WO2023185106A1 - 一种微机电系统麦克风及电子设备 - Google Patents

一种微机电系统麦克风及电子设备 Download PDF

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Publication number
WO2023185106A1
WO2023185106A1 PCT/CN2022/139536 CN2022139536W WO2023185106A1 WO 2023185106 A1 WO2023185106 A1 WO 2023185106A1 CN 2022139536 W CN2022139536 W CN 2022139536W WO 2023185106 A1 WO2023185106 A1 WO 2023185106A1
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Prior art keywords
suspended
diaphragm
area
support structure
back plate
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PCT/CN2022/139536
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English (en)
French (fr)
Inventor
邹泉波
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歌尔微电子股份有限公司
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Publication of WO2023185106A1 publication Critical patent/WO2023185106A1/zh

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    • 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
    • H04R19/005—Electrostatic transducers using semiconductor materials
    • 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
    • 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
    • H04R7/00—Diaphragms for electromechanical transducers; Cones
    • H04R7/02—Diaphragms for electromechanical transducers; Cones characterised by the construction
    • H04R7/04—Plane diaphragms
    • H04R7/06—Plane diaphragms comprising a plurality of sections or layers
    • 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 present disclosure relates to a microelectromechanical system microphone and electronic equipment.
  • the free diaphragm since the free diaphragm has a large movable range at the support point and the free diaphragm itself has no internal stress, its resonant frequency is low. Therefore, under the premise of a certain thickness of the diaphragm, the free diaphragm area is limited by the frequency response bandwidth of the diaphragm, so it is not easy to make it larger, and the corresponding acoustic noise is higher. It is difficult to meet the resonant frequency and high signal-noise requirements of electronic products for microphones at the same time. than the requirements.
  • the purpose of this disclosure is to provide a new type of micro-electromechanical system microphone and electronic equipment.
  • a microelectromechanical system microphone includes:
  • a diaphragm the diaphragm has a fixed part and a suspended part, the fixed part is fixed on the substrate, and the suspended part is located on the sound cavity;
  • the back plate is arranged on the substrate, a gap is formed between the back plate and the diaphragm, an annularly distributed support structure is formed on the back plate, and the support The structure extends toward the diaphragm and corresponds to the position of the suspended portion.
  • the supporting structure divides the suspended portion into an inner suspended area and an outer suspended area. The mechanical sensitivity of the inner suspended area and the outer suspended area is and critical voltage respectively match;
  • the suspended portion When the back plate and/or the diaphragm are energized, the suspended portion is configured to contact the support structure, so that both the inner suspended area and the outer suspended area can be excited by sound pressure. Produce vibration.
  • the difference between the mechanical sensitivity of the inner suspended area and the mechanical sensitivity of the outer suspended area is less than or equal to 15%;
  • the difference between the critical voltage of the inner floating region and the critical voltage of the outer floating region is less than or equal to 15%.
  • the support structure is a continuous annular structure
  • the support structure includes a plurality of protruding structures distributed at intervals.
  • the support structure includes a plurality of protrusions, and the plurality of protrusions are centrally symmetrically distributed relative to the center of the suspended portion.
  • the radial size ratio of the inner suspended area and the outer suspended area of the suspended part ranges from 0.6 to 0.8.
  • the inner and outer suspended areas are circular, and the radial dimension is a diameter.
  • the diameter of the inner suspended area ranges from 450 to 750 microns
  • the diameter of the outer suspended area ranges from 650 to 1100 microns
  • the thickness of the diaphragm ranges from 0.75 to 1.25 microns.
  • the diameter of the inner suspended area is 500 microns
  • the diameter of the outer suspended area is 750 microns
  • the thickness of the diaphragm is 1 micron.
  • a reinforcement layer is formed on the support structure.
  • the strengthening layer is polysilicon.
  • the suspended portion is spaced at least 2 microns from the substrate in its own vibration direction.
  • a microelectromechanical system microphone including:
  • the diaphragm is arranged on the substrate and located on the sound cavity;
  • the back plate is arranged on the substrate, and a gap is formed between the back plate and the diaphragm;
  • a support structure the support structure being disposed on the substrate and/or the back plate, the support structure being configured to support the diaphragm so as to divide the diaphragm into an inner suspended area and an outer suspended area, The mechanical sensitivity and critical voltage of the inner suspended region and the outer suspended region are respectively matched.
  • an electronic device includes the microelectromechanical system microphone described above, and the microelectromechanical system microphone is configured to convert sound signals into electrical signals in a working state.
  • One technical effect of the embodiments of the present disclosure is that by creatively arranging the support structure, the diaphragm is divided into an inner suspended area and an outer suspended area, so as to improve the relative hardness of the inner suspended area located inside the support structure, thereby ensuring the product frequency.
  • the bandwidth is increased while the diaphragm area is reduced, the noise is reduced, the signal-to-noise ratio is improved, and the overall performance of the microphone product is improved.
  • Figure 1 is a schematic structural diagram of a microelectromechanical system microphone according to an embodiment of the present disclosure
  • Figure 2 is a top view of a microelectromechanical system microphone according to an embodiment of the present disclosure
  • Figure 3 is a top view of a microelectromechanical system microphone including two support structures according to an embodiment of the present disclosure
  • FIG. 4 is a schematic structural diagram of a microelectromechanical system microphone according to an embodiment of the present disclosure.
  • any specific values are to be construed as illustrative only and not as limiting. Accordingly, other examples of the exemplary embodiments may have different values.
  • Microelectromechanical system (MEMS) microphones are microphones manufactured based on MEMS technology. Simply put, MEMS microphones use semiconductor materials to form capacitors and integrate the capacitors on micro silicon wafers. Microelectromechanical microphones formed using microelectromechanical technology have the characteristics of small size and high sensitivity, and the microelectromechanical microphones have good radio frequency interference (RFI) and electromagnetic interference (EMI) suppression capabilities. MEMS microphones are commonly used in electronic devices such as mid- to high-end mobile phones.
  • RFID radio frequency interference
  • EMI electromagnetic interference
  • the microelectromechanical system microphone includes: a substrate 1, a diaphragm 2 and a back plate 3. Among them, an acoustic cavity 001 is formed on the substrate 1 .
  • the diaphragm 2 has a fixed part 21 and a suspended part 22.
  • the fixed part 21 is fixed on the substrate 1 and the suspended part 22 is located on the sound cavity 001.
  • the back plate 3 is disposed on the substrate 1.
  • a gap is formed between the back plate 3 and the diaphragm 2.
  • An annularly distributed support structure 31 is formed on the back plate 3.
  • the support structure 31 extends toward the diaphragm 2 and is suspended in the air. Corresponding to the position of the portion 22, the support structure 31 divides the suspended portion 22 into an inner suspended area 221 and an outer suspended area 222.
