WO2022007002A1 - 一种压电式mems麦克风 - Google Patents

一种压电式mems麦克风 Download PDF

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Publication number
WO2022007002A1
WO2022007002A1 PCT/CN2020/103769 CN2020103769W WO2022007002A1 WO 2022007002 A1 WO2022007002 A1 WO 2022007002A1 CN 2020103769 W CN2020103769 W CN 2020103769W WO 2022007002 A1 WO2022007002 A1 WO 2022007002A1
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Prior art keywords
stress
piezoelectric
layer
electrode layer
layers
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English (en)
French (fr)
Inventor
段炼
张睿
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AAC Technologies Holdings Shenzhen Co Ltd
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AAC Acoustic Technologies Shenzhen Co Ltd
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Publication of WO2022007002A1 publication Critical patent/WO2022007002A1/zh
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R17/00—Piezoelectric transducers; Electrostrictive transducers
    • H04R17/02—Microphones
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; 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; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R23/00—Transducers other than those covered by groups H04R9/00 - H04R21/00
    • H04R23/02—Transducers using more than one principle simultaneously

Definitions

  • the utility model relates to the technical field of electro-acoustic conversion, in particular to a piezoelectric MEMS microphone.
  • Piezoelectric MEMS microphones have many advantages over traditional condenser MEMS microphones, including dust and water resistance, higher maximum output sound pressure (AOP), and more. Limited by the existing sputtering process of piezoelectric materials, piezoelectric films generally have stress, and the stress distribution is not uniform, which is difficult to control, and the existence of this residual stress leads to inevitable warpage and deformation of the diaphragm.
  • the piezoelectric MEMS microphones of the prior art usually have several partially anchored cantilever beam structures, and the design of the cantilever beams can improve the influence of residual stress on the diaphragm deformation to a certain extent.
  • the residual stress is unevenly distributed on the entire diaphragm, and the cantilever beam structure cannot avoid the gradient stress generated along the thickness direction of the film layer, which will still cause different degrees of warpage deformation of the piezoelectric film layer, affecting the piezoelectric The acoustic performance of the microphone.
  • the purpose of the present invention is to provide a piezoelectric MEMS microphone, which can solve the problem that the cantilever beam structure of the piezoelectric vibrating film in the prior art cannot avoid the gradient stress generated along the thickness direction of the film layer.
  • the technical solution of the present utility model provides a piezoelectric MEMS microphone, comprising: a base having a back cavity and a piezoelectric vibrating membrane, the piezoelectric vibrating membrane comprising an anchoring part fixedly supported by the base and a self-contained
  • the cantilever beam extending from the anchoring portion, the cantilever beam is suspended above the back cavity, and the cantilever beam includes a first electrode layer, a piezoelectric material layer and a second electrode layer that are sequentially stacked along the thickness direction.
  • the piezoelectric vibrating film further includes a plurality of stress layers and spaced apart from each other and fixed to at least any one of the first electrode layer, the piezoelectric material layer and the second electrode layer.
  • the stress layer includes a plurality of first stress layers attached to the surface of the first electrode layer spaced apart from each other, and/or a plurality of first stress layers attached to the surface of the second electrode layer spaced apart from each other. and/or a plurality of mutually spaced third stress layers interposed between any two adjacent layers of the first electrode layer, the piezoelectric material layer and the second electrode layer.
  • a plurality of the first stress layers and/or a plurality of the second stress layers are arranged symmetrically along the axial direction of the piezoelectric vibrating membrane.
  • the plurality of first stress layers and/or the plurality of second stress layers include radial stress layers extending from the center of the piezoelectric vibrating membrane toward the edge of the piezoelectric vibrating membrane.
  • the plurality of first stress layers and/or the plurality of second stress layers include circumferential stress layers extending along the circumferential direction of the piezoelectric vibrating membrane.
  • At least two of the circumferential stress layers are arc-shaped, spaced apart from each other, and encircled in a ring shape.
  • At least two of the radial stress layers are spaced apart and collinear.
  • the base includes a wall surrounding the back cavity
  • the piezoelectric diaphragm includes the cantilever beam facing the back cavity and the anchor extending from the edge of the cantilever beam a fixed part, the anchor part is fixedly connected to the surrounding wall; a plurality of the first stress layers and/or a plurality of the second stress layers are respectively arranged on the cantilever beam at intervals.
  • the base includes a surrounding wall enclosing the back cavity and a support portion fixed in the back cavity, the support portion is connected to and supports the anchor portion, and the cantilever beam extends from the back cavity.
  • An anchor edge extends and overhangs the back cavity.
  • the surface of the first electrode layer has a first stress groove along the thickness direction
  • the surface of the second electrode layer has a first protrusion along the thickness direction, and the first stress groove Opposite to the first protrusion, the first stress layer is embedded in the first stress groove;
  • the surface of the second electrode layer has a second stress groove along the thickness direction
  • the surface of the first electrode layer has a second protrusion along the thickness direction
  • the second stress groove is connected to the first stress groove.
  • the two protrusions are opposite to each other, and the second stress layer is embedded in the second stress groove.
  • the piezoelectric MEMS microphone provided by the present utility model includes: a base with a back cavity and a piezoelectric vibrating membrane, and the piezoelectric vibrating membrane includes an anchoring portion fixedly supported by the base and an anchor portion connected to the anchor.
  • the fixed part is integrally formed cantilever beam, the cantilever beam is suspended above the back cavity, the cantilever beam includes a first electrode layer, a piezoelectric material layer and a second electrode layer that are sequentially stacked along the thickness direction, and the piezoelectric vibrating film also includes and At least any one of the electrode layer, the piezoelectric material layer and the second electrode layer is adhered to a plurality of stress layers which are fixed and spaced apart from each other.
  • FIG. 1 is a perspective view of a piezoelectric MEMS microphone provided by an embodiment of the present invention
  • FIG. 2 is a schematic cross-sectional structural diagram of the piezoelectric MEMS microphone provided by the embodiment of FIG. 1 along the line A-A;
  • Fig. 3 is the cross-sectional structural schematic diagram of the piezoelectric vibrating film of the piezoelectric MEMS microphone shown in Fig. 1 along A'-A' line;
  • FIG. 4 is a schematic structural diagram of a piezoelectric MEMS microphone provided by another embodiment of the present invention.
