CN117857992A - MEMS chip and MEMS microphone structure - Google Patents

Abstract

The application provides a MEMS chip and MEMS microphone structure, this MEMS chip includes first MEMS structure, and wherein, first MEMS structure includes: a first base structure including two first base portions disposed at intervals; the polar plate is positioned between the two first substrate parts, two ends of the polar plate are respectively connected with the two first substrate parts, and the polar plate is not provided with a through hole; the first back electrode plate is positioned at one side of the electrode plate between the two first substrate parts, two ends of the first back electrode plate are respectively connected with the two first substrate parts, and the first back electrode plate is provided with a through hole; the first vibrating diaphragm is positioned at one side of the first back electrode plate between the two first substrate parts, which is far away from the electrode plate, and two ends of the first back electrode plate are respectively connected with the two first substrate parts, the first vibrating diaphragm is provided with a through hole, and a first interval is arranged between the first back electrode plate and the first vibrating diaphragm; the first electrode is positioned on one side of the first substrate structure far away from the polar plate and is connected with the first back polar plate, so that the problem that the MEMS microphone cannot effectively collect vibration signals is solved.

Description

MEMS chip and MEMS microphone structure

Technical Field

The present application relates to the field of MEMS, and in particular, to a MEMS chip and a MEMS microphone structure.

Background

Currently, with the rapid development of electronic products in recent decades, the microphone market is demanded to be changed in quality by miniaturization and light and thin products, and a MEMS (Micro-Electro-Mechanical System, micro Electro mechanical system) microphone is a microphone with more applications and better performance, and mainly comprises a housing, a circuit board, a MEMS chip and an ASIC chip. MEMS microphones are microphone components based on microelectromechanical systems and offer advantages over conventional ECM (Electret Capacitance Microphone, electret microphone) in terms of product size, performance parameters, reliability, cost of use, etc. Along with the continuous improvement of the cost performance of MEMS microphone products, the application river basin of the MEMS microphone is gradually expanded from the mobile phone market to various fields such as 3C, security and protection systems, conference systems, intelligent home and the like, and the MEMS microphone becomes the most important component product of the audio frequency entrance in the world today.

However, in the process of acquiring vibration signals, the existing MEMS microphone can collect the vibration signals by the MEMS chip and the spring piece, so that the output signals are signals of the vibration of the MEMS chip and the vibration of the spring piece, the amplitude and the phase of the output signals are different, the signal accuracy deviation can be caused in the superposition process, and the acquisition quality of the vibration signals is affected. In addition, the MEMS microphone also has the problem of complex process, and the yield is lower because of larger process deviation and large product difference.

Accordingly, there is a need to provide a new MEMS microphone to solve the above-mentioned problems.

The above information disclosed in the background section is only for enhancement of understanding of the background art from the technology described herein and, therefore, may contain some information that does not form the prior art that is already known in the country to a person of ordinary skill in the art.

Disclosure of Invention

The main aim of the application is to provide a MEMS chip and a MEMS microphone structure, so as to solve the problem that the MEMS microphone in the prior art cannot effectively collect vibration signals.

To achieve the above object, according to one aspect of the present application, there is provided a MEMS chip including a first MEMS structure, wherein the first MEMS structure includes: a first base structure including two first base portions disposed at intervals; the polar plate is positioned between the two first substrate parts, two ends of the polar plate are respectively connected with the two first substrate parts, and the polar plate is not provided with a through hole; the first back electrode plate is positioned at one side of the electrode plate between the two first substrate parts, two ends of the first back electrode plate are respectively connected with the two first substrate parts, and the first back electrode plate is provided with a through hole; the first vibrating diaphragm is positioned at one side of the first back electrode plate between the two first substrate parts, which is far away from the electrode plate, and two ends of the first back electrode plate are respectively connected with the two first substrate parts, the first vibrating diaphragm is provided with a through hole, and a first interval is arranged between the first back electrode plate and the first vibrating diaphragm; the first electrode is positioned on one side of the first substrate structure far away from the polar plate and is connected with the first back polar plate.

Optionally, the first MEMS structure further comprises: the second back electrode plate is positioned at one side of the first vibrating diaphragm between the two first substrate parts, which is far away from the electrode plate, and two ends of the second back electrode plate are respectively connected with the two first substrate parts, the second back electrode plate is provided with a through hole, and a second interval is arranged between the second back electrode plate and the first vibrating diaphragm; the second electrode is positioned on one side of the first substrate structure far away from the polar plate and is connected with the second back polar plate.