  • the mechanical sensitivity Sm and critical voltage Vp of the inner suspension region 221 and the outer suspension region 222 match correspondingly. That is, the mechanical sensitivities Sm of the inner suspended region 221 and the outer suspended region 222 are basically consistent, and the critical voltages Vp of the inner suspended region 221 and the outer suspended region 222 are basically consistent.
  • the inner suspended area 221 and the outer suspended area 222 can exhibit similar and identical acoustic performance and better realize the sound collecting function.
  • the suspended portion 22 is configured to contact the support structure 31 so that both the inner suspended area 221 and the outer suspended area 222 can be excited by sound pressure to generate mechanical vibration.
  • a sound cavity 001 is formed on the substrate 1 for accommodating structures to transmit sound.
  • the diaphragm 2 can be divided into a fixed part 21 and a suspended part 22 according to the connection with the substrate 1 .
  • the fixed part 21 is fixed to the substrate 1 and the suspended part 22 is located on the sound cavity 001 . That is, the suspended part 22 is located in the center and can vibrate; the fixed part 21 is located around it and cannot vibrate.
  • a part of the entire edge area of the diaphragm 2 serves as the fixed portion 21
  • the other entire area of the diaphragm 2 serves as the suspended portion 22 .
  • the area of the suspended portion 22 away from the fixed portion 21 can rest on the substrate 1 or on the edge of the acoustic cavity 001 .
  • the back plate 3 is arranged on the substrate 1 , and the back plate 3 is opposite to the diaphragm 2 .
  • a gap is formed between the back plate 3 and the diaphragm 2, and the back plate 3, the diaphragm 2 and the gap between them together form a capacitor.
  • an annularly distributed support structure 31 is formed on the back plate 3 .
  • the support structure 31 may be a protrusion 311 formed on the back plate 3 .
  • the support structure 31 extends toward the diaphragm 2 and corresponds to the position of the suspended portion 22 .
  • the support structure 31 is not located around the suspended part 22 .
  • the support structure 31 is distributed in the internal area of the suspended part 22 .
  • the support structure 31 divides the suspended portion 22 into an inner suspended area 221 and an outer suspended area 222 .
  • the support structure 31 is distributed in an annular shape, along the radial direction of the diaphragm 2 , the suspended portion 22 surrounded by the support structure 31 is the inner suspended area 221 , and the suspended portion outside the support structure 31 Part 22 is an outer suspended area 222. Under the simple support of the support structure 31, the inner suspended area 221 and the outer suspended area 222 can produce vibration responses to sound and air vibration respectively.
  • the difference in mechanical sensitivity between the inner suspended area 221 and the outer suspended area 222 is less than or equal to 15%.
  • the vibration effect expressed by the diaphragm can make the electrical signals generated by it basically consistent, and the two are relatively matched.
  • the difference in mechanical sensitivity Sm is less than 10%, close to 5% or less, and reaches the same absolute value of mechanical sensitivity Sm. In this way, when the two electrical signals in the inner and outer floating areas are used as differential capacitors and differential signals, higher accuracy can be ensured and it is less likely to cause distortion of the sound signal.
  • the difference between the critical voltage Vp of the inner floating region 221 and the outer floating region 222 may be less than 15%.
  • the difference in critical voltage Vp between the two can be minimized and the two can be relatively matched.
  • the critical voltage Vp of the inner suspended region 221 and the outer suspended region 222 meets the above numerical range, the two are more likely to exhibit similar and identical mechanical properties, thereby making the vibration performance of the diaphragm highly consistent and improving the acoustic performance.
  • the difference in critical voltage Vp is less than 10%, close to 7% and below, until the absolute value of critical voltage Vp is the same. In this way, especially in technical solutions using differential capacitors, errors in the two electrical signals can be reduced and abnormal distortion can be prevented.
  • the purpose is to divide the diaphragm 2 into an inner suspended area 221 and an outer suspended area 222 .
  • the annularly distributed support structure 31 can be distributed in a circular shape, a rectangular shape, an elliptical shape, etc.
  • the structure of the support structure 31 itself it is possible to choose a structure in which multiple protrusions are combined to form an annular distribution, or it can be a substantially complete annular protrusion 311.
  • the gap between the back plate 3 and the diaphragm 2 may be an air gap or a gap formed by other media.
  • the suspended portion 22 can be operated under the action of electromagnetic force.
  • the bottom is pushed toward the back plate 3 to form an abutting relationship with the support structure 31 , and the support structure 31 supports the diaphragm 2 .
  • both the inner suspended area 221 and the outer suspended area 222 can be excited by sound pressure to generate mechanical vibration, thereby changing the output voltage of the capacitor, so that the electronic device using it can convert the sound signal into an electrical signal.
  • the simple support structure 31 is located at the edge of the diaphragm 2. Due to the high mechanical sensitivity of this free diaphragm 2, after it is designed into a larger diaphragm 2, its resonant frequency will drop to a lower value. level, this phenomenon cannot meet the performance requirements of MEMS microphones. And if the area of the diaphragm 2 is relatively small, its signal-to-noise ratio will be limited to a certain extent, and the signal-to-noise ratio cannot be improved. In this technical solution, the support structure 31 is located between the edge of the diaphragm 2 and the center of the diaphragm 2 .
  • this solution moves the support structure 31 inward toward the center of the diaphragm 2 .
  • This arrangement greatly increases the hardness of the inner suspended area 221 and the outer suspended area 222, ensuring sufficient mechanical strength.
  • the resonant frequencies of both the inner suspended area 221 and the outer suspended area 222 are improved, and the diaphragm 2 as a whole has a wider frequency response capability and range.
  • Microelectromechanical system microphones using this structure can also increase the area of the diaphragm 2 to reduce noise, improve the overall signal-to-noise ratio, and improve product performance on the premise of ensuring sufficient frequency bandwidth.
  • the signal-to-noise ratio refers to the ratio of signal to noise in an electronic device or electronic system.
  • SNR signal-to-noise ratio
  • One technical effect of the embodiment of the present disclosure is that by creatively arranging the support structure 31, the diaphragm 2 is divided into an inner suspended area 221 and an outer suspended area 222, so as to improve the relative hardness of the inner suspended area 221 located inside the support structure 31. In turn, it can increase the area of the diaphragm 2 while ensuring the frequency bandwidth of the product, reduce noise, improve the signal-to-noise ratio, and improve the overall performance of the microphone product.
  • the support structure 31 is a continuous annular structure; or, the support structure 31 includes a plurality of protrusions 311 structures distributed at intervals.
  • the support structure 31 may be a continuous structure or a discontinuous structure.
