WO2022007000A1 - Microphone mems - Google Patents

Microphone mems Download PDF

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Publication number
WO2022007000A1
WO2022007000A1 PCT/CN2020/103746 CN2020103746W WO2022007000A1 WO 2022007000 A1 WO2022007000 A1 WO 2022007000A1 CN 2020103746 W CN2020103746 W CN 2020103746W WO 2022007000 A1 WO2022007000 A1 WO 2022007000A1
Authority
WO
WIPO (PCT)
Prior art keywords
diaphragm
mems microphone
inner cavity
back plate
main body
Prior art date
Application number
PCT/CN2020/103746
Other languages
English (en)
Chinese (zh)
Inventor
赵转转
柏杨
但强
王凯杰
李杨
张睿
Original Assignee
瑞声声学科技(深圳)有限公司
瑞声科技（南京）有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 瑞声声学科技(深圳)有限公司, 瑞声科技（南京）有限公司 filed Critical 瑞声声学科技(深圳)有限公司
Publication of WO2022007000A1 publication Critical patent/WO2022007000A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R19/00—Electrostatic transducers
    • H04R19/04—Microphones
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R1/00—Details of transducers, loudspeakers or microphones
    • H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
    • H04R1/22—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired frequency characteristic only 
    • H04R1/222—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired frequency characteristic only  for microphones
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R1/00—Details of transducers, loudspeakers or microphones
    • H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
    • H04R1/22—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired frequency characteristic only 
    • H04R1/28—Transducer mountings or enclosures modified by provision of mechanical or acoustic impedances, e.g. resonator, damping means
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R2201/00—Details of transducers, loudspeakers or microphones covered by H04R1/00 but not provided for in any of its subgroups
    • H04R2201/003—Mems transducers or their use

