CN217276654U - Pressure sensor applicable to high pressure detection - Google Patents
Pressure sensor applicable to high pressure detection Download PDFInfo
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- CN217276654U CN217276654U CN202220193701.1U CN202220193701U CN217276654U CN 217276654 U CN217276654 U CN 217276654U CN 202220193701 U CN202220193701 U CN 202220193701U CN 217276654 U CN217276654 U CN 217276654U
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Abstract
The application provides a pressure sensor that can be applied to high pressure detection includes: the bottom surface of the first substrate is upwards provided with a groove in a concave mode, the first substrate comprises an island structure located in the center and a fixed support structure located on the periphery, the groove is located between the island structure and the fixed support structure, and a first distance is reserved between the top of the groove and the top surface of the first substrate; the piezoresistance is embedded on the top surface of the first substrate and is positioned above the groove; a strain transfer layer disposed over the first substrate; the second substrate is covered on the strain transfer layer; and the third substrate is covered on the bottom surface of the first substrate. This application can be applied to pressure sensor that high pressure detected, sensitivity is higher.
Description
Technical Field
The application relates to the technical field of micro electro mechanical systems, in particular to a pressure sensor applicable to high-pressure detection.
Background
In recent years, in the fields of industrial control, automobiles, and the like, there is an increasing demand for pressure sensors for high-pressure measurement. Thin film strain gages using metal diaphragms are common, the principle of which is to produce a change in resistance through a change in geometry, thereby producing a sensitivity output. However, the greatest disadvantages are low sensitivity and large volume. With the development of system integration, demands for high sensitivity and miniaturization are made, and a pressure sensor based on semiconductor technology is a better choice.
The piezoresistive pressure sensor is widely applied, and the structure of the piezoresistive pressure sensor is usually a sensitive membrane hung on a cavity. For the high pressure sensor, the method is not suitable, because the high pressure sensor has a large measuring range, almost has a measuring range of about 1mpa or even higher, and the thicker the corresponding sensitive membrane is, the smaller the deformation amount of the sensitive membrane is, the easier the sensitive membrane enters a nonlinear area, and the sensitivity is lower. Since sensitivity is related to the thickness of bare silicon, typically the thickness of bare silicon is greater than 100 um. The thinner the thickness of the bare silicon film is, the higher the sensitivity can be, but if the bare silicon film is too thin, the silicon wafer transfer during the process is limited. Thus, for a particular structure, the sensitivity improvement is limited.
SUMMERY OF THE UTILITY MODEL
The application aims to provide a pressure sensor which is high in sensitivity and can be applied to high-pressure detection.
To achieve the above object, the present application provides a pressure sensor applicable to high pressure detection, comprising:
the first substrate comprises an island structure positioned in a central area and a fixed support structure positioned at the periphery, a groove is arranged between the island structure and the fixed support structure, and a first distance is reserved between the top of the groove and the top surface of the first substrate;
a strain transfer layer disposed over the first substrate;
a second substrate disposed over the strain transfer layer.
Further, the top surface of the first substrate is provided with a pressure resistance and is located within a projection of the recess on the top surface of the first substrate.
Further, the strain conversion layer comprises a central part and a peripheral part, a clamping groove is arranged between the central part and the peripheral part, the position of the clamping groove corresponds to the position of the groove, and the width of the projection of the clamping groove on the top surface of the first substrate is smaller than or equal to the width of the projection of the groove on the top surface of the first substrate.
Further, a third substrate is arranged below the first substrate.
Further, the projection of the second substrate on the top surface of the first substrate is equivalent to the projection of the strain conversion layer on the top surface of the first substrate, and is smaller than the projection of the third substrate on the top surface of the first substrate.
Further, the first substrate is provided with a pad, and the pad is positioned outside the projection of the second substrate on the top surface of the first substrate.
Further, the first substrate is provided with a wiring electrically connecting the piezoresistors and the bonding pads.
Furthermore, the number of the piezoresistors is four, and the piezoresistors are respectively distributed around the island structure of the first substrate and form a Wheatstone bridge.
