MEMS device, sensor and electronic equipment

Abstract

The embodiment of the invention provides an MEMS device, a sensor and an electronic device, the MEMS device comprises a matrix diaphragm and a back electrode, the back electrode is arranged on one side, away from the matrix, of the diaphragm, and a first cavity is formed between the back electrode and the diaphragm; a resonant cavity is formed in the back electrode, a first through hole and a second through hole are formed in the back electrode, the resonant cavity can be communicated with the outside through the first through hole, the resonant cavity and the first cavity are communicated through the second through hole, different vibration signals generated by different gases can be subjected to intensity detection, and screening of the vibration signals with different frequencies is achieved; and the detection accuracy of the MEMS device on different target gas concentrations in the gas sensor is improved.

Description

Technical Field

[0001] The present application belongs to the technical field of acoustic-to-electric conversion, and specifically, the present application relates to a MEMS device, a sensor and an electronic device. Background Art

[0002] In the field of acoustic-to-electric conversion technology, MEMS (Micro Electromechanical System) devices can convert information such as pressure into electrical signals or other usable signals, thereby achieving accurate measurement and monitoring of various parameters.

[0003] For example, in the application of gas sensors, MEMS devices can collect airflow information to monitor parameters such as gas pressure. However, when monitoring mixed gases with multiple components, the relevant gas sensors lack the ability to distinguish the different wavelengths of information generated by different gas vibrations, which affects the accuracy and reliability of gas concentration detection. Summary of the invention

[0004] One purpose of the embodiments of the present application is to provide a new technical solution for MEMS devices, sensors and electronic devices.

[0005] According to a first aspect of an embodiment of the present application, a MEMS device is provided, the MEMS device comprising:

[0006] matrix;

[0007] A diaphragm, wherein the diaphragm is arranged on the substrate;

[0008] A back pole, the back pole is arranged on a side of the diaphragm away from the substrate and forms a first cavity with the diaphragm;

[0009] The back pole has a resonance cavity therein, and a first through hole and a second through hole are provided on the back pole. The first through hole can connect the resonance cavity to the outside, and the second through hole connects the resonance cavity and the first cavity.

[0010] Optionally, the ratio of the cross-sectional dimension of the first through hole to the cross-sectional dimension of the resonance cavity is (0.005-0.02):1;

[0011] The ratio of the cross-sectional dimension of the first through hole to the cross-sectional dimension of the second through hole is 1:(0.4-1).

[0012] Optionally, the back pole has a plurality of resonance cavities therein, and a plurality of first through holes are provided on the back pole, and the plurality of first through holes are connected to the plurality of resonance cavities one-to-one.

[0013] Optionally, a plurality of groups of second through holes are provided on the back pole, and the plurality of groups of second through holes are connected one-to-one with the plurality of resonance cavities.

[0014] Optionally, each group of the second through holes includes a plurality of sub-through holes, and the plurality of sub-through holes are connected to the resonance cavity and the first cavity.

[0015] Optionally, the plurality of sub-through holes enclose an annular area, and a projection of the annular area on the diaphragm is located within a range of a projection of the resonance cavity on the diaphragm;

[0016] The projection of the first through hole on the diaphragm is located within the range of the projection of the annular area on the diaphragm.

[0017] Optionally, a plurality of protrusions are provided on a side of the back pole close to the diaphragm, and the protrusions are used to separate the back pole from the diaphragm.

[0018] Optionally, a second cavity is provided in the base, a through hole is provided on the diaphragm, and the through hole connects the first cavity and the second cavity.

[0019] According to a second aspect of an embodiment of the present application, a sensor is provided, wherein the sensor includes the MEMS device described in the first aspect.

[0020] According to a third aspect of the embodiments of the present application, an electronic device is provided, wherein the electronic device includes the MEMS device according to the first aspect; or,

[0021] Includes the sensor described in the second aspect.

[0022] A technical effect of this application is:

[0023] An embodiment of the present application provides a MEMS device, which includes a substrate diaphragm and a back pole, wherein the back pole is arranged on the side of the diaphragm away from the substrate and forms a first cavity between the back pole and the diaphragm; a resonance cavity is provided in the back pole, and a first through hole and a second through hole are provided on the back pole, wherein the first through hole can connect the resonance cavity to the outside, and the second through hole connects the resonance cavity and the first cavity, and can conduct intensity measurement of different vibration signals generated by different gases, realize screening of vibration signals of different frequencies, and improve the accuracy of the MEMS device in detecting different target gas concentrations in the gas sensor.