Definitions

  • the invention relates to the technical field of acoustics, in particular to a MEMS microphone.
  • a MEMS (Micro Electro Mechanic System, Micro Electro Mechanical System) microphone in the prior art is provided with a vibrating membrane at intervals on the base, and a back plate is provided above the vibrating membrane and further apart from the inner cavity.
  • the diaphragm and the back plate are parallel to each other, forming a flat capacitive system.
  • the sound wave airflow enters the cavity between the back plate and the diaphragm, the sound pressure acts on the diaphragm and causes the diaphragm to move. This movement changes the distance between the film and the back plate, thereby changing the capacitance and finally converting it into an electrical signal.
  • the corresponding function of the microphone is realized.
  • the air velocity near the edge of the diaphragm and the back plate is smaller than the air velocity in the central area of the inner cavity when the air flows, that is, the air flows between the diaphragm and the back plate.
  • Laminate damping The compression film damping has a great influence on the dynamic response of the MEMS chip. The greater the damping, the greater the mechanical noise.
  • An object of the present invention is to provide a MEMS microphone that reduces mechanical noise.
  • a MEMS microphone the MEMS microphone includes a base with a back cavity, a vibrating membrane arranged at intervals from the base, and a vibrating membrane covering the vibrating membrane and being spaced from the vibrating membrane
  • a back plate with an inner cavity the back plate has at least one convex portion raised in a direction away from the diaphragm.
  • the at least one protruding portion includes a first protruding portion
  • the back plate includes a fixing portion and a main body portion surrounded by and connected to the fixing portion, the fixing portion facing away from the diaphragm.
  • the first raised portion is formed by bulging in the direction of .
  • the first protruding portion is located on the outer periphery of the fixing portion.
  • the first protruding portion is spaced apart from the outer periphery of the fixing portion.
  • the at least one protruding portion further includes a second protruding portion, and the main body portion of the back plate is raised in a direction away from the diaphragm to form the second protruding portion.
  • the distance from the main body portion to the diaphragm gradually decreases from the central position of the main body portion to the direction of the fixing portion.
  • the main body of the back plate is provided with an acoustic hole that communicates the inner cavity and the external environment.
  • a first insulating layer is provided between the diaphragm and the back plate, and the fixing portion is fixedly connected to the first insulating layer.
  • a second insulating layer and several etching barrier walls are arranged between the diaphragm and the base.
  • the beneficial effect of the present invention is that: the back plate has at least one raised portion protruding in the direction away from the vibrating film, so that the distance between the position where the back plate has the raised portion and the vibrating film is greater than the distance between the back plate and the vibrating film average distance between.
  • This design makes the air velocity of the inner cavity corresponding to the raised portion smaller than the average velocity of the airflow in the inner cavity, thereby reducing the pressure film damping in the inner cavity and reducing the mechanical noise of the MEMS chip.
  • FIG. 1 is a cross-sectional view of a MEMS microphone according to Embodiment 1 of the present invention.
  • FIG. 2 is a cross-sectional view of a MEMS microphone according to Embodiment 2 of the present invention.
  • FIG. 3 is a cross-sectional view of a MEMS microphone according to Embodiment 3 of the present invention.
  • FIG. 4 is a cross-sectional view of a MEMS microphone according to Embodiment 4 of the present invention.
  • the MEMS microphone includes a base 1 having a back cavity 11 , a diaphragm 2 and a back plate 4 sequentially arranged on the surface of the base 1 .
  • the backplane 4 includes a fixed portion 46 and a main body portion 45 surrounded by and connected to the fixed portion 46 .
  • the fixed portion 46 of the backplane is the edge of the backplane 4 , wherein the main body portions 45 are arranged at intervals.
  • a first insulating layer 6 is provided between the back plate 4 and the vibrating membrane 2 , so as to isolate the back plate 4 from the vibrating membrane 2 , and the fixing portion 46 is fixedly connected to the first insulating layer 6 .
  • a second insulating layer 21 is disposed between the diaphragm 2 and the base 1 to isolate the diaphragm 2 from the base 1 , and the first insulating layer 6 at least partially covers the second insulating layer 21 .
  • the edge of the diaphragm 2 is connected to the base 1 through the second insulating layer 21 , only the edge end of the diaphragm 2 is connected to the second insulating layer 21 , and the position where the diaphragm 2 is not fixedly connected to the second insulating layer 21 can be Free vibration is performed, that is to say, the central area of the diaphragm 2 can vibrate freely, and the vibration effect of the diaphragm 2 is maintained. Since the second insulating layer 21 is disposed between the diaphragm 2 and the base 1 , a gap is formed between the diaphragm 2 and the base 1 . The displacement space for the vibration of the diaphragm 2 is increased.
  • An inner cavity 3 is formed between the back plate 4 (ie, the main body portion 45 ) and the diaphragm 2 , and a capacitor exists in the inner cavity 3 .
  • the diaphragm 2 vibrates, the height of the inner cavity 3 in the direction perpendicular to the diaphragm 2 is changed, thereby changing the capacitance value of the inner cavity 3, and the change of the capacitance is converted into a digital signal, and finally the function of the microphone is realized.
  • a plurality of etching barrier walls 5 may also be arranged between the diaphragm 2 and the base 1, and the etching barrier walls 5 can ensure a reliable stop of the etching process that may occur in the manufacturing process, thereby protecting the second The insulating layer 21 is not etched away.
