Pressure sensor

Abstract

The embodiment of the invention discloses a pressure sensor. The pressure sensor comprises a strain area; the supporting area is arranged on the periphery of the strain area; a substrate layer located in the strain region and the support region; the dielectric layer is located in the strain area and the supporting area and comprises a first surface close to the substrate layer and a second surface opposite to the first surface; the first metal layer is located in the supporting region and is arranged on the second surface of the dielectric layer; the variable-voltage resistance area is located in the strain area and arranged on the substrate layer, and the variable-voltage resistance area is configured to change the resistance value according to the pressure borne by the strain area; the diode region is located in the supporting region and arranged on the substrate layer, the diode region is electrically connected with the first metal layer, and the diode region and the substrate layer form at least one diode. By arranging the diode area surrounding the voltage variable resistor, a filtering and noise reduction access of the circuit is formed, high-frequency noise of the external environment is filtered out, electromagnetic interference of equipment is reduced, and stability and output precision of the sensor are enhanced.

Description

Technical Field

[0001] The present application relates to the technical field of pressure sensors, and in particular to a pressure sensor. Background Art

[0002] MEMS pressure sensors are widely used in automotive electronics, consumer electronics, industrial electronics and other fields. They place four piezoresistors that sense pressure changes in parallel at the center of the edge of the strain film to form a Wheatstone bridge circuit. When pressure acts on the strain film, the strain film deforms and generates deformation, which in turn generates stress. The stress change at the center of the edge of the strain film is the largest. The four piezoresistors placed there sense the change in stress, and their resistance values ​​increase or decrease in pairs, causing the bridge to be unbalanced, and the output voltage difference Vout=V2-V1 that is proportional to the loading pressure.

[0003] In the prior art, MEMS pressure sensors are manufactured using semiconductor processes. Usually, a back cavity is set in a silicon substrate. The interlayer between the back cavity and the surface is a silicon strain film. Doped regions are set around the silicon strain film to form a varistor. The heavily doped region and the metal layer are connected to the surface metal and the pad as leads through the ohmic contact between the heavily doped region and the metal layer, thereby outputting a test voltage.

[0004] However, when this MEMS pressure sensor is used in harsh environments such as automobiles and industries, high-frequency noise, electromagnetic interference, etc. in the environment are coupled to the output end of the piezoresistor, which will cause the MEMS pressure sensor's anti-interference ability to deteriorate, the output signal to be unstable, and the voltage to jump greatly, which will lead to problems such as poor signal-to-noise ratio and reduced accuracy. Summary of the invention

[0005] The present application provides a pressure sensor, aiming to effectively solve the problems of poor anti-interference ability and low signal-to-noise ratio of MEMS pressure sensors in the prior art.

[0006] According to the first aspect of the present application, the present application provides a pressure sensor, comprising: a strain region; a support region, arranged around the strain region; a substrate layer, located in the strain region and the support region; a dielectric layer, located in the strain region and the support region, arranged on the surface of the substrate layer, and comprising a first surface close to the substrate layer and an opposite second surface; a first metal layer, located in the support region, arranged on the second surface of the dielectric layer; a piezoresistive resistor region, located in the strain region, arranged on the substrate layer, the piezoresistive resistor region being configured to change the size of the resistance value according to the pressure applied to the strain region; a diode region, located in the support region, arranged on the substrate layer, the diode region being electrically connected to the first metal layer, and at least one diode is formed between the diode region and the substrate layer.

[0007] Through one or more of the above embodiments in the present application, at least the following technical effects can be achieved:

[0008] By integrating a diode on a pressure sensor using a bridge circuit, it is possible to filter out high-frequency noise and electromagnetic interference from the external environment, block their coupling to the output end, suppress common-mode noise, improve the sensor's signal-to-noise ratio and anti-interference ability, and make the sensor more stable and the output more accurate.

[0009] In addition, the diode in the above-mentioned pressure sensor is formed by the same doping process as that for manufacturing the varistor, and is easy to integrate into the MEMS pressure sensor chip without the need for additional process flow, with low cost and simple process. At the same time, because the filter structure has been integrated into the MEMS pressure sensor chip in advance, there is no need to add filter resistors and diodes in the back-end processing circuit or sensor conditioning chip, thereby reducing the use of large-area diodes in components or integrated circuits and reducing system costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The technical solution and other beneficial effects of the present application will be made apparent by describing in detail the specific implementation methods of the present application in conjunction with the accompanying drawings.