[0024] Other features and advantages of the present application will become apparent from the following detailed description of exemplary embodiments of the present application with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the application and, together with the description, serve to explain the principles of the application.

[0026] Figure 1A top view of a MEMS device provided in one embodiment of the present application;

[0027] Figure 2 for Figure 1 The cross-section diagram at AB in the middle;

[0028] Figure 3 for Figure 2 A partial enlarged view of the .

[0029] Among them: 1. substrate; 11. second cavity; 2. diaphragm; 21. through hole; 3. back pole; 31. resonance cavity; 32. first through hole; 33. second through hole; 34. protrusion; 35. conductive film; 4. first cavity; 5. solder pad. DETAILED DESCRIPTION

[0030] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application.

[0031] The embodiments of the present application will be described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and should not be understood as limiting the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0032] The term "first" or "second" in the specification and claims of this application may include one or more of the features explicitly or implicitly. In the description of this application, unless otherwise specified, "plurality" means two or more. In addition, "and / or" in the specification and claims means at least one of the connected objects, and the character " / " generally means that the objects connected before and after are in an "or" relationship.

[0033] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0034] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0035] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0036] MEMS devices can be used to detect physical, chemical or biological phenomena in the environment, such as acceleration, angular velocity, pressure, temperature, humidity and gas composition. MEMS devices can convert these environmental phenomena into electrical signals, thereby achieving measurement and monitoring of various environmental parameters.

[0037] For example, when MEMS devices are used in gas sensors, the gas sensors in related technologies lack the ability to distinguish different gases in a mixed gas, making it difficult to measure the concentrations of different components.

[0038] The MEMS device provided in the embodiment of the present application includes a base diaphragm and a back pole, wherein the back pole is arranged on the side of the diaphragm away from the base and forms a first cavity between the back pole and the diaphragm; a resonance cavity is provided in the back pole, and a first through hole and a second through hole are provided on the back pole, wherein the first through hole can connect the resonance cavity to the outside, and the second through hole connects the resonance cavity and the first cavity, and can strengthen different vibration signals generated by different gases, realize the screening of vibration signals of different frequencies, improve the accuracy of the MEMS device in detecting different target gas concentrations in the gas sensor, and ensure the accuracy and reliability of gas concentration detection.

[0039] Reference Figure 1 and Figure 2 , an embodiment of the present application provides a MEMS device, the MEMS device comprising:

[0040] Matrix 1;

[0041] A diaphragm 2, wherein the diaphragm 2 is arranged on the base 1;

[0042] A back pole 3, which is arranged on a side of the diaphragm 2 away from the substrate 1 and forms a first cavity 4 with the diaphragm 2;

[0043] The back pole 3 has a resonance cavity 31 therein. A first through hole 32 and a second through hole 33 are provided on the back pole 3 . The first through hole 32 can connect the resonance cavity 31 to the outside, and the second through hole 33 connects the resonance cavity 31 and the first cavity 4 .

[0044] In this embodiment, the base 1 is used to arrange and support the diaphragm 2 and the back pole 3, so as to ensure the arrangement stability of the diaphragm 2 and the back pole 3 while facilitating the diaphragm 2 and the back pole 3 to be arranged apart from each other.

[0045] The material of the diaphragm 2 can be polysilicon, so that the diaphragm 2 forms a movable thin film structure; see Figure 2 The main material of the back electrode 3 is silicon nitride, and a layer of conductive film 35 is embedded inside the silicon nitride. The material of the conductive film 35 can be a polycrystalline silicon film, so that the diaphragm 2 and the back electrode 3 form two plates of a capacitor; since a first cavity 4 is formed between the back electrode 3 and the diaphragm 2 to facilitate the vibration of the diaphragm 2, the distance between the diaphragm 2 and the back electrode 3 is changed by the vibration of the diaphragm 2, thereby sensing environmental signals such as vibration, temperature and humidity outside the MEMS device.

