Pressure sensor, preparation method thereof and MEMS chip

Abstract

The embodiment of the invention provides a pressure sensor, a preparation method thereof and an MEMS chip. The pressure sensor includes a first support, a second support, a support wall, a first electrode, and a second electrode. The first supporting piece is an elastic film layer; the second supporting piece and the first supporting piece are oppositely arranged; the supporting wall is arranged between the first supporting piece and the second supporting piece and fixedly connected with the first supporting piece and the second supporting piece to form a sealed cavity. The first electrode is located between the first supporting piece and the second supporting piece; the first electrode comprises a plurality of first sub-electrodes; the first sub-electrode extends from the first supporting piece to the direction close to the second supporting piece; the second electrode is located between the first supporting piece and the second supporting piece; the second electrode comprises a plurality of second sub-electrodes; the second sub-electrode extends from the second supporting piece to the direction close to the first supporting piece; the first sub-electrodes and the second sub-electrodes are alternately arranged in the first direction at intervals. The pressure sensor provided by the embodiment of the invention is higher in precision.

Description

Technical Field

[0001] The present invention relates to the field of sensor technology, and in particular to a pressure sensor and a preparation method thereof, and a MEMS chip. Background Art

[0002] Capacitive pressure sensor detection technology has the characteristics of good power consumption control, good consistency and mature process, so it is widely used in various industries. With the continuous development of sensor technology, higher requirements are put forward for the sensitivity of sensors. Capacitive pressure sensors in related technologies are usually variable-pole-distance capacitive pressure sensors, including two parallel plate electrodes set opposite to each other. The capacitance is changed by changing the distance between the two electrodes. The accuracy is low, which limits its application scenarios. Summary of the invention

[0003] The purpose of the embodiment of the present invention is to provide a pressure sensor and a method for manufacturing the same, and a MEMS chip, so as to improve the sensitivity of the pressure sensor. The specific technical solution is as follows:

[0004] The embodiment of the first aspect of the present application proposes a pressure sensor, which includes a first support member, a second support member, a support wall, a first electrode, and a second electrode. The first support member is an elastic membrane layer; the second support member is arranged opposite to the first support member; the support wall is arranged between the first support member and the second support member, and is fixedly connected to the two; the support wall, the first support member, and the second support member together constitute a sealed cavity; the first electrode is fixedly arranged on the first support member and is located between the first support member and the second support member; the first electrode includes a plurality of first sub-electrodes; the first sub-electrode extends from the first support member to a direction close to the second support member; the second electrode is fixedly arranged on the second support member and is located between the first support member and the second support member; the second electrode includes a plurality of second sub-electrodes; the second sub-electrode extends from the second support member to a direction close to the first support member; the plurality of first sub-electrodes and the plurality of second sub-electrodes are alternately arranged in the first direction; the first direction is a direction parallel to the second support member.

[0005] In some embodiments of the present application, the plurality of first sub-electrodes are electrically connected to each other, and the plurality of second sub-electrodes are electrically connected to each other.

[0006] In some embodiments of the present application, the first electrode further includes a first connecting electrode, and the plurality of first sub-electrodes are electrically connected via the first connecting electrode; the first connecting electrode is formed on a first side of the first support member facing the second support member, and is connected to each of the first sub-electrodes at the first side;

[0007] The second electrode further includes a second connecting electrode, and the plurality of second sub-electrodes are electrically connected via the second connecting electrode; the second connecting electrode is formed on a second side of the second support member facing the first support member, and is connected to each of the second sub-electrodes at the second side.

[0008] In some embodiments of the present application, there are multiple first connection electrodes, and the multiple first connection electrodes and the multiple first sub-electrodes are alternately arranged and connected end to end;

[0009] The number of the second connecting electrodes is multiple, and the multiple second connecting electrodes and the multiple second sub-electrodes are alternately arranged and connected end to end;

[0010] The plurality of first connection electrodes and the plurality of second connection electrodes are alternately arranged at intervals in the second direction;

[0011] The second direction is parallel to the second support member and perpendicular to the first direction.

[0012] In some embodiments of the present application, the first electrode has a first output end; the first output end is formed at an end of the first connecting electrode or at an end of the first sub-electrode located at an edge position;

[0013] The second electrode has a second output end; the second output end is formed at an end of the second connecting electrode or at an end of the second sub-electrode located at an edge position.

[0014] In some embodiments of the present application, the first sub-electrode includes: a first insulating support structure in a plate shape and a first conductive structure covering a side wall of the first insulating support structure; a first end of the first insulating support structure is fixedly connected to the first support member, and a second end extends in a direction close to the second support member;

[0015] The second sub-electrode includes: a second plate-shaped insulating support structure and a second conductive structure covering the side wall of the second insulating support structure; the first end of the second insulating support structure is fixedly connected to the second support member, and the second end extends in a direction close to the first support member.

[0016] In some embodiments of the present application, the first sub-electrode includes: a plate-shaped first conductive structure and a first insulating support structure covering a side wall and a second end of the first conductive structure; the first end of the first conductive structure is fixedly connected to the first support member, and the second end extends in a direction close to the second support member;

[0017] The second sub-electrode includes: a second plate-shaped conductive structure and a second insulating support structure covering the side wall and the second end of the second conductive structure; the first end of the second conductive structure is fixedly connected to the second support member, and the second end extends in a direction close to the first support member.

[0018] In some embodiments of the present application, the first connecting electrode includes: a first conductive layer and a first insulating layer;

[0019] The first conductive layer is electrically connected to the first conductive structure of the first sub-electrode, and the first conductive layer is located at the end of the plurality of first conductive structures close to the first support member; the first insulating layer is located at a side of the first conductive layer away from the first support member, and covers the first conductive layer;

[0020] The second connecting electrode comprises: a second conductive layer and a second insulating layer;

[0021] The second conductive layer is electrically connected to the second conductive structure of the second sub-electrode, and the second conductive layer is located at the end of the multiple second conductive structures close to the second support member; the second insulating layer is located on the side of the second conductive layer away from the second support member and covers the second conductive layer.

[0022] In some embodiments of the present application, the first support member includes: a third insulating layer and a protective layer stacked in layers; the plurality of first sub-electrodes and the first connecting electrode are formed on a side of the third insulating layer facing the second support member;

[0023] The pressure sensor also includes: a fourth insulating layer; the second support member and the fourth insulating layer are stacked; the fourth insulating layer is arranged between the second electrode and the second support member; the plurality of second sub-electrodes and the second connecting electrode are formed on a side of the fourth insulating layer facing the first support member.

[0024] In some embodiments of the present application, in the first direction, the distance between the first sub-electrode and the second sub-electrode adjacent thereto is 1-5 μm.

[0025] In some embodiments of the present application, the first support member and the support wall are made of the same material.

[0026] In some embodiments of the present application, the orthographic projection of the first support member on the plane where the second support member is located has an overlapping area with the second support member.