  • a plurality of etching stop walls 5 are arranged at intervals, and a second insulating layer 21 is provided between every two etching stop walls 5 .
  • the second insulating layer 21 and the etching barrier wall 5 jointly support the diaphragm 2 , so that the diaphragm 2 and the base 1 are spaced to form a gap.
  • the etch stop wall 5 can typically be made of, for example, oxide, thermal oxide, or TEOS. Its thickness can be between 0.1 and 1 ⁇ m.
  • a first protruding portion 41 that protrudes in a direction away from the diaphragm 2 , and the first protruding portion 41 is in the inner cavity 3 .
  • the corresponding position has a higher height, thereby increasing the distance between the back plate 4 and the diaphragm 2 at the first raised portion 41 .
  • the airflow can enter under the raised first protrusion 41 at the edge of the inner cavity 3 , so that the air in the inner cavity 3 is not compressed, thereby reducing the amount of air in the inner cavity 3 .
  • the compression film damping reduces the mechanical noise of MEMS microphones.
  • acoustic holes 42 penetrating the back plate 4 are evenly spaced on the back plate 4, the acoustic holes 42 communicate with the inner cavity 3 and the external environment, and the acoustic holes 42 are small through holes, so that the sound wave airflow can enter or Flowing out of the inner cavity 3 , the acoustic holes 42 are evenly distributed on the back plate 4 .
  • the sound wave air flow is transmitted to the MEMS microphone, the sound wave air flow passes through the acoustic hole 42 and enters the inner cavity 3 .
  • the entire back plate 4 is like a net with densely arranged holes in the middle.
  • the cross section of the back cavity 11 is an inverted isosceles trapezoid.
  • the back cavity 11 has atmospheric pressure. When the vibrating membrane 2 vibrates, the pressure in the back cavity 11 does not change, so that the free vibration of the vibrating membrane 2 is maintained.
  • the cross section of the first raised portion 41 is a similar isosceles triangle, and the structure of a similar sun hat or an isosceles triangle can be used to enhance the structural strength of the first raised portion 41 , so that the first raised portion 41 has a similar structure.
  • the portion 41 is not easily deformed.
  • the first protruding portion 41 ′ is disposed at the position of the outer peripheral edge of the fixing portion 46 of the back plate 4 , and protrudes from the fixing portion 46 of the back plate in a direction away from the diaphragm 2 .
  • the position of the first raised portion 41 ′ has changed, but the functions of the first raised portion 41 of the first embodiment and the first raised portion 41 ′ of the second embodiment are both used to
  • the edge position of the inner cavity 3 is perpendicular to the direction of the diaphragm 2 and the height space increases. After the sound wave airflow enters the inner cavity 3 through the acoustic hole 42, the sound wave airflow flows in the inner cavity 3.
  • the edge of the inner cavity 3 is perpendicular to the diaphragm 2.
  • the height space of the direction is increased, and the sound wave airflow no longer forms air compression at the edge of the inner cavity 3, thereby reducing the pressure film damping at the edge of the inner cavity 3.
  • the mechanical noise of the MEMS microphone is also reduced.
  • a second convex portion 43 is further provided in the central area of the main body portion 45 .
  • the second convex portion 43 is raised in the direction away from the diaphragm 2 .
  • the central axis of the raised portion 43 coincides with the central axis of the main body portion 45 and the diaphragm 2 .
  • the second raised portion 43 protrudes and extends from the bottom of the first raised portion 41 toward the central axis of the main body portion 45 , and gradually rises to form the second raised portion 43 , until the center of the main body portion 45 becomes the second raised portion 43 The apex of the bulge.
  • the second protrusion 43 is formed by the bulge in the middle of the main body portion 45 , and the distance from the main body portion 45 to the diaphragm 2 gradually decreases from the center position of the main body portion 45 to the direction of the fixing portion 46 .
  • the second raised portion 43 makes the height of the central region of the inner cavity 3 in the direction perpendicular to the diaphragm 2 greater than the average height of the inner cavity 3 .
  • the second protruding portion 43 is in the shape of an arc surface, and is formed by bulging from the central area of the body portion 45 to the direction away from the diaphragm 2 ; the back plate fixing portion 46 is fixedly connected to the first insulating
  • the cross section of the second raised portion 43 is in the shape of an arch bridge, the central part of the main body portion 45 is supported by the arch bridge shape and will not collapse downward, so that the central region of the main body portion 45 and the diaphragm 2 are kept relatively close. great distance.
  • the height of the central area of the inner cavity 3 is greater than the average height of the inner cavity 3. When the acoustic wave flows in the inner cavity 3, the airflow velocity in the central area of the inner cavity 3 is the smallest, thereby reducing the pressure film damping in the central area of the inner cavity 3. .
  • a second protruding portion 43 is also provided in the central region of the main body portion 45 .
  • the second raised portion 43 is disposed in the central area of the main body portion 45 .
  • the second raised portion 43 extends from the central area to the edge of the back plate 4 and gradually reduces the height of the raised portion.
  • the edge of the second raised portion 43 is connected to the first raised portion.
  • the hypotenuse of the raised portion 41' is connected.
  • Protrusions are provided on both the central area of the back plate 4 and the fixing portion 46 , which can improve the space size of the inner cavity 3 , thereby reducing the compression film damping in the inner cavity 3 .