  • the continuous structure may be a circular, rectangular or other annular structure, and the discontinuous structure may be a plurality of protrusions 311 structures arranged at intervals.
  • the plurality of protrusions 311 may be evenly distributed or non-uniformly distributed. Utilizing the supporting function of the support structure 31, the hardness of the inner suspended area 221 and the outer suspended area 222 can be significantly increased, and the resonant frequency can be increased.
  • Using a continuous ring structure as the support structure 31 can relatively significantly increase the hardness of the suspended area, especially the resonant frequency of the inner suspended area 221 increases more significantly.
  • Using a structure of multiple intermittent protrusions 311 to form the support structure 31 can better improve the overall vibration consistency of the suspended portion 22 .
  • this support structure 31 can assist the suspended part 22 to release the air pressure to a certain extent and reduce the risk of damage to the diaphragm 2 .
  • the support structure 31 includes a plurality of protrusions 311 , and the plurality of protrusions 311 are centrally symmetrically distributed relative to the center of the suspended portion 22 .
  • the plurality of protrusions 311 are arranged to be centrally symmetrically distributed relative to the center of the suspended portion 22 . This arrangement also makes the mechanical vibration of the diaphragm 2 more uniform and consistent.
  • the support structure 31 may not only form one ring-shaped structure, but may also form two rings of ring-shaped structure to divide the suspended portion 22 into three areas.
  • this embodiment can use a diaphragm 2 with a larger size.
  • this design method can further increase the size of the diaphragm 2, thereby reducing noise resistance and improving the signal-to-noise ratio.
  • the added ring-shaped structure can maintain sufficient rigidity of the suspended portion 22 to meet the requirements of resonant frequency and frequency response bandwidth.
  • Increasing the number of support structures 31 can be by using multiple continuous-structure support structures 31 , and the multiple continuous-structure support structures 31 are centrally symmetrically distributed relative to the center of the suspended portion 22 , that is, coaxially arranged; or, adding protrusions 311 The number increases the density of the plurality of protrusions 311 that are centrally symmetrically distributed relative to the center of the suspended portion 22 .
  • the support structure 31 forms a ring-shaped structure as an example to illustrate the specific features that can be adopted in this solution.
  • the radial size ratio of the inner suspended area 221 and the outer suspended area 222 of the suspended part 22 ranges from 0.6 to 0.8.
  • the suspended part 22 may be circular, rectangular or other irregular structure; the outer suspended area 222 may be circular, rectangular or other irregular structure; the inner suspended area 221 may be circular.
  • Shape also can be rectangular or other irregular structure. When it is a circle, the radial dimension is its diameter; when it is a rectangle, the radial dimension is the length of its long side; when it is other irregular structures, the radial dimension is the maximum length within it.
  • Both the inner floating region 221 and the outer floating region 222 can be supplied with a bias voltage to form a capacitance with the back plate 3 .
  • the bias voltage between the back electrode of the back plate 3 (the back electrodes of the inner and outer suspended areas 222 can be connected together) and the diaphragm 2 can make the displacements of the inner suspended area 221 and the outer suspended area 222 consistent, and
  • the inner suspended area 221 and the outer suspended area 222 are circular, and the radial dimension is a diameter.
  • the diameter of the inner suspended area 221 is D1
  • the diameter of the outer suspended area 222 is D2.
  • the diameter range of the inner suspended area 221 can be set to 450 to 750 microns
  • the diameter range of the outer suspended area 222 can be set to 650 to 1100 microns.
  • the thickness of the diaphragm 2 ranges from 0.75 microns to 1.25 microns.
  • the diameter of the inner suspended area 221 is 500 microns
  • the diameter of the outer suspended area 222 is 750 microns
  • the thickness of the diaphragm 2 is 1 micron.
  • the mechanical sensitivity range of the inner suspended region 221 is 2 to 9 nm/Pa.
  • the mechanical sensitivity of the inner suspended region 221 is 2.25 nm/Pa.
  • the diameter of the inner suspended area 221 is preferably 500 microns or 700 microns. It can ensure that the diaphragm 2 has sufficient mechanical strength, and at the same time reduce the acoustic resistance noise and improve the signal-to-noise ratio by increasing the area of the diaphragm 2 .
  • the radial size of the inner floating area 221 is 500um
  • the radial size of the outer floating area 222 can be 750um.
  • the mechanical sensitivity Sm of the inner suspended area 221 is about 2-3nm/Pa, the size of the entire membrane also becomes larger, the corresponding sound noise can be reduced by 3dB, and the resonant frequency fres of the diaphragm 2 itself is about 73kHz.
  • the radial size of the inner suspended area 221 is 700um, and the radial size of the outer suspended area 222 can be 900um.
  • the mechanical sensitivity Sm of the inner suspended area 221 is about 9nm/Pa, the size of the entire membrane also becomes larger, the corresponding sound noise can be reduced by 5dB, and the resonant frequency fres of the diaphragm 2 itself is about 37kHz.
  • the above two size designs of the suspended part 22 can make the sound resonance frequency of the suspended part 22 reach more than 30 kHz in actual operation, so that the free diaphragm 2 in the form of a simple support can achieve sufficient acoustic performance.
  • a reinforcement layer 312 is formed on the support structure 31 .
  • the support structure 31 needs to withstand the impact generated when the diaphragm 2 deforms.
  • the mechanical strength of the support structure 31 is enhanced by providing a reinforcement layer 312 on the support structure 31.
  • the reinforcement layer 312 can improve the overall consistency of the acoustic performance of the MEMS microphone and avoid changes in acoustic performance caused by deformation and damage of the support structure 31 .
  • the reinforcement layer 312 may be polysilicon.
  • a layer of polysilicon can be provided on the back plate 3 to form a chargeable substrate.
  • the deposition process of polysilicon usually uses Goen chemical vapor deposition, which has better structural strength and hardness. Therefore, in this solution, the process of forming a polysilicon layer can be used to form a strengthening layer 312 on the surface of the support structure 31 for forming contact with the suspended portion 22 of the diaphragm 2 .
  • polysilicon layer on the support structure 31 is isolated from the polysilicon layer on the surface and/or inside of the back plate 3 .
  • This kind of isolation can directly use physical isolation, for example, etching and eliminating the position of the polysilicon layer on the strengthening layer 312 close to the back plate 3 .
  • insulating materials such as silicon nitride and silicon oxide can be deposited in the grooves.
  • the suspended portion 22 is spaced at least 2 microns away from the substrate 1 in its own vibration direction.