[0027] An embodiment of the second aspect of the present application provides a method for preparing a pressure sensor, which is used to prepare the pressure sensor of any embodiment of the first aspect, comprising:

[0028] providing a second support member;

[0029] A second electrode and a support wall are prepared on a second support member; the support wall and the second support member form a receiving space;

[0030] Filling a sacrificial layer in the accommodation space and patterning the sacrificial layer;

[0031] preparing a first electrode on the sacrificial layer;

[0032] A first support member is prepared on the first electrode and the support wall, and the sacrificial layer is removed.

[0033] In some embodiments of the present application, the step of preparing the second electrode and the support wall on the second support member includes:

[0034] depositing a nitride layer on the second support;

[0035] Etching the nitride layer to form a support wall, a fourth insulating layer and a second insulating support structure;

[0036] A conductive film layer is formed on the sidewall of the second conductive structure and on the surface of the fourth insulating layer away from the second support member to form a second electrode;

[0037] The step of preparing the first electrode on the sacrificial layer comprises:

[0038] Etching the sacrificial layer to form a first groove;

[0039] preparing a conductive film layer on the sacrificial layer;

[0040] The conductive film layer is etched to form a through groove penetrating the conductive film layer in a third direction; a first insulating support structure is prepared in the through groove to form a first electrode.

[0041] In some embodiments of the present application, the step of preparing the second electrode and the support wall on the second support member includes:

[0042] Depositing a nitride layer on the second support member, and etching the nitride layer to form a second groove;

[0043] preparing a conductive film layer in the second groove;

[0044] depositing a nitride layer on the nitride layer and the conductive film layer;

[0045] Etching the nitride layer to form a support wall and a second insulating support structure; forming a second electrode;

[0046] The step of preparing the first electrode on the sacrificial layer comprises:

[0047] etching the sacrificial layer to form a third groove; depositing a nitride layer on the sacrificial layer;

[0048] Etching the nitride layer to form a fourth groove, a first insulating layer and a first insulating support structure;

[0049] A conductive film layer is prepared on the nitride layer; and a first electrode is formed.

[0050] An embodiment of the third aspect of the present application proposes a MEMS chip, comprising a first pin and a second pin and a pressure sensor of any embodiment of the first aspect; the first pin is electrically connected to the first electrode, and the second pin is electrically connected to the second electrode; the first pin and the second pin are used to be electrically connected to an external circuit.

[0051] In some embodiments of the present application, the MEMS chip further includes: a temperature-sensitive resistor, a third pin, and a fourth pin;

[0052] The temperature-sensitive resistor is arranged on the second supporting member;

[0053] The third pin and the fourth pin are used to be electrically connected to an external circuit; the third pin and the fourth pin are electrically connected to two output ends of the temperature-sensitive resistor respectively.

[0054] Beneficial effects of the embodiments of the present invention:

[0055] The pressure sensor of the embodiment of the present application includes a first electrode and a second electrode, the first electrode is fixedly arranged on the first support member, the first electrode includes a plurality of first sub-electrodes, and the first sub-electrodes extend from the first support member to the direction close to the second support member; the second electrode is fixedly arranged on the second support member, the second electrode includes a plurality of second sub-electrodes, and the second sub-electrodes extend from the second support member to the direction close to the first support member; the plurality of first sub-electrodes and the plurality of second sub-electrodes are alternately arranged in the first direction, that is, the plurality of first sub-electrodes and the plurality of second sub-electrodes form a vertical finger structure, and the first electrode and the second electrode form a capacitor; the first support member is an elastic film layer, which can be deformed under pressure. When subjected to pressure, the sealed cavity can respond to external air pressure, radio waves and other excitations, and the first support member drives the first electrode to move along a third direction, which is perpendicular to the direction of the first support member, so that the overlapping area of ​​the first sub-electrode and the second sub-electrode changes, that is, the facing area of ​​the first electrode and the second electrode changes, resulting in a change in the capacitor electrical signal; the measurement principle of the variable area capacitive sensor is based on the nonlinear characteristics of capacitance, and has higher accuracy than the variable pole distance capacitive sensor in the related art. In addition, the multiple first sub-electrodes and the multiple second sub-electrodes are distributed in an interdigitated finger shape, and multiple facing surfaces can be formed between the multiple first sub-electrodes and the multiple second sub-electrodes. Therefore, a smaller deformation of the first support member can cause a larger change in the facing area between the first electrode and the second electrode, thereby improving the sensitivity of the pressure sensor.

[0056] According to the pressure sensor prepared by the preparation method of the pressure sensor of the embodiment of the present application, when the first support member is subjected to pressure, the sealed cavity can respond to external air pressure, radio waves and other stimuli, and the first support member drives the first electrode to move along the third direction, so that the overlapping area of ​​the first sub-electrode and the second sub-electrode changes, that is, the facing area of ​​the first electrode and the second electrode changes, resulting in a change in the electrical signal of the capacitor; the measurement principle of the variable area capacitive sensor is based on the nonlinear characteristics of the capacitor, and has higher accuracy than the variable pole distance capacitive sensor in the related technology.

[0057] An embodiment of the third aspect of the present application proposes a MEMS chip, comprising a first pin and a second pin and a pressure sensor of any embodiment of the first aspect. When the first support member is subjected to pressure, the sealed cavity can respond to external air pressure, radio waves and other stimuli. The first support member drives the first electrode to move along a third direction, so that the overlapping area of ​​the first sub-electrode and the second sub-electrode changes, that is, the facing area of ​​the first electrode and the second electrode changes, resulting in a change in the electrical signal of the capacitor; the measurement principle of the variable area capacitive sensor is based on the nonlinear characteristics of the capacitor, and is higher in accuracy than the variable pole distance capacitive sensor in the related technology, thereby improving the measurement accuracy of the MEMS chip.

[0058] Of course, it is not necessary to achieve all of the advantages described above at the same time to implement any product or method of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention, and for ordinary technicians in this field, other embodiments can also be obtained based on these drawings.

[0060] Figure 1 This is a schematic structural diagram of a pressure sensor according to a first embodiment of the present application;

[0061] Figure 2 for Figure 1 A schematic diagram of the first support member in the figure moving downward;

[0062] Figure 3 is a schematic diagram of a local structure when the first sub-electrode and the second sub-electrode are arranged at the middle position of the pressure sensor;

[0063] Figure 4 for Figure 3 A schematic diagram of the first support member in the figure moving downward;

[0064] Figure 5A first arrangement diagram of the first electrode and the second electrode in an embodiment of the present application;

[0065] Figure 6 A second arrangement diagram of the first electrode and the second electrode in the embodiment of the present application;

[0066] Figure 7 A third arrangement diagram of the first electrode and the second electrode in the embodiment of the present application;

[0067] Figure 8 A fourth arrangement diagram of the first electrode and the second electrode in the embodiment of the present application;

[0068] Fig. 9 is a fifth arrangement diagram of the first electrode and the second electrode in the embodiment of the present application;

[0069] Fig.10 This is a schematic structural diagram of a pressure sensor according to a second embodiment of the present application;

[0070] Fig.11 This is a flow chart of a method for preparing a pressure sensor according to an embodiment of the present application;

[0071] Fig.12a This is a diagram of the preparation process of the pressure sensor of the first embodiment of the present application (steps 1 to 4);

[0072] Figure 12b This is a diagram of the preparation process of the pressure sensor of the first embodiment of the present application (steps 5 to 7);

[0073] Fig.12c This is a diagram of the preparation process of the pressure sensor of the first embodiment of the present application (steps 8 to 10);

[0074] Fig.13a This is a diagram of the preparation process of the pressure sensor of the second embodiment of the present application (steps 1 to 5);

[0075] Fig.13b This is a diagram of the preparation process of the pressure sensor of the second embodiment of the present application (steps 6 to 8);

[0076] Fig.13c This is a diagram of the preparation process of the pressure sensor of the second embodiment of the present application (steps 9 to 11);

[0077] Fig.14 A top view of a MEMS chip according to an embodiment of the present application;

[0078] Fig.15 for Fig.14 Horizontal cross-sectional view of

[0079] Fig.16 for Fig.14 AA section view;

[0080] Fig.17 for Fig.14 BB cross-sectional view.

