CN216410458U

CN216410458U - Pressure sensor

Info

Publication number: CN216410458U
Application number: CN202122824856.9U
Authority: CN
Inventors: 吕萍; 胡维; 李刚
Original assignee: Memsensing Microsystems Suzhou China Co Ltd
Current assignee: Memsensing Microsystems Suzhou China Co Ltd
Priority date: 2021-11-17
Filing date: 2021-11-17
Publication date: 2022-04-29
Anticipated expiration: 2031-11-17

Abstract

The application provides a pressure sensor, has solved the not enough problem of pressure sensor's sensitivity and stability among the prior art. The embodiment of the application can prevent the piezoresistor unit from being influenced by the charges of the section of the piezoresistor unit or the surface charges accumulated to the sensor from the outside by arranging the shielding pattern above the piezoresistor unit. Meanwhile, the shielding pattern is connected to the substrate through the first through hole structure, so that charges can be introduced into the substrate (fixed potential), the influence of the charges on the piezoresistive region is reduced, and the stability of a detection result is improved.

Description

Pressure sensor

Technical Field

The application relates to the field of micro-electromechanical systems, in particular to a pressure sensor.

Background

Pressure transducers (Pressure transducers) are devices or devices that can sense Pressure signals and convert them into usable output electrical signals according to a certain rule, and are widely used in the fields of consumer electronics, medical treatment, automobiles, and industrial control. However, as detection technology advances, higher requirements are placed on the sensitivity and stability of pressure sensors.

SUMMERY OF THE UTILITY MODEL

In view of the above, embodiments of the present application are directed to providing a pressure sensor to solve the problem of insufficient sensitivity and stability of the pressure sensor in the prior art.

The application provides a pressure sensor, includes: a substrate; the sensitive layer is arranged on the substrate and comprises at least one group of piezoresistor units; the dielectric layer is arranged on the sensitive layer; at least one shielding pattern disposed on the dielectric layer over the at least one group of piezoresistive units; and at least one first through hole structure penetrating through the dielectric layer, the first through hole structure being electrically connected to the at least one shielding pattern and the substrate, respectively.

In one embodiment, the shielding pattern comprises a first portion, wherein a projection of the first portion of the at least one shielding pattern on the sensitive layer covers the at least one group of piezoresistive units.

In one embodiment, the shape of the projection of the first portion of the at least one shielding pattern on the sensitive layer is the same as the shape of the corresponding at least one group of piezoresistive units.

In one embodiment, the at least one group of the piezoresistor units comprises a first lightly doped region, a heavily doped region and a second lightly doped region, and the ends of the first lightly doped region, the heavily doped region and the second lightly doped region are electrically connected in sequence; the first part of the at least one shielding pattern comprises a first region, a second region and a third region which are sequentially connected, and projections of the first region, the second region and the third region on the sensitive layer respectively cover the first lightly doped region, the heavily doped region and the second lightly doped region; the projection shapes of the first region, the second region and the third region on the sensitive layer are respectively the same as the shapes of the first lightly doped region, the heavily doped region and the second lightly doped region.

In one embodiment, the projection of the first region on the sensitive layer has a size equal to or slightly larger than that of the first lightly doped region; the projection size of the second region on the sensitive layer is equal to or slightly larger than the size of the heavily doped region; the projection size of the third area on the sensitive layer is equal to or slightly larger than the size of the second lightly doped area.

In one embodiment, the first lightly doped region and the second lightly doped region are substantially parallel, and the first lightly doped region and the second lightly doped region are respectively substantially perpendicular to the heavily doped region; the first region and the third region are substantially parallel, and the first region and the third region are respectively substantially perpendicular to the second region.

In one embodiment, the first lightly doped region, the heavily doped region and the second lightly doped region are substantially in the same line; the first region, the second region, and the third region are substantially collinear.

In one embodiment, the shielding pattern further includes a second portion having both ends electrically connected to the first via structure and the first portion, respectively.

In one embodiment, the pressure sensor further comprises: the pin is arranged on the dielectric layer and is used for being electrically connected with an external circuit; the interconnection pattern is arranged on the dielectric layer and is electrically connected with the pins; and the second through hole structure penetrates through the dielectric layer, and two ends of the second through hole structure are respectively and electrically connected with the interconnection pattern and the piezoresistor unit.

In one embodiment, the interconnection pattern and the shielding pattern are made of the same material.

In one embodiment, the material of the shielding pattern is doped polysilicon or metal.

In one embodiment, the material of the shielding pattern is aluminum.