[0046] See also Figure 1 and Figure 2 Two externally connected pads 5 are provided on the back pole 3, one pad 5 is electrically connected to the diaphragm 2, and the other pad 5 is electrically connected to the conductive film 35. The two pads 5 serve as signal transmission interfaces of the MEMS device to convert the vibration signal into an electrical signal and transmit it to the processing circuit, so that the processing circuit can analyze and process the electrical signal.

[0047] In one embodiment, the back electrode 3 can form a resonance cavity 31 in the back electrode 3 by multiple deposition and etching, and a first through hole 32 and a second through hole 33 are respectively formed at both ends of the resonance cavity 31. The second through hole 33 connects the resonance cavity 31 and the first through hole 32 to the first cavity 4. The sound pressure outside the MEMS device is transmitted to the first cavity 4 through the first through hole 32, the resonance cavity 31 and the second through hole 33. The change in sound pressure in the first cavity 4 will cause the diaphragm to deform, and then the capacitance value of the capacitor formed by the diaphragm 2 and the back electrode 3 will change to achieve the purpose of signal monitoring.

[0048] In this embodiment, see Figure 3 , S is the cross-sectional area of ​​the first through hole 32, L is the extended length of the first through hole 32, the cross-sectional area of ​​the first through hole 32 is smaller than the cross-sectional area of ​​the resonance cavity 31, and the cross-sectional area of ​​the second through hole 33 is smaller than the cross-sectional area of ​​the resonance cavity 31, so as to form a vibration channel with small ends and large middle; different gases will generate vibration wavelength signals of different frequencies when vibrating, and by adjusting the size of the vibration channel, the vibration channel can resonate with the vibration signal of the corresponding wavelength, thereby enhancing the intensity of the vibration signal of the corresponding wavelength and realizing the concentration monitoring of the corresponding gas of the corresponding wavelength.

[0049] Specifically, according to the Helmholtz resonance principle, the cavity resonance frequency

[0050] Wherein, c is the speed of sound, V is the volume of the resonance cavity 31, and by adjusting the S, V, and L parameters, the resonance of vibration signals of different frequencies can be achieved, thereby realizing the concentration monitoring of different gas components.

[0051] Optionally, in Figure 3 In the vertical direction shown, the ratio of the extension length of the resonance cavity 31 to the extension length of the first through hole 32 is greater than 10, for example, the ratio of the extension length of the resonance cavity 31 to the extension length of the first through hole 32 is 12, 18, 25, 30, 40 or 50, so as to increase the volume of the resonance cavity 31 and enhance the intensity of the resonance response of the vibration signal of the corresponding wavelength in the resonance cavity 31.

[0052] In this embodiment, since the cross-sectional areas of the first through hole 32 and the second through hole 33 are both smaller than the cross-sectional area of ​​the resonance cavity 31, different vibration signals generated by different gases will form multiple reflections inside the vibration channel when entering the resonance cavity 31; and by adjusting the size of the cavity inside the vibration channel, the pass rate of the target frequency vibration signal can be improved, thereby effectively improving the MEMS device's pickup of the target signal.

[0053] In a specific embodiment, when a MEMS device is applied to a gas sensor, due to the complex composition of the gas detected by the gas sensor, the gas sensor designed in the related art has difficulty in distinguishing the signals generated by different gas vibrations, and is therefore unable to collect effective vibration signals, thus affecting the accuracy of detecting different gas concentrations.

[0054] In the MEMS device provided in the embodiment of the present application, a micropore formed by a first through hole 32 and a second through hole 33 and a resonance cavity 31 connected to the micropore are arranged in the back pole 3, and gas molecules excited by infrared signals or the like can generate vibration signals. When the vibration signal generated by the gas enters the resonance cavity 31 through the micropore, it will be reflected inside the resonance cavity 31, so as to change the transmission path of the vibration signal and enhance the intensity of the vibration signal. Moreover, the MEMS device provided in the embodiment of the present application can enhance the intensity of different vibration signals generated by different gases, realize the screening of vibration signals of different frequencies, and enhance the accuracy of the MEMS device in detecting different target gas concentrations in the gas sensor, thereby ensuring the accuracy and reliability of gas concentration detection.