[0011] Figure 1 is a schematic diagram of a pressure sensor;

[0012] Figure 2 A schematic diagram of a circuit structure of a pressure sensor;

[0013] Figure 3 It is a structural schematic diagram of a pressure sensor;

[0014] Figure 4 A schematic diagram of a circuit structure of a pressure sensor provided according to an embodiment of the present application;

[0015] Figure 5 A schematic diagram of the structure of a pressure sensor provided according to an embodiment of the present application;

[0016] Figure numerals: 10 - substrate layer; 20 - dielectric layer; 21 - through hole; 22 - blind hole; 30 - first metal layer; 31 - first sub-metal layer; 32 - second sub-metal layer; 40 - varistor region; 50 - diode region; 52 - depletion layer; 60 - lead region; 70 - back cavity; 80 - strain film; 90 - doped substrate region. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0018] 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" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0019] 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, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0020] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0021] The disclosure below provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the various specific processes and material examples provided by the present application, but those of ordinary skill in the art can appreciate the application of other processes and / or the use of other materials.

[0022] MEMS pressure sensors are widely used in automotive electronics, consumer electronics, industrial electronics and other fields. Figure 1 This is a schematic diagram of a pressure sensor. The four piezoresistors that sense pressure changes are placed parallel to each other at the center of the edge of the strain film. Figure 2 Schematic diagram of the circuit structure of a pressure sensor. Figure 2 The resistors in the circuit are connected to form a Whistler bridge circuit. When pressure acts on the strain film, the strain film deforms and generates deformation, which in turn generates stress. The stress change at the center of the edge of the strain film is the largest. The four piezoresistors placed there sense the change in stress, and their resistance values ​​increase or decrease in pairs, causing the bridge to be unbalanced, and the output voltage difference Vout=V2-V1, which is proportional to the loading pressure.

[0023] Figure 3 Schematic diagram of the structure of a pressure sensor, the pressure sensor includes a substrate layer 10', a back cavity 70' located in the substrate layer, a strain film 80' on the back cavity, a piezoresistive resistor area 40', a lead area 60', a dielectric layer 20', a doped substrate area 90' and a first metal layer 30', the piezoresistive resistor is electrically connected to a power supply voltage terminal VDD, a ground voltage terminal GND, a first voltage terminal V1 and a second voltage terminal V2 through the lead area and the first metal layer, the doped substrate area is connected to the substrate voltage terminal Vsub, the piezoresistive resistor is used as a boundary to divide the strain area A1' and the support area A2', when pressure acts on the strain area, a voltage proportional to the pressure change is output from the first voltage terminal V1 and the second voltage terminal V2.

[0024] However, when the pressure sensor using this circuit is used in harsh environments such as automobiles and industries, high-frequency noise, electromagnetic interference, etc. in the environment are coupled to the output end of the piezoresistor, which will cause the MEMS pressure sensor's anti-interference ability to deteriorate, the output signal to be unstable, and the voltage to jump greatly, which will lead to problems such as poor signal-to-noise ratio and reduced accuracy.

[0025] In order to solve the problems of poor anti-interference ability and low signal-to-noise ratio of pressure sensors in the prior art, an embodiment of the present application provides a pressure sensor. Figure 4A circuit structure schematic diagram of a pressure sensor provided according to an embodiment of the present application is given, wherein the pressure sensor includes a first voltage terminal V1, a second voltage terminal V2, a ground voltage terminal GND and a power supply voltage terminal VDD, wherein the ground voltage terminal GND is coupled to a reference ground, the power supply voltage terminal VDD receives a power supply voltage, and the magnitude of the pressure applied to the pressure sensor is calculated based on a voltage difference between the first voltage terminal V1 and the second voltage terminal V2.

[0026] The pressure sensor also includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first diode D1, a second diode D2, a third diode D3 and a fourth diode D4. Among them, the first resistor R1 is electrically connected between the first voltage terminal V1 and the power supply voltage terminal VDD, the second resistor R2 is electrically connected between the power supply voltage terminal VDD and the second voltage terminal V2, the third resistor R3 is electrically connected between the second voltage terminal V2 and the ground voltage terminal GND, and the fourth resistor R4 is electrically connected between the ground voltage terminal GND and the first voltage terminal V1. When the pressure on the strain area of ​​the pressure sensor changes, the resistance values ​​of the first resistor R1 and the third resistor R3 increase or decrease synchronously, and the resistance values ​​of the second resistor R2 and the fourth resistor R4 decrease or increase synchronously. In some embodiments, the resistance value of the first resistor R1 is equal to the resistance value of the third resistor R3; the resistance value of the second resistor R2 is equal to the resistance value of the fourth resistor R4.