  • FIG. 5 is a schematic cross-sectional structural diagram of the piezoelectric MEMS microphone provided in the embodiment of FIG. 4 along the line B-B;
  • FIG. 6 is a perspective view of a piezoelectric MEMS microphone provided by another embodiment of the present invention.
  • FIG. 7 is a schematic cross-sectional structure diagram of the piezoelectric MEMS microphone provided in the embodiment of FIG. 6 along the C-C line;
  • FIG. 8 is an enlarged schematic view of the structure of part d in the embodiment of FIG. 7;
  • FIG. 9 is a schematic structural diagram of a stress layer sandwiched in a piezoelectric vibrating film provided by an embodiment of the present invention.
  • the technical scheme of the present invention provides a piezoelectric MEMS microphone
  • the piezoelectric MEMS microphone includes: a base 10 having a back cavity 12 and a piezoelectric diaphragm 20 fixed to the base 10 and suspended in the back cavity 12 .
  • the diaphragm 20 includes an anchor portion 20a fixedly supported by the base 10 and a cantilever beam 20b extending from the anchor portion 20a.
  • the anchor portion 20a and the cantilever beam 20b are integrally formed, and the cantilever beam 20b is suspended on the back.
  • the cantilever beam 20b includes a first electrode layer 21, a piezoelectric material layer 22, and a second electrode layer 23 that are stacked in sequence along the thickness direction. At least any one of the material layer 22 and the second electrode layer 23 is adhered to a plurality of stress layers which are fixed and spaced apart from each other.
  • the microphone disclosed by the utility model is a piezoelectric MEMS microphone, which has the advantages of dustproof, waterproof and higher maximum output sound pressure compared with the traditional condenser microphone. Under the action of sound pressure, it vibrates up and down, and the piezoelectric material layer 22 in the piezoelectric diaphragm 20 generates electric charges, and the generated electric charges are collected by the effective electrodes and converted into voltage signals to be transmitted to the relevant circuits; however, the piezoelectric material layer 22 generates electric charges.
  • the piezoelectric diaphragm 20 of the microphone is formed by the sputtering deposition process of the piezoelectric material layer 22.
  • the piezoelectric MEMS microphone includes: a base 10 with a back cavity 12 and a piezoelectric vibrating membrane 20 , and the piezoelectric vibrating membrane 20 is fixed and suspended above the back cavity 12 to achieve sound pressure under the action of Vibrate up and down.
  • the piezoelectric vibrating film 20 is divided into an anchoring portion 20a and a cantilever beam 20b, wherein the anchoring portion 20a is fixedly supported by the supporting portion 13 in the back cavity 12 of the base 10 , or is supported by the enclosure 12 surrounding the back cavity 12 .
  • the wall 11 provides fixed support.
  • the piezoelectric vibrating film 20 is a vibrating film obtained by processing an electrode layer and a piezoelectric material layer 22 .
  • the structure is divided (from top to bottom) and includes: a first electrode layer 21 , a piezoelectric material layer 22 and a second electrode layer 23 , wherein the second electrode layer 23 is fixedly connected to the part of the base 10 .
  • the obtained piezoelectric vibrating film 20 forms a structure of a plurality of cantilever beams 20b fixed to the base 10 at one end and an anchoring portion integrally formed with the cantilever beam 20b.
  • the cantilever beam 20 b includes: a first electrode layer 21 , a piezoelectric material layer 22 and a second electrode layer 23 . It should be noted that when the stress generated in the deposition process of the piezoelectric material layer 22 is released in the diaphragm processing process, there is still residual stress on the piezoelectric vibrating film 20. By dividing the piezoelectric vibrating film 20, the Reduce the influence of residual stress and reduce the warpage of the diaphragm.
  • the cantilever beam of the piezoelectric vibrating film 20 is A stress layer is added on the surface of 20b or the inner composite layer of piezoelectric vibrating film 20.
  • a stress layer is added on the surface of 20b or the inner composite layer of piezoelectric vibrating film 20.
  • at least any one of the first electrode layer 21, the piezoelectric material layer 22 and the second electrode layer 23 is attached and fixed to each other and is spaced apart. a stress layer. Stress layers with spaced shape structures are formed by exposing and etching using stress blocks or stress plates.
  • the stress layer By arranging the stress layer of the shape structure on the cantilever beam 20b of the piezoelectric vibrating film 20 at intervals, the stress layer can compensate the deformation caused by the stress and gradient stress of the piezoelectric vibrating film 20 and reduce the stress of the vibrating film. Warpage and deformation under the action of gradient stress.
  • the stress layer has the characteristics of easy control and stable stress.
  • the material of the stress layer can be silicon oxide, silicon nitride, metal, etc.
  • the material of the stress layer is not limited in this embodiment. Materials with stable stress and other mechanical parameters that are easy to control can be used to make the stress layer of the present invention.
  • the stress layer is preferably a polysilicon (Poly-Si) layer, a silicon nitride (SiN) layer, a silicon oxide (SiO) layer or a metal layer or the like.
  • the stress layer includes a plurality of first stress layers 31 which are attached to the surface of the first electrode layer 21 and are spaced apart from each other, and/or are attached to the first stress layer 31 .
  • a plurality of second stress layers 32 spaced apart on the surfaces of the two electrode layers 23 ; and/or sandwiched between any two adjacent layers of the first electrode layer 21 , the piezoelectric material layer 22 and the second electrode layer 23 A plurality of third stress layers 33 spaced apart from each other.
  • the stress layer may include: a first stress layer 31 , a second stress layer 32 , and a third stress layer 33
  • the method of adding a stress layer on the surface or inner composite layer of the piezoelectric vibrating film 20 may be specifically: setting a sticker a plurality of first stress layers 31 spaced apart from each other on the surface of the first electrode layer 21, and/or a plurality of second stress layers 32 spaced apart from the surface of the second electrode layer 23; and/or A plurality of first stress layers 31 spaced from each other are provided on the surface of an electrode layer 21, and a plurality of second stress layers 32 spaced from each other are provided on the surface of the second electrode layer 23; in addition, the stress layers can also be provided on the piezoelectric vibrating film In the middle of the composite layer 20, for example, between the first electrode layer 21 and the second electrode layer 23, there are a plurality of third stress layers 33 spaced from each other.
  • the third stress layer 33 can be sandwiched between the first electrode layer 21 and the second electrode layer 23.
  • the piezoelectric material layers 22 may be interposed between the second electrode layer 23 and the piezoelectric material layer 22 , or may be fused into the piezoelectric material layer 22 .