[0081] Description of reference numerals:

[0082] Thermistor 20; N-type silicon 21; P-type silicon 22; first pin 30; second pin 40; third pin 50; fourth pin 60; release hole 11; second support member 100; first support member 200; protective layer 210; third insulating layer 220; support wall 300; first electrode 400; first sub-electrode 410; first insulating support structure 411; first conductive structure 412; first connecting electrode 420; first conductive layer 421; first insulating layer 422; first output terminal 430; second electrode 500; second sub-electrode 510; second insulating support structure 511; second conductive structure 512; second connecting electrode 520; second conductive layer 521; second insulating layer 522; second output terminal 530; fourth insulating layer 800; nitride layer 600; conductive film layer 700; sacrificial layer 900. DETAILED DESCRIPTION

[0083] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field based on this application belong to the scope of protection of the present invention.

[0084] A capacitive pressure sensor is a pressure sensor that uses a capacitive sensitive element to convert the measured pressure into an electrical output that is related to it. The characteristics are low input energy, high dynamic response, small natural effect, and good environmental adaptability. Capacitive pressure sensors have lower power consumption than piezoresistive pressure sensors. The capacitive pressure sensor in the related art is usually a variable-pole-gap capacitive pressure sensor, which includes two parallel plate electrodes arranged opposite to each other. The capacitance is changed by changing the distance between the two electrodes. The accuracy is low, which limits its application scenarios. In order to solve this problem, the present application proposes a pressure sensor, a preparation method thereof, and a MEMS chip.

[0085] like Figure 1 As shown, Figure 1This is a schematic diagram of the structure of a pressure sensor of the first embodiment of the present application. The embodiment of the first aspect of the present application proposes a pressure sensor, which includes a first support member 200, a second support member 100, a support wall 300, a first electrode 400, and a second electrode 500. Specifically, the first support member 200 is an elastic membrane layer; the second support member 100 is arranged opposite to the first support member 200; the support wall 300 is arranged between the first support member 200 and the second support member 100, and is fixedly connected to the two; the support wall 300, the first support member 200 and the second support member 100 together constitute a sealed cavity; the first electrode 400 is fixedly arranged on the first support member 200 and is located between the first support member 200 and the second support member 100; the first electrode 400 includes a plurality of first sub-electrodes 410; the first sub-electrodes 410 extends from the first support member 200 in a direction close to the second support member 100; the second electrode 500 is fixedly arranged on the second support member 100 and is located between the first support member 200 and the second support member 100; the second electrode 500 includes a plurality of second sub-electrodes 510; the second sub-electrodes 510 extend from the second support member 100 in a direction close to the first support member 200; the plurality of first sub-electrodes 410 and the plurality of second sub-electrodes 510 are alternately arranged at intervals in the first direction; the first direction is a direction parallel to the second support member 100.

[0086] like Figure 1 For convenience of illustration, Figure 1 Three directions are defined in the figure, wherein the first direction is parallel to the first support member 200, the third direction is perpendicular to the first direction, and the second direction ( Figure 1 In other words, the first direction is parallel to the first support member 200, the second direction is parallel to the first support member 200 and perpendicular to the first direction, and the third direction is perpendicular to the first direction and the second direction and perpendicular to the first support member 200.

[0087] It is understandable that the sealed cavity can be a vacuum environment or contain a gas at a certain pressure. It can be designed according to actual needs and this application does not limit this.

[0088] The pressure sensor of the embodiment of the present application includes a first electrode 400 and a second electrode 500, the first electrode 400 is fixedly arranged on the first support member 200, the first electrode 400 includes a plurality of first sub-electrodes 410, and the first sub-electrodes 410 extend from the first support member 200 to the direction close to the second support member 100; the second electrode 500 is fixedly arranged on the second support member 100, the second electrode 500 includes a plurality of second sub-electrodes 510, and the second sub-electrodes 510 extend from the second support member 100 to the direction close to the first support member 200; the plurality of first sub-electrodes 410 and the plurality of second sub-electrodes 510 are alternately arranged at intervals in the first direction, that is, the plurality of first sub-electrodes 410 and the plurality of second sub-electrodes 510 form a vertical finger structure, and the first electrode 400 and the second electrode 500 form a capacitor; the first support member 200 is an elastic membrane layer, which can be deformed under pressure. When subjected to pressure, the sealed cavity can respond to external air pressure, radio waves and other excitations, such as Figure 2 As shown, Figure 2 for Figure 1 The schematic diagram of the first support member 200 moving downward in FIG. 2 shows that the first support member 200 drives the first electrode 400 to move along the third direction, which is perpendicular to the first support member 200, so that the overlapping area of ​​the first sub-electrode 410 and the second sub-electrode 510 changes, that is, the area directly facing the first electrode 400 and the second electrode 500 changes, resulting in a change in the capacitor electrical signal; the measurement principle of the variable area capacitive sensor is based on the nonlinear characteristics of capacitance, and has higher accuracy than the variable pole pitch capacitive sensor in the related art. In addition, the multiple first sub-electrodes 410 and the multiple second sub-electrodes 510 are distributed in an interdigitated finger shape, and multiple directly opposite faces can be formed between the multiple first sub-electrodes 410 and the multiple second sub-electrodes 510. Therefore, a smaller deformation of the first support member 200 can cause a larger change in the directly facing area between the first electrode 400 and the second electrode 500, thereby improving the sensitivity of the pressure sensor.

[0089] Correspondingly, the sensitivity and excitation conversion rate of the sensor have also been improved. It can achieve higher measurement sensitivity under the same volume. Under the condition of unchanged external excitation, the conversion rate of the sensor to excitation is improved, thereby outputting more signals, improving the signal-to-noise ratio and reducing the complexity of the subsequent amplification circuit.

[0090] Therefore, in some embodiments, in the initial state, the facing area between the first electrode 400 and the second electrode 500 can be set to 0, and the first sub-electrode 410 and the second sub-electrode 510 do not have an overlapping area, so that the initial capacitance value is 0. Then, from the initial state of the sensor to the extreme state, the capacitance can be continuously variable from 0 to the full scale. Compared with a pressure sensor with a certain initial capacitance value, the pressure sensor of the embodiment of the present application has higher sensitivity.

