Bottom port surface mount silicon condenser microphone package

• US 8,624,384 B1
• Filed: 11/02/2012
• Issued: 01/07/2014
• Est. Priority Date: 11/28/2000
• Status: Expired due to Term

• Current Assignee: Knowles Electronics Llc (Knowles Corporation)
• Original Assignee: Knowles Electronics Llc (Knowles Corporation)
• Inventors: Minervini, Anthony D.
• Primary Examiner(s): Chambliss, Alonzo
• Application Number:
  US13/668,035
• Time in Patent Office: 431 Days
• Field of Search: None
• US Class Current: 257/704
• CPC Class Codes: B81B 2201/0257 Microphones or microspeakers
• CPC Class Codes: B81B 2207/092 Buried interconnects in the substrate or in the lid
• CPC Class Codes: B81B 3/0021 Transducers for transforming electrical into mechanical energy or vice versa dynamo-electric machines H02K99/00; electrostatic machines H02N1/00; piezoelectric devices H10N30/00
• CPC Class Codes: B81B 7/0038 using materials for controlling the level of pressure, contaminants or moisture inside of the package, e.g. getters
• CPC Class Codes: B81B 7/0058 for protecting against damages due to external chemical or mechanical influences, e.g. shocks or vibrations
• CPC Class Codes: B81B 7/0061 suitable for fluid transfer from the MEMS out of the package or vice versa, e.g. transfer of liquid, gas, sound
• CPC Class Codes: B81B 7/0064 for protecting against electromagnetic or electrostatic interferences
• CPC Class Codes: B81B 7/007 Interconnections between the MEMS and external electrical signals
• CPC Class Codes: B81C 1/00158 Diaphragms, membranes manufacture process for semi-permeable inorganic membranes B01D67/0039
• CPC Class Codes: B81C 1/00301 Connecting electric signal lines from the MEMS device with external electrical signal lines, e.g. through vias
• CPC Class Codes: B81C 3/00 Assembling of devices or systems from individually processed components
• CPC Class Codes: H01L 21/78 with subsequent division of the substrate into plural individual devices cutting to change the surface-physical characteristics or shape of semiconductor bodies H01L21/304
• CPC Class Codes: H01L 23/10 characterised by the material or arrangement of seals between parts, e.g. between cap and base of the container or between leads and walls of the container
• CPC Class Codes: H01L 23/15 Ceramic or glass substrates H01L23/142, H01L23/145, H01L23/147 take precedence
• 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: H01L 2924/1461 MEMS
• CPC Class Codes: H04R 1/04 Structural association of microphone with electric circuitry therefor in deaf-aid sets H04R25/00
• CPC Class Codes: H04R 1/222 for microphones H04R1/24, H04R1/26 take precedence
• CPC Class Codes: H04R 1/2892 Mountings or supports for transducers
• CPC Class Codes: H04R 19/005 : using semiconductor materials
• CPC Class Codes: H04R 19/016 : for microphones
• CPC Class Codes: H04R 19/04 : Microphones H04R19/01 takes precedence
• CPC Class Codes: H04R 2201/003 : Mems transducers or their use of the electrostatic type H04R19/005
• CPC Class Codes: H04R 2225/49 : Reducing the effects of electromagnetic noise on the functioning of hearing aids, by, e.g. shielding, signal processing adaptation, selective (de)activation of electronic parts in hearing aid
• CPC Class Codes: H04R 23/00 : Transducers other than those covered by groups H04R9/00 - H04R21/00 diaphragms for transducers of the distributed-mode type H04R7/045
• CPC Class Codes: H04R 2410/03 : Reduction of intrinsic noise in microphones
• CPC Class Codes: H04R 3/00 : Circuits for transducers , loudspeakers or 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
• CPC Class Codes: Y10T 29/49798 : Dividing sequentially from leading end, e.g., by cutting or breaking

Abstract

The present invention relates to a surface mount package for a silicon condenser microphone and methods for manufacturing the surface mount package. The surface mount package uses a limited number of components which simplifies manufacturing and lowers costs, and features a substrate that performs functions for which multiple components were traditionally required, including providing an interior surface on which the silicon condenser die is mechanically attached, providing an interior surface for making electrical connections between the silicon condenser die and the package, and providing an exterior surface for surface mounting the package to a device'"'"'s printed circuit board and for making electrical connections between package and the device'"'"'s printed circuit board.