[0027] The first end of the first diode D1 is connected to the first voltage terminal V1, the first end of the second diode D2 is connected to the power supply voltage terminal VDD, the first end of the third diode D3 is connected to the second voltage terminal V2, the first end of the fourth diode D4 is connected to the ground voltage terminal GND, and the second ends of the first diode D1 to the fourth diode D4 are all connected to the substrate voltage terminal. The diodes added between the voltage terminal and the substrate voltage terminal of the pressure sensor constitute multiple filtering and noise reduction paths, filtering out high-frequency noise from the external environment and blocking it from coupling to the output terminal. Common-mode noise is suppressed, electromagnetic interference of the equipment is reduced, the signal-to-noise ratio and anti-interference ability of the pressure sensor are improved, and the stability and output accuracy of the sensor are enhanced.

[0028] For the realization of the above circuit structure, the process of manufacturing a diode structure on an existing pressure sensor chip is difficult and the manufacturing cost is high. If it is added to the peripheral circuit outside the chip, the number of large-area diodes in the integrated circuit will increase, which will increase the system cost and reduce the integration.

[0029] In response to the above technical issues, Figure 5A schematic diagram of the structure of a pressure sensor provided according to an embodiment of the present application is given. The pressure sensor includes a strain area A1 and a support area A2. The support area A2 is arranged around the strain area A1. The scope of the strain area A1 and the support area A2 includes the substrate layer 10 and all structures in the direction perpendicular to the substrate layer 10. It should be noted that the boundary between the strain area A1 and the support area A2 is not limited. Figure 5 In the example shown, the edge of the varistor region 40 farthest from the center is used as the dividing line. In some other embodiments, the edge of the top of the back cavity 70 may also be used as the dividing line.

[0030] The pressure sensor also includes a substrate layer 10, a dielectric layer 20, a first metal layer 30, a piezoresistive resistor area 40 and a diode area 50. The substrate layer 10 is located in the strain area A1 and the support area A2. The dielectric layer 20 is located in the strain area A1 and the support area A2, is arranged on the surface of the substrate layer 10, and includes a first surface close to the substrate layer 10 and an opposite second surface. The first metal layer 30 is located in the support area A2 and is arranged on the second surface of the dielectric layer 20. The piezoresistive resistor area 40 is located in the strain area A1 and is arranged on the substrate layer 10. The piezoresistive resistor area 40 is configured to change the size of the resistance value according to the pressure applied to the strain area A1. The diode area 50 is located in the support area A2 and is arranged on the substrate layer 10. The diode area 50 is electrically connected to the first metal layer 30, and the diode area 50 forms at least one diode with the substrate layer 10.

[0031] In some embodiments, the dielectric layer 20 may include an electrically insulating material, and the dielectric layer 20 is continuously disposed on the surface of the substrate layer 10 , so that the substrate layer 10 is insulated from the first metal layer 30 .

[0032] In some embodiments, the pressure sensor also includes a first voltage terminal V1, a second voltage terminal V2, a ground voltage terminal GND and a power supply voltage terminal VDD electrically connected to the first metal layer 30, wherein the ground voltage terminal GND is coupled to a reference ground, and the power supply voltage terminal VDD receives a power supply voltage. When the resistance value of the voltage-variable resistor area 40 changes, the magnitude of the pressure applied to the strain area A1 is calculated based on the voltage difference between the first voltage terminal V1 and the second voltage terminal V2. The first metal layer 30 includes a plurality of first sub-metal layers 31 arranged at intervals, and the first sub-metal layer 31 is electrically connected to the first voltage terminal V1, the second voltage terminal V2, the ground voltage terminal GND or the power supply voltage terminal VDD. The first metal layer 30 can be configured in the form of a wire, a pad, etc., and the pad is used to connect to the voltage terminal of the pressure sensor to receive or output a voltage signal.