[0091] Figure 1 2 shows the initial state of the pressure sensor, on this basis, the first support member 200 can be deformed upward or downward; Figure 2 As shown, the center position of the sealed cavity changes more significantly with pressure, and the first support member 200 produces an arc deformation, which may affect the accuracy of the pressure sensor. The accuracy can be ensured through correction.

[0092] When the first support member 200 is Figure 1 The state shown can be deformed upward or downward, and the initial state can be set to a centered state, that is, the first sub-electrode 410 and the second sub-electrode 510 have a certain overlapping area, then the initial capacitance value is not 0, and the capacitance value can be set to 0 in the extreme state.

[0093] like Figure 3 and Figure 4 As shown, Figure 3 is a schematic diagram of a local structure when the first sub-electrode 410 and the second sub-electrode 510 are arranged in the middle position of the pressure sensor, Figure 4 for Figure 3 In the schematic diagram of the first support member 200 moving downward, if one wants to reduce the influence of the arc deformation of the first support member 200 on the accuracy of the pressure sensor, the first sub-electrode 410 and the second sub-electrode 510 can be set at the center of the pressure sensor, and the deformation of the first support member 200 at the center is approximately linear.

[0094] Specifically, the material of the first support member 200 and the support wall 300 can be SiN x ; The second support member 100 may be a silicon-based substrate, which may be a glass substrate or a flexible film.

[0095] In some embodiments of the present application, the orthographic projection of the first support member 200 on the plane where the second support member 100 is located has an overlapping area with the second support member 100. In this way, the first sub-electrode 410 and the second sub-electrode 510 can extend along the third direction, which is convenient for processing and helps to improve the accuracy of the pressure sensor. Specifically, Figure 1 As shown, the orthographic projection of the first support member 200 on the plane where the second support member 100 is located can completely overlap with the second support member 100 , and the support wall 300 can be vertically arranged to both the first support member 200 and the second support member 100 .

[0096] In some embodiments of the present application, Figures 1 to 4 As shown, the plurality of first sub-electrodes 410 are electrically connected to each other, and the plurality of second sub-electrodes 510 are electrically connected to each other, which facilitates wiring. The plurality of first sub-electrodes 410 and second sub-electrodes 510 can be arranged in a smaller space to achieve higher measurement sensitivity.

[0097] In the first embodiment of the present application, Figure 1 As shown, the first sub-electrode 410 includes a first insulating support structure 411 in the shape of a plate and a first conductive structure 412 covering the side wall of the first insulating support structure 411; the first insulating support structure 411 is in the shape of a plate, for example, it can be a rectangular plate, the first end of the first insulating support structure 411 is fixedly connected to the first support member 200, and the second end extends in a direction close to the second support member 100; the first conductive structure 412 is arranged on the side wall of the first insulating support structure 411 and completely covers the side wall of the first insulating support structure 411; the second sub-electrode 510 includes a second insulating support structure 511 in the shape of a plate and a second conductive structure 512 covering the side wall of the second insulating support structure 511; the second insulating support structure 511 is in the shape of a plate, for example, it can be a rectangular plate, the first end of the second insulating support structure 511 is fixedly connected to the second support member 100, and the second end extends in a direction close to the first support member 200; the second conductive structure 512 is arranged on the side wall of the second insulating support structure 511 and completely covers the side wall of the second insulating support structure 511.

[0098] In this way, the first conductive structure 412 and the second conductive structure 512 on the side walls of the two adjacent first insulating support structures 411 and the second insulating support structure 511 form a capacitor, and the change in the overlapping area of ​​the adjacent first sub-electrode 410 and the second sub-electrode 510 causes the electrical signal of the capacitor to change; the first insulating support structure 411 has a supporting effect on the first conductive structure 412, and the second insulating support structure 511 has a supporting effect on the second conductive structure 512, thereby preventing the first conductive structure 412 and the second conductive structure 512 from being insufficiently strong, deformed or broken, and thus causing insufficient accuracy of the pressure sensor.

[0099] In addition, the first conductive structure 412 is only formed on the side wall of the first support structure. When the deformation of the first support member 200 is too large, the end of the first electrode 400 may abut against the second support member 100. The first conductive structure 412 is not arranged at the end of the first insulating support structure 411, and has a certain insulating effect; the second conductive structure 512 is the same. In addition, due to the supporting effect of the first insulating support structure 411 and the second insulating support structure 511, when the sacrificial layer 900 is released by the wet release process, the first insulating support structure 411 and the second insulating support structure 511 arranged in a vertical finger structure can support the upper and lower surfaces of the sealed cavity, so that the upper and lower surfaces of the sealed cavity of the pressure sensor maintain a certain distance, thereby avoiding the situation where the upper and lower plates of conventional flat capacitors are adhered after wet release, and increasing the process applicability.

[0100] Specifically, the first conductive structure 412 and the second conductive structure 512 may be metal film layers, uniformly covering the corresponding sidewalls. The first conductive structure 412 and the second conductive structure 512 may be made of Al (aluminum), Mo (molybdenum) or ITO (indium tin oxide); the first insulating support structure 411 and the second insulating support structure 511 may be made of PS (polystyrene) or SiN x .

[0101] In the first embodiment of the present application, Figure 1 As shown, the first support member 200 includes a third insulating layer 220 and a protective layer 210 which are stacked; a plurality of first sub-electrodes 410 and a first connecting electrode 420 are formed on the side of the third insulating layer 220 facing the second support member 100. Specifically, the third insulating layer 220 covers the surface of the first electrode 400 away from the second support member 100, and at least one release hole 11 is provided on the third insulating layer 220; the protective layer 210 is provided on the side of the third insulating layer 220 away from the substrate, covers the third insulating layer 220 and fills the release hole 11. The third insulating layer 220 covers the surface of the first electrode 400 away from the second support member 100, and plays an insulating role. The protective layer 210 can isolate external water and oxygen, and plays a role in protecting the internal structure of the pressure sensor. In the process of preparing the first electrode 400, a sacrificial layer 900 is required. After the preparation is completed, a release process (either wet or dry method) is performed through the release hole 11, and the sacrificial layer 900 is removed. By blocking the pressure in the front cavity of the release hole 11, a gauge pressure or absolute pressure device can be made. Finally, the hole is sealed with nitride to form a sealed cavity, so that the sealed cavity is a stable environment.

[0102] Specifically, the protective layer 210 and the third insulating layer 220 may be nitride layers for insulation and isolation from air and water vapor. The sacrificial layer 900 may be an oxide layer, such as SiO2. There may be multiple release holes 11 to ensure uniformity of the release process.