  • the ratio of the thickness of the stress layer to the total thickness of the cantilever beam 20b is about 0.05-0.3, preferably, the ratio is 0.1-0.2.
  • a plurality of first stress layers 31 and/or a plurality of second stress layers 32 are arranged symmetrically along the axial direction of the piezoelectric vibrating membrane 20 .
  • a plurality of first stress layers 31 are provided on the surface of the first electrode layer 21 , the plurality of first stress layers 31 are arranged on the surface of the first electrode layer 21 at intervals, and the plurality of first stress layers 31 are arranged along the pressure
  • the axial direction of the first electrode layer 21 of the electric vibrating membrane 20 is arranged symmetrically; similarly, when a plurality of second stress layers 32 are arranged on the second electrode layer 23, the plurality of second stress layers 32 are arranged at intervals from each other.
  • the surface of the second electrode layer 23 , and the plurality of second stress layers 32 are symmetrically arranged along the axial direction of the second electrode layer 23 of the piezoelectric vibrating film 20 .
  • the stress layers are uniformly arranged on the piezoelectric vibrating film 20, so that the pressure
  • the gradient stress in the thickness direction of the electric vibrating film 20 is compensated relatively uniformly, so as to avoid warping and deformation of the piezoelectric vibrating film 20 caused by the gradient stress.
  • the sputtering process parameters for forming the piezoelectric diaphragm 20 or the diaphragm are changed or adjusted, the direction and size of the residual stress distribution in the diaphragm will be different.
  • the stress layer is provided on one electrode layer 21 and/or the second electrode layer 23, the position and thickness of the stress layer can be optimized according to the actual situation.
  • the plurality of first stress layers 31 and/or the plurality of second stress layers 32 include radial stress layers extending from the center of the piezoelectric vibrating film 20 toward the edge of the piezoelectric vibrating film 20 .
  • the first stress layer 31 includes a radial stress layer
  • the radial stress layer is a stress layer disposed from the center of the first electrode layer 21 of the piezoelectric vibrating film 20 toward the edge of the first electrode layer 21 .
  • the electric vibrating membrane 20 is a circular diaphragm, and the position of the radial stress layer can be any position in the radial direction passing through the center of the first electrode layer 21; similarly, the second stress layer 32 also includes a radial stress layer, The radial stress layer is a stress layer provided from the center of the second electrode layer 23 of the piezoelectric diaphragm 20 toward the edge of the second electrode layer 23 .
  • the structures and positions of the first stress layer 31 and the second stress layer 32 on the piezoelectric vibrating film 20 are defined, that is, the radial positions of the first electrode layer 21 and the second electrode layer 23 are defined, and
  • the shape and structure of the first stress layer 31 and the second stress layer 32 are defined as radial stress layers, so as to prevent the gradient stress in the thickness direction of the piezoelectric vibrating film 20 from causing deformation and warping in the radial direction of the piezoelectric vibrating film 20 .
  • the plurality of first stress layers 31 and/or the plurality of second stress layers 32 include circumferential stress layers extending along the circumferential direction of the piezoelectric diaphragm 20 .
  • the first stress layer 31 includes a circumferential stress layer
  • the circumferential stress layer is a stress layer disposed along the axial direction of the first electrode layer 21 of the piezoelectric vibrating membrane 20 , and the position of the stress layer may be the first Any part or all parts on any axis of an electrode layer 21
  • the second stress layer 32 includes a circumferential stress layer, and the circumferential stress layer is from the second electrode layer 23 of the piezoelectric vibrating film 20 along the first
  • the stress layer is provided on any axial position of the two electrode layers 23; the position of the first stress layer 31 and the second stress layer 32 in the axial direction of the piezoelectric vibrating film 20 is defined by this embodiment, and the first stress layer 31 and the second stress layer 32 are defined
  • the shape is provided on any axial position of the two electrode layers 23
  • the first electrode layer 21 is provided with a plurality of radial stress layers
  • the second electrode layer 23 is provided with a plurality of circumferential stress layers.
  • the plurality of radial stress layers are arranged at intervals, and the plurality of circumferential stress layers are arranged at intervals. Since the direction and size of the stress distribution in the diaphragm will be different, a radial stress layer is arranged on the first electrode layer 21 of the piezoelectric diaphragm 20, and a circumferential stress layer is arranged on the second electrode layer 23 to minimize the gradient The effect of stress on the deformation and warpage of the piezoelectric diaphragm 20 .
  • the first stress layer 31 may include multiple circumferential stress layers, for example, the first stress layer 31 includes four circumferential stress layers.
  • the first stress layer 31 in this embodiment includes at least two circumferential stress layers, the two circumferential stress layers are arranged on the first electrode layer 21 in an arc shape, and the two circumferential stress layers are spaced apart from each other The arrangement is encircled in a ring shape to minimize the deformation and warpage of the first electrode layer 21 of the piezoelectric diaphragm 20 caused by stress in the axial direction.
  • the second stress layer 32 may also include two circumferential stress layers, the two circumferential stress layers are arc-shaped and spaced apart from each other to form a ring, and are disposed on the second electrode layer 23 .
  • the phenomenon of deformation and warpage caused by gradient stress to any axial part of the piezoelectric diaphragm 20 can be reduced.
  • the first stress layer 31 provided on the first electrode layer 21 of the piezoelectric vibrating film 20 is a radial stress layer.
  • Two radial stress layers are arranged at intervals in the same radial direction. It can be understood that the positions of the two radial stress layers are collinear and located at any diameter part passing through the center of the first electrode layer 21; Two radial stress layers are spaced radially from the center of the layer 23 toward the edge of the piezoelectric diaphragm 20 .
  • the position and size of the first stress layer 31 and/or the second stress layer 32 can also be optimized according to the actual situation, so as to maximize the reduction of the gradient stress against the pressure The influence of the electric diaphragm 20.
  • the base 10 includes a surrounding wall 11 enclosing a back cavity 12
  • the piezoelectric diaphragm 20 includes a cantilever beam 20 b facing the back cavity 12 and a self-cantilever beam Anchoring portion 20a extending from the edge of 20b, the anchoring portion 20a is fixedly connected to the surrounding wall 11; a plurality of first stress layers 31 and/or a plurality of second stress layers 32 are respectively arranged on the cantilever beam 20a at intervals.
  • the piezoelectric material layer 22 in the piezoelectric diaphragm 20 generates charges. Therefore, in order to prevent the piezoelectric diaphragm 20 from vibrating up and down 20.