In one embodiment, the first via structure includes a conductive structure, and a material of the conductive structure is the same as a material of the shielding pattern.

In one embodiment, the sensitive layer comprises four groups of piezoresistive units; the at least one shielding pattern is specifically four shielding patterns, and the four shielding patterns are respectively and correspondingly arranged above the four groups of piezoresistor units.

In one embodiment, the at least one first via structure is specifically four first via structures, and each first via structure is electrically connected to a corresponding shielding pattern.

In one embodiment, the sensitive layer comprises: two groups of first piezoresistor units which are oppositely arranged; two groups of second piezoresistor units which are oppositely arranged; the at least one shielding pattern is specifically: two first shielding patterns disposed oppositely; and two second shielding patterns disposed oppositely; the first piezoresistor units and the first parts of the first shielding patterns are respectively rectangular in a long strip shape, and the two first shielding patterns are respectively and correspondingly arranged above the two groups of first piezoresistor units; the second piezoresistor units and the first parts of the second shielding patterns are respectively in a U shape, and the two second shielding patterns are respectively and correspondingly arranged above the two groups of second piezoresistor units.

The application provides a pressure sensor, among the prior art pressure sensor's sensitivity and the not enough problem of stability. The embodiment of the application can prevent the piezoresistor unit from being influenced by the charges of the section of the piezoresistor unit or the surface charges accumulated to the sensor from the outside by arranging the shielding pattern above the piezoresistor unit. Meanwhile, the shielding pattern is connected to the substrate through the first through hole structure, so that charges can be introduced into the substrate (fixed potential), the influence of the charges on the piezoresistive region is reduced, and the stability of a detection result is improved. The shape of the first part of at least one shielding pattern is basically the same as that of the piezoresistor unit, so that the shielding pattern can play a shielding role and reduce the coverage area, the pressure hysteresis generated by the self gravity of the shielding pattern is reduced, and the sensitivity and the stability of the pressure sensor can be improved.

Drawings

FIG. 1 is a schematic diagram of a pressure sensor of a comparative example;

FIG. 2 is a schematic diagram of a pressure sensor according to an embodiment of the present application;

FIG. 3 illustrates a top view of a pressure sensor in accordance with an embodiment of the present application;

FIG. 4 is a schematic cross-sectional view taken along section line AA in FIG. 3;

FIG. 5 is a schematic cross-sectional view taken along section line BB in FIG. 3;

FIG. 6 is an enlarged view of a portion of the area S in FIG. 3;

FIG. 7 is a schematic cross-sectional view taken along section line CC in FIG. 6;

FIG. 8 is a top view of a pressure sensor according to another embodiment of the present application;

FIG. 9 is a top view of a pressure sensor according to another embodiment of the present application;

FIG. 10 is a top view of a pressure sensor according to another embodiment of the present application;

fig. 11 is a top view of a pressure sensor according to another embodiment of the present application.

Description of the reference numerals

1-a substrate; 2-a sensitive layer; 3-a dielectric layer; 4-lightly doped region; 5-heavily doped region; 6-through holes; 7-a pin; 8-a pressure chamber;

10-a substrate; 11-a pressure chamber; 20-a sensitive layer; 21-a varistor unit; 211/211' -a first lightly doped region; 212/212' -heavily doped regions; 213/213' -a second lightly doped region; 2101-a first piezoresistive unit; 2102-a second piezoresistive unit; 30-a dielectric layer; 40-a shielding pattern; 41/41' -a first part; 42-a second portion; 401 — a first shielding pattern; 402-a second shielding pattern; 50-a first via structure; 60-pin; 70-an interconnect pattern; 80-a second via structure; 90-interconnect line.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The pressure sensor is the most common sensor in industrial practice, is widely applied to various industrial automatic control environments, and relates to a plurality of industries such as water conservancy and hydropower, railway traffic, intelligent buildings, production automatic control, aerospace, military industry, petrochemical industry, oil wells, electric power, ships, machine tools, pipelines and the like.

With the development of semiconductor technology, semiconductor pressure sensors have come to be developed. Its advantages are small size, light weight, high accuracy and high temp. The piezoresistive pressure sensor is one kind of semiconductor pressure sensor, and has the advantages of high sensitivity, simple process, capacity of being processed in batch, etc. The piezoresistive pressure sensor is formed by doping piezoresistor units on a sensitive film to form a piezoresistor unit and connecting the piezoresistor units into a Wheatstone bridge based on the piezoresistive effect principle of silicon. The piezoresistive pressure sensor is characterized in that a piezoresistor unit is formed on a pressure sensitive film by an ion implantation method, when the external pressure changes, the pressure sensitive film generates tensile or compressive stress, so that the resistance value of the piezoresistor unit changes, and therefore, the change value of the external pressure can be obtained by detecting the change value of the resistance value of a resistor strip.