[0103] In the first embodiment of the present application, Figure 1As shown, the pressure sensor further includes a fourth insulating layer 800; the second support member 100 and the fourth insulating layer 800 are stacked; the fourth insulating layer 800 is arranged between the second electrode 500 and the second support member 100, and a plurality of second sub-electrodes 510 and second connecting electrodes 520 are formed on the side of the fourth insulating layer 800 facing the first support member 200. In other words, the fourth insulating layer 800 is arranged between the second support member 100 and the second electrode 500, and isolates the second support member 100 and the second electrode 500. The fourth insulating layer 800 can isolate the second support member 100 and the second electrode 500, thereby reducing the mutual influence between the two, so that the pressure sensor can be applied to a larger temperature range and has a wider application scenario. Specifically, the fourth insulating layer 800 can be a nitride layer.

[0104] In some embodiments of the present application, Figure 1 Shown and Figure 5 As shown, Figure 5 This is a first arrangement diagram of the first electrode 400 and the second electrode 500 in the embodiment of the present application, wherein the number of the first sub-electrodes 410 and the second sub-electrodes 510 are both multiple; the multiple first sub-electrodes 410 and the multiple second sub-electrodes 510 are alternately arranged at intervals along the first direction; the first electrode 400 also includes a first connecting electrode 420, and the multiple first sub-electrodes 410 are electrically connected through the first connecting electrode 420; the first connecting electrode 420 is formed on the first side of the first support member 200 toward the second support member 100, and is connected to each of the first sub-electrodes 410 on the first side; the second electrode 500 also includes a second connecting electrode 520, and the multiple second sub-electrodes 510 are electrically connected through the second connecting electrode 520; the second connecting electrode 520 is formed on the second side of the second support member 100 toward the first support member 200, and is connected to each of the second sub-electrodes 510 on the second side. With such arrangement, the first electrode 400 and the second electrode 500 are distributed in an interdigitated finger shape, and there can be a plurality of facing surfaces between the first sub-electrode 410 and the second sub-electrode 510. Therefore, a smaller deformation of the first support member 200 can cause a larger change in the facing area between the first electrode 400 and the second electrode 500, thereby improving the sensitivity of the pressure sensor.

[0105] In some embodiments of the present application, Figure 5 As shown, in the first direction, the distance a between the first sub-electrode 410 and the second sub-electrode 510 adjacent thereto is 1-5 μm. The smaller the value of a, the more first sub-electrodes 410 and second sub-electrodes 510 can be arranged in the pressure sensor with the same volume, that is, the more the number of interdigitated electrodes is, so that the same deformation amount can cause a greater change in the facing area, and correspondingly, the greater the capacitance change amount. The stress distribution at the top of the sealed cavity can also be adjusted by the density and spacing of the first electrode 400 and the second electrode 500.

[0106] In some embodiments of the present application, Figures 5 to 8 As shown, Figure 6 4 is a second arrangement diagram of the first electrode 400 and the second electrode 500 in the embodiment of the present application. Figure 7 4 is a third arrangement diagram of the first electrode 400 and the second electrode 500 in the embodiment of the present application. Figure 8 This is a fourth arrangement diagram of the first electrode 400 and the second electrode 500 in the embodiment of the present application. A plurality of first sub-electrodes 410 extend along the second direction, a first connecting electrode 420 extends along the first direction, and the first connecting electrode 420 is formed at the end of the first sub-electrode 410 close to the first support member 200; a plurality of second sub-electrodes 510 extend along the second direction, a second connecting electrode 520 extends along the first direction, and the second connecting electrode 520 is formed at the end of the second sub-electrode 510 close to the second support member 100; the second direction is parallel to the second support member 100 and perpendicular to the first direction. All the first sub-electrodes 410 are connected together by one first connecting electrode 420, and all the second sub-electrodes 510 are connected together by one second connecting electrode 520, and the connection method is simple and convenient for wiring.

[0107] Furthermore, if Figures 5 to 8 As shown, the first connection electrode 420 and the second connection electrode 520 are arranged opposite to each other, and the orthographic projections of the first electrode 400 and the second electrode 500 on the second support member 100 do not have an overlapping area, which can avoid the occurrence of a short circuit at the maximum range.

[0108] In some embodiments of the present application, Figure 5 and Figure 6 As shown, the first electrode 400 has a first output terminal 430; the first output terminal 430 is formed at the end of the first connection electrode 420; the second electrode 500 has a second output terminal 530; the second output terminal 530 is formed at the end of the second connection electrode 520. Figure 7 and Figure 8 As shown, the first output terminal 430 can also be arranged at the end of the first sub-electrode 410 located at the edge position; the second output terminal 530 can also be arranged at the end of the second sub-electrode 510 located at the edge position. In addition, in the embodiment of the present application, the number of the first output terminal 430 and the second output terminal 530 is not limited. Figure 8 As shown, there may be a second output terminal 530 located between two first output terminals 430. The first output terminal 430 and the second output terminal 530 are electrically connected to the external circuit; the positions of the first output terminal 430 and the second output terminal 530 can be designed according to actual conditions, and this application does not limit this.

[0109] In some embodiments of the present application, Fig. 9 As shown, Fig. 9 This is a fifth arrangement diagram of the first electrode 400 and the second electrode 500 in the embodiment of the present application. The number of the first connection electrodes 420 is multiple, and the multiple first connection electrodes 420 and the multiple first sub-electrodes 410 are alternately arranged and connected end to end; the number of the second connection electrodes 520 is multiple, and the multiple second connection electrodes 520 and the multiple second sub-electrodes 510 are alternately arranged and connected end to end; the multiple first connection electrodes 420 and the multiple second connection electrodes 520 are alternately arranged in the second direction. The orthographic projections of the first electrode 400 and the second electrode 500 on the second support member 100 are both strip-shaped, simple in shape, and easy to process.

[0110] In the second embodiment of the present application, Fig.10 As shown, Fig.10 This is a structural schematic diagram of a pressure sensor of a second embodiment of the present application, wherein a first sub-electrode 410 comprises: a first conductive structure 412 in the form of a plate and a first insulating support structure 411 covering the side wall and the second end of the first conductive structure 412; the first conductive structure 412 is in the form of a plate, the first end of the first conductive structure 412 is fixedly connected to the first support member 200, and the second end extends in a direction close to the second support member 100; the first insulating support structure 411 is arranged on the outer wall of the first conductive structure 412, and completely covers the outer wall of the first conductive structure 412 exposed in the sealed cavity; the second sub-electrode 510 comprises: a second conductive structure 512 in the form of a plate and a second insulating support structure 511 covering the side wall and the second end of the second conductive structure 512; the second conductive structure 512 is in the form of a plate, the first end of the second conductive structure 512 is fixedly connected to the second support member 100, and the second end extends in a direction close to the first support member 200; the second insulating support structure 511 is arranged on the outer wall of the second conductive structure 512, and completely covers the outer wall of the second conductive structure 512 exposed in the sealed cavity. The two adjacent first conductive structures 412 and the second conductive structure 512 form a capacitor, and the change in the overlapping area of ​​the adjacent first sub-electrode 410 and the second sub-electrode 510 causes the electrical signal of the capacitor to change; the first insulating support structure 411 supports the first conductive structure 412, and the second insulating support structure 511 supports the second conductive structure 512, thereby preventing the first conductive structure 412 and the second conductive structure 512 from being insufficiently strong, deformed or broken, and thus causing insufficient accuracy of the pressure sensor.