Optionally, the first interval is equal to the second interval.

Optionally, the plate is a rigid semiconductor material.

Optionally, the MEMS chip further comprises a second MEMS structure, the second MEMS structure comprising: a second base structure comprising two second base portions disposed at intervals; the third back electrode plate is positioned on one side, far away from the second base parts, between the two second base parts, and two ends of the third back electrode plate are respectively connected with the two second base parts, and the third back electrode plate is provided with a through hole; the second vibrating diaphragm is positioned at one side of the second base part of the third back electrode plate between the two second base parts, two ends of the second vibrating diaphragm are respectively connected with the two second base parts, the second vibrating diaphragm is provided with a through hole, and a third interval is arranged between the third back electrode plate and the second vibrating diaphragm; the third electrode is positioned at one side of the third back electrode plate of the second substrate structure and is connected with the third back electrode plate; the first MEMS structure is connected with the second MEMS structure, and the first vibrating diaphragm is positioned between the third back electrode plate and the first back electrode plate.

Optionally, the second MEMS structure further comprises: the fourth back electrode plate is positioned at one side of the second base part of the second vibrating diaphragm between the two second base parts, two ends of the fourth back electrode plate are respectively connected with the two second base parts, the fourth back electrode plate is provided with a through hole, and a fourth interval is arranged between the fourth back electrode plate and the second vibrating diaphragm; and the fourth electrode is positioned at one side of the fourth back electrode plate of the second substrate structure and is connected with the fourth back electrode plate.

Optionally, the third interval is equal to the fourth interval.

Optionally, the first substrate portion has a first protruding portion, the first protruding portion is located on a side, away from the polar plate, of the first substrate portion, the second substrate portion has a second protruding portion, the second protruding portion is located on a side, away from the second diaphragm, of the third back polar plate of the second substrate portion, the first protruding portion and the first diaphragm form a first groove, and the second protruding portion and the third back polar plate form a second groove.

To achieve the above object, according to one aspect of the present application, there is provided a MEMS microphone structure including: a circuit board having an acoustic hole; the MEMS chip of any one of claims 1 to 8, the MEMS chip being connected to a wiring board; the ASIC chip is connected with the electrode of at least one MEMS chip and is connected with the circuit board; and the shell is positioned on the circuit board and covers the MEMS chip and the ASIC chip.

By using the technical scheme of the application, the polar plate without the through hole is added on the basis of the original structure of the MEMS chip, so that sound signals cannot enter the MEMS chip, only vibration signals can enter the MEMS chip, the purposes of effectively picking up the vibration signals and filtering the sound signals are achieved, the accuracy and the quality of collecting the vibration signals are improved, and the problem that the MEMS microphone cannot effectively collect the vibration signals is solved.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and together with the description serve to explain the application and do not constitute an undue limitation to the application. In the drawings:

FIG. 1 shows a first MEMS structural schematic according to an embodiment of the present application;

FIG. 2 shows a schematic side cross-sectional view of the structure of FIG. 1;

FIG. 3 is a schematic view showing the structure of the second back plate added to the structure of FIG. 1;

FIG. 4 shows a schematic side cross-sectional view of the structure of FIG. 3;

FIG. 5 shows a schematic diagram of a first MEMS structure and a second MEMS structure according to another embodiment of the present application;

FIG. 6 shows a schematic diagram of a MEMS microphone structure in accordance with yet another embodiment of the application;

fig. 7 shows a schematic diagram of a MEMS microphone sound processing flow in accordance with yet another embodiment of the present application.

Wherein the above figures include the following reference numerals:

100. a MEMS chip; 101. a first base structure; 102. a polar plate; 103. a first back plate; 104. a first diaphragm; 105. a first electrode; 106. a second back plate; 107. a first interval; 108. a second interval; 109. a second electrode; 110. a third back plate; 111. a second diaphragm; 112. a fourth back plate; 113. a second base structure; 114. a third interval; 115. a fourth interval; 116. a first protrusion; 117. a second protruding portion; 118. a first groove; 119. a second groove; 200. an ASIC chip; 300. a housing; 400. a circuit board; 401. and (5) sound holes.