Fig. 1 shows a schematic view of a pressure sensor of a comparative example. As shown in fig. 1, the pressure sensor of the comparative example includes a substrate 1, a sensitive layer 2, and a dielectric layer 3. The sensitive layer 2 is formed on a pressure chamber 8 of the substrate 1, and specifically, the sensitive layer 2 (the region of the substrate 1 within the range of the dotted line frame) is formed by ion doping at least a partial region of the substrate 1 above the pressure chamber 8. The sensitive layer 2 is used for sensing pressure and generates corresponding deformation according to the pressure. The surface of the sensitive layer 2 is provided with a piezoresistor unit, the piezoresistor unit comprises a lightly doped region 4 and a heavily doped region 5, the lightly doped region 4 is equivalent to piezoresistance, and the heavily doped region 5 is equivalent to a lead. The piezoresistor units are correspondingly arranged above the pressure cavities 8 of the substrate 1. A dielectric layer 3 is arranged above the sensitive layer 2, a through hole 6 is arranged at the position, above the heavily doped region, of the dielectric layer 3, and metal is deposited in the through hole 6. An electrical connection structure (not shown) and a lead 7 are formed on the upper surface of the dielectric layer 3.

Since the piezoresistor unit of the piezoresistive pressure sensor is prepared by a semiconductor doping process, the piezoresistor unit is easily influenced by an internal electric field or an external electric field, and the doping distribution of the piezoresistor is changed to generate output drift. In some small-scale pressure sensors, the influence of errors caused by output drift is relatively large. In special application occasions, such as application scenes of filling silicone oil at high pressure, under the action of an external electric field, electric charges can be accumulated at the junction of the oil and the sensor, so that the output of the piezoresistive sensor is drifted. Such as electrostatic Discharge (ESD) on some package structures, can also cause output drift. In addition, in some special applications, such as strong light irradiation, the carrier doping distribution is also changed, and output drift occurs. Because the output drift affects not only the sensitivity of the pressure sensor but also the service life of the pressure sensor, it is necessary to optimize the chip to reduce the output drift, so as to improve the accuracy and performance stability of the pressure sensor.

In view of this, an embodiment of the present disclosure provides a pressure sensor, which can stabilize interface charges around a voltage-sensitive resistor unit, or introduce charges into a fixed potential without affecting a detection result, so as to improve sensitivity and performance stability of the pressure sensor.

Fig. 2 is a schematic diagram of a pressure sensor according to an embodiment of the present application. As shown in fig. 2, the pressure sensor specifically includes: a substrate 10, a sensitive layer 20, a dielectric layer 30, at least one shielding pattern 40, and a first via structure (not shown).

The substrate 10 is used to provide support for other structures. The substrate 10 may be an insulating material, such as silicon oxide or a resin material, in one embodiment, the substrate 10 is made of a semiconductor material, specifically, N-type single crystal silicon, or gallium nitride or silicon carbide, and the substrate 10 and the sensitive layer 20 thereon may be separated by a dielectric layer, which may be an insulating material, such as silicon oxide, silicon nitride or a stack thereof. It should be understood that in other embodiments, the pressure sensor may also be fabricated using SOI (silicon on insulator).

A pressure chamber 11 is provided in the substrate 10 to provide a reference pressure. The pressure chamber 11 may be a sealed vacuum chamber or an atmospheric pressure chamber.

The sensitive layer 20 is formed on a partial area of the substrate 10. Specifically, the sensitive layer 20 is above the region of the pressure chamber 11 in the substrate 10, that is, the sensitive layer 20 may be the region of the substrate 10 within the range of the dotted line frame, and the sensitive layer 20 is formed by ion doping a predetermined position of the substrate 10 above the region of the pressure chamber. The sensitive layer 20 comprises at least one set of piezoresistors 21. The piezoresistor 21 is correspondingly formed above the pressure cavity 11, and the piezoresistor unit 21 is used for acquiring pressure and generating corresponding deformation according to the received pressure.

A dielectric layer 30 is disposed on the sensitive layer 20. The material of the dielectric layer 30 may be silicon oxide, silicon nitride or a combination of silicon oxide and silicon nitride.

At least one shielding pattern 40 is correspondingly disposed on the dielectric layer above at least one group of the varistor units 21. Further, the projection of the shielding pattern 40 on the sensitive layer 20 covers the piezoresistive unit 21.