[0033] In some embodiments, the voltage-variable resistor area 40 is disposed in the substrate layer 10, connected to the first surface of the dielectric layer 20, and located on the inner side of the strain area A1 at the junction of the strain area A1 and the support area A2. The voltage-variable resistor area 40 includes a first resistor R1 electrically connected between the first voltage terminal V1 and the power supply voltage terminal VDD, a second resistor R2 electrically connected between the power supply voltage terminal VDD and the second voltage terminal V2, a third resistor R3 electrically connected between the second voltage terminal V2 and the ground voltage terminal GND, and a fourth resistor R4 electrically connected between the ground voltage terminal GND and the first voltage terminal V1. When the pressure on the strain area A1 changes, the resistance values ​​of the first resistor R1 and the third resistor R3 increase or decrease synchronously, and the resistance values ​​of the second resistor R2 and the fourth resistor R4 decrease or increase synchronously. The resistance value of the first resistor R1 is equal to the resistance value of the third resistor R3, and the resistance value of the second resistor R2 is equal to the resistance value of the fourth resistor R4.

[0034] Please refer to Figure 1 , exemplarily, the first resistor R1 and the third resistor R3 are symmetrically arranged, the second resistor R2 and the fourth resistor R4 are symmetrically arranged, and the center of each resistor is located at a vertex of the rhombus on a cross section perpendicular to the thickness direction of the substrate layer 10. When the pressure on the strain area A1 changes, the resistance values ​​of the first resistor R1 and the third resistor R3 increase or decrease synchronously, and the resistance values ​​of the second resistor R2 and the fourth resistor R4 decrease or increase synchronously. Figure 5 FIG. 2 shows two resistors that change synchronously in the voltage-variable resistance region, for example, Figure 5 The two resistors shown in the figure may be a first resistor R1 and a third resistor R3, or a second resistor R2 and a fourth resistor R4. It should be noted that: Figure 5 The structural diagram shown in the figure is only a schematic illustration of the layered structure of the pressure sensor and is not limited to the display of a specific cross-section of the pressure sensor.

[0035] exist Figure 5 In the illustrated embodiment, the diode region 50 is disposed on the substrate layer 10 and is in contact with the first surface of the dielectric layer 20. The substrate layer 10 and the diode region 50 are made of single crystal silicon, and the diode region 50 and the substrate layer 10 are doped to exhibit opposite conductivity types, and the doping concentration of the diode region 50 is greater than the doping concentration of the substrate layer 10. Exemplarily, the substrate layer 10 is N-type doped, and the diode region 50 is heavily P-type doped.

[0036] In some embodiments, the diode region 50 includes a plurality of sub-diode regions arranged at intervals, and the projection of the sub-diode region on the dielectric layer 20 overlaps at least partially with the projection of the corresponding first sub-metal layer 31 on the dielectric layer 20. Each sub-diode region and the substrate layer 10 form a diode, and a depletion layer 52 is formed at the boundary between the sub-diode region and the substrate layer 10. For the diode composed of the sub-diode region and the substrate layer 10, its positive electrode is the sub-diode region, which is electrically connected to the first metal layer 30 and then connected to each voltage terminal of the pressure sensor, and its negative electrode is the substrate layer 10, which is connected to the substrate voltage terminal Vsub through the doped substrate region 90. When working, the voltage of the substrate voltage terminal Vsub is greater than or equal to the power supply voltage terminal VDD, the diode is in a reverse bias cut-off state, and a stable junction capacitance is formed in the depletion layer 52, which can be used as an integrated filter capacitor to filter high-frequency noise. The diode region 50 can be integrated on the MEMS pressure sensor simultaneously with the varistor region through conventional semiconductor doping processes, without the need for additional semiconductor process steps, the process is simple, the cost is low, and the integration of the pressure sensor chip can be increased.

[0037] exist Figure 5 In the illustrated embodiment, the first metal layer 30 further includes a second sub-metal layer 32, and the pressure sensor further includes a doped substrate region 90. The doped substrate region 90 is located in the support region A2, is disposed in the substrate layer 10, and is in contact with the first surface of the dielectric layer 20. The doped substrate region 90 is connected to the second sub-metal layer 32 through a through hole 21 penetrating the dielectric layer 20, and the second sub-metal layer 32 is connected to the substrate voltage terminal Vsub. Exemplarily, the doped substrate region 90 can be N-type heavily doped, connected to the second sub-metal layer 32 through the through hole 21, and provides the substrate voltage terminal Vsub for the entire substrate layer 10.

