Fully wafer-level-packaged MEMS microphone and method for manufacturing the same

• US 10,306,372 B2
• Filed: 08/26/2014
• Issued: 05/28/2019
• Est. Priority Date: 08/26/2014
• Status: Active Grant

• Current Assignee: Goertek Microelectronics Co., Ltd. (Goertek Incorporated)
• Original Assignee: Goertek Incorporated
• Inventors: Zou, Quanbo, Wang, Zhe
• Primary Examiner(s): Monikang, George C
• Application Number:
  US15/311,152
• Publication Number:
  US 20170164117A1
• Time in Patent Office: 1,736 Days
• Field of Search: 381111-115
• CPC Class Codes: B81B 2201/0257 Microphones or microspeakers
• CPC Class Codes: B81B 2203/0127 Diaphragms, i.e. structures separating two media that can control the passage from one medium to another; Membranes, i.e. diaphragms with filtering function
• CPC Class Codes: B81B 2203/04 Electrodes
• CPC Class Codes: B81B 2207/012 the micromechanical device and the control or processing electronics being separate parts in the same package
• CPC Class Codes: B81B 2207/07 Interconnects
• CPC Class Codes: B81B 3/001 Structures having a reduced contact area, e.g. with bumps or with a textured surface
• CPC Class Codes: B81B 7/00 Microstructural systems; Auxiliary parts of microstructural devices or systems
• CPC Class Codes: B81C 1/0023 Packaging together an electronic processing unit die and a micromechanical structure die MEMS packages B81B7/0032; MEMS packaging processes B81C1/00261
• CPC Class Codes: B81C 1/00888 Multistep processes involving only mechanical separation, e.g. grooving followed by cleaving
• CPC Class Codes: B81C 2203/0118 Bonding a wafer on the substrate, i.e. where the cap consists of another wafer
• CPC Class Codes: B81C 2203/058 Aligning components using methods not provided for in B81C2203/051 - B81C2203/052
• CPC Class Codes: B81C 2203/0785 Transfer and j oin technology, i.e. forming the electronic processing unit and the micromechanical structure on separate substrates and joining the substrates
• CPC Class Codes: B81C 2203/0792 Forming interconnections between the electronic processing unit and the micromechanical structure
• CPC Class Codes: H04R 19/005 using semiconductor materials
• CPC Class Codes: H04R 19/04 Microphones H04R19/01 takes precedence
• CPC Class Codes: H04R 2201/003 Mems transducers or their use
• CPC Class Codes: H04R 31/00 Apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor manufacture of microstructural arrangements of deformable or non-deformable structures in general B81C1/00182
• CPC Class Codes: H04R 31/006 Interconnection of transducer parts of diaphragm and outer suspension by moulding H04R31/003

Abstract

The present invention provides a method for manufacturing a fully wafer-level-packaged MEMS microphone and a microphone manufactured with the same, the method comprises: separately manufacturing a first packaging wafer, an MEMS microphone wafer and a second packaging wafer; performing wafer-to-wafer bonding for the three wafers to form a plurality of fully wafer-level-packaged MEMS microphone units; singulating the fully wafer-level-packaged MEMS microphone units to form a plurality of fully wafer-level-packaged MEMS microphones, which are fully packaged at wafer level and do not need any further process after die singulation. The method can improve cost-effectiveness, performance consistency, manufacturability, quality, scaling capability of the packaged MEMS microphone.

Claims

1. A method of manufacturing a fully wafer-level-packaged MEMS microphone, comprising:

separately manufacturing a first packaging wafer, a MEMS microphone wafer and a second packaging wafer, wherein the first packaging wafer comprises a plurality of first packaging units, the second packaging wafer comprises a plurality of second packaging units, and the MEMS microphone wafer comprises a plurality of MEMS microphone units, each of which comprises a silicon substrate formed with a back hole therein and an acoustic sensing part supported on the silicon substrate and aligned with the back hole that comprise a portion of a back chamber between the first packaging unit and the silicon substrate, and wherein the first packaging units and/or the second packaging units and/or the MEMS microphone units comprise ASICs, and the first packaging units or the second packaging units also comprise acoustic ports for allowing an acoustic signal to reach the acoustic sensing part;

performing wafer-to-wafer bonding for the MEMS microphone wafer and the first packaging wafer and for the second packaging wafer and the MEMS microphone wafer, such that the first packaging units, the MEMS microphone units and the second packaging units are correspondingly aligned to form a plurality of fully wafer-level-packaged MEMS microphone units, in each of which electrical connections among the acoustic sensing part, the ASICs and surface mountable pads formed on the outer side of each of the first packaging unit and/or the outer side of each of the second packaging unit are realized by interconnection wires or conductive pads or through-silicon-vias or the combination thereof;

singulating the fully wafer-level-packaged MEMS microphone units to form a plurality of fully wafer-level-packaged MEMS microphones.

2. The method of claim 1, wherein the acoustic sensing part at least includes:

a compliant diaphragm;

a perforated backplate; and

an air gap formed between the diaphragm and the backplate, wherein the diaphragm and the backplate are used to form electrode plates of a variable condenser.

3. The method of claim 1, wherein the wafer-to-wafer bonding is realized by any of metal-metal bonding, metal eutectic bonding, soldering, and conductive adhesive bonding.