Claims

1. A solder reflow surface mount microelectromechanical system (MEMS) microphone device comprising:

a substrate comprising multiple layers of non-conductive material, each layer having a predetermined coefficient of thermal expansion, and the substrate having a planar upper surface and a planar lower surface, the upper surface having an interior region and a peripheral region that completely surrounds the interior region, the substrate further comprising;

a first plurality of metal pads formed on the upper surface of the substrate;

a second plurality of metal pads formed on the lower surface of the substrate and arranged within a perimeter of the lower surface of the substrate, wherein the second plurality of metal pads are configured to mechanically attach and electrically couple the surface mount MEMS microphone device to pads on a surface of an external printed circuit board;

one or more electrical traces formed completely within the substrate, wherein the traces electrically couple one or more of the first plurality of metal pads on the upper surface of the substrate to one or more of the second plurality of metal pads on the lower surface of the substrate; and

a port formed in the interior region of the substrate and passing completely through the substrate, wherein one of the second plurality of formed metal pads is an annular ring that completely surrounds the port in the substrate;

a MEMS microphone die mounted to the upper surface of the substrate and electrically coupled to at least one of the first plurality of metal pads on the upper surface of the substrate, the MEMS microphone die having an acoustic passage that is disposed directly over and acoustically coupled to the port in the substrate; and

a single-piece cover having a predetermined shape that comprises a top region and a substantially vertical sidewall region that adjoins the central region at a substantially perpendicular angle and that completely surrounds and supports the top region, the sidewall region having a predetermined height, an exterior sidewall surface, an interior sidewall surface, and a bottom surface,

wherein the bottom surface of the sidewall region is aligned with and attached to the peripheral region of the upper surface of the substrate, and

wherein the predetermined shape of the cover and the predetermined height of the sidewall region, in cooperation with the interior region of the upper surface of the substrate, forms a protective enclosure for the MEMS microphone die and defines an acoustic chamber for the MEMS microphone die.

2. A surface mount MEMS microphone device according to claim 1, further comprising a metal pad with an opening, wherein the opening surrounds the port in the substrate, and the metal pad is interposed between the MEMS microphone die and the upper surface of the substrate.

3. A surface mount MEMS microphone device according to claim 1, further comprising a metal pad with an opening, wherein the opening surrounds the port in the substrate, and the MEMS microphone die contacts the metal pad when mounted on the upper surface of the substrate.

4. A surface mount MEMS microphone device according to claim 1, wherein the non-conductive material is FR-4 material.

5. A surface mount MEMS microphone device according to claim 1, further comprising at least one passive electrical device formed within the substrate.

6. A surface mount MEMS microphone device according to claim 1, wherein the enclosure protects the MEMS microphone die from at least one of light, electromagnetic interference, and physical damage.

7. A surface mount MEMS microphone device according to claim 6, wherein the substrate further comprises acoustic material that substantially blocks environmental contaminants from entering the acoustic chamber through the port.

8. A surface mount MEMS microphone device according to claim 1, wherein a diaphragm of the MEMS microphone die defines a front volume and a back volume in the acoustic chamber, and the port formed in the substrate is acoustically coupled to the front volume.

9. A surface mount microelectromechanical system (MEMS) microphone device comprising:

a printed circuit board comprising multiple layers of non-conductive material each layer having a predetermined coefficient of thermal expansion and the printed circuit board having a planar upper surface and a planar lower surface, the upper surface having an interior region and a peripheral region that completely surrounds the interior region, the printed circuit board comprising;

a first plurality of metal pads formed on the upper surface of the printed circuit board;

a second plurality of metal pads formed on the lower surface of the printed circuit board and arranged within a perimeter of the lower surface of the printed circuit board, wherein the second plurality of metal pads are configured to mechanically attach and electrically couple the surface mount MEMS microphone device to pads on a surface of an external printed circuit board;

one or more circuit traces formed completely within the printed circuit board, wherein the circuit traces electrically couple one or more of the first plurality of metal pads on the upper surface of the printed circuit board to one or more of the second plurality of metal pads on the lower surface of the printed circuit board, wherein the circuit traces are patterned in at least one conductive layer interposed between the multiple layers of non-conductive material; and

a port formed in the interior region of the printed circuit board and passing completely through the printed circuit board, wherein one of the second plurality of formed metal pads is an annular ring that completely surrounds the port in the printed circuit board;