[0111] In addition, due to the supporting effect of the first insulating support structure 411 and the second insulating support structure 511, when the sacrificial layer 900 is released by the wet release process, the first electrode 400 and the second electrode 500 arranged in a vertical finger structure can support the upper and lower surfaces of the sealed cavity, so that the upper and lower surfaces of the sealed cavity of the pressure sensor maintain a certain distance, thereby avoiding the situation where the upper and lower plates of a conventional flat-plate capacitor stick together after wet release, thereby increasing the process applicability.

[0112] In the second embodiment of the present application, Fig.10 As shown, the first connection electrode 420 includes a first conductive layer 421 and a first insulating layer 422; the first conductive layer 421 is electrically connected to the plurality of first conductive structures 412, and the first conductive layer 421 is located at the end of the plurality of first conductive structures 412 close to the first support 200; the first insulating layer 422 is located at the side of the first conductive layer 421 away from the first support 200, and covers the first conductive layer 421; the second connection electrode 520 includes a second conductive layer and a second insulating layer; the second conductive layer is electrically connected to the plurality of second conductive structures 512, and the second conductive layer is located at the end of the plurality of second conductive structures 512 close to the second support 100; the second insulating layer is located at the side of the second conductive layer away from the second support 100, and covers the second conductive layer. The first conductive layer 421 electrically connects the plurality of first conductive structures 412, and the second conductive layer electrically connects the plurality of second conductive structures 512; the first insulating layer 422 covers the first conductive layer 421, and the second insulating layer covers the second conductive layer to prevent the occurrence of a short circuit.

[0113] In the second embodiment of the present application, Fig.10 As shown, the first support member 200 covers the surface of the first electrode 400 away from the second support member 100; a release hole 11 is provided on the pressure sensor, and the release hole 11 passes through the first support member 200 and the first insulating layer 422; the release hole 11 is filled with a nitride layer 600. The first support member 200 covers the surface of the first electrode 400 away from the second support member 100, and plays an insulating role. In the process of preparing the first electrode 400, it is necessary to facilitate the sacrificial layer 900. After the preparation is completed, the release process is performed through the release hole 11, the sacrificial layer 900 is removed, and then the release hole 11 is filled to form a sealed cavity. Specifically, the first support member 200 can be a nitride layer for insulation and isolation from air and water vapor.

[0114] like Fig.10 In the embodiment shown, the first support member 200, the support wall 300 and the first insulating layer 422 may be made of the same material, and may all be nitride layers. The second support member 100 may be an insulating substrate, and the second electrode 500 and the support wall 300 may be directly prepared on the insulating substrate. Fig.10The illustrated embodiment not only improves the accuracy and sensitivity, but also simplifies the process and allows the size of the pressure sensor to be made smaller.

[0115] like Fig.11 As shown, Fig.11 The flowchart of the method for preparing the pressure sensor of the embodiment of the present application is as follows. The embodiment of the second aspect of the present application provides a method for preparing the pressure sensor, which is used to prepare the pressure sensor of any embodiment of the first aspect, including:

[0116] S1, providing a second support member 100;

[0117] S2, preparing a second electrode 500 and a supporting wall 300 on the second supporting member 100; the supporting wall 300 and the second supporting member 100 form a receiving space;

[0118] S3, filling the sacrificial layer 900 in the accommodation space, and performing patterning on the sacrificial layer 900;

[0119] S4, preparing a first electrode 400 on the sacrificial layer 900;

[0120] S5 , preparing the first support member 200 on the first electrode 400 and the support wall 300 , and removing the sacrificial layer 900 .

[0121] According to the pressure sensor prepared by the preparation method of the pressure sensor of the embodiment of the present application, when the first support member 200 is subjected to pressure, the sealed cavity can respond to external air pressure, radio waves and other stimuli, and the first support member 200 drives the first electrode 400 to move along the third direction, so that the overlapping area of ​​the first sub-electrode 410 and the second sub-electrode 510 changes, that is, the facing area of ​​the first electrode 400 and the second electrode 500 changes, resulting in a change in the electrical signal of the capacitor; the measurement principle of the variable area capacitive sensor is based on the nonlinear characteristics of the capacitor, and has higher accuracy than the variable pole distance capacitive sensor in the related technology.

[0122] like Figures 12a to 12c As shown, Fig.12a This is a diagram of the preparation process of the pressure sensor of the first embodiment of the present application (steps 1 to 4), Figure 12b This is a diagram of the preparation process of the pressure sensor of the first embodiment of the present application (steps 5 to 7), Fig.12c This is a diagram of the preparation process of the pressure sensor of the first embodiment of the present application (steps 8 to 10). In the first embodiment of the present application, S2, preparing a second electrode 500 and a support wall 300 on a second support member 100, including:

[0123] Step 1, depositing a nitride layer 600 on the second support member 100;

[0124] Step 2, etching the nitride layer 600 to form the support wall 300, the fourth insulating layer 800 and the second insulating support structure 511;

[0125] Step 3, preparing a conductive film layer 700 on the sidewall of the second conductive structure 512 and the surface of the fourth insulating layer 800 away from the second support member 100 to form a second electrode 500;

[0126] S4, preparing the first electrode 400 on the sacrificial layer 900, including:

[0127] Step 5: etching the sacrificial layer 900 to form a first groove;

[0128] Step 6: preparing a conductive film layer 700 on the sacrificial layer 900;

[0129] Step 7: Etch the conductive film layer 700 and form a through groove penetrating the conductive film layer 700 in the third direction; prepare a first insulating support structure 411 in the through groove to form a first electrode 400 .

[0130] like Figures 13a to 13c As shown, Fig.13a This is a diagram of the preparation process of the pressure sensor of the second embodiment of the present application (steps 1 to 5), Fig.13b This is a diagram of the preparation process of the pressure sensor of the second embodiment of the present application (steps 6 to 8), Fig.13c FIG. 1 is a diagram of the preparation process of the pressure sensor of the second embodiment of the present application (step 9 to step 11). In the second embodiment of the present application, S2, preparing the second electrode 500 and the support wall 300 on the second support member 100, comprising:

[0131] Step 1: depositing a nitride layer 600 on the second support member 100 and etching the nitride layer 600 to form a second groove;

[0132] Step 2, preparing a conductive film layer 700 in the second groove;

[0133] Step 3, depositing a nitride layer 600 on the nitride layer 600 and the conductive film layer 700;

[0134] Step 4, etching the nitride layer 600 to form the support wall 300 and the second insulating support structure 511; forming the second electrode 500;

[0135] S4, preparing the first electrode 400 on the sacrificial layer 900, including:

[0136] Step 6, etching the sacrificial layer 900 to form a third groove; depositing a nitride layer 600 on the sacrificial layer 900;

[0137] Step 7, etching the nitride layer 600 to form a fourth groove, a second insulating layer 522 and a first insulating support structure 411;

[0138] Step 8: Prepare a conductive film layer 700 on the nitride layer 600; and form a first electrode 400.