  • the deformation and warpage caused by residual stress which in turn affect the up and down vibration of the piezoelectric vibrating film 20.
  • the part of the piezoelectric vibrating film 20 facing the back cavity 12 is the cantilever beam 20a, which extends from the periphery of the cantilever beam 20a.
  • the part of the surrounding wall 11 fixed on the base 10 is the anchoring part 20a, and the piezoelectric vibrating film 20 forms a cantilever beam 20a through this arrangement.
  • a first stress layer 31 disposed on the surface of the electrode layer 21), and or a second stress layer 32 disposed on the side of the cantilever beam 20a of the piezoelectric diaphragm 20 facing the back cavity 12 to avoid the cantilever beam of the piezoelectric diaphragm 20 20a is deformed and warped due to the influence of the gradient stress in the thickness direction, which affects the acoustic performance of the piezoelectric MEMS microphone.
  • the base 10 includes a surrounding wall 11 enclosing a back cavity 12 and a support portion 13 fixed in the back cavity 12 , the support portion 13 is connected to and supports the anchor
  • the anchoring portion 20a and the cantilever beam 20b extend from the edge of the anchoring portion 20a and are suspended on the back cavity 12 .
  • the piezoelectric vibrating film 20 needs to adopt different installation methods according to the actual structure of the base 10 .
  • the support portion 13 is usually located at the center of the back cavity 12 or in the back cavity 12; further, the anchor portion 20a of the piezoelectric diaphragm 20 is fixedly connected to the support portion 13 of the base 10, and the cantilever beam 20b is suspended Above the back cavity 12 of the base 10 , the piezoelectric vibrating film 20 has good mobility, vibrates up and down under the action of external sound pressure, and has high sensitivity.
  • the piezoelectric The vibrating film 20 is patterned and etched, so that steps are formed on the surface of the piezoelectric vibrating film 20. These steps can affect the surface morphology of the piezoelectric film when the subsequent piezoelectric film is deposited, and are formed on the surface of the piezoelectric film layer. Corrugated structure, the stress layer embedded in the corrugated structure can also better release and compensate the gradient stress, and obtain a relatively flat piezoelectric diaphragm 20 .
  • the surface of the first electrode layer 21 has a first stress groove along the thickness direction
  • the surface of the second electrode layer 23 has a first protrusion along the thickness direction
  • the first stress groove and the first protrusion are
  • the first stress layer 31 is embedded in the first stress groove; or the surface of the second electrode layer 23 has the second stress groove 231 along the thickness direction, and the surface of the first electrode layer 21 has the second stress groove 231 along the thickness direction
  • the second protrusion 211 and the second stress groove 231 are opposite to the second protrusion 211
  • the second stress layer 32 is embedded in the second stress groove 231 .
  • the structure of the piezoelectric vibrating film 20 for example, patterning and etching the surface of the first electrode layer 21 along the thickness direction, so that the surface of the first electrode layer 21 has the first stress concave along the thickness direction.
  • the surface of the second electrode layer 23 opposite to the first stress groove has a first protrusion along the thickness direction to fix the first stress layer 31 in the first stress groove.
  • the surface of the first electrode layer 21 needs to be subjected to multiple annular patterning and etching processes, and the processed piezoelectric diaphragm 20 has multiple first stresses in the same radial direction.
  • a plurality of raised second protrusions 211 are formed on the surface of the second electrode layer 23 opposite to the plurality of first stress grooves, and the plurality of first stress grooves form a wave structure, and a plurality of The second protrusions 211 form a wave structure, and a plurality of circumferential stress layers are respectively arranged in the corresponding first stress grooves according to the size of the structure; Perform radial patterning and etching on the surface of the first electrode layer 21 of the piezoelectric vibrating film 20 to obtain the first stress groove in the radial direction of the piezoelectric vibrating film 20 and the first stress groove in the radial direction.
  • the surface of the opposite second electrode layer 23 is formed with a radial convex portion, so as to fix the radial stress layer in the radial first stress groove.
  • the second electrode layer 23 of the piezoelectric vibrating film 20 can also be patterned and etched to obtain a second stress groove 231 on the surface of the second electrode layer 23 and a second stress groove 231 on the surface of the first electrode layer 21 .
  • Two protruding parts 211 are provided.
  • the piezoelectric MEMS microphone provided by the present invention includes: a base 10 having a back cavity 12 and a piezoelectric vibrating membrane 20 , and the piezoelectric vibrating membrane 20 includes an anchor portion 20 a fixedly supported by the base 10 and an anchor portion 20 a.
  • 20a is an integrally formed cantilever beam 20b, the cantilever beam 20b is suspended above the back cavity 12, and the cantilever beam 20b includes a first electrode layer 21, a piezoelectric material layer 22 and a second electrode layer 23 that are sequentially stacked along the thickness direction.
  • the surface of the electrode layer 21 is provided with a plurality of first stress layers 31 spaced apart from each other, and/or the surface of the second electrode layer 23 is provided with a plurality of second stress layers 32 spaced apart from each other, and/or on the surface of the piezoelectric vibrating film.
  • a third stress layer 33 is sandwiched between any two adjacent layers.
  • a stress layer is provided on the surface of the first electrode layer 21 and/or the second electrode layer 23 of the piezoelectric vibrating membrane 20 and/or a third stress layer 33 is sandwiched between any two adjacent layers of the piezoelectric vibrating membrane , which can compensate the stress and gradient stress generated by the piezoelectric diaphragm 20 during the deposition process of the piezoelectric material, reduce the warping deformation of the piezoelectric diaphragm 20 under the action of stress and gradient stress, and ensure the piezoelectric MEMS microphone. performance.
  • the method of disposing the stress layer on the piezoelectric vibrating film is not limited to the above embodiment, and the specific shape, structure, thickness and symmetry of the stress layer are determined by the actual piezoelectric vibration.
  • the existence form and actual shape of the stress of the film are determined.
  • the setting of the stress layer The method also needs to be adjusted accordingly, such as setting the position, angle, and size of the stress layer.