a MEMS microphone die mounted to the upper surface of the printed circuit board and electrically coupled to at least one of the first plurality of metal pads on the upper surface of the printed circuit board, the MEMS microphone die and insert instead having an acoustic passage that is disposed directly over and acoustically coupled to the port in the printed circuit board; and

a single-piece cover having a predetermined shape that comprises a top region and a substantially vertical sidewall region that adjoins the central region at a substantially perpendicular angle and that completely surrounds and supports the top region, the sidewall region having a predetermined height, an exterior sidewall surface, an interior sidewall surface, and a bottom surface,

wherein the bottom surface of the sidewall region is aligned with and mechanically attached to the peripheral region of the upper surface of the printed circuit board,

wherein the predetermined shape of the cover and the predetermined height of the sidewall region, in cooperation with the interior region of the upper surface of the printed circuit board, forms a protective enclosure for the MEMS microphone die and defines an acoustic chamber for the MEMS microphone die,

wherein the cover has a first length and a first width, and the printed circuit board has a second length and a second width, and

wherein the first length of the cover and second length of the printed circuit board are substantially equal, and the first width of the cover and second width of the printed circuit board are substantially equal.

10. A surface mount MEMS microphone device according to claim 9, further comprising a metal pad with an opening, wherein the opening surrounds the port in the printed circuit board, and the metal pad is interposed between the MEMS microphone die and the upper surface of the printed circuit board.

11. A surface mount MEMS microphone device according to claim 9, further comprising a metal pad with an opening, wherein the opening surrounds the port in the printed circuit board, and the MEMS microphone die contacts the metal pad when mounted on the upper surface of the printed circuit board.

12. A surface mount MEMS microphone device according to claim 9, wherein the non-conductive material is FR-4 material.

13. A surface mount MEMS microphone device according to claim 9, further comprising at least one passive electrical device formed within the printed circuit board.

14. A surface mount MEMS microphone device according to claim 9, wherein the enclosure protects the MEMS microphone die from at least one of light, electromagnetic interference, and physical damage.

15. A surface mount MEMS microphone device according to claim 9, wherein the printed circuit board further comprises acoustic material that substantially blocks environmental contaminants from entering the acoustic chamber through the port.

16. A surface mount MEMS microphone device according to claim 9, wherein a diaphragm of the MEMS microphone die defines a front volume and a back volume in the acoustic chamber, and the port formed in the printed circuit board is acoustically coupled to the front volume.

17. A surface mount microelectromechanical system (MEMS) microphone device comprising:

a substrate comprising multiple layers of non-conductive material each layer having a predetermined coefficient of thermal expansion and having a planar upper surface and a planar lower surface, the upper surface having an interior region and a peripheral region that completely surrounds the interior region, the substrate further comprising;

a first plurality of metal pads formed on the upper surface of the substrate;

a second plurality of metal pads formed on the lower surface of the substrate and arranged within a perimeter of the lower surface of the substrate, wherein the second plurality of metal pads are configured to mechanically couple and electrically couple the surface mount MEMS microphone device to pads on a surface of an external printed circuit board; and

one or more wiring traces formed completely within the substrate, wherein the wiring traces electrically couple one or more of the first plurality of metal pads on the upper surface of the substrate to one or more of the second plurality of metal pads on the lower surface of the substrate, wherein the wiring traces are patterned in at least one conductive layer interposed between the multiple layers of non-conductive material; and

a port formed in the interior region of the substrate and passing completely through the substrate, wherein one of the second plurality of formed metal pads is an annular ring that completely surrounds the port in the substrate;

a MEMS microphone die physically coupled to the upper surface of the substrate and electrically coupled to at least one of the first plurality of metal pads on the upper surface of the substrate, the MEMS microphone die having an acoustic passage that is disposed directly over and acoustically coupled to the port in the substrate; and

a single-piece cover having a predetermined shape that comprises a central region and a substantially vertical sidewall region that adjoins the central region and that completely surrounds and supports the central region, the sidewall region having a predetermined height, an exterior surface, an interior surface, and a bottom surface,

wherein the bottom surface of the sidewall region is aligned with and physically coupled to the peripheral region of the upper surface of the substrate, thereby forming protective enclosure for the MEMS microphone die, and

wherein the interior of the protective enclosure is an acoustic chamber having a volume defined by the predetermined height of sidewall region, the predetermined shape of the cover, and the width and length of the central region of the cover.