[0055] In some embodiments, the ratio of the cross-sectional dimension of the first through hole 32 to the cross-sectional dimension of the resonance cavity 31 is (0.005-0.02):1;

[0056] The ratio of the cross-sectional dimension of the first through hole 32 to the cross-sectional dimension of the second through hole 33 is 1:(0.4-1).

[0057] In the above embodiment, the first through hole 32 can be a circular through hole, the resonance cavity 31 is a cylindrical cavity, the centers of the first through hole 32 and the resonance cavity 31 are opposite to each other, and in a cross section perpendicular to the axial direction of the first through hole 32 and the resonance cavity 31, the cross-sectional size of the first through hole 32 is smaller than the cross-sectional size of the resonance cavity 31, so that a cup-shaped structure is formed by the first through hole 32.

[0058] The cross-sectional size of the second through hole 33 is smaller than or equal to the cross-sectional size of the first through hole 32 , so as to increase the multiple reflections of the gas in the resonance cavity 31 and improve the signal intensity generated when the gas molecules vibrate in the resonance cavity 31 .

[0059] Specifically, the ratio of the cross-sectional size of the first through hole 32 to the cross-sectional size of the resonance cavity 31 can be 0.008:1, 0.010:1, 0.012:1, 0.015:1 or 0.018:1, so as to facilitate the gas molecules to enter the resonance cavity 31 through the first through hole 32, while enhancing the vibration reflection of the gas molecules in the resonance cavity 31 and improving the signal strength generated by the vibration of the gas molecules.

[0060] In other embodiments, the first through hole 32 can be a triangular through hole, a square through hole or a polygonal (pentagonal or more polygonal) through hole, and the resonance cavity 31 can be a triangular prism cavity, a square prism cavity or a polygonal cavity, all of which can enhance the gas molecule vibration signal.

[0061] In some embodiments, see Figure 1 and Figure 2 The back pole 3 has a plurality of resonance cavities 31 , and a plurality of first through holes 32 are provided on the back pole 3 . The plurality of first through holes 32 are connected to the plurality of resonance cavities 31 in a one-to-one manner.

[0062] In the above embodiment, the first through hole 32 connects the resonance cavity 31 to the outside, and the number of the first through holes 32 can be equal to the number of the resonance cavities 31. One first through hole 32 corresponds to one resonance cavity 31. By connecting multiple resonance cavities 31 in parallel, vibration signals of different frequencies can be further enhanced, thereby effectively improving the signal strength generated by the target gas and ensuring the accuracy of the concentration detection of the target gas.

[0063] In the above embodiment, a plurality of groups of first through holes 32 are provided on the back pole 3. A group of first through holes 32 may include a plurality of first through holes 32. A group of first through holes 32 corresponds to connecting one resonance cavity 31 to increase the gas path of the airflow from the first through holes 32 into the resonance cavity 31, thereby enhancing the amplitude of gas reflection in the resonance cavity 31.

[0064] In some embodiments, see Figure 1 and Figure 2A plurality of groups of second through holes 33 are provided on the back pole 3 , and the plurality of groups of second through holes 33 are connected one-to-one with the plurality of resonance cavities 31 .

[0065] In the above embodiment, the second through holes 33 connect the resonance cavity 31 and the first cavity 4 together, and the cross-sectional size of each group of second through holes 33 is smaller than the cross-sectional size of the resonance cavity 31, that is, the sum of the cross-sectional sizes of a group of multiple first through holes 32 is smaller than the cross-sectional size of the resonance cavity 31; a group of first through holes 32 corresponds to connecting one resonance cavity 31 to the first cavity 4, which can facilitate the enhancement of vibration signals of different frequencies in the resonance cavity 31, and at the same time, realize the vibration of the diaphragm 2 by transmitting the vibration signal to the first cavity 4, thereby achieving the purpose of monitoring vibration signals of different frequencies.

[0066] In one embodiment, see Figure 2 and Figure 3 Each group of second through holes 33 includes a plurality of sub-through holes, and the plurality of sub-through holes are connected to the resonance cavity 31 and the first cavity 4 .