  • the suspended portion 22 when one of the back plate 3 or the diaphragm 2 is energized, or when both the back plate 3 and the diaphragm 2 are energized, the suspended portion 22 can be generated under the sound pressure. Mechanical vibration. Ensure that the suspended portion 22 is always at least 2 microns away from the substrate 1 in its own vibration direction (that is, marked H in Figure 4), giving the diaphragm 2 enough space to vibrate, so as to improve the mechanical sensitivity of the diaphragm 2 and enhance its The range of responses to sound also improves the overall performance of the MEMS microphone.
  • the acoustic cavity 001 formed by the substrate 1 below the inner suspended area 221 is the acoustic cavity 001 formed by the substrate 1 , while the substrate 1 exists below the outer suspended area 222 .
  • the substrate 1 will affect the vibration performance of the outer suspended area 222 to a certain extent. If the substrate 1 is close to the outer suspended area 222, the outer suspended area 222 will be subject to air resistance when vibrating and will not be able to form a good response vibration to the sound vibration. In this solution, it is preferable to leave a space of no less than 2 microns between the diaphragm 2 and the substrate 1 to improve the vibration expression of the outer suspended area 222.
  • the support structure 31 can also be provided on the substrate 1. As long as the support structure 31 can resist and support the diaphragm 2, the diaphragm 2 can be divided into an inner suspended area 221 and an outer suspended area 222. That’s it. By adjusting the position of the support structure 31 relative to the suspended portion 22 of the diaphragm 2 , the inner suspended region 221 and the outer suspended region 222 can form correspondingly matched and substantially consistent mechanical sensitivities Sm and critical voltage Vp. In this way, the inner suspended area 221 and the outer suspended area 222 can be used together for acoustic-electric conversion, and the sound signal expression is basically the same.
  • the support structure 31 can also be divided into discrete support points. For solutions that use the diaphragm suspended portion 22 in a rectangular, square or other shape, the support structure 31 does not need to be surrounded by a ring structure.
  • a microphone unit includes a shell, a chip and the above-mentioned microelectromechanical system microphone.
  • the chip and the microelectromechanical system microphone are both located in the shell, and the chip is electrically connected to the microelectromechanical system microphone.
  • the microphone unit includes a housing, a chip located inside the housing, and the above-mentioned MEMS microphone.
  • the chip is electrically connected to the microelectromechanical system microphone and is used to increase power supply to the microelectromechanical system microphone so that a capacitor can be formed inside it.
  • an electronic device includes the above-mentioned microelectromechanical system microphone, and the microelectromechanical system microphone is configured to convert sound signals into electrical signals in a working state.
  • the microphone unit inside it can receive the user's voice signal and complete the conversion of the voice signal into an electrical signal.
  • electronic devices can be mobile phones, TVs, computers, smart watches, etc.