At least one first via structure 50 penetrates the dielectric layer 30, and the first via structure 50 is electrically connected to at least one shielding pattern 40 and the substrate 10, respectively.

In an embodiment of the present application, the pressure sensor further includes a pin 60, an interconnection pattern 70, a second via structure 80, and an interconnection line 90. The pins 60, the interconnection pattern 70, the second via structures 80, and the interconnection lines 90 are used to make electrical connections between components of the pressure sensor to constitute a circuit of the pressure sensor.

In the embodiment of the present application, the shielding pattern 40 functions as a shield to prevent the varistor unit 21 from being influenced by the cross-sectional charge itself or the surface charge accumulated to the sensor from the outside. And the shielding pattern 40 is connected to the substrate 10 through the first via structure 50, so that charges can be introduced into the substrate 10 (fixed potential), the influence of the charges on the piezoresistive region is reduced, and the stability of the detection result is improved. Meanwhile, the shielding layer also prevents the output drift caused by the redistribution of carriers caused by strong light irradiation.

Fig. 3-7 are schematic diagrams of a pressure sensor according to an embodiment of the present application. As shown in fig. 3 to 7, the pressure sensor specifically includes: a substrate 10, a sensitive layer 20, a dielectric layer 30, at least one shielding pattern 40, and a first via structure 50.

To facilitate the illustration of the internal structure of the pressure sensor, the pressure sensor shown in fig. 3 is a top view with the medium layer 30 omitted.

As shown in fig. 3 and 7, the sensitive layer 20 is disposed on the substrate 10 and includes at least one group of piezoresistive units 21. The sensitive layer 20 covers the upper surface of the substrate 10. The material of the sensitive layer 20 may be any semiconductor material with voltage variation characteristics, and in one embodiment, the material of the sensitive layer 20 is silicon. When the external pressure changes, the sensitive layer 20 on the pressure chamber 11 is stressed and deformed. The piezoresistive unit 21 is formed by doping a predetermined position of the sensitive layer 20. The doping mode can be ion implantation or diffusion, the doped ions can be boron ions, when the sensitive layer 20 is subjected to external pressure, the piezoresistor unit 21 deforms, and then the change value of the external pressure can be obtained through the change of the resistance value of the piezoresistor unit 21. The doping types of the first lightly doped region 211, the heavily doped region 212, and the second lightly doped region 213 are the same. The heavily doped region 212 has a doping concentration greater than that of the first and second lightly doped

regions

211 and 213, respectively.

The varistor unit 21 may be formed by doping in a predetermined region. In a specific application, the number of the piezo-resistor units 21 may be set according to a specific requirement, and in one embodiment, the number of the piezo-resistor units 21 may be four, and these piezo-resistor units 21 may be used to form a wheatstone bridge, and pressure value measurement may be implemented by the wheatstone bridge.

As shown in fig. 3, in one embodiment, the first varistor unit 2101 includes a first lightly doped region 211, a heavily doped region 212, and a second lightly doped region 213, and ends of the first lightly doped region 211, the heavily doped region 212, and the second lightly doped region 213 are electrically connected in sequence. The first lightly doped region 211, the heavily doped region 212, and the second lightly doped region 213 are substantially located on the same line. Wherein the first lightly doped region 211 and the second lightly doped region 213 are electrically connected to each other through the heavily doped region 212. The heavily doped region 212 functions as a conductive line, and the first and second lightly doped

regions

211 and 213 serve to sense pressure. That is, the first lightly doped region 211 and the second lightly doped region 213 correspond to a piezoresistive structure, and the heavily doped region 212 corresponds to a conductive line.

In another embodiment, the first lightly doped region 211 ' and the second lightly doped region 213 ' in the second varistor unit 2102 are substantially parallel, and the heavily doped region 212 ' is substantially perpendicular to the first lightly doped region 211 ' and the second lightly doped region 213 ', respectively. That is, the second varistor unit 212 is approximately "U" shaped.

It will be appreciated that in other implementations, the shape, size, and relative position of the piezoresistive unit 21 may be adapted as desired.

In the present embodiment, the four varistor units 21 are arranged two by two in opposition, and specifically, it can be considered that the four varistor units 21 are arranged in the middle regions of the four sides of one square. Wherein the shape of the two opposing piezoresistive units 21 is substantially the same. In this embodiment, the shape of one set of two opposing first varistor units 2101 is an elongated shape, and the shape of the other set of two opposing second varistor units 2102 is approximately "U" shaped.