4. The method of claim 1, wherein in each of the fully wafer-level-packaged MEMS microphone units, the first packaging unit comprises the ASICs and the acoustic port, the second packaging unit comprises a cavity, the back hole in the MEMS microphone unit and the cavity are merged to form the back chamber, and the surface mountable pads are formed on the outer side of the first packaging unit.

5. The method of claim 4, wherein in each of the fully wafer-lever-packaged MEMS microphone units, the acoustic sensing part includes a perforated backplate supported on the silicon substrate and a compliant diaphragm supported on the backplate with an air gap sandwiched therebetween, and wherein dimples are formed on the inner side of the first packaging unit to protect the diaphragm from sticking thereto.

6. The method of claim 1, wherein in each of the fully wafer-level-packaged MEMS microphone units, the first packaging unit comprises the acoustic port, the second packaging unit comprises the ASICs, and the surface mountable pads are formed on the outer side of the first packaging unit.

7. The method of claim 6, wherein in each of the fully wafer-level-packaged MEMS microphone units, the acoustic sensing part includes a perforated backplate supported on the silicon substrate and a compliant diaphragm supported on the backplate with an air gap sandwiched therebetween, and wherein dimples are formed on the inner side of the first packaging unit to protect the diaphragm from sticking thereto.

8. A fully wafer-level-packaged MEMS microphone, comprising:

a first packaging unit;

a MEMS microphone unit, comprising a silicon substrate formed with a back hole therein, and an acoustic sensing part supported on the silicon substrate and aligned with the back hole that comprise a portion of a back chamber between the first packaging unit and the silicon substrate; and

a second packaging unit,

wherein the first packaging unit and/or the second packaging unit and/or the MEMS microphone unit comprise ASICs, and the first packaging unit or the second packaging unit also comprises an acoustic port for allowing an acoustic signal to reach the acoustic sensing part,

wherein the first packaging unit, the MEMS microphone unit and the second packaging unit are aligned, the MEMS microphone unit is bonded to the first packaging unit and the second packaging unit is bonded to the MEMS microphone unit, and

wherein the electrical connections among the acoustic sensing part, the ASICs and surface mountable pads formed on the outer side of the first packaging unit and/or the outer side of the second packaging unit are realized by interconnection wires or conductive pads or through-silicon-vias or the combination thereof.

9. The fully wafer-level-packaged MEMS microphone of claim 8, wherein the acoustic sensing part at least includes:

a compliant diaphragm;

a perforated backplate; and

an air gap formed between the diaphragm and the backplate, wherein the diaphragm and the backplate are used to form electrode plates of a variable condenser.

10. The fully wafer-level-packaged MEMS microphone of claim 8, wherein the first packaging unit comprises the ASICs and the acoustic port, the second packaging unit comprises a cavity, the back hole in the MEMS microphone unit and the cavity are merged to form the back chamber, and the surface mountable pads are formed on the outer side of the first packaging unit.

11. The fully wafer-level-packaged MEMS microphone of claim 10, wherein the acoustic sensing part includes a perforated backplate supported on the silicon substrate and a compliant diaphragm supported on the backplate with an air gap sandwiched therebetween, and wherein dimples are formed on the inner side of the first packaging unit to protect the diaphragm from sticking thereto.

12. The fully wafer-level-packaged MEMS microphone of claim 8, wherein the first packaging unit comprises the acoustic port, the second packaging unit comprises the ASICs, and the surface mountable pads are formed on the outer side of the first packaging unit.

13. The fully wafer-level-packaged MEMS microphone of claim 12, wherein the acoustic sensing part includes a perforated backplate supported on the silicon substrate and a compliant diaphragm supported on the backplate with an air gap sandwiched therebetween, and wherein dimples are formed on the inner side of the first packaging unit to protect the diaphragm from sticking thereto.

14. A method of manufacturing a fully wafer-level-packaged MEMS microphone, comprising:

separately manufacturing a first packaging wafer, a MEMS microphone wafer, wherein the first packaging wafer comprises a plurality of first packaging units, and the MEMS microphone wafer comprises a plurality of MEMS microphone units, each of which comprises a silicon substrate formed with a back hole therein, and an acoustic sensing part supported on the silicon substrate and aligned with the back hole that comprises a portion of a back chamber between the first packaging unit and the silicon substrate, and wherein the first packaging units and/or the MEMS microphone units comprise ASICs;

performing wafer-to-wafer bonding for the MEMS microphone wafer and the first packaging wafer with the back hole side of the MEMS microphone wafer being away from the first packaging wafer, such that the first packaging units and the MEMS microphone units are correspondingly aligned to form a plurality of fully wafer-level-packaged MEMS microphone units, in each of which the electrical connections among the acoustic sensing part, the ASICs and surface mountable pads formed on the outer side of the first packaging unit are realized by interconnection wires or conductive pads or through-silicon-vias or the combination thereof;

singulating the fully wafer-level-packaged MEMS microphone units to form a plurality of fully wafer-level-packaged MEMS microphones.

15. The method of claim 14, wherein in each of the fully wafer-level-packaged MEMS microphone units, the acoustic sensing part and the ASICs are integrally formed on the MEMS microphone unit, and the surface mountable pads are formed on the outer side of the first packaging unit.