  • the microelectromechanical system microphone provided in this solution can be made using a semiconductor vapor deposition method. Its preparation method may mainly include the following steps:
  • silicon is used as the substrate 1, a layer of silicon dioxide is deposited on the substrate 1, and is selectively masked and etched.
  • the first low-stress polysilicon is deposited, doped and annealed to obtain diaphragm 2.
  • a sacrificial layer is deposited on the diaphragm 2. These sacrificial layers may be low-temperature deposited silicon oxide, silicon nitride, etc. Furthermore, grooves are etched on the sacrificial layer for further deposition of material.
  • a polysilicon layer is deposited on the sacrificial layer through a high-temperature deposition process.
  • Part of the polysilicon layer can be used as a conductive area of the back plate 3, and the polysilicon layer deposited in the sacrificial layer groove located at the edge of the diaphragm 2 can be used as a conductive point, which is used to connect the diaphragm 2 and the back plate. 3 are connected to different electrodes respectively.
  • the polysilicon layer deposited in the sacrificial layer groove located in the central area of the diaphragm 2 (the suspended portion 22 ) can be used as the reinforcement layer 312 of the support structure 31 .
  • the polysilicon layer used for electrical connection, the strengthening layer 312, and the back plate 3 are not electrically connected to prevent the strengthening layer 312 from being short-circuited with the diaphragm 2, and the back plate 3 with the diaphragm 2. Film 2 short circuit and other phenomena.
  • This part of the structure can be formed using a low-temperature silicon nitride deposition process. That is, the back plate 3 can be formed using a combined stacked structure of silicon nitride and polysilicon.
  • welding points 4 further etching grooves on the material of the back plate 3 and depositing materials such as chromium nickel aluminum as welding points 4.
  • materials such as chromium nickel aluminum as welding points 4.
  • two welding points 4 can be provided above the material of the back plate 3, and the two welding points 4 are used to form electrical connections with the diaphragm 2 and the back plate 3 respectively. In other embodiments, more welding points 4 may also be deposited for connection to different areas of the back plate 3 or the diaphragm 2 .

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Multimedia (AREA)
  • Electrostatic, Electromagnetic, Magneto- Strictive, And Variable-Resistance Transducers (AREA)

Abstract

一种微机电系统麦克风及电子设备，微机电系统麦克风包括衬底、振膜和背极板。振膜具有固定部和悬空部，背极板上形成有支撑结构，支撑结构将悬空部划分为内悬空区和外悬空区。

Description

一种微机电系统麦克风及电子设备
本公开要求于2022年03月31日提交中国专利局，申请号为202210343062.7，申请名称为“一种微机电系统麦克风及电子设备”的中国专利申请的优先权，其全部内容通过引用结合在本公开中。
技术领域
本公开涉及一种微机电系统麦克风及电子设备。
背景技术
相关技术中，由于自由振膜在支撑点处的可活动幅度大，并且自由振膜自身的无内应力，这使得其谐振频率较低。因此在振膜厚度一定的前提下，自由振膜面积受限于振膜的频率响应带宽，因此不易做大，对应的声学噪声较高，难以同时满足电子产品对麦克风的谐振频率和高信噪比的要求。
因此，有必要对自由振膜在微机电系统麦克风中的应用进行改进。
发明内容
本公开的目的在于提供一种新型的微机电系统麦克风及电子设备。
根据本公开的一个方面，提供了一种微机电系统麦克风。该微机电系统麦克风包括：
衬底，所述衬底上形成声腔；
振膜，所述振膜具有固定部和悬空部，所述固定部固定在所述衬底上，所述悬空部位于所述声腔上；
背极板，所述背极板设置在所述衬底上，所述背极板与所述振膜之间形成有间隙，所述背极板上形成有环形分布的支撑结构，所述支撑结构朝向所述振膜延伸并且与所述悬空部的位置对应，所述支撑结构将所述悬空 部划分为内悬空区和外悬空区，所述内悬空区和所述外悬空区的机械灵敏度和临界电压分别对应匹配；
在所述背极板和/或振膜通电的情况下，所述悬空部被配置为能与所述支撑结构抵接，使所述内悬空区和所述外悬空区均能被声压激发产生振动。
可选地，所述内悬空区的机械灵敏度和所述外悬空区的机械灵敏度的差值小于或等于15％；
所述内悬空区的临界电压和所述外悬空区的临界电压差值小于或等于15％。
可选地，所述支撑结构为连续的环状结构；
或者，所述支撑结构包括间隔分布的多个凸起结构。
可选地，所述支撑结构包括多个凸起，多个所述凸起相对于所述悬空部的中心呈中心对称分布。