As shown in fig. 3, the shielding pattern 40 is disposed on the dielectric layer 30, the shielding pattern 40 includes a first portion 41 and a second portion 42, an orthographic projection of at least one first portion 41 on the sensitive layer 20 covers the varistor unit 21, and a shape and a size of the projection of the first portion 41 on the sensitive layer 20 are substantially the same as a shape and a size of the varistor unit 21. That is, the projected area of the first portion 41 on the sensitive layer 20 is equal to or slightly larger than the varistor unit 21.

Specifically, the first portion 41 of the at least one shielding pattern 40 includes a first region, a second region and a third region connected in sequence, and projections of the first region, the second region and the third region on the sensitive layer 20 respectively cover the first lightly doped region 211, the heavily doped region 212 and the second lightly doped region 213. The shape and size of the projection of the first region, the second region and the third region on the sensitive layer are substantially the same as the shape and size of the first lightly doped region 211, the heavily doped region 212 and the second lightly doped region 213, respectively.

As shown in fig. 4, the first via structure 50 penetrates the dielectric layer 30, and the first via structure 50 is electrically connected to the shield pattern 40 and the substrate 10, respectively. Both ends of the second portion 42 of the shielding pattern 40 are electrically connected to the first via structure 50 and the first portion 41, respectively. The first via structure 50 is substantially perpendicular to the surface of the dielectric layer 30, and the first via structure 50 includes a conductive structure therein, which may be a metal, such as aluminum, gold, copper, or silver. Both ends of the conductive structure are electrically connected to the shield pattern 40 and the substrate 10, respectively, so that the potentials of the shield pattern 40 and the substrate 10 are the same.

In an embodiment, the first via structure 50 includes a conductive structure, and the material of the conductive structure is the same as the material of the shielding pattern 40, so that the conductive structure 50 and the shielding pattern 40 can be formed in one process, which can improve the production efficiency of the pressure sensor, and meanwhile, the material is the same, so that the bonding property between the conductive structure 50 and the shielding pattern 40 is better, the connection between the conductive structure and the shielding pattern 40 is more stable, and the reliability of the pressure sensor is improved.

In order to facilitate the display of the corresponding relationship between the shielding pattern 40 and the varistor unit 21, the shielding pattern 40 in fig. 3 is illustrated in a transparent form. As shown in fig. 3, the shielding pattern 40 functions as a shield to prevent the varistor unit 21 from being affected by the charge of its own cross section or the surface charge accumulated to the sensor from the outside. And the shielding pattern 40 is connected to the substrate 10 through the first via structure 50, so that charges can be introduced into the substrate 10 (fixed potential), the influence of the charges on the piezoresistive region is reduced, and the stability of the detection result is improved. Meanwhile, the shielding pattern 40 also serves to prevent output drift caused by redistribution of carriers due to strong light irradiation. In one embodiment, the substrate 10 may be grounded.

As shown in fig. 3, the sensitive layer 20 includes four groups of piezoresistive units 21. The at least one shielding pattern 40 may be one, two, three or more, in the present embodiment, the at least one shielding pattern 40 is specifically four shielding patterns 40, and the four shielding patterns 40 are respectively disposed above the four groups of varistor units 21.

As shown in fig. 3, the pressure sensor specifically includes four first through hole structures 50, the four first through hole structures 50 are respectively disposed corresponding to the four shielding patterns 40, and each first through hole structure 50 is electrically connected to the corresponding shielding pattern 40.

The orthographic projections of four shielding patterns 40 on the sensitive layer 20 cover the piezoresistor units 21, and the shape of the projection of the first part 41 of at least one shielding pattern 40 on the sensitive layer 20 is the same as that of the corresponding at least one group of piezoresistor units 21. In the present embodiment, the shape and size of the projection of the first portions 41 of the two opposing first shielding patterns 401 on the sensitive layer 20 are substantially the same as the shape and size of the varistor unit 21. The area of the projection of the first portion 41' of the second shielding pattern 402 on the sensitive layer 20 is larger than the area of the projection of the piezoresistive unit 21 on the sensitive layer 20.

Specifically, the first portions 41 of the two first shield patterns 401 respectively disposed above the two elongated first piezoresistive units 2101 are respectively elongated rectangles, the size of the long side of the rectangle is slightly larger than or substantially equal to the sum of the sizes of the first lightly doped region 211, the heavily doped region 212 and the second lightly doped region 213 in the length direction, and the size of the short side of the rectangle is slightly larger than or substantially equal to the size of the first lightly doped region 211, the heavily doped region 212 or the second lightly doped region 213 in the width direction. The first portions 41 ' of the second shield patterns 402, which are respectively disposed over the two "U" -shaped second varistor units 2102, have a rectangular shape, a long side of which has a size slightly greater than or substantially equal to a size of the heavily doped region 212 ' in the length direction, and a short side of which has a size slightly greater than a size of the first lightly doped region 211 ' in the length direction.