[0139] The following describes in detail the preparation methods of the pressure sensor of the first embodiment and the pressure sensor of the second embodiment of the present application.

[0140] like Figures 12a to 12c As shown, the method for preparing the pressure sensor of the first embodiment of the present application comprises the following steps:

[0141] Step 1, providing a second support member 100; depositing a nitride layer 600 on the second support member 100;

[0142] Step 2, etching the nitride layer 600 to form the support wall 300, the fourth insulating layer 800 and the second insulating support structure 511;

[0143] Step 3: preparing a conductive film layer 700 on the sidewall of the second conductive structure 512 and the surface of the fourth insulating layer 800 away from the second support member 100 to form a second electrode 500;

[0144] Step 4, filling the sacrificial layer 900 in the cavity surrounded by the second support member 100 and the support wall 300;

[0145] Step 5: etching the sacrificial layer 900 to form a first groove;

[0146] Step 6: preparing a conductive film layer 700 on the sacrificial layer 900;

[0147] Step 7, etching the conductive film layer 700, and forming a through groove penetrating the conductive film layer 700 in the third direction; preparing a first insulating support structure 411 in the through groove to form a first electrode 400;

[0148] Step 8, preparing a third insulating layer 220 on the first electrode 400 and the support wall 300, and forming a release hole 11 on the third insulating layer 220;

[0149] Step 9, removing the sacrificial layer 900 through the release hole 11;

[0150] Step 10: Prepare a protective layer 210 on the third insulating layer 220 , the protective layer 210 fills the release hole 11 , and the protective layer 210 and the third insulating layer 220 together constitute the first support member 200 ;

[0151] Complete preparation.

[0152] like Figures 13a to 13cAs shown, the method for preparing the pressure sensor of the second embodiment of the present application includes the following steps:

[0153] Step 1, providing a second support member 100; depositing a nitride layer 600 on the second support member 100, and etching the nitride layer 600 to form a second groove;

[0154] Step 2, preparing a conductive film layer 700 in the second groove;

[0155] Step 3, depositing a nitride layer 600 on the nitride layer 600 and the conductive film layer 700;

[0156] like Fig.13a As shown, the nitride layer 600 deposited in step 3 covers the nitride layer 600 deposited in step 1 and the conductive film layer 700 prepared in step 2. Since the materials are the same, the nitride layers 600 deposited in step 1 and step 3 are integrated;

[0157] Step 4: Etching the nitride layer 600 to form the support wall 300 and the second insulating support structure 511; forming the second electrode 500;

[0158] Step 5, filling the sacrificial layer 900 in the cavity surrounded by the second support member 100 and the support wall 300;

[0159] Step 6, etching the sacrificial layer 900 to form a third groove; depositing a nitride layer 600 on the sacrificial layer 900;

[0160] Step 7, etching the nitride layer 600 to form a fourth groove, a second insulating layer 522 and a first insulating support structure 411;

[0161] Step 8: Prepare a conductive film layer 700 on the nitride layer 600; form a first electrode 400;

[0162] Step 9, depositing a nitride layer 600 on the first electrode 400 and the support wall 300;

[0163] Step 10, forming a release hole 11, wherein a portion of the release hole 11 penetrates the first conductive layer 421, the first insulating layer 422 and the nitride layer 600;

[0164] Step 11, removing the sacrificial layer 900 through the release hole 11; and filling the release hole 11 with the nitride layer 600 to form the first support member 200;

[0165] Complete preparation.

[0166] like Figures 14 to 17 As shown, Fig.14 is a top view of the MEMS chip of an embodiment of the present application, Fig.15 for Fig.14 A horizontal cross-sectional view of Fig.16for Fig.14 AA section view, Fig.17 for Fig.14 BB cross-sectional view. The embodiment of the third aspect of the present application proposes a MEMS chip, including a first pin 30 and a second pin 40 and a pressure sensor of any embodiment of the first aspect; the first pin 30 is electrically connected to the first electrode 400, and the second pin 40 is electrically connected to the second electrode 500; the first pin 30 and the second pin 40 are used to be electrically connected to an external circuit. Specifically, the first pin 30 and the second pin 40 are respectively connected to the positive and negative electrodes of the capacitor, which are equivalent to the first output terminal 430 and the second output terminal 530 described above (see Figure 5 ).

[0167] MEMS (Micro-Electro-Mechanical System), also known as micro-electromechanical system, microsystem, micromachine, etc., refers to high-tech devices with a size of several millimeters or even smaller.

[0168] An embodiment of the third aspect of the present application proposes a MEMS chip, including a first pin 30 and a second pin 40 and a pressure sensor of any embodiment of the first aspect. When the first support member 200 is subjected to pressure, the sealed cavity can respond to external air pressure, radio waves and other stimuli. The first support member 200 drives the first electrode 400 to move along the third direction, so that the overlapping area of ​​the first sub-electrode 410 and the second sub-electrode 510 changes, that is, the facing area of ​​the first electrode 400 and the second electrode 500 changes, resulting in a change in the electrical signal of the capacitor; the measurement principle of the variable area capacitive sensor is based on the nonlinear characteristics of the capacitor, and is higher in accuracy than the variable pole distance capacitive sensor in the related technology, thereby improving the measurement accuracy of the MEMS chip.

[0169] like Fig.16 and Fig.17 As shown, in some embodiments of the present application, the MEMS chip further includes a thermistor 20, a third pin 50 and a fourth pin 60; the thermistor 20 is disposed on the second support member 100; the third pin 50 and the fourth pin 60 are used to be electrically connected to an external circuit; the third pin 50 and the fourth pin 60 are electrically connected to two output ends of the thermistor 20, respectively. Specifically, a PN junction formed by a P-type silicon 22 and an N-type silicon 21 forms the thermistor 20, the third pin 50 and the fourth pin 60 are connected to the P-type silicon 22 and the N-type silicon 21, respectively, and the thermistor 20 is used to compensate for the influence of temperature changes on the pressure measurement accuracy. Specifically, as Fig.14 As shown, the first to fourth pins (30-60) may all be formed on the top of the MEMS chip.

[0170] like Fig.15 and Fig.16As shown, the second connecting electrode 520 includes a second conductive layer 521 and a second insulating layer 522; the second conductive layer 521 is electrically connected to multiple second conductive structures 512, and the second conductive layer 521 is located at the end of the multiple second conductive structures 512 close to the second support member 100; the second insulating layer 522 is located at the end of the second conductive layer 521 away from the second support member 100, and covers the second conductive layer 521.

[0171] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0172] Each embodiment in this specification is described in a related manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0173] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A pressure sensor, characterized in that: The pressure sensor comprises: A first supporting member, wherein the first supporting member is an elastic membrane layer; a second supporting member, the second supporting member being arranged opposite to the first supporting member; A support wall, the support wall is disposed between the first support member and the second support member and is fixedly connected to the first support member and the second support member; the support wall, the first support member and the second support member together form a sealed cavity; A first electrode, the first electrode is fixedly disposed on the first support member and is located between the first support member and the second support member; the first electrode includes a plurality of first sub-electrodes; the first sub-electrodes extend from the first support member toward a direction close to the second support member; a second electrode, the second electrode being fixedly disposed on the second support member and being located between the first support member and the second support member; the second electrode comprising a plurality of second sub-electrodes; the second sub-electrodes extending from the second support member toward a direction close to the first support member; The plurality of first sub-electrodes and the plurality of second sub-electrodes are alternately arranged in a first direction; the first direction is a direction parallel to the second support member.