可选地，所述悬空部的所述内悬空区与所述外悬空区的径向尺寸比例范围为0.6至0.8。
可选地，所述内悬空区和外悬空区呈圆形，所述径向尺寸为直径。
可选地，所述内悬空区的直径范围为450至750微米；
所述外悬空区的直径范围为650至1100微米；
所述振膜的厚度范围为0.75至1.25微米。
可选地，所述内悬空区的直径为500微米；
所述外悬空区的直径为750微米；
所述振膜的厚度为1微米。
可选地，所述支撑结构上形成有强化层。
可选地，所述强化层为多晶硅。
可选地，在所述背极板和/或振膜通电的情况下，所述悬空部在自身的振动方向上与所述衬底间隔至少2微米。
根据本公开的另一方面，还提供了一种微机电系统麦克风，包括：
衬底，所述衬底上形成声腔；
振膜，所述振膜设置在衬底上并位于所述声腔上；
背极板，所述背极板设置在所述衬底上，所述背极板与所述振膜之间形成有间隙；
支撑结构，所述支撑结构设置在所述衬底和/或背极板上，所述支撑结构被配置为对振膜形成支撑，以将所述振膜划分为内悬空区和外悬空区，所述内悬空区和所述外悬空区的机械灵敏度和临界电压分别对应匹配。
根据本公开的另一个方面，提供了一种电子设备。该电子设备包括上述微机电系统麦克风，所述微机电系统麦克风被设置为在工作状态下将声音信号转为电信号。
本公开实施例的一个技术效果在于，通过创造性地设置支撑结构，将振膜划分为内悬空区和外悬空区，以提高位于支撑结构内部的内悬空区的相对硬度，进而能够在保证产品频率带宽的同时增大振膜面积，降低噪音，提高信噪比，提高麦克风产品整体性能。
通过以下参照附图对本公开的示例性实施例的详细描述，本公开的其它特征及其优点将会变得清楚。
附图说明
构成说明书的一部分的附图描述了本公开的实施例，并且连同说明书一起用于解释本公开的原理。
图1是本公开实施例的一种微机电系统麦克风的结构简图；
图2是本公开实施例的一种微机电系统麦克风的俯视图；
图3是本公开实施例的一种微机电系统麦克风包括两个支撑结构的俯视图；
图4是本公开实施例的一种微机电系统麦克风的结构示意图。
附图标记说明：
1、衬底；2、振膜；3、背极板；31、支撑结构；001、声腔；21、固定部；22、悬空部；221、内悬空区；222、外悬空区；311、凸起；312、强化层；4、焊接点；H、衬底与振膜之间的距离。
具体实施方式
现在将参照附图来详细描述本公开的各种示例性实施例。应注意到：除非另外具体说明，否则在这些实施例中阐述的部件和步骤的相对布置、数字表达式和数值不限制本公开的范围。
以下对至少一个示例性实施例的描述实际上仅仅是说明性的，决不作为对本公开及其应用或使用的任何限制。
对于相关领域普通技术人员已知的技术和设备可能不作详细讨论，但在适当情况下，所述技术和设备应当被视为说明书的一部分。
在这里示出和讨论的所有例子中，任何具体值应被解释为仅仅是示例性的，而不是作为限制。因此，示例性实施例的其它例子可以具有不同的值。
应注意到：相似的标号和字母在下面的附图中表示类似项，因此，一旦某一项在一个附图中被定义，则在随后的附图中不需要对其进行进一步讨论。
本公开提供了一种微机电系统麦克风。微机电系统(MEMS)麦克风是基于MEMS技术制造的麦克风，简单的说，微机电系统麦克风利用半导体材料形成电容器，并将电容器集成在微硅晶片上。采用微机电工艺形成的微机电麦克风具有体积小、灵敏度高的特点，并且微机电麦克风具有良好的射频干扰(RFI)及电磁干扰(EMI)抑制能力。MEMS麦克风常用于中高端手机等电子设备中。
本公开提供的这种微机电系统麦克风包括：衬底1、振膜2和背极板3。其中，衬底1上形成声腔001。振膜2具有固定部21和悬空部22，固定部21固定在衬底1上，悬空部22位于声腔001上。背极板3设置在衬底1上，背极板3与振膜2之间形成有间隙，背极板3上形成有环形分布的支撑结构31，支撑结构31朝向振膜2延伸并且与悬空部22的位置对应，支撑结构31将悬空部22划分为内悬空区221和外悬空区222。
所述内悬空区221和外悬空区222的机械灵敏度Sm和临界电压Vp对应匹配。即，内悬空区221和外悬空区222的机械灵敏度Sm基本表现一致，内悬空区221和外悬空区222的临界电压Vp基本表现一致。通过这种设计， 内悬空区221与外悬空区222能够表现出相似、相同的声学性能，更好的实现收声功能。
在背极板3和/或振膜2通电的情况下，悬空部22被配置为能与支撑结构31抵接，使内悬空区221和外悬空区222均能被声压激发产生机械振动。
如图1和图4所示，衬底1上形成有声腔001，用于容置结构以传递声音。振膜2可根据与衬底1的连接分为固定部21和悬空部22，其中固定部21与衬底1固定，悬空部22位于声腔001上。也即，悬空部22位于中央、可以振动；固定部21位于其周围，不可振动。
在一种形式下，所述振膜2整体的一部分边缘区域作为所述固定部21，所述振膜2整的其它区域作为悬空部22。悬空部22的远离所述固定部21的区域可以搭在所述衬底1上，或者搭在所述声腔001的边缘。
背极板3设置在衬底1上，背极板3与振膜2相对设置。背极板3与振膜2之间形成有间隙，背极板3、振膜2以及两者之间的间隙共同构成电容器。
如图2所示，背极板3上形成有环形分布的支撑结构31。所述支撑结构31可以为所述背极板3上形成凸起311。支撑结构31朝向振膜2延伸并且与悬空部22的位置对应。如图2所示，所述支撑结构31不是位于所述悬空部22的周围，从投影方向上看，所述支撑结构31分布在所述悬空部22的内部区域。所述支撑结构31将悬空部22划分为内悬空区221和外悬空区222。由于所述支撑结构31呈环形分布，所以沿着所述振膜2的径向，被所述支撑结构31包围在内的悬空部22为内悬空区221，在所述支撑结构31以外的悬空部22为外悬空区222。在支撑结构31的简易支撑作用下，所述内悬空区221和外悬空区222可以分别对声音、空气振动产生振动响应。
可选地，所述内悬空区221与外悬空区222的机械灵敏度的差值小于或等于15％。在内、外悬空区的机械灵敏度符合上述特点的情况下，在微机电麦克风中，振膜所表达出的振动效果能够使得其产生的电信号基本保持一致，两者相对匹配。将内、外悬空区的两路电信号分别作为声音信号 或者两者结合作为差分信号，其声学效果整体得到提升。优选的，机械灵敏度Sm的差值小于10％，接近5％及以下，达到机械灵敏度Sm的绝对值相同。这样，在将内、外悬空区的两路电信号作为差分电容、差分信号时能够保证更高的准确性，不易造成声音信号失真。
可选地，所述内悬空区221与外悬空区222的临界电压Vp的差值可以小于15％。通过对施加的偏置电压、电势进行控制，并且对内悬空区221和外悬空区222的尺寸进行控制，能够使得两者的临界电压Vp差值尽量减小，两者相对匹配。内悬空区221与外悬空区222的临界电压Vp符合上述数值范围时，两者更容易表现出相近、相同的机械性能，进而使得振膜的振动表现一致性高，提高声学性能。优选地，临界电压Vp的差值小于10％，接近7％及以下，达到临界电压Vp的绝对值相同。这样，尤其是在采用差分电容的技术方案中，能够减小两路电信号出现误差，防止出现异常失真。
可选地，对环形分布的支撑结构31，其目的在于将振膜2分为内悬空区221和外悬空区222。本方案对于环形分布的支撑结构31，其可以环绕呈圆形分布、矩形分布、椭圆形分布等。进一步地，对于支撑结构31自身的结构，可以选择多个凸点组合形成环形分布的结构，或者可以是一个基本完整的环形凸起311。
当声压作用于振膜2时，振膜2会随之振动，进而改变振膜2与背极板3之间的电容。其中，背极板3和振膜2之间的间隙可为空气间隙，也可以是其他介质构成的间隙。
在背极板3与振膜2两者至少之一通入偏置电压的情况下，或者背极板3和振膜2都通入电势的情况下，所述悬空部22能够在电磁力的作用下被推向所述背极板3，从而与支撑结构31形成抵接关系，支撑结构31对所述振膜2形成支撑作用。并且，内悬空区221和外悬空区222均能被声压激发产生机械振动，进而改变电容器的输出电压，使得应用其的电子设备能将声音信号转化为电信号。