The projected area of the first portion 41 on the sensitive layer 20 is equal to or slightly larger than the piezoresistive unit 21. The shape of the projection of the first portion 41 on the sensitive layer 20 is substantially the same as the shape of the piezoresistive unit 21, which reduces the effective area covered and thus reduces the pressure hysteresis. The influence of the added shielding layer on the detection precision is avoided.

The material of the shielding pattern 40 may be a material with good conductivity, such as doped polysilicon or metal. The thickness of the shielding pattern 40 is 10nm to 50nm, and for example, the thickness of the shielding pattern 40 is 20nm, 30nm, 40nm, or the like.

In one embodiment, the material of the shielding pattern 40 is doped polysilicon. The doped polysilicon has good bonding property with the dielectric layer 30, has the advantages of good conductivity, low thermal expansion coefficient and the like, and can ensure the reliability and the accuracy of the pressure sensor.

In one embodiment, the material of the shielding pattern 40 is a metal, and specifically, the material of the shielding pattern 40 may be a metal with low density and good conductivity. For example, the material of the shielding pattern 40 is aluminum. Because the Young's modulus and the thermal expansion coefficient of the metal material are respectively different from those of the dielectric layer 30 by a large amount, hysteresis can be caused, and the aluminum has the characteristic of low density, so that the pressure and temperature hysteresis brought by the metal material can be reduced. The thickness of the shielding pattern 40 is 10nm to 50nm, for example, the thickness of the shielding pattern 40 is 20nm, 30nm, 40nm, etc. Since the thickness of the shielding pattern 40 is thin, the weight of the shielding pattern 40 can be reduced, and thus, the problem of the detection accuracy being lowered due to the pressure of the shielding pattern 40 itself can be solved.

As shown in fig. 3, in an embodiment of the present application, the pressure sensor further includes a pin 60, an interconnection pattern 70, and a second via structure 80.

As shown in fig. 3, a pin 60 is disposed on the dielectric layer 30 for electrical connection to an external circuit. In the present embodiment, the pressure sensor includes four pins 60, and specifically, the four pins 60 may be a power supply terminal, a ground terminal, an output positive terminal, and an output negative terminal, respectively. In the present embodiment, the upper surface of the substrate 10 of the pressure sensor is substantially square, the corresponding upper surface of the dielectric layer 30 is also square, and the four pins 60 are respectively disposed at positions close to four vertices of the square.

As shown in fig. 3, an interconnection pattern 70 is disposed on the dielectric layer 30 to be electrically connected to the leads 60. In the present embodiment, the interconnection pattern 70 connects the four pins 60 in sequence.

As shown in fig. 5 to 7, the second via structure 80 penetrates through the dielectric layer 30, and both ends of the second via structure 80 are electrically connected to the interconnection pattern 70 and the varistor unit 21, respectively. In the present embodiment, the varistor unit 21 is connected with the interconnection line 90, and the second via structure 80 is connected to the interconnection line 90 and the interconnection pattern 70. In the present embodiment, the interconnection pattern 70 and the second via structure 80 are used to electrically connect the respective structures in the pressure sensor to form a complete circuit of the pressure sensor. It should be understood that in other embodiments of the present application, the interconnect pattern 70 may be adapted according to the needs of the circuit structure.

The interconnection pattern 70 and the shielding pattern 40 may be the same material. The interconnection pattern 70 and the shielding pattern 40 are made of the same material, and the interconnection pattern 70 and the shielding pattern 40 can be formed through the same process, so that the production efficiency of the pressure sensor can be improved, and the production cost of the pressure sensor can be reduced.

In one embodiment, the material of the interconnection pattern 70 and the material of the shielding pattern 40 are both doped polysilicon, and the shielding pattern 40 and the interconnection pattern 70 can be formed simultaneously by one etching process.

In one embodiment, the material of the interconnection pattern 70 and the shielding pattern 40 is metal, and the interconnection pattern 70 and the shielding pattern 40 may be formed by electroplating, chemical vapor deposition, physical vapor deposition, and the like. For example, the interconnection pattern 70 and the shielding pattern 40 are made of aluminum.

It should be understood that in other embodiments of the present application, a protective layer or a packaging structure, etc. may also be disposed over the shielding pattern 40, the interconnection pattern 70, and the dielectric layer 30 to protect the pressure sensor.

