Side-ported MEMS microphone assembly

• US 20100128914A1
• Filed: 11/26/2008
• Published: 05/27/2010
• Est. Priority Date: 11/26/2008
• Status: Active Grant

• Current Assignee: Invensense Incorporated (TDK Corporation)
• Original Assignee: Analog Devices, Inc.
• Inventors: Khenkin, Aleksey S.
• Granted Patent: US 8,351,634 B2
• Time in Patent Office: Days
• US Class Current: 381/361
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48137 the bodies being arranged next to each other, e.g. on a common substrate
• 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 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/1461 MEMS
• CPC Class Codes: H04R 19/005 using semiconductor materials
• CPC Class Codes: H04R 19/04 Microphones H04R19/01 takes precedence
• CPC Class Codes: H04R 2499/11 Transducers incorporated or for use in hand-held devices, e.g. mobile phones, PDA's, camera's
• CPC Class Codes: H04R 31/006 Interconnection of transducer parts of diaphragm and outer suspension by moulding H04R31/003

Abstract

A side-ported MEMS microphone package defines an acoustic path from a side of the package substrate to a microphone die disposed within a chamber defined by the substrate and a lid attached to the substrate. Optionally or alternatively, a circuit board, to which the microphone package is mounted, may define an acoustic path from an edge of the circuit board to a location under the microphone package, adjacent a bottom port on the microphone package. In either case, the acoustic path may be a hollow passage through at least a portion of the substrate or the circuit board. The passage may be defined by holes, channels, notches, etc. defined in each of several layers of a laminated substrate or circuit board, or the passage may be defined by holes drilled, molded or otherwise formed in a solid or laminated substrate or circuit board.

Claims

1. A side-ported microphone package, comprising:

a substrate;

a lid attached to a first surface of the substrate to define a chamber therebetween; and

a microphone die disposed within the chamber;

wherein the substrate at least partially defines an acoustic path from outside the chamber to the microphone die, such that at least a portion of the acoustic path defined by the substrate is oriented other than perpendicular to the first surface of the substrate.

2. A side-ported microphone package according to claim 1, wherein the at least a portion of the defined acoustic path is oriented parallel to the first surface of the substrate.

3. A side-ported microphone package according to claim 1, wherein the substrate defines:

an aperture in the first surface within a boundary defined by a locus of points where the lid is attached to the substrate;

an opening on a surface of the substrate and outside the boundary; and

a hollow passage in communication with the aperture and with the opening, such that the passage, the aperture and the opening form at least a portion of the defined acoustic path.

4. A side-ported microphone package according to claim 3, wherein the opening is defined by a surface of the substrate that is substantially perpendicular to the first surface.

5. A side-ported microphone package according to claim 3, wherein the opening is defined by the first surface.

6. A side-ported microphone package according to claim 3, wherein:

the substrate comprises a second surface on substantially an opposite side of the substrate from the first surface; and

at least a portion of the passage is open at the second surface.

7. A side-ported microphone package according to claim 6, wherein the second surface comprises a solderable portion configured into an open shape, extending from a location proximate an edge of the substrate to another location proximate an edge of the substrate, so as to substantially bound the open portion of the passage between the solderable portion and the edge of the substrate.

8. A side-ported microphone package according to claim 7, wherein the solderable portion is U shaped, with ends of the U shape proximate the edge of the substrate.

9. A side-ported microphone package according to claim 3, wherein:

the substrate comprises a second surface on substantially an opposite side of the substrate from the first surface; and

none of the passage is open at the second surface.

10. A side-ported microphone package according to claim 3, wherein:

the substrate comprises a laminate;

a first layer of the laminate defines the aperture; and

a second layer of the laminate defines at least a portion of the passage.

11. A side-ported microphone package according to claim 3, wherein the aperture is adjacent to, and in line with, a receiver portion of the microphone die.

12. A side-ported microphone package according to claim 3, wherein the microphone die is disposed between the aperture and the chamber.

13. A side-ported microphone package according to claim 3, wherein the aperture is in communication with the chamber.

14. A side-ported microphone package according to claim 1, wherein the substrate comprises a printed circuit board.

15. A side-ported microphone package according to claim 1, wherein the substrate comprises ceramic.

16. A side-ported microphone package according to claim 1, wherein the substrate comprises plastic.

17. A side-ported microphone package according to claim 1, wherein the substrate comprises at least one wall, and the lid is attached to the at least one wall.

18. A side-ported microphone package, comprising:

a substrate having a first surface and a second surface, the second surface being on substantially an opposite side of the substrate from the first surface;

a lid attached to the first surface of the substrate to define a chamber therebetween; and

a microphone die disposed within the chamber;

wherein;

the second surface defines an opening;

the substrate at least partially defines an acoustic path between the opening and the microphone die; and

the second surface comprises a solderable portion configured into an open shape, extending from a location proximate an edge of the substrate to another location proximate an edge of the substrate, so as to substantially bound the opening between the solderable portion and the edge of the substrate, wherein the solderable portion does not surround the opening.