[0038] In some embodiments, the pressure sensor further includes a lead area 60, which is located in the support area A2, disposed in the substrate layer 10, and connected to the first surface of the dielectric layer 20. One end of the lead area 60 is connected to the varistor area 40, and the other end is connected to the first metal layer 30 through a through hole 21 that penetrates the dielectric layer 20. The through hole 21 is filled with metal, and the through hole 21 is in metal contact with the first metal layer 30, and is in ohmic contact with the lead area 60.

[0039] The lead region 60 and the piezoresistive resistor region 40 are made of single crystal silicon, and are doped to exhibit the same conductivity type, the doping concentration of the lead region 60 is greater than the doping concentration of the piezoresistive resistor region 40, and the conductivity type of the lead region 60 and the piezoresistive resistor region 40 is opposite to that of the substrate layer 10. Exemplarily, the piezoresistive resistor region 40 is P-type doped, and the lead region 60 is P-type heavily doped.

[0040] In some embodiments, the pressure sensor further includes a back cavity 70. The back cavity 70 is disposed on the substrate layer 10 and is open in a direction away from the dielectric layer 20. The projection of the first cross section of the back cavity 70 at least partially overlaps with the projection of the strain region A1 in a thickness direction perpendicular to the substrate layer 10, wherein the first cross section is the cross section with the largest area among all cross sections of the back cavity 70 in a direction parallel to the surface of the substrate layer 10. The substrate layer 10 located in the strain region A1 between the back cavity 70 and the dielectric layer 20 forms a strain film 80, and when the strain film 80 is subjected to pressure, the resistance value of the pressure-variable resistor region 40 changes.

[0041] In some embodiments, the substrate layer 10 is a semiconductor N-type doped <crystal direction 100> silicon wafer with a doping concentration of 1x10 14 cm -3 ~1x10 17 cm -3 ; The doping concentration of the doped substrate region 90 is greater than 1x10 20 cm -3 The doping type of the varistor region 40 is P type, and its doping concentration is 1x10 17 cm -3 ~1x10 20 cm -3 The doping type of the lead region 60 is P type, and its doping concentration is greater than 1x10 20 cm -3 The dielectric layer 20 may include silicon oxide or a composite structure of silicon oxide and silicon nitride. The first metal layer 30 may include metal aluminum (Al), gold (Au), platinum (Pt), and alloy metal layers thereof.

[0042] In the structure shown in the above embodiment, the diode region, the varistor region, the lead region, etc. are doped regions arranged at intervals or continuously, and are formed by doping, deposition, etc. in semiconductor processes. The specific steps of doping, deposition, etc. of each region can be designed according to actual needs, and the embodiment of the present application does not specifically limit this. Among them, the number of doped regions and the doping concentration and doping ions of each doped region can be determined according to the performance design requirements of the device.

[0043] The present application forms a more integrated diode structure on a MEMS pressure sensor using a bridge circuit, and utilizes the junction capacitance of the diode to filter out high-frequency noise and electromagnetic interference from the external environment, thereby blocking their coupling to the output end, suppressing common-mode noise, improving the signal-to-noise ratio and anti-interference ability of the sensor, and making the sensor more stable and having higher output accuracy.

[0044] In addition, the above-mentioned diode area is formed by the same doping process as that for manufacturing varistor, and is easy to be integrated into the MEMS pressure sensor chip without the need for additional process flow, low cost and simple process; at the same time, because the diode area has been integrated into the MEMS pressure sensor chip in advance, there is no need to add filter resistors and diodes in the back-end processing circuit or sensor conditioning chip, thereby reducing the use of large-area diodes in components or integrated circuits and reducing system costs.

[0045] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0046] In summary, although the present application has been disclosed as above with preferred embodiments, the above preferred embodiments are not intended to limit the present application. Ordinary technicians in this field can make various changes and modifications without departing from the spirit and scope of the present application. Therefore, the scope of protection of the present application shall be based on the scope defined in the claims.

Claims

1. A pressure sensor, characterized in that: include: strain area; A support area, arranged around the strain area; A substrate layer, located in the strain region and the support region; a dielectric layer, located in the strain region and the support region, disposed on the surface of the substrate layer, and comprising a first surface close to the substrate layer and an opposite second surface; A first metal layer, located in the support area and disposed on the second surface of the dielectric layer; A pressure-variable resistance region, located in the strain region and disposed on the substrate layer, wherein the pressure-variable resistance region is configured to change the magnitude of the resistance value according to the pressure applied to the strain region; The diode region is located in the support region and is disposed on the substrate layer. The diode region is electrically connected to the first metal layer. The diode region and the substrate layer form at least one diode.