现有技术中简易支撑结构31位于振膜2边缘位置，由于这种自由振膜2的机械灵敏度较高，将其设计成尺寸较大的振膜2后，其谐振频率会下降到较低的水平，这种现象无法满足MEMS麦克风的性能需求。而如果振膜 2的面积相对较小，其信噪比在一定程度上会受到限制，无法提高信噪比。在本技术方案中，支撑结构31位于振膜2的边缘与振膜2中心之间。相对于现有技术的简易支撑振膜2而言，本方案将支撑结构31向振膜2中心内移。这种设置使得内悬空区221与外悬空区222的硬度大大提升，保证了足够的机械强度。在实际工作中，内悬空区221和外悬空区222的谐振频率都得到提升，振膜2整体具有更宽的频率响应能力和范围。采用这种结构的微机电系统麦克风，在保证足够频率带宽的前提下，还可以加大振膜2面积，以降低噪音，提高整体的信噪比，提升产品性能。其中，信噪比(SNR)是指一个电子设备或者电子系统中信号与噪声的比例，一般来说，信噪比越大，说明混在信号里的噪声越小，声音回放的音质量越高，否则相反。
本公开实施例的一个技术效果在于，通过创造性地设置支撑结构31，将振膜2划分为内悬空区221和外悬空区222，以提高位于支撑结构31内部的内悬空区221的相对硬度，进而能够在保证产品频率带宽的同时增大振膜2面积，降低噪音，提高信噪比，提高麦克风产品整体性能。
可选地，支撑结构31为连续的环状结构；或者，支撑结构31包括间隔分布的多个凸起311结构。在本实施例中，支撑结构31可为连续结构，也可为非连续结构。连续结构可为圆形或者矩形或者其他的环状结构，非连续结构可为间隔设置的多个凸起311结构。根据实际设计或者生产需要，多个凸起311可以均匀分布，也可以非均匀分布。利用支撑结构31的支撑作用，能够显著提高内悬空区221、外悬空区222的硬度，提高谐振频率。采用连续环形结构作为支撑结构31能够相对更明显的提高悬空区的硬度，尤其是内悬空区221的谐振频率上升更明显。采用间断的多个凸起311结构形成支撑结构31能够更好的提高悬空部22整体的振动一致性。而且，在悬空部22受到大气流冲击的情况下，这种支撑结构31能够一定程度上协助悬空部22释放气压，降低振膜2破损的风险。
可选地，在如图2所示的实施方式中，支撑结构31包括多个凸起311，多个凸起311相对于悬空部22的中心呈中心对称分布。
在本实施例中，考虑到支撑结构31的稳定性和加工难度，将多个凸起311设置为相对于悬空部22的中心呈中心对称分布。这种设置也使得振膜2的机械振动更为均匀与一致。
可选地，所述支撑结构31可以不仅形成一圈环形结构，还可以形成两圈环形结构以将悬空部22分成三个区域。如图3所示，这种实施方式可以采用具有更大尺寸的振膜2。这种设计方式一方面可以进一步增大振膜2尺寸，进而降低噪音声阻，提高信噪比。而增加的一圈环形结构能够使悬空部22保持足够的刚性，以满足谐振频率、频响带宽的要求。其中，增加支撑结构31数量可为采用多个连续结构的支撑结构31，多个连续结构的支撑结构31相对于悬空部22的中心呈中心对称分布，即同轴设置；或者，增加凸起311的数量，增大多个凸起311相对于悬空部22的中心呈中心对称分布的密度。
以下以支撑结构31形成一圈环形结构的技术方案为例，说明本方案可以采用的具体特征。
可选地，悬空部22的内悬空区221与外悬空区222的径向尺寸比例范围为0.6至0.8。
在本实施例中，悬空部22可为圆形，也可为矩形或者其他不规则结构；外悬空区222可为圆形，也可为矩形或者其他不规则结构；内悬空区221可为圆形，也可为矩形或者其他不规则结构。当为圆形时，径向尺寸为其直径；当为矩形时，径向尺寸为其长边长度；当为其他不规则结构时，径向尺寸为其内的最大长度。
内悬空区221和外悬空区222都可以通入偏置电压从而与背极板3形成电容。优化设计内悬空区221与外悬空区222的径向尺寸，使得内悬空区221和外悬空区222有接近或一致的机械灵敏度(Sm)及临界电压(Vp)。这样在工作时背极板3的背电极(内、外悬空区222背电极可连接在一起)和振膜2之间的偏压可以让内悬空区221和外悬空区222的位移一致，而声压信号作用到整个振膜2上也使内悬空区221和外悬空区222的位移一致，因此电信号(Vout＝w/Gap*VB)保持一致。从而在增大振膜2的同时降低了声阻及其噪声，也因有效电容(Cm)提升而降低了寄生电容(Cp)对 机械灵敏度的损失，提高了机械灵敏度Sm＝SSm·VB/Gap)·SCm/SCmSCp)S，所以信噪比(SNR)提升，提升了微机电系统麦克风的整体性能。
可选地，所述内悬空区221和外悬空区222呈圆形，所述径向尺寸为直径。
如图2所示，内悬空区221的直径为D1,外悬空区222的直径为D2。在本方案中，可以将内悬空区221的直径范围设置为450至750微米，将外悬空区222的直径范围设置在650至1100微米。振膜2的厚度范围则为0.75微米至1.25微米。通过前述将支撑结构31设置于振膜2边缘与振膜2中部之间，使得在这种结构下保证振膜2机械强度的同时外悬空区222的径向尺寸可相应做大。即可增大振膜2面积，降低声阻噪音，提高信噪比，提高微机电系统麦克风的整体性能。
可选地，所述内悬空区221的直径为500微米，所述外悬空区222的直径为750微米，所述振膜2的厚度为1微米。
可选地，所述内悬空区221的机械灵敏度范围为2至9纳米/帕。例如，所述内悬空区221的机械灵敏度为2.25纳米/帕。
在本实施例中，优选内悬空区221的直径为500微米或700微米。能够保证振膜2具有足够机械强度的同时，通过增大振膜2面积降低声阻噪音，提高信噪比。例如，内悬空区221的径向尺寸为500um，外悬空区222的径向尺寸可为750um。此时，内悬空区221的机械灵敏度Sm约为2-3nm/Pa，整膜尺寸也变大，相应的声噪可降低3dB，振膜2自身的共振频率fres约73kHz。
可选地，内悬空区221的径向尺寸为700um，外悬空区222的径向尺寸可为900um。此时，内悬空区221的机械灵敏度Sm约为9nm/Pa，整膜尺寸也变大，相应的声噪可降低5dB，振膜2自身的共振频率fres约37kHz。
以上两种悬空部22的尺寸设计都能够使悬空部22在实际工作中的声音谐振频率达到30kHz以上，从而利用简易支撑形式的自由振膜2达到足够的声学性能。
可选地，支撑结构31上形成有强化层312。在实际工作状态下，支撑结构31需要承受振膜2形变时产生的冲击作用。在本实施方式中，通过在 支撑结构31上设置强化层312，以加强支撑结构31的机械强度。强化层312能够提升微机电系统麦克风的声学性能整体一致性，避免支撑结构31的变形、破损造成声学性能变化。
可选地，强化层312可以为多晶硅。在实际加工过程中，背极板3上可以通过设置一层多晶硅而形成可带电的基板。而多晶硅的沉积工艺通常采用高恩化学气相沉积，其结构强度和硬度都更好。因此，在本方案中，可以利用形成多晶硅层的工艺在支撑结构31的表面上形成一层强化层312，用于与振膜2的悬空部22形成接触。
特别的，在采用多晶硅作为强化层312且背极板3也采用多晶硅层实现带电的技术方案中，为了避免多晶硅强化层312与振膜2之间形成电导通而造成电容失效，可选地，将支撑结构31上的多晶硅层与背极板3表面和/或内部的多晶硅层形成隔断。这种隔断可以直接采用物理隔断，例如将强化层312上靠近背极板3的多晶硅层的位置刻蚀消除。之后还可以在凹槽中沉积上氮化硅、氧化硅等绝缘材料。
可选地，在背极板3和/或振膜2通电的情况下，悬空部22在自身的振动方向上与衬底1间隔至少2微米。
在本实施例中，在背极板3或振膜2两者之一通电的情况下，或者背极板3和振膜2两者都通电的情况下，悬空部22可在声压下产生机械振动。保证悬空部22在自身的振动方向上与衬底1始终间隔至少2微米(即为图4中的标注H)，给予振膜2足够的振动空间，以提高振膜2的机械灵敏度，增强其响应声音的范围，也提高了微机电系统麦克风的整体性能。
优选地，在如图4所示的技术方案中，所述内悬空区221的下方为衬底1形成的声腔001，而在外悬空区222下方存在衬底1。衬底1一定程度上会影响外悬空区222的振动表现。如果衬底1距离外悬空区222较近，则外悬空区222振动时会受到空气阻力而无法对声音振动形成良好的响应振动。本方案优选在振膜2与衬底1之间留有不小于2微米的空间，以提高外悬空区222的振动表达。