It should be understood that the pressure sensor of the embodiments of the present application may be any type of pressure sensor, such as a differential pressure sensor or an absolute pressure sensor, and the measuring range of the pressure sensor may be any measuring range, and may be adaptively adjusted as needed.

Fig. 8 is a top view of a pressure sensor according to another embodiment of the present application. The difference from the above-described embodiment is that the shape of the shielding pattern 40 is different. As shown in fig. 8, in the present embodiment, the pressure sensor includes: two sets of first varistor units 2101 arranged oppositely and two sets of second varistor units 2102 arranged oppositely. The at least one shielding pattern 40 is specifically: two first shield patterns 401 disposed oppositely and two second shield patterns 402 disposed oppositely.

In particular, the shape of the projection of the first portion 41 of at least one shielding pattern 40 on the sensitive layer 20 is the same as the shape of the corresponding at least one group of piezoresistive units 21. In the present embodiment, the two second shield patterns 402 and the two sets of second varistor units 2102 have substantially the same shape and size. The second varistor units 2102 and the first portions 41' of the second shield patterns 402 have a "U" shape, respectively, and the two "U" shaped second shield patterns 402 are disposed above the two sets of second varistor units 2102, respectively.

Two first shielding patterns 401 are respectively disposed above the two groups of first varistor units 2101; the projection of the first part 41 of the first shielding pattern 401 on the sensitive layer 20 covers the first piezoresistive unit 2101, and the area of the projection of the shape of the first part 41 of the first shielding pattern 401 on the sensitive layer 20 is larger than the area of the projection of the first piezoresistive unit 2101 on the sensitive layer 20. The shape of the first varistor unit 2101 is approximately a long rectangular shape, the shape of the first shielding pattern 401 pattern is a rectangular shape, the size of the long side of the first shielding pattern 401 is larger than the size of the long side of the first varistor unit 2101, and the size of the short side of the first shielding pattern 401 is larger than the size of the short side of the first varistor unit 2101.

Fig. 9 is a top view of a pressure sensor according to another embodiment of the present application. The difference from the above-described embodiment is that the shape of the shielding pattern 40 is different. As shown in fig. 9, in the present embodiment, the pressure sensor includes: two sets of first varistor units 2101 arranged oppositely and two sets of second varistor units 2102 arranged oppositely. The at least one shielding pattern 40 is specifically: two first shield patterns 401 disposed oppositely and two second shield patterns 402 disposed oppositely.

In particular, the shape of the projection of the first portion 41 of at least one shielding pattern 40 on the sensitive layer 20 is the same as the shape of the corresponding at least one group of piezoresistive units 21. In the present embodiment, the two first shield patterns 401 and the two groups of first varistor units 2101 are substantially the same in shape and size; the two second shield patterns 402 and the two sets of first varistor units 2102 have substantially the same shape and size.

Specifically, the first varistor units 2101 and the first portions 41 of the first shield patterns 401 are respectively shaped as long rectangles, and the two first shield patterns 401 are respectively disposed above the two sets of first varistor units 2101. The second varistor units 2102 and the first portions 41' of the second shield patterns 402 are respectively shaped like a "U", and the two second shield patterns 402 are respectively disposed above the two sets of second varistor units 2102.

The application provides a pressure sensor, among the prior art pressure sensor's sensitivity and the not enough problem of stability. The embodiment of the present application can prevent the varistor unit 21 from being affected by the charge of the cross section itself or the surface charge accumulated to the sensor from the outside by providing the shielding pattern 40 above the varistor unit 21. Meanwhile, the shielding pattern 40 is connected to the substrate 10 through the first via structure 50, so that charges can be introduced into the substrate 10 (fixed potential), the influence of the charges on the piezoresistive region is reduced, and the stability of the detection result is improved. The shape of the first portion 41 of the at least one shielding pattern 40 and the shape and size of the varistor unit 21 are substantially the same, so that the shielding pattern 40 can reduce the coverage area while performing a shielding function, thereby reducing the pressure hysteresis generated by the gravity of the shielding pattern 40 itself, and improving the sensitivity and stability of the pressure sensor.

It is to be understood that the shape and size of the shielding pattern 40 may be adapted as desired, for example as shown in fig. 10, the first portion 41 of the shielding pattern 40 may cover the entire sensitive layer, for example as shown in fig. 11, and the first portion 41 of the shielding pattern 40 may be "back" shaped. In addition, the projection of the shielding pattern 40 on the substrate 10 may also cover the entire substrate 10.