18. A surface mount MEMS microphone device according to claim 17, further comprising a metal pad with an opening, wherein the opening surrounds the port in the substrate, and the metal pad is interposed between the MEMS microphone die and the upper surface of the substrate.

19. A surface mount MEMS microphone device according to claim 17, further comprising a metal pad with an opening, wherein the opening surrounds the port in the substrate, and the MEMS microphone die contacts the metal pad when physically coupled to the upper surface of the substrate.

20. A surface mount MEMS microphone device according to claim 17, wherein the non-conductive is comprises FR-4 material.

21. A surface mount MEMS microphone device according to claim 17, further comprising at least one passive electrical device formed within the substrate.

22. A surface mount MEMS microphone device according to claim 17, wherein the enclosure protects the MEMS microphone die from at least one of light, electromagnetic interference, and physical damage.

23. A surface mount MEMS microphone device according to claim 17, wherein the substrate further comprises acoustic material that substantially blocks environmental contaminants from entering the acoustic chamber through the port.

24. A surface mount MEMS microphone device according to claim 17, wherein a diaphragm of the MEMS microphone die defines a front volume and a back volume in the acoustic chamber, and the port formed in the substrate is acoustically coupled to the front volume.

25. A surface mount microelectromechanical system (MEMS) microphone device comprising:

a printed circuit board having a multi-layer core of conductive and non-conductive materials wherein the non-conductive material has a predetermined coefficient of thermal expansion, and, wherein the printed circuit board has a planar upper surface and a planar lower surface, the upper surface having an interior region and a peripheral region that completely surrounds the interior region, the printed circuit board further comprising;

a first metal layer formed on the upper surface of the printed circuit board and patterned into a first plurality of metal pads, wherein at least one pad of the first plurality of metal pads is formed in the peripheral region of the upper surface of the printed circuit board;

a second metal layer formed on the lower surface of the printed circuit board and patterned into a second plurality of metal pads, the second plurality of metal pads arranged within a perimeter of the lower surface of the printed circuit board, wherein the second plurality of metal pads are configured to mechanically couple and electrically couple the surface mount MEMS microphone device to pads on a surface of an external printed circuit board;

one or more wiring traces formed completely within the printed circuit board, wherein the wiring traces electrically couple one or more of the first plurality of metal pads on the upper surface of the printed circuit board to one or more of the second plurality of metal pads on the lower surface of the printed circuit board, wherein the wiring traces are patterned in at least one conductive layer interposed between two layers of non-conductive material; and

a port formed in the interior region of the printed circuit board and passing completely through the printed circuit board, wherein one of the second plurality of patterned metal pads is an annular ring that completely surrounds the port in the printed circuit board;

a MEMS microphone die physically coupled to the upper surface of the multi-layer printed circuit board and electrically coupled to at least one of the first plurality of patterned metal pads, the MEMS microphone die having an acoustic passage that is disposed directly over and acoustically coupled to the port in the multi-layer printed circuit board; and

a single-piece cover having a predetermined shape that comprises a central region and a substantially vertical sidewall region that adjoins the central region and that completely surrounds and supports the central region, the sidewall region having a predetermined height, an exterior surface, an interior surface, and a bottom surface,

wherein the bottom surface of the sidewall region is aligned with and physically coupled to the peripheral region of the upper surface of the printed circuit board, thereby forming protective enclosure for the MEMS microphone die, and

wherein the interior of the protective enclosure is an acoustic chamber having a volume defined by the predetermined height of sidewall region, the predetermined shape of the cover, and the width and length of the central region of the cover.

26. A surface mount MEMS microphone device according to claim 25, further comprising a metal pad with an opening, wherein the opening surrounds the port in the printed circuit board, and the metal pad is interposed between the MEMS microphone die and the upper surface of the printed circuit board.

27. A surface mount MEMS microphone device according to claim 25, further comprising a metal pad with an opening, wherein the opening surrounds the port in the printed circuit board, and the MEMS microphone die contacts the metal pad when physically coupled to the upper surface of the printed circuit board.

28. A surface mount MEMS microphone device according to claim 25, further comprising at least one passive electrical device formed within the printed circuit board.

29. A surface mount MEMS microphone device according to claim 25, wherein the enclosure protects the MEMS microphone die from at least one of light, electromagnetic interference, and physical damage.

30. A surface mount MEMS microphone device according to claim 25, wherein the printed circuit board further comprises acoustic material that substantially blocks environmental contaminants from entering the acoustic chamber through the port.