  • the specific design should be optimized by finite element simulation and actual test results. Any design that adds a stress layer on the diaphragm structure and aims to reduce the influence of the gradient stress of the piezoelectric diaphragm is within the protection scope of this patent.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Piezo-Electric Transducers For Audible Bands (AREA)

Abstract

本实用新型提供了一种压电式MEMS麦克风，包括：具有背腔的基座及压电振膜，压电振膜包括由基座固定支撑的锚定部及与锚定部一体成型的悬臂梁，悬臂梁悬置于背腔上方，悬臂梁包括沿厚度方向依次层叠设置的第一电极层、压电材料层及第二电极层，压电振膜还包括与第一电极层、压电材料层及第二电极层中的至少任意一层贴合固定的相互间隔设置的多个应力层。本方案通过在压电振膜的悬臂梁结构上设置相互间隔的多个应力层，可对压电振膜在压电材料沉积过程中产生的梯度应力进行补偿，减小压电振膜在应力和梯度应力作用下发生翘曲形变，保障了压电式MEMS麦克风的性能。

Description

一种压电式MEMS麦克风 技术领域
本实用新型涉及电声转换技术领域，尤其涉及一种压电式MEMS麦克风。
 背景技术
压电式MEMS麦克风相比于传统的电容式MEMS麦克风具有很多优势，包括防尘性和防水性，较高的最大输出声压（AOP）等。受限于压电材料现有的溅射工艺，压电薄膜普遍存在应力，且应力分布不均匀, 较难以控制, 而这一残余应力的存在导致膜片不可避免发生翘曲和形变。
现有技术的压电式MEMS麦克风通常具有若干个部分锚定的悬臂梁结构，该悬臂梁的设计可以一定程度上改善残余应力对膜片形变的影响。但是,该残余应力在整个膜片上分布不均匀，悬臂梁结构无法避免沿着膜层厚度方向产生的梯度应力，这仍会引起压电膜层不同程度的翘曲形变，影响了压电式麦克风的声学性能。
因此，有必要提供一种新的压电式麦克风。
 技术问题
本实用新型的目的在于提供一种压电式MEMS麦克风，可以解决现有技术中的压电振膜的悬臂梁结构无法避免沿着膜层厚度方向产生的梯度应力的问题。
 技术解决方案
本实用新型的技术方案提供一种压电式MEMS麦克风，包括：具有背腔的基座及压电振膜，所述压电振膜包括由所述基座固定支撑的锚定部及自所述锚定部延伸的悬臂梁，所述悬臂梁悬置于所述背腔上方，所述悬臂梁包括沿厚度方向依次层叠设置的第一电极层、压电材料层及第二电极层，所述压电振膜还包括与所述第一电极层、所述压电材料层及所述第二电极层中的至少任意一层贴合固定的相互间隔设置的多个应力层。
可选的，所述应力层包括贴设于所述第一电极层的表面的相互间隔的多个第一应力层，和/或贴设于所述第二电极层的表面的相互间隔的多个第二应力层；和/或夹设于所述第一电极层、压电材料层与第二电极层中任意相邻两层之间的多个相互间隔的第三应力层。
可选的，多个所述第一应力层和/或多个所述第二应力层沿所述压电振膜的轴向对称设置。
可选的，多个所述第一应力层和/或多个所述第二应力层包括自所述压电振膜的中心朝所述压电振膜的边缘延伸的径向应力层。
可选的，多个所述第一应力层和/或多个所述第二应力层包括沿所述压电振膜的周向延伸的周向应力层。
可选的，至少两个所述周向应力层呈弧形且相互间隔设置并围成环状。
可选的，至少两个所述径向应力层相互间隔设置且共线。
可选的，所述基座包括围成所述背腔的围壁，所述压电振膜包括与所述背腔正对的所述悬臂梁以及自所述悬臂梁边缘延伸的所述锚定部，所述锚定部固定连接于所述围壁；多个所述第一应力层和/或多个所述第二应力层分别间隔设置于所述悬臂梁。
可选的，所述基座包括围成所述背腔的围壁以及固定于所述背腔内的支撑部，所述支撑部连接并支撑所述锚定部，所述悬臂梁自所述锚定部边缘延伸并悬置于所述背腔。
可选的，所述第一电极层的表面沿着厚度方向具有第一应力凹槽，及所述第二电极层的表面沿着厚度方向具有第一凸起部，所述第一应力凹槽与所述第一凸起部相背，所述第一应力层镶嵌于所述第一应力凹槽；或
所述第二电极层的表面沿着厚度方向具有第二应力凹槽，及所述第一电极层的表面沿着厚度方向具有第二凸起部，所述第二应力凹槽与所述第二凸起部相背，所述第二应力层镶嵌于所述第二应力凹槽。
 有益效果
本实用新型的有益效果在于：本实用新型提供的压电式MEMS麦克风，包括：具有背腔的基座及压电振膜，压电振膜包括由基座固定支撑的锚定部及与锚定部一体成型的悬臂梁，悬臂梁悬置于背腔上方，悬臂梁包括沿厚度方向依次层叠设置的第一电极层、压电材料层及第二电极层，压电振膜还包括与第一电极层、压电材料层及第二电极层中的至少任意一层贴合固定的相互间隔设置的多个应力层。本方案通过在压电振膜的悬臂梁结构上设置相互间隔的多个应力层，可对压电振膜在压电材料沉积过程中产生的梯度应力进行补偿，减小压电振膜在应力和梯度应力作用下发生翘曲形变，保障了压电式MEMS麦克风的性能。
 附图说明
图1为本实用新型的实施例提供的压电式MEMS麦克风的立体图；
图2为图1的实施例提供的压电式MEMS麦克风沿A-A线的剖面结构示意图；
图3为图1所示的压电式MEMS麦克风的压电振膜沿A’-A’线的剖视结构示意图；
图4为本实用新型的另一实施例提供的压电式MEMS麦克风的结构示意图；
图5为图4实施例提供的压电式MEMS麦克风沿B-B线的剖面结构示意图；
图6为本实用新型的又一实施例提供的压电式MEMS麦克风的立体图；
图7为图6实施例提供的压电式MEMS麦克风沿C-C线的剖面结构示意图；
图8为图7实施例中d部分的结构放大示意图；