Furthermore, the number of the piezoresistors is four, and every two piezoresistors are distributed on two opposite sides of the island structure of the first substrate respectively in a group, so that a Wheatstone bridge is formed.
Further, the shape of the groove and/or the clamping groove is square, circular or circular arc.
Further, the strain transfer layer has a coefficient of thermal expansion close to that of the first substrate.
Further, the thickness of the first substrate is greater than the thickness of the second substrate is greater than the thickness of the strain transfer layer.
Further, the thickness of the first substrate is 500-600um, the thickness of the second substrate is 230-350um, the thickness of the strain transfer layer is 40-50um, and the first distance between the top of the groove and the top surface of the first substrate is 40-100 um.
Further, the first substrate is monocrystalline silicon, the second substrate is monocrystalline silicon, glass or metal, and the strain transfer layer is polycrystalline silicon, silicon oxide, silicon nitride or aluminum oxide.
This application can be applied to pressure sensor that high pressure detected, the below of pressure drag position, the concave recess that is equipped with of first substrate makes first substrate is including island structure and solid structure two parts, because the existence of island structure, the rigidity of island structure is stronger than the rigidity of the first substrate of pressure drag below groove position, therefore the stress that the first substrate of pressure drag below, recess top position received can increase to the sensitivity that this application can be applied to pressure sensor that high pressure detected has been increased. And the integral strength of the pressure sensor which can be applied to high-pressure detection is also ensured, because the fixed support structure and the island structure of the first substrate have thicker thickness relative to the groove position, the test which simultaneously considers high pressure and higher sensitivity is satisfied.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the description below are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a top view of a pressure sensor applicable to high pressure detection according to a first embodiment of the present disclosure;
FIG. 2 is a side view, partially in section, of a pressure sensor that may be used for high pressure sensing, according to a first embodiment of the present disclosure;
FIG. 3 is a side view, partially in section, of a pressure sensor that may be used for high pressure sensing, according to a second embodiment of the present disclosure;
fig. 4 is a schematic structural diagram of a top view portion of a pressure sensor applicable to high pressure detection according to a third embodiment of the present disclosure.
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. Furthermore, it should be understood that the detailed description and specific examples, while indicating exemplary embodiments of the invention, are given by way of illustration and explanation only, and are not intended to limit the scope of the invention. In the present application, unless otherwise specified, the use of directional terms such as "upper", "lower", "left" and "right" generally refer to upper, lower, left and right in the actual use or operation of the device, and specifically to the orientation of the drawing figures.
The present application provides a pressure sensor applicable to high pressure detection, which will be described in detail below. It should be noted that the following description of the embodiments is not intended to limit the preferred order of the embodiments of the present application. In the following embodiments, the descriptions of the respective embodiments have respective emphasis, and reference may be made to related descriptions of other embodiments for parts that are not described in detail in a certain embodiment.
Referring to fig. 1-2, a pressure sensor applicable to high pressure detection according to a first embodiment of the present disclosure includes:
a first substrate 10 including an island structure 8 located in a central region and a supporting structure 9 located at the periphery, a groove 11 being provided between the island structure 8 and the supporting structure 9, and a first distance being provided between the top of the groove 11 and the top surface of the first substrate 10; the material of the first substrate 10 is typically monocrystalline silicon, and may also be SOI; the groove 11 can be formed by corrosion of a potassium hydroxide solution or dry etching;
a strain transfer layer 40 disposed over the first substrate 10; the strain-transfer layer 40 is typically made of a rigid material, such as polysilicon, silicon oxide SiO2, silicon nitride Si3N4, or other materials such as aluminum oxide, and has a coefficient of thermal expansion close to that of the first substrate 10, and may be formed by deposition growth, epitaxy, or other techniques;
a second substrate 20 disposed over the strain transfer layer 40.
Further, the top surface of the first substrate 10 is provided with piezoresistors 2 and is located in the projection of the groove 11 on the top surface of the first substrate 10; the piezoresistance 2 can be formed by implantation.
Further, a third substrate 30 is disposed below the first substrate 10.