在本技术方案中，所述支撑结构31也可以设置在衬底1上，支撑结构31只要对振膜2能够形成抵顶、支撑，使得振膜2分为内悬空区221和外 悬空区222即可。通过调整支撑结构31相对于振膜2的悬空部22的位置，能够使得内悬空区221与外悬空区222形成具有对应匹配、基本一致的机械灵敏度Sm和临界电压Vp。进而使得内悬空区221和外悬空区222能够共同用作声电转换，声音信号表达基本一致。所述支撑结构31也可以分成离散的支撑点，对于应用呈矩形、正方形等振膜悬空部22的方案中，支撑结构31可以不围成环形结构。
根据本公开的另一个方面，提供了一种麦克风单体。该麦克风单体包括外壳、芯片和上述的一种微机电系统麦克风，芯片和微机电系统麦克风均位于外壳内，芯片与微机电系统麦克风电连接。
在本实施中，麦克风单体包括外壳和位于外壳内部的芯片和上述微机电系统麦克风。芯片与微机电系统麦克风电连接，用于给微机电系统麦克风提高供电，使其内部能够形成电容器。
根据本公开的再一个方面，提供了一种电子设备。该电子设备包括上述的一种微机电系统麦克风，微机电系统麦克风被设置为在工作状态下将声音信号转为电信号。
在本实施例中，当电子设备工作时，其内部的麦克风单体能够接收用户的声音信号，并完成声音信号向电信号的转变。其中，电子设备可为手机、电视、电脑、智能手表等等。
可选地，本方案提供微机电系统麦克风可以采用半导体气相沉积方法制成。其制备方法可以主要包括以下步骤：
首先，以硅作为衬底1，在衬底1上沉积一层二氧化硅，并选择性地掩蔽和刻蚀。第二，沉积第一种低应力多晶硅，掺杂并退火得到振膜2。第三，在振膜2上沉积牺牲层，这些牺牲层可以是低温沉积的氧化硅、氮化硅等。并且，在牺牲层上刻蚀形成凹槽，以便进一步沉积材料。第四，在牺牲层上通过高温沉积工艺沉积多晶硅层。该多晶硅层的其中一部分可以作为背极板3的导电区域，沉积在位于振膜2边缘的牺牲层凹槽中的多晶硅层则可以用作导电点，其用于使振膜2、背极板3分别连接到不同的电极。而沉积在位于振膜2中心区域(悬空部22)的牺牲层凹槽中的多晶硅层，即可用作支撑结构31的强化层312。
通过刻蚀工艺可以使得用于电连接的、用于强化层312的、用于背极板3的多晶硅层不形成电导通，以防止强化层312与振膜2短路，背极板3与振膜2短路等现象。
第五，进一步在多晶硅层上沉积形成背极板3的结构层，这部分结构可以采用低温氮化硅沉积工艺形成。也即，背极板3可以采用氮化硅与多晶硅的组合层叠结构形成。
第六，在背极板3材料上进一步刻蚀凹槽并沉积铬镍铝等材料作为焊接点4。可选地，所述背极板3材料上方可以设置两个焊接点4，两个焊接点4分别用于与振膜2和背极板3形成电连接。在其它实施方式中，也可以沉积更多焊接点4，用于连接至背极板3或振膜2的不同区域。
上文实施例中重点描述的是各个实施例之间的不同，各个实施例之间不同的优化特征只要不矛盾，均可以组合形成更优的实施例，考虑到行文简洁，在此则不再赘述。
虽然已经通过示例对本公开的一些特定实施例进行了详细说明，但是本领域的技术人员应该理解，以上示例仅是为了进行说明，而不是为了限制本公开的范围。本领域的技术人员应该理解，可在不脱离本公开的范围和精神的情况下，对以上实施例进行修改。本公开的范围由所附权利要求来限定。

Claims (13)

  1. 一种微机电系统麦克风，包括：
    衬底(1)，所述衬底(1)上形成声腔(001)；
    振膜(2)，所述振膜(2)具有固定部(21)和悬空部(22)，所述固定部(21)固定在所述衬底(1)上，所述悬空部(22)位于所述声腔(001)上；
    背极板(3)，所述背极板(3)设置在所述衬底(1)上，所述背极板(3)与所述振膜(2)之间形成有间隙，所述背极板(3)上形成有环形分布的支撑结构(31)，所述支撑结构(31)朝向所述振膜(2)延伸并且与所述悬空部(22)的位置对应，所述支撑结构(31)将所述悬空部(22)划分为内悬空区(221)和外悬空区(222)，所述内悬空区(221)和所述外悬空区(222)的机械灵敏度和临界电压分别对应匹配；
    在所述背极板(3)和/或振膜(2)通电的情况下，所述悬空部(22)被配置为能与所述支撑结构(31)抵接，使所述内悬空区(221)和所述外悬空区(222)均能被声压激发产生振动。
  2. 根据权利要求1所述的一种微机电系统麦克风，其中，所述内悬空区(221)的机械灵敏度和所述外悬空区(222)的机械灵敏度的差值小于或等于15％；
    所述内悬空区(221)的临界电压和所述外悬空区(222)的临界电压的差值小于或等于15％。
  3. 根据权利要求1或2所述的一种微机电系统麦克风，其中，所述支撑结构(31)为连续的环状结构；
    或者，所述支撑结构(31)包括间隔分布的多个凸起(311)结构。
  4. 根据权利要求1-3任一项所述的一种微机电系统麦克风，其中，所述支撑结构(31)包括多个凸起(311)，多个所述凸起(311)相对于所述悬空部(22)的中心呈中心对称分布。
  5. 根据权利要求1-4任一项所述的一种微机电系统麦克风，其中，所述悬空部(22)的所述内悬空区(221)与所述外悬空区(222)的径向尺寸比例范围为0.6至0.8。
  6. 根据权利要求1-5任一项所述的一种微机电系统麦克风，其中，所述内悬空区(221)和外悬空区(222)呈圆形，径向尺寸为直径。
  7. 根据权利要求1-6任一项所述的一种微机电系统麦克风，其中，所述内悬空区(221)的直径范围为450至750微米；
    所述外悬空区(222)的直径范围为650至1100微米；
    所述振膜(2)的厚度范围为0.75至1.25微米。
  8. 根据权利要求1-7任一项所述的一种微机电系统麦克风，其中，所述内悬空区(221)的直径为500微米；
    所述外悬空区(222)的直径为750微米；
    所述振膜(2)的厚度为1微米。
  9. 根据权利要1-8任一项所述的一种微机电系统麦克风，其中，所述支撑结构(31)上形成有强化层(312)。
  10. 根据权利要求1-9任一项所述的一种微机电系统麦克风，其中，所述强化层(312)为多晶硅。
  11. 根据权利要求1-10任一项所述的一种微机电系统麦克风，其中，在所述背极板(3)和/或所述振膜(2)通电的情况下，所述悬空部(22)在自身的振动方向上与所述衬底(1)间隔至少2微米。
  12. 一种微机电系统麦克风，其中，包括：
    衬底(1)，所述衬底(1)上形成声腔(001)；
    振膜(2)，所述振膜(2)设置在衬底(1)上并位于所述声腔(001)上；
    背极板(3)，所述背极板(3)设置在所述衬底(1)上，所述背极板(3)与所述振膜(2)之间形成有间隙；
    支撑结构(31)，所述支撑结构(31)设置在所述衬底(1)和/或背极板(3)上，所述支撑结构(31)被配置为对振膜(2)形成支撑，以将所述振膜(2)划分为内悬空区(221)和外悬空区(222)，所述内悬空区(221)和所述外悬空区(222)的机械灵敏度和临界电压分别对应匹配。
  13. 一种电子设备，其中，包括权利要求1-12任一项所述的微机电系统麦克风，所述微机电系统麦克风被设置为在工作状态下将声音信号转为 电信号。
PCT/CN2022/139536 2022-03-31 2022-12-16 一种微机电系统麦克风及电子设备 WO2023185106A1 (zh)

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CN213694056U (zh) * 2020-12-25 2021-07-13 潍坊歌尔微电子有限公司 麦克风以及电子设备
CN113613151A (zh) * 2021-07-30 2021-11-05 歌尔微电子股份有限公司 微机电系统麦克风、麦克风单体及电子设备

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CN111770423A (zh) * 2020-06-24 2020-10-13 杭州士兰集昕微电子有限公司 微型麦克风及微型麦克风的制造方法
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