The above description is only exemplary of the present application and should not be taken as limiting the present application, as any modifications, equivalents and the like that are within the spirit and principle of the present application should be included in the scope of the present application.

Claims

1. A pressure sensor, comprising:

a substrate;

the sensitive layer is arranged on the substrate and comprises at least one group of piezoresistor units;

the dielectric layer is arranged on the sensitive layer;

at least one shielding pattern disposed on the dielectric layer over the at least one group of piezoresistive units; and

and the first through hole structure penetrates through the dielectric layer, and is electrically connected with the at least one shielding pattern and the substrate respectively.

2. A pressure sensor according to claim 1, characterized in that the shielding pattern comprises a first part, wherein a projection of the first part of the at least one shielding pattern on the sensitive layer covers the at least one group of piezoresistive units.

3. A pressure sensor according to claim 2, wherein the shape of the projection of the first portion of the at least one shielding pattern onto the sensitive layer is the same as the shape of the corresponding at least one group of piezoresistive units.

4. The pressure sensor of claim 2, wherein the at least one group of piezoresistor units comprises a first lightly doped region, a heavily doped region and a second lightly doped region, and the ends of the first lightly doped region, the heavily doped region and the second lightly doped region are electrically connected in sequence;

the first part of the at least one shielding pattern comprises a first region, a second region and a third region which are sequentially connected, and projections of the first region, the second region and the third region on the sensitive layer respectively cover the first lightly doped region, the heavily doped region and the second lightly doped region;

the projection shapes of the first region, the second region and the third region on the sensitive layer are respectively the same as the shapes of the first lightly doped region, the heavily doped region and the second lightly doped region.

5. The pressure sensor of claim 4, wherein the projection of the first region on the sensitive layer has a size equal to or slightly larger than the size of the first lightly doped region; the projection size of the second region on the sensitive layer is equal to or slightly larger than the size of the heavily doped region; the projection size of the third area on the sensitive layer is equal to or slightly larger than the size of the second lightly doped area.

6. The pressure sensor of claim 4, wherein the first lightly doped region and the second lightly doped region are substantially parallel, and the first lightly doped region and the second lightly doped region are each substantially perpendicular to the heavily doped region;

the first region and the third region are substantially parallel, and the first region and the third region are respectively substantially perpendicular to the second region.

7. The pressure sensor of claim 4, wherein the first lightly doped region, the heavily doped region, and the second lightly doped region are substantially collinear;

the first region, the second region, and the third region are substantially collinear.

8. The pressure sensor of claim 2, wherein the shielding pattern further comprises a second portion, both ends of the second portion being electrically connected to the first via structure and the first portion, respectively.

9. The pressure sensor of claim 1, further comprising:

the pin is arranged on the dielectric layer and is used for being electrically connected with an external circuit;

the interconnection pattern is arranged on the dielectric layer and is electrically connected with the pins; and

and the second through hole structure penetrates through the dielectric layer, and two ends of the second through hole structure are respectively and electrically connected with the interconnection pattern and the piezoresistor unit.

10. The pressure sensor of claim 9, wherein the interconnect pattern and the shield pattern are the same material.

11. The pressure sensor of claim 1, wherein the material of the shielding pattern is doped polysilicon or metal.

12. The pressure sensor of claim 1, wherein the material of the shielding pattern is aluminum.

13. The pressure sensor of claim 1, wherein the first via structure comprises a conductive structure, and wherein a material of the conductive structure is the same as a material of the shielding pattern.

14. The pressure sensor of claim 1, wherein the sensing layer comprises four groups of piezoresistive units; the at least one shielding pattern is specifically four shielding patterns, and the four shielding patterns are respectively and correspondingly arranged above the four groups of piezoresistor units.

15. The pressure sensor of claim 14, wherein the at least one first via structure is specifically four first via structures, and each of the first via structures is electrically connected to a corresponding shielding pattern.

16. The pressure sensor of claim 2, wherein the sensing layer comprises:

two groups of first piezoresistor units which are oppositely arranged; and

two groups of second piezoresistor units which are oppositely arranged;

the at least one shielding pattern is specifically:

two first shielding patterns disposed oppositely; and

two second shielding patterns disposed oppositely;

the first piezoresistor units and the first parts of the first shielding patterns are respectively rectangular in a long strip shape, and the two first shielding patterns are respectively and correspondingly arranged above the two groups of first piezoresistor units;

the second piezoresistor units and the first parts of the second shielding patterns are respectively in a U shape, and the two second shielding patterns are respectively and correspondingly arranged above the two groups of second piezoresistor units.