图9为本实用新型实施例提供的应力层夹设于压电振膜内的结构示意图。
 本发明的实施方式
下面结合附图和实施方式对本实用新型作进一步说明。
为了解决现有技术中的压电振膜的悬臂梁结构无法避免沿着膜层厚度方向产生的梯度应力的技术问题，本实用新型的技术方案提供一种压电式MEMS麦克风；
参考图1至图3，以及参考图7，该压电式MEMS麦克风包括：具有背腔12的基座10及固定于基座10并悬置于背腔12的压电振膜20，压电振膜20包括由基座10固定支撑的锚定部20a及与自锚定部20a延伸的悬臂梁20b，优选地，锚定部20a与悬臂梁20b一体成型，该悬臂梁20b悬置于背腔12上方，该悬臂梁20b包括沿厚度方向依次层叠设置的第一电极层21、压电材料层22及第二电极层23，压电振膜20还包括与第一电极层21、压电材料层22及第二电极层23中的至少任意一层贴合固定的相互间隔设置的多个应力层。
本实用新型公开的麦克风为压电式MEMS麦克风，相对于传统的电容式麦克风具有：防尘、防水及较高的最大输出声压等优势，该压电式麦克风是通过压电振膜20在声压的作用下进行上下振动，而压电振膜20中的压电材料层22产生电荷，而产生的电荷被有效电极收集，并转换为电压信号，以传递到相关电路；然而，压电式麦克风的压电振膜20是通过压电材料层22的溅射沉积工艺，在该压电材料层22溅射沉积的过程中一般存在应力或梯度应力等残余应力，该残余应力会使得压电振膜20发声形变，进而对压电式麦克风的性能造成影响，为了使得释放残余应力，本实用新型对压电式MEMS麦克风及其压电振膜20进行设计。具体的，该压电式MEMS麦克风包括：具有背腔12的基座10及压电振膜20，将压电振膜20固定并悬置在背腔12上方，以实现在声压的作用下进行上下振动。优选的，将压电振膜20分为锚定部20a和悬臂梁20b，其中，锚定部20a由基座10背腔12内的支撑部13固定支撑，或由围成背腔12的围壁11进行固定支撑。
参阅图2及图3，该压电振膜20为利用电极层和压电材料层22进行加工得到的振膜，在结构划分（自上而下）包括：第一电极层21、压电材料层22、第二电极层23，其中，第二电极层23与基座10的部位固定连接。将压电振膜20沿着厚度方向上进行贯通破分后，得到的压电振膜20形成与基座10单端固定的多个悬臂梁20b结构及与悬臂梁20b一体成型的锚定部20a，则悬臂梁20b包括：第一电极层21、压电材料层22以及第二电极层23。需要说明的是，当压电材料层22沉积工艺中产生的应力在膜片加工工艺中被释放出来时，压电振膜20上仍存在残余应力，通过对压电振膜20进行划分，可降低残余应力的影响，减小膜片发生翘曲。
进一步的，由于压电振膜20在厚度方向上仍可能存在梯度应力，为了避免梯度应力对压电振膜20翘曲、形变，本实用新型实施例中，在压电振膜20的悬臂梁20b表面或压电振膜20内部复合层增加设置应力层，如在第一电极层21、压电材料层22及第二电极层23中的至少任意一层贴合固定的相互间隔设置的多个应力层。通过利用应力块或应力板进行曝光、刻蚀形成相互间隔的形状结构的应力层。通过将该形状结构的应力层间隔设置在压电振膜20的悬臂梁20b上，通过该应力层可对压电振膜20的应力和梯度应力造成的形变进行补偿，减小振膜在应力和梯度应力的作用下发生的翘曲与形变。该应力层为具有容易控制、应力稳定的特性，应力层的材料可为氧化硅、氮化硅、金属等，本实施例不对应力层的材料进行限定，凡是在硅片上分布较为均匀、应力稳定的应力等力学参数容易控制的材料, 均可用于制作本实用新型的应力层。优选的，应力层优选为多晶硅(Poly-Si)层，氮化硅(SiN)层，氧化硅（SiO）层或金属层等。
参阅图2、图5和图9，在本实用新型实施例中，应力层包括贴设于第一电极层21的表面的相互间隔的多个第一应力层31，和/或贴设于第二电极层23的表面的相互间隔的多个第二应力层32；和/或夹设于第一电极层21、压电材料层22与第二电极层23中任意相邻两层之间的多个相互间隔的第三应力层33。具体的，应力层可包括：第一应力层31、第二应力层32、第三应力层33，在压电振膜20的表面或内部复合层增加设置应力层的方式可具体为：设置贴合于第一电极层21表面的相互间隔的多个第一应力层31，和/或设置贴合于第二电极层23表面的相互间隔的多个第二应力层32；和/或在第一电极层21表面设有相互间隔的多个第一应力层31，同时在第二电极层23表面设置相互间隔的多个第二应力层32；此外，应力层还可设置在压电振膜20的复合层中间，如第一电极层21与第二电极层23之间设有相互间隔的多个第三应力层33，如，第三应力层33可以夹设于第一电极层21与压电材料层22之间，或夹设于第二电极层23与压电材料层22之间，还可以融合于压电材料层22中。需要说明的是，应力层厚度与悬臂梁20b总厚度的比值大约为0.05-0.3，优选的，比值为0.1-0.2。通过上述的在压电振膜20设置应力层，可避免压电振膜20沿着厚度方向上的梯度应力造成压电振膜20翘曲、形变。
参阅图1和图4，在实施例中，多个第一应力层31和/或多个第二应力层32沿压电振膜20的轴向对称设置。具体的，第一电极层21表面设有多个第一应力层31，多个第一应力层31相互间隔设置在第一电极层21的表面，且这多个第一应力层31沿着压电振膜20的第一电极层21的轴向呈对称设置；同理，当在第二电极层23上设置多个第二应力层32时，将多个第二应力层32相互间隔设置在第二电极层23的表面，且这多个第二应力层32沿着压电振膜20的第二电极层23的轴向呈对称设置。通过上述对第一电极层21上设置的第一应力层31、第二电极层23上设置的第二应力层32的位置限定，使得应力层均匀设置在压电振膜20上，以使得压电振膜20厚度方向上的梯度应力得到较为均匀的补偿，避免梯度应力造成压电振膜20翘曲、形变。需要注意的是，当形成压电振膜20或膜片的溅射工艺参数发生变化或调整，膜片内残余应力分布的方向、大小都会出现差异，因此，在对压电振膜20的第一电极层21和/或第二电极层23进行设置应力层时，应力层的位置、厚度可以根据实际情况进行优化。