2. The pressure sensor according to claim 1, characterized in that: The plurality of first sub-electrodes are electrically connected to each other, and the plurality of second sub-electrodes are electrically connected to each other.

3. The pressure sensor according to claim 2, characterized in that: The first electrode further includes a first connecting electrode, and the plurality of first sub-electrodes are electrically connected via the first connecting electrode; the first connecting electrode is formed on a first side of the first support member facing the second support member, and is connected to each of the first sub-electrodes at the first side; The second electrode further includes a second connecting electrode, and the plurality of second sub-electrodes are electrically connected via the second connecting electrode; the second connecting electrode is formed on a second side of the second support member facing the first support member, and is connected to each of the second sub-electrodes at the second side.

4. The pressure sensor according to claim 3, characterized in that: The number of the first connecting electrodes is multiple, and the multiple first connecting electrodes and the multiple first sub-electrodes are alternately arranged and connected end to end; The number of the second connecting electrodes is multiple, and the multiple second connecting electrodes and the multiple second sub-electrodes are alternately arranged and connected end to end; The plurality of first connection electrodes and the plurality of second connection electrodes are alternately arranged at intervals in the second direction; The second direction is parallel to the second support member and perpendicular to the first direction.

5. The pressure sensor according to claim 3, characterized in that: The first electrode has a first output end; the first output end is formed at an end of the first connecting electrode or at an end of the first sub-electrode located at an edge position; The second electrode has a second output end; the second output end is formed at an end of the second connecting electrode or at an end of the second sub-electrode located at an edge position.

6. The pressure sensor according to claim 3, characterized in that: The first sub-electrode comprises: a first insulating support structure in a plate shape and a first conductive structure covering a side wall of the first insulating support structure; a first end of the first insulating support structure is fixedly connected to the first support member, and a second end thereof extends in a direction close to the second support member; The second sub-electrode includes: a second plate-shaped insulating support structure and a second conductive structure covering the side wall of the second insulating support structure; the first end of the second insulating support structure is fixedly connected to the second support member, and the second end extends in a direction close to the first support member.

7. The pressure sensor according to claim 3, characterized in that: The first sub-electrode comprises: a plate-shaped first conductive structure and a first insulating support structure covering the sidewall and the second end of the first conductive structure; the first end of the first conductive structure is fixedly connected to the first support member, and the second end extends in a direction close to the second support member; The second sub-electrode includes: a second plate-shaped conductive structure and a second insulating support structure covering the side wall and the second end of the second conductive structure; the first end of the second conductive structure is fixedly connected to the second support member, and the second end extends in a direction close to the first support member.

8. The pressure sensor according to claim 7, characterized in that: The first connecting electrode comprises: a first conductive layer and a first insulating layer; The first conductive layer is electrically connected to the first conductive structure of the first sub-electrode, and the first conductive layer is located at the end of the plurality of first conductive structures close to the first support member; the first insulating layer is located at a side of the first conductive layer away from the first support member, and covers the first conductive layer; The second connecting electrode comprises: a second conductive layer and a second insulating layer; The second conductive layer is electrically connected to the second conductive structure of the second sub-electrode, and the second conductive layer is located at the end of the multiple second conductive structures close to the second support member; the second insulating layer is located on the side of the second conductive layer away from the second support member and covers the second conductive layer.

9. The pressure sensor according to claim 3, characterized in that: The first support member comprises: a third insulating layer and a protective layer which are stacked; the plurality of first sub-electrodes and the first connecting electrode are formed on a side of the third insulating layer facing the second support member; The pressure sensor also includes: a fourth insulating layer; the second support member and the fourth insulating layer are stacked; the fourth insulating layer is arranged between the second electrode and the second support member; the plurality of second sub-electrodes and the second connecting electrode are formed on a side of the fourth insulating layer facing the first support member.

10. The pressure sensor according to claim 2, characterized in that: In the first direction, a distance between the first sub-electrode and the second sub-electrode adjacent thereto is 1-5 μm.

11. The pressure sensor according to claim 1, characterized in that: The first supporting member and the supporting wall are made of the same material.

12. The pressure sensor according to claim 1, characterized in that: The orthographic projection of the first support member on the plane where the second support member is located has an overlapping area with the second support member.

13. A method for preparing a pressure sensor, characterized in that: Used to prepare the pressure sensor according to any one of claims 1 to 12, comprising: providing a second support member; A second electrode and a support wall are prepared on a second support member; the support wall and the second support member form a receiving space; Filling a sacrificial layer in the accommodation space and patterning the sacrificial layer; preparing a first electrode on the sacrificial layer; A first support member is prepared on the first electrode and the support wall, and the sacrificial layer is removed.

14. The method for preparing a pressure sensor according to claim 13, characterized in that: The method of preparing the second electrode and the supporting wall on the second supporting member comprises: depositing a nitride layer on the second support; Etching the nitride layer to form a support wall, a fourth insulating layer and a second insulating support structure; A conductive film layer is formed on the sidewall of the second conductive structure and on the surface of the fourth insulating layer away from the second support member to form a second electrode; The step of preparing the first electrode on the sacrificial layer comprises: Etching the sacrificial layer to form a first groove; preparing a conductive film layer on the sacrificial layer; The conductive film layer is etched to form a through groove penetrating the conductive film layer in a third direction; a first insulating support structure is prepared in the through groove to form a first electrode.

15. The method for preparing a pressure sensor according to claim 13, characterized in that: The method of preparing the second electrode and the supporting wall on the second supporting member comprises: Depositing a nitride layer on the second support member, and etching the nitride layer to form a second groove; preparing a conductive film layer in the second groove; depositing a nitride layer on the nitride layer and the conductive film layer; Etching the nitride layer to form a support wall and a second insulating support structure; forming a second electrode; The step of preparing the first electrode on the sacrificial layer comprises: etching the sacrificial layer to form a third groove; depositing a nitride layer on the sacrificial layer; Etching the nitride layer to form a fourth groove, a first insulating layer and a first insulating support structure; A conductive film layer is prepared on the nitride layer; and a first electrode is formed.

16. A MEMS chip, characterized in that: comprising a first pin and a second pin and the pressure sensor according to any one of claims 1 to 12; The first pin is electrically connected to the first electrode, and the second pin is electrically connected to the second electrode; The first pin and the second pin are used to be electrically connected to an external circuit.

17. The MEMS chip according to claim 16, characterized in that: The MEMS chip further includes: a temperature-sensitive resistor, a third pin and a fourth pin; The temperature-sensitive resistor is arranged on the second supporting member; The third pin and the fourth pin are used to be electrically connected to an external circuit; the third pin and the fourth pin are electrically connected to two output ends of the temperature-sensitive resistor respectively.

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