2. The pressure sensor according to claim 1, characterized in that: The pressure sensor further includes a first voltage terminal, a second voltage terminal, a ground voltage terminal and a power supply voltage terminal electrically connected to the first metal layer, the ground voltage terminal is coupled to a reference ground, and the power supply voltage terminal receives a power supply voltage; When the resistance value of the voltage-variable resistor area changes, the magnitude of the pressure applied to the strain area is calculated according to the voltage difference between the first voltage end and the second voltage end.

3. The pressure sensor according to claim 2, characterized in that: The first metal layer includes a plurality of first sub-metal layers arranged at intervals, and the first sub-metal layers are electrically connected to the first voltage terminal, the second voltage terminal, the ground voltage terminal or the power supply voltage terminal.

4. The pressure sensor according to claim 3, characterized in that: The diode region includes a plurality of sub-diode regions arranged at intervals, and projections of the sub-diode regions on the dielectric layer at least partially overlap with projections of corresponding first sub-metal layers on the dielectric layer.

5. The pressure sensor according to claim 1, characterized in that: The diode region is connected to the first surface of the dielectric layer.

6. The pressure sensor according to claim 1, characterized in that: The substrate layer and the diode region are made of single crystal silicon, and the diode region and the substrate layer are doped to exhibit opposite conductivity types.

7. The pressure sensor according to claim 1, characterized in that: A depletion layer is formed at a boundary between the substrate layer and the diode region.

8. The pressure sensor according to claim 2, characterized in that: The voltage-variable resistor area includes a first resistor electrically connected between the first voltage terminal and the power supply voltage terminal, a second resistor electrically connected between the power supply voltage terminal and the second voltage terminal, a third resistor electrically connected between the second voltage terminal and the ground voltage terminal, and a fourth resistor electrically connected between the ground voltage terminal and the first voltage terminal; When the pressure on the strain area changes, the resistance values ​​of the first resistor and the third resistor increase or decrease synchronously, and the resistance values ​​of the second resistor and the fourth resistor decrease or increase synchronously.

9. The pressure sensor according to claim 8, characterized in that: The resistance value of the first resistor is equal to the resistance value of the third resistor; the resistance value of the second resistor is equal to the resistance value of the fourth resistor.

10. The pressure sensor according to claim 1, wherein: The pressure sensor further comprises a lead area, which is located in the support area, arranged in the substrate layer, and connected to the first surface of the dielectric layer; One end of the lead area is connected to the voltage-variable resistor area, and the other end is connected to the first metal layer through a through hole penetrating the dielectric layer.

11. The pressure sensor according to claim 10, characterized in that: The lead area and the varistor area are made of single crystal silicon, are doped to exhibit the same conductivity type, the doping concentration of the lead area is greater than the doping concentration of the varistor area, and the conductivity type of the lead area and the varistor area is opposite to that of the substrate layer.

12. The pressure sensor according to claim 1, wherein: The pressure sensor also includes a back cavity; The back cavity is arranged on the substrate layer and is open in a direction away from the dielectric layer; The first cross section of the back cavity at least partially overlaps with the projection of the strain region in a thickness direction perpendicular to the substrate layer, wherein the first cross section is the cross section with the largest area among all cross sections of the back cavity in a surface direction parallel to the substrate layer; The substrate layer located in the strain region between the back cavity and the dielectric layer forms a strain film. When the strain film is subjected to pressure, the resistance value of the pressure-variable resistor region changes.

13. The pressure sensor according to claim 1, wherein: The first metal layer further includes a second sub-metal layer, and the pressure sensor further includes a doped substrate region; The doped substrate region is located in the support region, is disposed on the substrate layer, and is in contact with the first surface of the dielectric layer; The doped substrate region is connected to the second sub-metal layer through a through hole penetrating the dielectric layer, and the second sub-metal layer is connected to the substrate voltage terminal.

14. The pressure sensor according to claim 13, characterized in that: The doped substrate region is made of single crystal silicon. The doped substrate region and the substrate layer are doped to exhibit the same conductivity type. The doping concentration of the doped substrate region is greater than the doping concentration of the substrate layer.

15. The pressure sensor according to any one of claims 1 to 14, characterized in that: The substrate layer is of N-type conductivity, and the piezoresistive resistor region is of P-type conductivity.

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