参阅图1，在本实施例中，多个第一应力层31和/或多个第二应力层32包括自压电振膜20的中心朝压电振膜20的边缘延伸的径向应力层。优选的，第一应力层31包含径向应力层，该径向应力层为自压电振膜20的第一电极层21的中心朝第一电极层21的边缘方向设置的应力层，由于压电振膜20为圆形的膜片，该径向应力层的位置可为通过第一电极层21圆心的任意直径方向上的部位；同理，第二应力层32也包含径向应力层，该径向应力层为自压电振膜20的第二电极层23的中心朝第二电极层23的边缘方向设置的应力层。通过本实施例对压电振膜20上的第一应力层31、第二应力层32的结构及位置进行限定，即限定第一电极层21、第二电极层23的径向上的位置，及限定第一应力层31和第二应力层32的形状结构为径向应力层，以防止压电振膜20厚度方向上的梯度应力对压电振膜20的径向上造成形变、翘曲的现象。
参阅图4，在本实用新型的另一实施例中，多个第一应力层31和/或多个第二应力层32包括沿压电振膜20的周向延伸的周向应力层。优选的，第一应力层31包括周向应力层，该周向应力层为沿着压电振膜20的第一电极层21的轴向上设置的应力层，该应力层的位置可为第一电极层21的任一轴向上的任意部位或所有部位；第二应力层32包含周向应力层，该周向应力层为自压电振膜20的第二电极层23的沿着第二电极层23的任一轴向的位置上设置的应力层；通过本实施例限定第一应力层31、第二应力层32在压电振膜20的轴向上的位置，且限定第一应力层31、第二应力层32的形状结构为周向应力层，以防止梯度应力在压电振膜20的轴向上造成形变、翘曲的现象。
在本实用新型的又一实施例中，第一电极层21设有多个径向应力层，且第二电极层23设有多个周向应力层。该多个径向应力层之间间隔设置，及多个周向应力层之间间隔设置。由于膜片内应力分布的方向、大小都会出现差异，在压电振膜20的第一电极层21设置径向应力层，及在第二电极层23设置周向应力层，以最大化降低梯度应力对压电振膜20形变和翘曲的影响。
参阅图4，在本实施例中，至少两个周向应力层呈弧形且相互间隔设置并围成环状。具体的，第一应力层31可包含多个周向应力层，如第一应力层31包含4个周向应力层。优选的，本实施例的第一应力层31包含至少两个周向应力层，这两个周向应力层呈弧形设置于第一电极层21，且两个周向应力层之间相互间隔设置围成环状，以最大化降低应力对压电振膜20的第一电极层21的轴向造成形变、翘曲的现象。同理，第二应力层32也可以包含两个周向应力层，这两个周向应力层呈弧形且相互间隔设置围成环状，设置于第二电极层23。通过本实施例对第一应力层31及第二应力层32的位置、形状结构的限定，可降低梯度应力对压电振膜20任一轴向上的部位造成形变、翘曲的现象。
参阅图1，在本实用新型的另一实施例中，至少两个径向应力层相互间隔设置且共线。具体的，在压电振膜20的第一电极层21设置的第一应力层31为径向应力层，优选的，可沿着压电振膜20的中心朝压电振膜20边缘方向的同一径向上间隔设置两个径向应力层，可以理解的是，这两个径向应力层的位置为共线位于通过第一电极层21圆心的任一直径部位；同理，在第二电极层23的中心朝压电振膜20边缘方向的径向上间隔设置两个径向应力层，这两个径向应力层位置为共线位于通过第二电极层23圆心的任意直径。通过上述对多个径向应力层相互间隔及共线的设置，第一应力层31和/或第二应力层32的位置及尺寸也可以根据实际情况进行优化，以最大化降低梯度应力对压电振膜20的影响。
参阅图1至图2，在本实用新型的实施例中，基座10包括围成背腔12的围壁11，压电振膜20包括与背腔12正对的悬臂梁20b以及自悬臂梁20b边缘延伸的锚定部20a，锚定部20a固定连接于围壁11；多个第一应力层31和/或多个第二应力层32分别间隔设置于悬臂梁20a。具体的，由于该压电式麦克风是通过压电振膜20在声压的作用下进行上下振动，使得压电振膜20中的压电材料层22产生电荷，因此，为了防止压电振膜20由于残余应力造成的形变、翘曲，进而影响压电振膜20的上下振动，优选的，以背腔12正对的压电振膜20部位为悬臂梁20a，以自悬臂梁20a周缘延伸并固定在基座10的围壁11部位为锚定部20a，压电振膜20通过该种设置方式形成悬臂梁20a，其中，在压电振膜20的悬臂梁20a朝向外部的一面（第一电极层21的表面）设置的第一应力层31，和或在压电振膜20的悬臂梁20a朝向背腔12的一面设置第二应力层32，以避免压电振膜20的悬臂梁20a沿着厚度方向上的梯度应力的影响发生形变、翘曲的现象，影响压电式MEMS麦克风的声学性能。
参阅图4至图5，在本实用新型的另一实施例中，基座10包括围成背腔12的围壁11以及固定于背腔12内的支撑部13，支撑部13连接并支撑锚定部20a，悬臂梁20b自锚定部20a边缘延伸并悬置于背腔12上。具体的，将压电振膜20安装固定在基座10上时，由于压电振膜20需要根据实际基座10的结构采用不同的安装方式。优选的，该支撑部13通常位于背腔12的中心位置或背腔12内；进一步的，压电振膜20的锚定部20a与基座10的支撑部13固定连接，悬臂梁20b悬置在基座10的背腔12上方，使得压电振膜20具有较好的机动性，在外部声压的作用下进行上下振动，具有较高的灵敏度。
参阅图6至图8，在另一实施例中，当将应力层设置在压电振膜20朝向外部的表面时，即将第一应力层31设置在第一电极层21时，可对压电振膜20进行图形化和刻蚀处理，使得压电振膜20表面形成台阶，这些台阶在后续的压电薄膜沉积的时, 能够影响压电薄膜的表面形貌, 在压电膜层表面形成波浪(corrugated)结构，将应力层镶嵌于该波浪结构也可以较好的释放和补偿梯度应力，得到较为平整的压电振膜20。