When a force acts on the second substrate 20, the strain conversion layer 40 converts the vertically applied load into a planar pressure that can be sensed by the piezoresistance 2, thereby generating a measurement result output. Due to the island structure 8, the rigidity of the island structure 8 is stronger than that of the first substrate 10 at the position of the groove 11 under the piezoresistive structure 2, so that the stress applied to the first substrate 10 at the position of the groove 11 under the piezoresistive structure 2 is increased, thereby increasing the sensitivity of the pressure sensor applicable to high-pressure detection. Moreover, the overall strength of the pressure sensor applicable to high pressure detection is ensured, because the supporting structures 9 and the island structures 8 of the first substrate 10 have a relatively thick thickness relative to the positions of the grooves 11, thereby satisfying the test of both high pressure and high sensitivity. Moreover, the first distance can be controlled by a process, and the thickness can be flexibly set according to the force or pressure range.
Generally, the thickness of the first substrate 10 is greater than the thickness of the second substrate 20 is greater than the thickness of the strain transfer layer 40. For example, the thickness of the first substrate 10 is 500-600um, the thickness of the second substrate 20 is 230-350um, the thickness of the strain transfer layer 40 is 40-50um, and the first distance between the top of the groove 11 and the top surface of the first substrate 10 is 40-100 um. In one embodiment, the first distance between the top of the groove 11 and the top surface of the first substrate 10 is 45um, and the range of the pressure sensor applicable to high pressure detection is up to 1 mpa.
Further, the strain conversion layer 40 includes a central portion 41 and a peripheral portion 42, a clamping groove 43 is provided between the central portion 41 and the peripheral portion 42, the position of the clamping groove 43 corresponds to the position of the groove 11, and the width of the projection of the clamping groove 43 on the top surface of the first substrate 10 is less than or equal to the width of the projection of the groove 11 on the top surface of the first substrate 10. That is, the piezoresistor 2 is also located in the region of the clamping groove 43, so that the flexibility of deformation of the piezoresistor 2 is further improved, and the overall sensitivity of the pressure sensor applicable to high pressure detection is improved.
Further, the projection of the second substrate 20 on the top surface of the first substrate 10 is equivalent to the projection of the strain conversion layer 40 on the top surface of the first substrate 10, and is smaller than the projection of the third substrate 30 on the top surface of the first substrate 10. That is, it can be said that the size of the periphery of the second substrate 20 is equivalent to the size of the periphery of the strain conversion layer 40, and the size of the periphery of the first substrate 10 and the size of the periphery of the third substrate 30 are larger than the size of the periphery of the second substrate 20 and the size of the periphery of the strain conversion layer 40. The second substrate 20 and the third substrate 30 are made of monocrystalline silicon, glass, or metal, or other suitable materials that can be easily conceived by those skilled in the art, and may be formed by using a bonding technique, such as anodic bonding, eutectic bonding, thermocompression bonding, or the like; the third substrate 30 and the second substrate 20 are used for capping, and the main purpose is to form a closed cavity, so that the absolute pressure is measured during measurement
Further, the first substrate 10 is provided with pads 5, and the pads 5 are located outside the projection of the second substrate 20 on the top surface of the first substrate 10. That is, the pad 5 is located at a portion of the first substrate 10 larger than the strain conversion layer 40.
The number of the pads 5 is generally plural, and may be entirely located on one side of the top surface of the first substrate 10 (as shown in fig. 1), or may be partially located on two sides, such as two opposite sides (as shown in fig. 3), or may be adjacent to two sides, or may be located on multiple sides, and may be adjusted according to the situation of each practical application.
Further, the first substrate 10 is provided with a wiring 3, and the wiring 3 electrically connects the piezoresistors 2 and the pads 5.
The four piezoresistors 2 are respectively distributed around the island structure 8 of the first substrate 10 to form a Wheatstone bridge; of course, two by two groups may be distributed on two opposite sides of the island structure 8 of the first substrate 10 (as shown in fig. 4) and form a wheatstone bridge; of course, the adjustment can be made according to the actual application.
