

electrically shielding the transducer comprises electrically coupling the conductive layer and the conductive portions to form a shield against electromagnetic interference.

25. The method of claim 19, wherein the substrate comprises a printed circuit board;

the printed circuit board comprises at least one layer of a conductive material and at least one layer of an insulating material;

the cover comprises a conductive portion;

providing a spacer, the spacer comprises a conductive portion, disposing the spacer between the printed circuit board and the cover; and

electrically shielding the transducer comprises providing a conductive adhesive to electrically couple the conductive layer and the conductive portions to form a shield against electromagnetic interference.

26. The method of claim 19, providing an environmental barrier, the environmental barrier being disposed within the aperture.

27. The method of claim 26, the environmental barrier comprising a nonconductive material.

28. The method of claim 19, wherein providing the aperture comprises providing the aperture in the cover or the substrate or both the cover and the substrate.

29. The method of claim 19, further comprising:

forming a recess within the chamber; and

coupling the transducer to the recess to form a cavity.

30. The method of claim 29, wherein the cavity comprises a back volume or an acoustic port.

31. The method of claim 19, further comprising:

forming a passage through the housing; and

coupling the transducer to the passage to form at least a portion of a cavity.

32. The method of claim 31, wherein the cavity comprises a back volume or an acoustic port.

33. The method of claim 19, wherein each of the cover and the spacer comprise an inner surface, a portion of the cover inner surface and a portion of the spacer inner surface comprising a conductive material, and electrically shielding the transducer comprises electrically coupling the cover inner surface conductive material and the spacer inner surface conductive material.

34. The method of claim 19, comprising:

wherein electrically shielding the transducer comprises providing an inner lining for the chamber.

35. The method of claim 34, the substrate comprises at least one layer of a conductive material and at least one layer of an insulating material, the conductive layer forming a portion of the inner lining;

the cover comprises a conductive portion; and

providing a spacer, the spacer comprising a conductive portion, the conductive portions of the spacer and the cover forming a portion of the inner lining.

36. The method of claim 19, comprising providing the substrate or the cover with one or more lead pads and electrically coupling the lead pads to the transducer.

37. The method of claim 36, further comprising:

providing the substrate or the cover with an electrical ground plane and, the electrical ground plane being electrically coupled to at least one of the lead pads.

42. The method of claim 19, providing a sealing ring, the sealing ring being attached to the housing adjacent the aperture.

38. A method for producing a MEMS transducer, the method comprising:

providing a printed circuit board comprising at least one layer of conductive material and at least one layer of insulating material;

providing a cover comprising at least one layer of conductive material;

providing and cooperating a spacer to the cover and the printed circuit board to form a housing, the spacer comprising a sidewall at least partially covered by a conductive layer, the conductive layer including a portion of an inner lining for providing a shield against an electromagnetic interference;

forming an aperture within the housing adapted for receiving a signal; and

mounting a transducer within the housing.

39. A method for producing a MEMS transducer, the method comprising:

providing a substrate including an upper surface having a recess formed within, the substrate comprising a layer of conductive material;

mounting a transducer to the upper surface overlapping at least a portion of the recess so that a back volume is formed between the transducer and the substrate;

placing a cover over the transducer, the cover comprising an aperture and a layer of conductive material;

providing and cooperating a spacer to the cover and the substrate to form a housing, the spacer comprising a conductive material; and

wherein the conductive layers electrically coupled to form an inner lining for providing a shield against an electromagnetic interference;

providing a sealing ring, the sealing ring formed on a surface of the substrate opposite the upper surface adjacent the back volume.

43. A method for producing a MEMS transducer, the method comprising:

providing a substrate, the substrate comprising a first insulating layer and a first conductive layer;

providing a cover comprising a conductive material;

providing a cavity within the cover or the substrate or both the cover and the substrate;

providing and joining the substrate and the cover to form a housing;

mounting a transducer within the housing; and

providing and attaching a sealing ring to the housing adjacent the cavity.