具体的，第一电极层21的表面沿着厚度方向具有第一应力凹槽，及第二电极层23的表面沿着厚度方向具有第一凸起部，第一应力凹槽与第一凸起部相背，第一应力层31镶嵌于第一应力凹槽；或第二电极层23的表面沿着厚度方向具有第二应力凹槽231，及第一电极层21的表面沿着厚度方向具有第二凸起部211，第二应力凹槽231与第二凸起部211相背，第二应力层32镶嵌于第二应力凹槽231。通过上述的压电振膜20的结构设定，如对第一电极层21表面沿着厚度方向进行图形化和刻蚀处理，使得第一电极层21的表面沿着厚度方向具有第一应力凹槽，而该第一应力凹槽相背的第二电极层23的表面沿着厚度方向具有第一凸起部，将第一应力层31固定于第一应力凹槽内。需要说明的是，压电振膜20的图形化和刻蚀方式可根据振膜内的应力分布实际情况来决定，如根据压电振膜20内的应力分布选择在第一电极层21表面设置相互间隔的多个周向应力层时，需要将第一电极层21的表面进行多个环状图形化、刻蚀处理，处理后的压电振膜20的同一径向上具有多个第一应力凹槽，同时，与多个第一应力凹槽相背的第二电极层23表面会形成凸起的多个第二凸起部211，多个第一应力凹槽组成波浪结构，及多个第二凸起部211组成波浪结构，将多个周向应力层分别根据结构大小设置于相应的第一应力凹槽内；本实施例还可以根据压电振膜20内的应力分布实际情况，在压电振膜20的第一电极层21的表面进行径向的图形化和刻蚀处理，得到压电振膜20径向上的第一应力凹槽，以及与径向上的第一应力凹槽相背的第二电极层23表面形成径向上的凸起部，以满足将径向应力层固定于该径向的第一应力凹槽内。同理，还可以对压电振膜20的第二电极层23进行图形化和刻蚀处理，在第二电极层23表面得到第二应力凹槽231，及在第一电极层21表面得到第二凸起部211。通过上述对压电振膜20的结构处理方式，可较好的释放和补偿压电振膜20内的梯度应力，得到较为平整的压电振膜20，提升麦克风声学性能。
本实用新型提供的压电式MEMS麦克风，包括：具有背腔12的基座10及压电振膜20，压电振膜20包括由基座10固定支撑的锚定部20a及与锚定部20a一体成型的悬臂梁20b，悬臂梁20b悬置于背腔12上方，悬臂梁20b包括沿厚度方向依次层叠设置的第一电极层21、压电材料层22及第二电极层23，第一电极层21的表面设有相互间隔的多个第一应力层31，和/或第二电极层23的表面设有相互间隔的多个第二应力层32，和/或在压电振膜的任意相邻两层之间夹设第三应力层33。本方案通过在压电振膜20的第一电极层21和/或第二电极层23表面设置应力层和/或在压电振膜的任意相邻两层之间夹设第三应力层33，可对压电振膜20在压电材料沉积过程中产生的应力和梯度应力进行补偿，减小压电振膜20在应力和梯度应力作用下发生翘曲形变，保障了压电式MEMS麦克风的性能。
本实用新型提供的压电式MEMS麦克风，其中，对于在压电振膜设置应力层的方式不限于以上实施方式，具体的应力层的形状结构、厚度以及对称性等要由实际的压电振膜的应力的存在形式和实际形状来决定，事实上，当形成压电振膜的溅射工艺参数发生变化或者调整，膜片内残余应力分布的方向，大小都会出现差异，因此应力层的设置方式也需要做出对应的调整，比如设置应力层的位置，角度，尺寸等，当中具体设计应该由有限元仿真和实际测试结果进行设计优化。凡是在振膜结构上添加应力层，且以减小压电振膜的梯度应力影响为目的的设计，均在本专利保护范围之内。
以上的仅是本实用新型的实施方式，在此应当指出，对于本领域的普通技术人员来说，在不脱离本实用新型创造构思的前提下，还可以做出改进，但这些均属于本实用新型的保护范围。

Claims (10)

  1. 一种压电式MEMS麦克风，包括：具有背腔的基座及压电振膜，所述压电振膜包括由所述基座固定支撑的锚定部及自所述锚定部延伸的悬臂梁，所述悬臂梁悬置于所述背腔上方，其特征在于，所述悬臂梁包括沿厚度方向依次层叠设置的第一电极层、压电材料层及第二电极层，所述压电振膜还包括与所述第一电极层、所述压电材料层及所述第二电极层中的至少任意一层贴合固定的相互间隔设置的多个应力层。
  2. 根据权利要求1所述的压电式MEMS麦克风，其特征在于，所述应力层包括贴设于所述第一电极层的表面的相互间隔的多个第一应力层；和/或贴设于所述第二电极层的表面的相互间隔的多个第二应力层；和/或夹设于所述第一电极层、压电材料层与第二电极层中任意相邻两层之间的多个相互间隔的第三应力层。
  3. 根据权利要求1所述的压电式MEMS麦克风，其特征在于，所述应力层沿所述压电振膜的轴向对称设置。
  4. 根据权利要求1所述的压电式MEMS麦克风，其特征在于，所述应力层包括自所述压电振膜的中心朝所述压电振膜的边缘延伸的径向应力层。
  5. 根据权利要求1-4任一项所述的压电式MEMS麦克风，其特征在于，所述应力层包括沿所述压电振膜的周向延伸的周向应力层。
  6. 根据权利要求5所述的压电式MEMS麦克风，其特征在于，至少两个所述周向应力层呈弧形且相互间隔设置并围成环状。
  7. 根据权利要求6所述的压电式MEMS麦克风，其特征在于，至少两个所述径向应力层相互间隔设置且共线。
  8. 根据权利要求1所述的压电式MEMS麦克风，其特征在于，所述基座包括围成所述背腔的围壁，所述压电振膜包括与所述背腔正对的所述悬臂梁以及自所述悬臂梁边缘延伸的所述锚定部，所述锚定部固定连接于所述围壁；多个所述应力层分别间隔设置于所述悬臂梁。
  9. 根据权利要求1所述的压电式MEMS麦克风，其特征在于，所述基座包括围成所述背腔的围壁以及固定于所述背腔内的支撑部，所述支撑部连接并支撑所述锚定部，所述悬臂梁自所述锚定部边缘延伸并悬置于所述背腔。
  10. 根据权利要求1所述的压电式MEMS麦克风，其特征在于，所述第一电极层的表面沿着厚度方向具有第一应力凹槽，及所述第二电极层的表面沿着厚度方向具有第一凸起部，所述第一应力凹槽与所述第一凸起部相背，所述第一应力层镶嵌于所述第一应力凹槽；或
    所述第二电极层的表面沿着厚度方向具有第二应力凹槽，及所述第一电极层的表面沿着厚度方向具有第二凸起部，所述第二应力凹槽与所述第二凸起部相背，所述第二应力层镶嵌于所述第二应力凹槽。
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