Detailed Description

It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present application. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the present application. As used herein, the singular is also intended to include the plural unless the context clearly indicates otherwise, and furthermore, it is to be understood that the terms "comprises" and/or "comprising" when used in this specification are taken to specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof.

It will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element or intervening elements may also be present. Furthermore, in the description and in the claims, when an element is described as being "connected" to another element, the element may be "directly connected" to the other element or "connected" to the other element through a third element.

As described in the background art, in the prior art, in the process of acquiring vibration signals, the MEMS chip and the spring piece can collect the vibration signals, so that the output signals are signals of the vibration of the MEMS chip and the vibration of the spring piece, the amplitude and the phase of the output signals are different, and in the superposition process, the signal accuracy deviation can be caused to influence the acquisition quality of the vibration signals. In order to solve the technical problems, the application provides a MEMS chip and a MEMS microphone structure.

In an exemplary embodiment of the present application, there is provided a MEMS chip, as shown in fig. 1, including a first MEMS structure, wherein the first MEMS structure includes:

a first base structure 101 comprising two first base portions arranged at intervals;

the material of the first base structure may be silicon, gallium arsenide, or other semiconductor materials, and the first base structure may be a structure as shown in fig. 2, or may be any structure that meets the above requirements.

A polar plate 102 disposed between the two first base portions and having both ends connected to the two first base portions, respectively, the polar plate 102 having no through hole;

the external mixed signal generally comprises an acoustic signal and a vibration signal, the first MEMS structure is provided with a polar plate without a through hole, so that the acoustic signal cannot enter the first MEMS structure, and the vibration signal is continuously transmitted into the first MEMS structure in a solid propagation mode.

A first back plate 103 located at one side of the plate 102 between the two first base portions, and having both ends connected to the two first base portions, respectively, the first back plate 103 having a through hole;

the material of the first back electrode plate is other semiconductor materials such as polysilicon, monocrystalline silicon and the like, and the first back electrode plate is used as a electrode plate of a capacitor, and the shape of the through hole can be round, square, elliptic or other shapes.

A first diaphragm 104, which is located at one side of the first back plate 103 between the two first base portions, which is far away from the plate 102, and two ends of which are respectively connected with the two first base portions, wherein the first diaphragm 104 has a through hole, and a first interval is provided between the first back plate 103 and the first diaphragm 104;

because the sound signal is blocked by the polar plate and cannot enter the first MEMS structure, the vibration signal forces the first vibrating diaphragm to respond in a solid transmission mode to generate displacement, so that the first interval between the first vibrating diaphragm and the first back polar plate is changed, further the change of capacitance is caused, and the vibration signal is converted into an electric signal.

A first electrode 105, which is located on the side of the first base structure 101 away from the plate 102, is connected to the first back plate 103.

The first electrode is used for outputting an electric signal and further processing, and the material of the first electrode can be conductive materials such as copper, graphite tungsten alloy and the like. The first MEMS structure is used as a basic realization model, has a simple structure, realizes effective separation of sound signals and vibration signals, and improves the collection quality of the vibration signals.

In order to further improve the signal-to-noise ratio and sensitivity of the MEMS microphone, in a specific embodiment of the present application, as shown in fig. 3, the first MEMS structure further includes: a second back-electrode plate 106, which is located at one side of the first diaphragm 104 between the two first base portions, which is far from the electrode plate 102, and two ends of which are respectively connected with the two first base portions, wherein the second back-electrode plate 106 has a through hole, and a second interval 108 is provided between the second back-electrode plate 106 and the first diaphragm 104; the second back electrode plate is made of other semiconductor materials such as polysilicon, monocrystalline silicon and the like, and is used as a capacitor electrode plate, and the shape of the through hole can be round, square, elliptic or other shapes. The structure is provided with the second back electrode plate, the first back electrode plate and the first vibrating diaphragm form a first interval, a first capacitor is formed, the second back electrode plate and the first vibrating diaphragm form a second interval, and a second capacitor is formed. When external signals enter the MEMS chip, the first interval and the second interval change due to vibration of the first vibrating diaphragm, and then capacitance values of the corresponding first capacitor and the corresponding second capacitor change. Because the polar plate is the structure without the through hole, when external signals enter the MEMS, the interval between the polar plate and the first vibrating diaphragm is not changed, and therefore, no influence is caused on signal output. As shown in fig. 4, a second electrode 109 is located on a side of the first base structure away from the plate 102 and is connected to the second back plate 106. The second electrode is used for outputting an electric signal and further processing, and the material of the second electrode can be conductive materials such as copper, graphite tungsten alloy and the like. The first capacitor and the second capacitor can be respectively used as signal output units, signals can be output through the first electrode and the second electrode respectively, a plurality of signals can be output, and the sensitivity and the signal to noise ratio of the MEMS microphone can be improved through the output accumulation of different output units.

