# US 9,438,972 B2 · Silicon based MEMS microphone, a system and a package with the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,438,972 B2 - Document ID: US9438972B2 - Status: Granted - Kind: B2 - Application number: 13/582,141 - Filed: 2011-12-29 - Published: 2014-10-09 - Granted: 2016-09-06 - Earliest claimed: 2011-12-29 - Assignees: Goertek Inc. - Applicants: Zhe Wang; Mengjin Cai - Inventors: Zhe Wang; Mengjin Cai - Web page: https://patentgrep.com/patent/US9438972B2 ## CPC - H04R 1/02: Casings; Cabinets {; Supports therefor;} Mountings therein (H04R1/28 takes precedence {; attachments for microphones H04R1/08; mounting of transducers in earpieces H04R1/1075}) - B81B 7/0061: {suitable for fluid transfer from the MEMS out of the package or vice versa, e.g. transfer of liquid, gas, sound} - H04R 1/086: {Protective screens, e.g. all weather or wind screens} - H04R 7/04: Plane diaphragms - H04R 19/005: {using semiconductor materials} - B81B 2201/0257: Microphones or microspeakers - H04R 19/04: Microphones (H04R19/01 takes precedence) - H04R 2201/003: Mems transducers or their use - H04R 2201/02: Details casings, cabinets or mounting therein for transducers covered by H04R1/02 but not provided for in any of its subgroups - H04R 2207/00: Details of diaphragms or cones for electromechanical transducers or their suspension covered by H04R7/00 but not provided for in H04R7/00 or in H04R2307/00 - H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K) - B81B: MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES (piezoelectric, electrostrictive or magnetostrictive elements per se H10N30/00, H10N35/00) ## Abstract The present invention relates to a silicon based MEMS microphone, comprising a silicon substrate and an acoustic sensing part supported on the silicon substrate, wherein a mesh-structured back hole is formed in the substrate and aligned with the acoustic sensing part, the mesh-structured back hole includes a plurality of mesh beams which are interconnected with each other and supported on the side wall of the mesh-structure back hole, the plurality of mesh beams and the side wall define a plurality of mesh holes which all have a tapered profile and merge into one hole in the vicinity of the acoustic sensing part at the top side of the silicon substrate. The mesh-structured back hole can help to streamline the air pressure pulse caused, for example, in a drop test and thus reduce the impact on the acoustic sensing part of the microphone, and also serve as a protection filter to prevent alien substances such as particles entering the microphone. ## Claims ### Claim 1 A silicon based MEMS microphone, comprising: a silicon substrate, an acoustic sensing part supported on the silicon substrate, the acoustic sensing part including a diaphragm, a perforated backplate and an air gap between the diaphragm and the backplate, and a mesh-structured back hole formed in the substrate and aligned with the acoustic sensing part, wherein the mesh-structured back hole includes a plurality of mesh beams which are interconnected with each other and supported on the side wall of the mesh-structure back hole; the plurality of mesh beams and the side wall define a plurality of mesh holes which all have a tapered profile and merge into one hole in the vicinity of the acoustic sensing part at the top side of the silicon substrate. ### Claim 2 (depends on 1) The silicon based MEMS microphone of claim 1, wherein the mesh-structured back hole is formed from the bottom side of the silicon substrate using a controlled deep reactive ion etching process. ### Claim 3 (depends on 1) The silicon based MEMS microphone of claim 1, wherein the plurality of mesh holes are uniformly and/or symmetrically distributed across the mesh-structured back hole. ### Claim 4 (depends on 1) The silicon based MEMS microphone of claim 1, wherein the mesh-structured back hole is provided with a circular shape, a square shape, a rectangular shape or other polygonal shape. ### Claim 5 (depends on 1, 2, 3, 4) The silicon based MEMS microphone of any claim of claims 1-4, wherein the diaphragm is a compliant diaphragm; and wherein the diaphragm and the backplate are used to form electrode plates of a variable condenser. ### Claim 6 (depends on 5) The silicon based MEMS microphone of claim 5, wherein said compliant diaphragm is formed with a part of a silicon device layer stacked on the silicon substrate with an oxide layer sandwiched in between; said perforated backplate is located above the diaphragm and formed with CMOS passivation layers with a metal layer imbedded therein which serves as an electrode plate of the backplate; and the acoustic sensing part of the said microphone further includes an interconnection column provided between the center of the diaphragm and the center of the backplate for mechanically suspending and electrically wiring out the diaphragm using CMOS metal interconnection method, and the periphery of the diaphragm is free to vibrate. ### Claim 7 (depends on 6) The silicon based MEMS microphone of claim 6, wherein the mesh-structured back hole includes a central mesh beam extending from the bottom side to the top side of the silicon substrate and attaching to the center of the diaphragm. ### Claim 8 (depends on 5) The silicon based MEMS microphone of claim 5, wherein said compliant diaphragm is formed with a part of a silicon device layer stacked on the silicon substrate with an oxide layer sandwiched in between; said perforated backplate is located above the diaphragm and formed with CMOS passivation layers with a metal layer imbedded therein which serves as an electrode plate of the backplate; and the acoustic sensing part of the said microphone further includes an interconnection column provided between the edge of diaphragm and the edge of the backplate for electrically wiring out the diaphragm using CMOS metal interconnection method, and the periphery of the diaphragm is fixed. ### Claim 9 (depends on 1, 2, 3, 4, 5, 6, 7, 8) A microphone system, comprising a silicon based MEMS microphone of any claim of claims 1-8 and a CMOS circuitry integrated on a single chip. ### Claim 10 (depends on 1, 2, 3, 4, 5, 6, 7, 8) A microphone package, comprising a PCB board; a silicon based MEMS microphone of any claim of claims 1-8, mounted on the PCB board; and a cover, enclosing the microphone, wherein an acoustic port is formed on any of the PCB board and the cover, and aligned with the mesh-structured back hole of the microphone.