[0067] In this embodiment, multiple sub-through holes can form a circular ring structure, which is coaxial with the resonance cavity 31, balancing the flow distance from the resonance cavity 31 to each sub-through hole; and multiple sub-through holes connect one resonance cavity 31 to the first cavity 4, increasing the airflow path from the resonance cavity 31 to the first cavity 4, thereby improving the vibration efficiency of the diaphragm 2.

[0068] In some embodiments, see Figure 1 and Figure 2 , the multiple sub-through holes of each group of second through holes 33 enclose an annular area, and the projection of the annular area on the diaphragm 2 is located within the range of the projection of the resonance cavity 31 on the diaphragm 2;

[0069] The projection of the first through hole 32 on the diaphragm 2 is located within the range of the projection of the annular area on the diaphragm 2 .

[0070] In the above embodiment, Figure 1 is a top view of the MEMS device, each sub-through hole can be as follows Figure 1 The small holes shown by the dotted circle, the multiple sub-through holes of each group of second through holes 33 are connected to the same resonance cavity 31 to the first cavity 4, increasing the airflow path from the resonance cavity 31 to the first cavity 4; and the projection of the first through hole 32 on the diaphragm 2 is located at the center of the annular area, that is, the first through hole 32 and the second through hole 33 are staggered on the upper and lower sides of the resonance cavity 31, so that after the gas enters the resonance cavity 31 from the first through hole 32, it will not be directly output from the second through hole 33, but will form multiple reflections in the resonance cavity 31, increasing the intensity of the target gas vibration signal, thereby effectively improving the MEMS device to pick up the target gas concentration signal, and improving the accuracy of the target gas concentration test.

[0071] In some embodiments, see Figure 2 and Figure 3 A plurality of protrusions 34 are provided on one side of the back pole 3 close to the diaphragm 2 , and the protrusions 34 are used to separate the back pole 3 and the diaphragm 2 .

[0072] In the above embodiment, when the gas vibration signal is transmitted to the first cavity 4, the diaphragm 2 is driven to vibrate, so as to detect vibration signals of different frequencies. The diaphragm 2 will vibrate back and forth between approaching and moving away from the back pole 3. To prevent the diaphragm 2 from sticking to the back pole 3 when approaching the back pole 3, the diaphragm 2 can be separated from the back pole 3 by a plurality of protrusions 34 provided on the back pole 3, so as to reduce the contact area between the back pole 3 and the diaphragm 2, so that the diaphragm 2 can be quickly separated after approaching the back pole 3.

[0073] In a specific embodiment, the protrusion 34 can be an elastic body such as plastic or rubber. The protrusion 34 can be slightly compressed when the diaphragm 2 is close to the back pole 3. After compression, the protrusion 34 will generate elastic potential energy, which can bounce the diaphragm 2 away from the back pole 3, thereby ensuring the flexibility of the vibration of the diaphragm 2.

[0074] In some embodiments, see Figure 2 A second cavity 11 is disposed in the base 1 , and a through hole 21 is disposed on the diaphragm 2 . The through hole 21 connects the first cavity 4 and the second cavity 11 .

[0075] In the above embodiment, the first cavity 4 and the second cavity 11 are respectively formed on both sides of the diaphragm 2 so as to provide a vibration space for the reciprocating vibration of the diaphragm 2; one or more through holes 21 can be set on the diaphragm 2, and the first cavity 4 and the second cavity 11 are connected through the through holes 21, which can prevent the pressure in one of the first cavity 4 and the second cavity 11 from being too high and crushing the diaphragm 2, and prevent the pressure in one of the first cavity 4 and the second cavity 11 from being too low and hindering the vibration of the diaphragm 2, thereby realizing flexible vibration of the diaphragm 2 on the basis of ensuring the structural integrity of the diaphragm 2.

[0076] An embodiment of the present application also provides a sensor, which includes the above-mentioned MEMS device.

[0077] In the above embodiments, the sensor may be an airflow sensor, a vibration sensor, a flow sensor or a pressure sensor, so as to monitor the gas composition, vibration intensity, flow rate or air pressure in the airflow through a MEMS device, thereby improving the efficiency and accuracy of monitoring.