In a specific embodiment of the present application, as shown in fig. 3, the first interval 107 is equal to the second interval 108. In the above structure, the first and second capacitors are arranged at equal distances, so that the first and second capacitors form a differential capacitor, and the output signals form differential signals with equal amplitudes and opposite phases. Compared with the original structure, the signal output by the microphone is doubled, the sensitivity is increased by 6dB, the quality of the collected vibration signal is obviously improved, and the product performance can be improved.

In one embodiment of the present application, as shown in fig. 1, the plate 102 is a rigid semiconductor material. In the structure, when external signals are input into the MEMS chip, the rigid material can meet the condition that the polar plate is not deformed, the interval formed by the polar plate and the first vibrating diaphragm is not changed, and the output of other signals is not influenced. The material of the rigid polar plate can be a commonly used semiconductor material, such as silicon, polysilicon and the like, and the semiconductor material also comprises an insulating dielectric layer, wherein the material of the insulating dielectric layer can be a silicon nitride material or other materials meeting the requirements.

In a specific embodiment of the present application, as shown in fig. 5, the MEMS chip further includes a second MEMS structure, where the second MEMS structure includes: a second base structure 113 including two second base portions disposed at intervals; the material of the second base structure may be silicon, gallium arsenide, or other semiconductor materials, and the second base structure may be a structure as shown in fig. 2, or may be any structure that meets the above requirements. A third back plate 110 located at a side between the two second base portions and away from the second base portions, and having both ends connected to the two second base portions, respectively, the third back plate 110 having a through hole; the third back electrode plate is made of other semiconductor materials such as polysilicon and monocrystalline silicon, and is used as a capacitor electrode plate, and the through hole can be round, square, elliptic or other shapes. A second diaphragm 111 disposed on one side of the second base portion of the third back electrode plate 110 between the two second base portions, and having two ends connected to the two second base portions, wherein the second diaphragm 111 has a through hole, and a third space 114 is provided between the third back electrode plate 110 and the second diaphragm 111; the signal is transmitted to a second diaphragm in the second MEMS structure and forces the second diaphragm to displace in response, resulting in a change in a third separation between the second diaphragm and a third backplate, which in turn results in a change in capacitance. A third electrode, located on one side of the third back electrode plate 110 of the second base structure 113, and connected to the third back electrode plate 110; the third electrode is used for outputting an electric signal and further processing, and the material of the third electrode can be conductive materials such as copper, graphite tungsten alloy and the like. The first MEMS structure is connected to the second MEMS structure, and the first diaphragm 104 is located between the third back plate 110 and the first back plate 103. In a practical configuration, as shown in fig. 5, the structure further includes a second back plate, where the second back plate is located between the third back plate and the first diaphragm. In the MEMS chip structure described above, the first MEMS structure constitutes a first differential unit, and the second MEMS structure constitutes a second differential unit. The MEMS chip structure forms two groups of signal collection arrays and two differential output units, can output two groups of differential signals in parallel, and improves the product performance.

In a specific embodiment of the present application, the second MEMS structure further includes: a fourth back plate 112 located at one side of the second base portion of the second diaphragm 111 between the two second base portions, and having both ends connected to the two second base portions, respectively, the fourth back plate 112 having a through hole, and a fourth space 115 being provided between the fourth back plate 112 and the second diaphragm 111; the fourth back electrode plate is made of other semiconductor materials such as polysilicon and monocrystalline silicon, and is used as a capacitor electrode plate, and the shape of the through hole can be round, square, elliptic or other shapes. The structure is provided with the fourth back electrode plate, the third back electrode plate and the second vibrating diaphragm form a third interval, and then a third capacitor is formed, and the fourth back electrode plate and the second vibrating diaphragm form a fourth interval, so that a fourth capacitor is formed. And the fourth electrode is positioned on one side of the fourth back electrode plate of the second substrate structure and is connected with the fourth back electrode plate. The fourth electrode is used for outputting an electric signal and further processing, and the material of the fourth electrode can be conductive materials such as copper, graphite tungsten alloy and the like. When external signals enter the MEMS chip, the third interval and the fourth interval are changed due to the vibration of the second vibrating diaphragm, and then the capacitance values of the corresponding third capacitor and fourth capacitor are changed to respectively serve as signal output units, signals are respectively output through the third electrode and the fourth electrode, a plurality of signals can be output, and the sensitivity and the signal to noise ratio of the MEMS microphone can be improved through the output accumulation of different output units.