19. A side-ported microphone package according to claim 18, wherein the solderable portion is U shaped, with ends of the U shape proximate the edge of the substrate.

20. A side-ported microphone package, comprising:

a substrate;

a lid attached to the substrate to define a chamber therebetween; and

a microphone die disposed within the chamber;

wherein the substrate defines a sound input port in communication with the microphone die, such that the sound input port is oriented substantially perpendicular to the microphone die.

21. A side-ported microphone package, comprising:

a substrate having a top surface, a bottom surface and an end surface, the end surface defining an opening;

a lid attached to the substrate to define a chamber therebetween; and

a microphone die disposed within the chamber;

wherein the substrate defines at least a portion of an acoustic path from the opening to the microphone die.

22. A kit of parts for assembling a side-ported microphone package, the kit comprising:

a first layer defining a hollow channel or notch in a surface of the first layer, the channel or notch extending from an edge of the first layer and terminating at a location away from any edge of the first layer;

a second layer defining a bore, such that when the first and second layers are assembled in registration with each other, the bore is in communication with the channel or notch;

at least one wall configured such that when the at least one wall is attached to the second layer in registration therewith, the bore is in communication with a volume defined by the at least one wall; and

a lid.

23. A kit of parts as recited in claim 22, wherein the first layer comprises a printed circuit board, and the second layer comprises a printed circuit board.

24. A kit of parts as recited in claim 23, wherein the lid comprises a printed circuit board.

25. A kit of parts as recited in claim 22, wherein the lid comprises a printed circuit board.

26. A kit of parts as recited in claim 22, wherein the first layer, the second layer, the at least one wall and the lid comprise ceramic.

27. A kit of parts as recited in claim 22, wherein the first layer, the second layer, the at least one wall and the lid comprise plastic.

28. A method for producing a side-ported microphone package, the method comprising:

disposing a microphone die, relative to a substrate;

attaching a lid to a first surface of the substrate to define a chamber within which the microphone die is, or will be, disposed;

defining at least a portion of an acoustic path from outside the chamber, through at least a portion of the substrate, to an aperture defined by the first surface within a boundary defined by a locus of points where the lid is, or will be, attached to the substrate, such that at least a portion of the defined acoustic path is oriented other than perpendicular to the first surface of the substrate.

29. A method according to claim 28, wherein defining the at least a portion of the acoustic path comprises laminating a plurality of layers of the substrate, wherein a first layer of the substrate defines the first aperture;

and a second layer of the substrate defines at least a portion of the acoustic path.

30. A method according to claim 28, wherein defining the at least a portion of the acoustic path comprises boring at least one hole at least partially through the substrate.

31. A method according to claim 28, wherein defining the at least a portion of the acoustic path comprises defining an opening in a second surface of the substrate that is substantially perpendicular to the first surface, the opening being in communication with the acoustic path.

32. A method according to claim 28, wherein defining the at least a portion of the acoustic path comprises defining an opening in the first surface, the opening being in communication with the acoustic path.

33. A method according to claim 28, wherein defining the at least a portion of the acoustic path comprises defining an opening in a second surface of the substrate, the second surface being on substantially an opposite side of the substrate from the first surface, the opening being in communication with the acoustic path;

the method further comprising providing a solderable portion on the second surface, the solderable portion being configured into an open shape, extending from a location proximate an edge of the substrate to another location proximate an edge of the substrate, so as to substantially bound the opening between the solderable portion and the edge of the substrate.

34. A method according to claim 33, wherein the solderable portion is U shaped, with ends of the U shape proximate the edge of the substrate.

35. A method for producing a side-ported microphone assembly, the method comprising:

attaching a bottom side of a bottom-ported microphone package to a surface of a circuit board;

defining an opening in the surface of the circuit board adjacent a present or expected future location of the bottom port of the microphone package; and

defining a hollow acoustic path from a side of the circuit board, through at least a portion of the circuit board, to the opening.

36. A method according to claim 35, wherein defining the acoustic path comprises laminating a plurality of layers of the circuit board, wherein a first layer of the circuit board defines the opening, and a second layer of the circuit board defines at least a portion of a hollow passage in communication with the opening and extending to the side of the circuit board.

37. A method according to claim 35, wherein defining the acoustic path comprises boring at least one hole at least partially through the circuit board, the hole being in communication with the opening.

38. A method according to claim 35, further comprising providing a solderable portion on the surface of the circuit board, the solderable portion being configured into an open shape, extending from a location proximate an edge of the circuit board to another location proximate an edge of the circuit board, so as to substantially bound the opening between the solderable portion and the edge of the circuit board.