[0078] Specifically, in the MEMS device of the sensor, a first through hole 32, a second through hole 33 and a resonance cavity 31 are arranged in the back pole 3. When the vibration signal generated by the gas enters the resonance cavity 31 through the first through hole 32, it will be reflected inside the resonance cavity 31, so as to enhance the strength of the vibration signal. Moreover, the MEMS device can enhance the strength of different vibration signals generated by different gases, realize the screening of vibration signals of different frequencies, and enhance the accuracy of the MEMS device in detecting different target gas concentrations in the gas sensor, thereby ensuring the accuracy and reliability of gas concentration detection.

[0079] The embodiment of the present application further provides an electronic device, which includes the above-mentioned MEMS device; or,

[0080] Including the above-mentioned sensor.

[0081] In the above embodiments, the electronic device includes but is not limited to one of a speaker, a microphone, a smart watch, a mobile phone, a tablet computer, an e-book reader, an audio player, a video player, a computer, a set-top box, a smart TV, and a wearable device.

[0082] The MEMS device of the electronic device includes a substrate diaphragm and a back pole, wherein the back pole is arranged on the side of the diaphragm away from the substrate and forms a first cavity with the diaphragm; a resonance cavity is provided in the back pole, and a first through hole and a second through hole are provided on the back pole, wherein the first through hole can connect the resonance cavity to the outside, and the second through hole connects the resonance cavity and the first cavity, and can conduct intensity measurement of different vibration signals generated by different gases, realize screening of vibration signals of different frequencies, improve the accuracy of the MEMS device in detecting different target gas concentrations in the gas sensor, and ensure the accuracy and reliability of gas concentration detection.

[0083] Although some specific embodiments of the present application have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are only for illustration, not for limiting the scope of the present application. It should be understood by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. A MEMS device, characterized in that: include: Matrix (1); A diaphragm (2), wherein the diaphragm (2) is arranged on the base (1); a back pole (3), the back pole (3) being arranged on a side of the diaphragm (2) away from the substrate (1) and forming a first cavity (4) between the back pole (3) and the diaphragm (2); The back pole (3) has a resonance cavity (31) therein, and the back pole (3) is provided with a first through hole (32) and a second through hole (33), wherein the first through hole (32) can connect the resonance cavity (31) to the outside, and the second through hole (33) connects the resonance cavity (31) and the first cavity (4).

2. The MEMS device according to claim 1, characterized in that: The ratio of the cross-sectional dimension of the first through hole (32) to the cross-sectional dimension of the resonance cavity (31) is (0.005-0.02):1; The ratio of the cross-sectional dimension of the first through hole (32) to the cross-sectional dimension of the second through hole (33) is 1:(0.4-1).

3. The MEMS device according to claim 1, characterized in that: The back pole (3) has a plurality of resonance cavities (31) therein, and a plurality of first through holes (32) are provided on the back pole (3), wherein the plurality of first through holes (32) are connected one-to-one with the plurality of resonance cavities (31).

4. The MEMS device according to claim 3, characterized in that: The back pole (3) is provided with a plurality of groups of second through holes (33), and the plurality of groups of second through holes (33) are connected one-to-one with the plurality of resonance cavities (31).

5. The MEMS device according to claim 4, characterized in that: Each group of the second through holes (33) comprises a plurality of sub-through holes, and the plurality of sub-through holes are connected to the resonance cavity (31) and the first cavity (4).

6. The MEMS device according to claim 5, characterized in that: The plurality of sub-through holes enclose an annular area, and the projection of the annular area on the diaphragm (2) is located within the range of the projection of the resonance cavity (31) on the diaphragm (2); The projection of the first through hole (32) on the diaphragm (2) is located within the range of the projection of the annular area on the diaphragm (2).

7. The MEMS device according to claim 1, characterized in that: A plurality of protrusions (34) are provided on one side of the back pole (3) close to the diaphragm (2), and the protrusions (34) are used to separate the back pole (3) and the diaphragm (2).

8. The MEMS device according to claim 1, characterized in that: A second cavity (11) is arranged in the base (1), a through hole (21) is arranged on the diaphragm (2), and the through hole (21) connects the first cavity (4) and the second cavity (11).

9. A sensor, characterized in that: A MEMS device comprising any one of claims 1 to 8.

10. An electronic device, characterized in that: A MEMS device comprising any one of claims 1 to 8; or Comprising the sensor as claimed in claim 9.

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