In a specific embodiment of the present application, the third interval 114 is equal to the fourth interval 115. In the structure, as the distance between the third interval and the fourth interval is equal, the third capacitor and the fourth capacitor form a differential capacitor, the output signals form differential signals with equal amplitude and opposite phases, compared with the original structure, the output signals of the microphone are doubled, the sensitivity is increased by 6dB, the quality of collecting vibration signals is obviously improved, and the product performance can be improved.

In another specific embodiment of the present application, as shown in fig. 5, the first base portion has a first protrusion 116, the first protrusion 116 is located on a side of the first base portion away from the plate, the second base portion has a second protrusion 117, the second protrusion 117 is located on a side of the third back plate of the second base portion away from the second diaphragm, the first protrusion 116 and the first diaphragm form a first groove 118, and the second protrusion 117 and the third back plate form a second groove 119. In a practical configuration, as shown in fig. 5, the structure further includes a second back plate, where the second back plate is located between the third back plate and the first diaphragm. The pressure relief groove is formed at the joint between the two groups of differential units, and the groove structure can be that one differential unit is independently provided with one groove, or the two differential units share one groove, and the structure shown in fig. 5 is that the two differential units are respectively provided with one groove. The structure can reduce the vibration resistance of the diaphragm and reduce vibration damping. In addition, the structure increases the distance of the signal output unit, which is beneficial to reducing signal interference.

In another exemplary embodiment of the present application, there is provided a MEMS microphone structure, as shown in fig. 6, including:

a wiring board 400, wherein the wiring board 400 has an acoustic hole 401;

in the above structure, the wiring board provides structural support for the MEMS chip and the ASIC chip, and is connected to the ASIC chip. External signals enter the MEMS chip through the sound holes of the circuit board.

Any one of the MEMS chips 100, wherein the MEMS chip 100 is connected to the wiring board 400;

in the MEMS microphone structure, the MEMS chip is configured to convert an external sound signal into an electrical signal, and then transmit the electrical signal to the ASIC chip through the electrode for further processing. The MEMS chip is connected with the ASIC chip in a bonding mode.

An ASIC chip 200, wherein the ASIC chip 200 is connected to at least one electrode of the MEMS chip 100 and to the wiring board 400;

in the above structure, the ASIC chip is used for processing the electrical signal output by the MEMS chip, and the ASIC chip is connected with the circuit board by bonding.

And a case 300 disposed on the circuit board 400 and covering the MEMS chip 100 and the ASIC chip 200.

The MEMS microphone housing may be a metallic material that serves to protect the MEMS chip, ASIC chip, and circuit board.

As shown in fig. 7, when the external mixed signal enters the MEMS chip through the sound control on the circuit board, the plate 102 filters out the sound signal, and only the residual vibration signal enters the MEMS chip. Then, the first diaphragm 104 and the second diaphragm 111 displace in response to the vibration signal, resulting in a change in differential capacitance. For example, the first and second intervals 107 and 108 form differential positive signals 1 to n and differential negative signals 1 to n, respectively, and the third and fourth intervals 114 and 115 form differential positive signals 1 to n and differential negative signals 1 to n, respectively. And outputting a differential signal through the first electrode and the second electrode in parallel. Finally, further signal processing takes place in the ASIC chip 200.

From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects:

1) In the MEMS structure, through the polar plate that does not have the through-hole, make sound signal unable entering MEMS chip inside, only vibration signal can get into inside the MEMS chip, reach the purpose of effectively picking up vibration signal and filtering sound signal to realized improving accuracy and the quality of collecting vibration signal, alleviateed the unable problem of effectively collecting vibration signal of MEMS microphone.