Correspondingly, the grooves 11 can be a plurality of grooves which are square, circular or arc-shaped, are not communicated with each other and exist independently, and can be communicated with each other to form a square ring shape, a circular ring shape or other shapes similar to a circular ring shape; this is also true of the clamp groove 43 (as shown in fig. 1).
The present application provides a pressure sensor applicable to high pressure detection, and the principle and the implementation of the present application are described herein by using specific examples, and the above description of the embodiments is only used to help understand the method and the core idea of the present application; meanwhile, for a person skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.
Claims (14)
1. A pressure sensor applicable to high pressure detection, comprising:
the first substrate comprises an island structure positioned in a central area and a fixing and supporting structure positioned on the periphery, a groove is arranged between the island structure and the fixing and supporting structure, and a first distance is reserved between the top of the groove and the top surface of the first substrate;
a strain transfer layer disposed over the first substrate;
a second substrate disposed over the strain transfer layer.
2. The pressure sensor applicable to high pressure detection as claimed in claim 1, wherein the top surface of the first substrate is provided with a piezoresistive property and is located within a projection of the recess on the top surface of the first substrate.
3. The pressure sensor applicable to high pressure detection according to claim 2, wherein the strain transfer layer comprises a central portion and a peripheral portion, a clamping groove is arranged between the central portion and the peripheral portion, the position of the clamping groove corresponds to the position of the groove, and the width of the projection of the clamping groove on the top surface of the first substrate is smaller than or equal to the width of the projection of the groove on the top surface of the first substrate.
4. The pressure sensor applicable to high pressure detection according to claim 2, wherein a third substrate is provided below the first substrate.
5. The pressure sensor applicable to high pressure detection of claim 4, wherein the projection of the second substrate on the top surface of the first substrate is comparable to the projection of the strain transfer layer on the top surface of the first substrate, and is smaller than the projection of the third substrate on the top surface of the first substrate.
6. The pressure sensor applicable to high pressure detection of claim 5, wherein the first substrate is provided with pads located outside a projection of the second substrate on a top surface of the first substrate.
7. The pressure sensor applicable to high pressure testing as claimed in claim 6, wherein said first substrate is provided with a wiring electrically connecting said piezoresistive and said bonding pad.
8. The pressure sensor applicable to high pressure detection as claimed in claim 2, wherein the number of the piezoresistors is four, and the four piezoresistors are respectively distributed around the island structure of the first substrate and form a wheatstone bridge.
9. The pressure sensor applicable to high pressure detection according to claim 2, wherein the number of the piezoresistors is four, and two piezoresistors are distributed in groups on two opposite sides of the island structure of the first substrate, and form a wheatstone bridge.
10. Pressure sensor applicable to high pressure detection according to claim 3, characterized in that the shape of the groove and/or the pinching groove is square or circular arc.
11. The pressure sensor applicable to high pressure sensing of claim 1, wherein the strain-transfer layer has a coefficient of thermal expansion close to that of the first substrate.
12. The pressure sensor applicable to high pressure sensing of claim 1, wherein the thickness of the first substrate is greater than the thickness of the second substrate is greater than the thickness of the strain-transfer layer.
13. The pressure sensor as claimed in claim 1, wherein the thickness of the first substrate is 500-600um, the thickness of the second substrate is 230-350um, the thickness of the strain-transfer layer is 40-50um, and the first distance between the top of the groove and the top surface of the first substrate is 40-100 um.
14. The pressure sensor applicable to high pressure detection of claim 1, wherein the first substrate is single crystal silicon, the second substrate is single crystal silicon, glass or metal, and the strain transfer layer is polysilicon, silicon oxide, silicon nitride or aluminum oxide.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN202220193701.1U CN217276654U (en) | 2022-01-24 | 2022-01-24 | Pressure sensor applicable to high pressure detection |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202220193701.1U CN217276654U (en) | 2022-01-24 | 2022-01-24 | Pressure sensor applicable to high pressure detection |
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| CN217276654U true CN217276654U (en) | 2022-08-23 |
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| CN202220193701.1U Active CN217276654U (en) | 2022-01-24 | 2022-01-24 | Pressure sensor applicable to high pressure detection |
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