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Health & Medical Sciences (AREA)
  • Otolaryngology (AREA)
  • Pressure Sensors (AREA)
  • Electrostatic, Electromagnetic, Magneto- Strictive, And Variable-Resistance Transducers (AREA)

Abstract

Un microphone MEMS est divulgué. Le microphone MEMS comprend une base comprenant une cavité arrière, une membrane agencée séparément de la base avec un espace entre elles, et un panneau arrière recouvrant la membrane et agencé séparément de la membrane avec une cavité interne entre eux. Le panneau arrière comprend au moins une partie en saillie faisant saillie dans la direction éloignée de la membrane. La présence de la partie en saillie augmente la distance entre le panneau arrière et la membrane, de sorte qu'après qu'un flux d'air d'ondes acoustiques passe à travers un trou acoustique et pénètre dans la cavité interne, le débit du flux d'air d'ondes acoustiques dans la cavité interne correspondant à la partie en saillie soit plus petit que le débit de flux d'air moyen dans la cavité interne, ce qui permet d'abaisser l'amortissement du film de pression et de réduire le bruit mécanique du microphone MEMS.
PCT/CN2020/103746 2020-07-06 2020-07-23 Microphone mems WO2022007000A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202010642539.2 2020-07-06
CN202010642539.2A CN111757228A (zh) 2020-07-06 2020-07-06 一种mems麦克风

Publications (1)

Publication Number Publication Date
WO2022007000A1 true WO2022007000A1 (fr) 2022-01-13

Family

ID=72679514

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2020/103746 WO2022007000A1 (fr) 2020-07-06 2020-07-23 Microphone mems

Country Status (2)

Country Link
CN (1) CN111757228A (fr)
WO (1) WO2022007000A1 (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN219124365U (zh) * 2022-12-29 2023-06-02 瑞声科技(新加坡)有限公司 Mems麦克风
CN218959124U (zh) * 2022-12-29 2023-05-02 瑞声声学科技(深圳)有限公司 Mems麦克风

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103067833A (zh) * 2012-12-27 2013-04-24 山东共达电声股份有限公司 一种背极板和传声器
US20150078593A1 (en) * 2013-09-13 2015-03-19 Omron Corporation Acoustic transducer and microphone
CN204231667U (zh) * 2014-11-19 2015-03-25 北京卓锐微技术有限公司 一种硅电容麦克风
CN206932407U (zh) * 2017-06-30 2018-01-26 歌尔科技有限公司 Mems麦克风

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1791281A (zh) * 2004-12-13 2006-06-21 中国科学院声学研究所 一种硅微电容传声器芯片及其制备方法
US8193596B2 (en) * 2008-09-03 2012-06-05 Solid State System Co., Ltd. Micro-electro-mechanical systems (MEMS) package
US8987842B2 (en) * 2012-09-14 2015-03-24 Solid State System Co., Ltd. Microelectromechanical system (MEMS) device and fabrication method thereof
WO2020133375A1 (fr) * 2018-12-29 2020-07-02 共达电声股份有限公司 Capteur acoustique mems, microphone mems, et dispositif électronique

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103067833A (zh) * 2012-12-27 2013-04-24 山东共达电声股份有限公司 一种背极板和传声器
US20150078593A1 (en) * 2013-09-13 2015-03-19 Omron Corporation Acoustic transducer and microphone
CN204231667U (zh) * 2014-11-19 2015-03-25 北京卓锐微技术有限公司 一种硅电容麦克风
CN206932407U (zh) * 2017-06-30 2018-01-26 歌尔科技有限公司 Mems麦克风

Also Published As

Publication number Publication date
CN111757228A (zh) 2020-10-09

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