2) In the MEMS microphone structure, when external mixed signals enter the MEMS chip through sound control on the circuit board, the polar plate filters out sound signals, and only residual vibration signals enter the MEMS chip. Then, the first diaphragm and the second diaphragm are displaced in response to the vibration signal, resulting in a change in the differential capacitance value, and the differential signal is output through the first electrode and the second electrode. Finally, further signal processing takes place in the ASIC chip.

The foregoing description is only of the preferred embodiments of the present application and is not intended to limit the same, but rather, various modifications and variations can be made by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims (9)

1. A MEMS chip comprising a first MEMS structure, wherein the first MEMS structure comprises:

a first base structure including two first base portions disposed at intervals;

the polar plate is positioned between the two first substrate parts, two ends of the polar plate are respectively connected with the two first substrate parts, and the polar plate is not provided with a through hole;

the first back electrode plate is positioned at one side of the electrode plate between the two first substrate parts, two ends of the first back electrode plate are respectively connected with the two first substrate parts, and the first back electrode plate is provided with a through hole;

the first vibrating diaphragm is positioned at one side of the first back electrode plate between the two first substrate parts, which is far away from the electrode plate, and two ends of the first back electrode plate are respectively connected with the two first substrate parts, the first vibrating diaphragm is provided with a through hole, and a first interval is arranged between the first back electrode plate and the first vibrating diaphragm;

the first electrode is positioned on one side of the first substrate structure far away from the polar plate and is connected with the first back polar plate.

2. The MEMS chip of claim 1, wherein the first MEMS structure further comprises:

the second back electrode plate is positioned at one side of the first vibrating diaphragm between the two first substrate parts, which is far away from the electrode plate, and two ends of the second back electrode plate are respectively connected with the two first substrate parts, the second back electrode plate is provided with a through hole, and a second interval is arranged between the second back electrode plate and the first vibrating diaphragm;

and the second electrode is positioned on one side of the first substrate structure far away from the polar plate and is connected with the second back polar plate.

3. The MEMS chip of claim 2, wherein the first spacing is equal to the second spacing.

4. The MEMS chip of claim 1, wherein the plate is a rigid semiconductor material.

5. The MEMS chip of claim 1, further comprising a second MEMS structure, the second MEMS structure comprising:

a second base structure comprising two second base portions disposed at intervals;

the third back electrode plate is positioned on one side, far away from the second base parts, between the two second base parts, and two ends of the third back electrode plate are respectively connected with the two second base parts, and the third back electrode plate is provided with a through hole;

the second vibrating diaphragm is positioned on one side of the second base part of the third back electrode plate between the two second base parts, two ends of the second vibrating diaphragm are respectively connected with the two second base parts, the second vibrating diaphragm is provided with a through hole, and a third interval is arranged between the third back electrode plate and the second vibrating diaphragm;

the third electrode is positioned at one side of the third back electrode plate of the second substrate structure and is connected with the third back electrode plate;

the first MEMS structure is connected with the second MEMS structure, and the first vibrating diaphragm is positioned between the third back electrode plate and the first back electrode plate.

6. The MEMS chip of claim 5, wherein the second MEMS structure further comprises:

the second vibrating diaphragm is arranged between the first base parts, the second base parts are arranged on one side of the second vibrating diaphragm, two ends of the second vibrating diaphragm are respectively connected with the first base parts, the second base parts are provided with a plurality of through holes, and a second interval is arranged between the second vibrating diaphragm and the second vibrating diaphragm;

and the fourth electrode is positioned at one side of the fourth back electrode plate of the second substrate structure and is connected with the fourth back electrode plate.

7. The MEMS chip of claim 6, wherein the third spacing is equal to the fourth spacing.

8. The MEMS chip of claim 5, wherein the first base portion has a first protrusion on a side of the first base portion remote from the plate, the second base portion has a second protrusion on a side of the third backplate of the second base portion remote from the second diaphragm, the first protrusion and the first diaphragm forming a first groove, and the second protrusion and the third backplate forming a second groove.

9. A MEMS microphone structure, the MEMS microphone structure comprising:

a circuit board having an acoustic port;

the MEMS chip of any one of claims 1 to 8, which is connected to the wiring board;

the ASIC chip is connected with at least one electrode of the MEMS chip and is connected with the circuit board;

and the shell is positioned on the circuit board and covers the MEMS chip and the ASIC chip.