Surface mount silicon condenser microphone package

• US 8,121,331 B2
• Filed: 05/19/2011
• Issued: 02/21/2012
• Est. Priority Date: 11/28/2000
• Status: Expired due to Fees

• 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:
  US13/111,537
• Publication Number:
  US 20110210409A1
• Time in Patent Office: 278 Days
• Field of Search: None
• US Class Current: 381/360
• 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. The inventive package uses a limited number of components which simplifies manufacturing and lowers costs, and features a substrate which 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 die and the package, and providing an exterior surface for making electrical connections between package and a user'"'"'s printed circuit board. In some embodiments, the acoustic port is located in the substrate directly under the silicon condenser die which decreases the thickness of the inventive package.

Claims

1. A surface mount silicon condenser microphone package comprising:

a planar substrate comprising a rigid printed circuit board having a top surface and a bottom surface, the top surface having a peripheral portion and a central portion;

a non-planar cover having a peripheral portion and a central portion;

a package housing formed by the mechanical attachment of the bottom of the peripheral portion of the cover to the peripheral portion of the top surface of the substrate;

a silicon condenser microphone die mechanically attached to the central portion of the top surface of the substrate and physically protected by the package housing;

a plurality of solder pads on the bottom surface of the substrate, the solder pads configured to mechanically attach and electrically connect the package to the surface of an external printed circuit board using a solder reflow process;

a plurality of bond pads on the top surface of the substrate, at least one of the bond pads electrically connected to the silicon condenser microphone die;

a plurality of electrical pathways within the substrate, with at least one electrical pathway between one of the bond pads on the top surface of the substrate and one of the solder pads on the bottom surface of the substrate; and

an acoustic port in the package housing, the acoustic port configured to allow the passage of sound waves from the exterior of the package housing into the interior of the package housing.

2. The package of claim 1, where:

the acoustic port is in the substrate and positioned directly under the silicon condenser microphone die.

3. The package of claim 1, where:

the acoustic port is in the substrate and positioned adjacent to but not directly under the silicon condenser microphone die.

4. The package of claim 1, where:

the acoustic port is in the cover.

5. The package of claim 1, where:

the rigid printed circuit board comprises an FR-4 material.

6. A surface mount silicon condenser microphone package comprising:

a planar substrate comprising a rigid printed circuit board having a top surface and a bottom surface, the top surface having a peripheral portion and a central portion;

a planar side portion comprising a rigid printed circuit board having side walls on the perimeter of the side portion and a window on the interior of the side portion;

a planar cover comprising a rigid printed circuit board having a top surface and a bottom surface, the bottom surface having a peripheral portion and a central portion;

a package housing formed by the mechanical attachment of the peripheral portion of the bottom surface of the cover to the top of the side walls of the side portion, and by the mechanical attachment of the bottom of the side walls of the side portion to the peripheral portion of the top surface of the substrate;

a silicon condenser microphone die mechanically attached to the central portion of the top surface of the substrate and physically protected by the package housing;

a plurality of solder pads on the bottom surface of the substrate, the solder pads configured to mechanically attach and electrically connect the package to the surface of an external printed circuit board using a solder reflow process;

a plurality of bond pads on the top surface of the substrate, at least one of the bond pads electrically connected to the silicon condenser microphone die;

a plurality of electrical pathways within the substrate, with at least one electrical pathway between one of the bond pads on the top surface of the substrate and one of the solder pads on the bottom surface of the substrate; and

an acoustic port in the package housing, the acoustic port configured to allow the passage of sound waves from the exterior of the package housing into the interior of the package housing.

7. The package of claim 6, where:

the acoustic port is in the substrate and positioned directly under the silicon condenser microphone die.

8. The package of claim 6, where:

the acoustic port is in the substrate and positioned adjacent to but not directly under the silicon condenser microphone die.

9. The package of claim 6, where:

The acoustic port is in the cover.

10. The package of claim 6, where:

the rigid printed circuit boards of the substrate, side portion, and cover comprise an FR-4 material.

11. A surface mount MEMS microphone package comprising:

a planar substrate having a top surface and a bottom surface, the top surface having a peripheral portion and a central portion;

a non-planar cover having a peripheral portion and a central portion;

a package housing formed by the mechanical attachment of the bottom of the peripheral portion of the cover to the peripheral portion of the top surface of the substrate,

a MEMS microphone die mechanically attached to the central portion of the top surface of the substrate and physically protected by the package housing;

a plurality of solder pads on the bottom surface of the substrate, the plurality of solder pads configured to mechanically attach and electrically connect the package to the surface of an external printed circuit board using a solder reflow process; and

an acoustic port in the substrate, the acoustic port positioned directly under the MEMS microphone die and configured to allow the passage of sound waves from the exterior of the package housing into the interior of the package housing.

12. The package of claim 11, where:

the substrate is a rigid printed circuit board.

13. The package of claim 11, where:

the MEMS microphone die is a silicon condenser microphone die.