CN118624067A - Piezoelectric resonant pressure sensor, compensation system and preparation method - Google Patents
Piezoelectric resonant pressure sensor, compensation system and preparation method Download PDFInfo
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Abstract
The application provides a piezoelectric resonance type pressure sensor, a compensation system and a preparation method, and relates to the technical field of manufacturing of sensitive elements and sensors in the electronic core industry. The piezoelectric resonant pressure sensor includes a piezoelectric component, a resonant component, and a pressure sensitive component. The piezoelectric assembly is directly or indirectly connected to an external circuit. The resonant assembly is arranged on one side of the piezoelectric assembly, and the resonant cavity is arranged on one side of the resonant assembly, which is away from the piezoelectric assembly. The pressure sensitive component is connected to one side of the resonant component, which is away from the piezoelectric component, and one side of the pressure sensitive component, which is away from the resonant component, is provided with a pressure cavity for receiving pressure to be detected. The pressure sensitive film is formed at the position where the pressure sensitive component is provided with the pressure cavity, and at least part of the pressure sensitive film seals the resonant cavity. According to the piezoelectric resonant pressure sensor provided by the example of the application, the range of pressure measurement of the piezoelectric resonant pressure sensor can be enlarged, and the application range of the piezoelectric resonant pressure sensor is further enlarged.
Description
Technical Field
The application relates to the technical field of manufacturing of sensitive elements and sensors in the electronic core industry, in particular to a piezoelectric resonance type pressure sensor, a compensation system and a preparation method.
Background
The pressure sensor can convert the received pressure signal into an electric signal according to a certain rule and output the electric signal to other equipment, and belongs to a sensitive element. The pressure sensor is widely applied to the technical fields of national defense, automobiles, petroleum, aerospace, intelligent hardware and the like, and belongs to the technical field of electronic core industry.
With the development of Micro-Electro-MECHANICAL SYSTEM (MEMS) technology, the pressure sensor can be combined with MEMS technology to realize mass production of the pressure sensor, so that the production efficiency of the pressure sensor is improved.
Pressure sensors can be classified into piezoelectric resonance type pressure sensors, piezoresistive type pressure sensors, capacitive type pressure sensors, piezoelectric type pressure sensors, etc. according to the difference of the operating principle. The piezoelectric resonant pressure sensor has the advantages of high stability, high accuracy and the like, and is widely applied to high-accuracy requirements and severe environments, such as aerospace, petroleum and the like.
Based on the structure of the existing piezoelectric resonance type pressure sensor, the pressure detection range of the piezoelectric resonance type pressure sensor is smaller, and the application range of the piezoelectric resonance type pressure sensor can be possibly affected.
Disclosure of Invention
The application provides a piezoelectric resonance type pressure sensor, which is used for expanding the pressure detection range of the piezoelectric resonance type pressure sensor and expanding the application range of the piezoelectric resonance type pressure sensor.
In a first aspect, an example of the present application provides a piezoelectric resonant pressure sensor for use in the electronics core industry. The piezoelectric resonant pressure sensor includes a piezoelectric component, a resonant component, and a pressure sensitive component. The piezoelectric assembly is directly or indirectly connected to an external circuit. The resonant assembly is arranged on one side of the piezoelectric assembly, and the resonant cavity is arranged on one side of the resonant assembly, which is away from the piezoelectric assembly. The pressure sensitive component is connected to one side of the resonant component, which is away from the piezoelectric component, and one side of the pressure sensitive component, which is away from the resonant component, is provided with a pressure cavity for receiving pressure to be detected. The pressure sensitive film is formed at the position where the pressure sensitive component is provided with the pressure cavity, and at least part of the pressure sensitive film seals the resonant cavity.
According to the piezoelectric resonance type pressure sensor provided by the example of the application, the pressure cavity can receive the pressure to be detected, the pressure to be detected can be transmitted to the piezoelectric component and the resonance component through the pressure sensitive component, and the pressure to be detected is detected through the characteristics of the piezoelectric component. The piezoelectric component is arranged on one side of the resonant component, which is away from the pressure sensitive component, so that the piezoelectric component is arranged separately from the pressure cavity for receiving the pressure to be detected. And the resonant assembly is provided with a resonant cavity. Under the condition that the piezoelectric component drives the resonance component to vibrate, the resonant cavity can provide deformation space for the piezoelectric component, so that the deformation of the piezoelectric component is reduced, and the possibility of damage of the piezoelectric component is further reduced.
Under the condition that the possibility of breakage of the piezoelectric component is reduced, the piezoelectric resonant pressure sensor provided by the example of the application can bear larger pressure to be detected, so that the range of pressure measurement of the piezoelectric resonant pressure sensor is increased, the measuring range of the piezoelectric resonant pressure sensor is enlarged, the application range of the piezoelectric resonant pressure sensor is enlarged, and the piezoelectric resonant pressure sensor can be widely applied to the technical field of electronic core industry.
In addition, in the example of the application, the pressure sensitive film is formed at the position where the pressure sensitive component is provided with the pressure cavity, and at least part of the pressure sensitive film seals the resonant cavity, so that the resonant cavity is at least partially overlapped with the pressure cavity. Based on the structure, the volume of the resonant piezoelectric sensor can be reduced, which is beneficial to miniaturization of the piezoelectric resonant pressure sensor and integration development of the piezoelectric resonant pressure sensor.
In some possible implementations, the pressure sensitive component is provided with a pressure chamber at a location where it encloses the resonant cavity.
Because the pressure sensitive film is formed at the position where the pressure sensitive component is provided with the pressure cavity, at least part of the pressure sensitive film seals the resonant cavity, so that the projection of the resonant cavity coincides with the projection of the pressure cavity along the direction from the resonant cavity to the pressure cavity. And because the pressure sensitive component is provided with the pressure cavity at the position for sealing the resonant cavity, the projection of the resonant cavity can completely fall into the projection range of the pressure cavity along the direction from the resonant cavity to the pressure cavity, the volume of the piezoelectric resonant pressure sensor can be further reduced, and the miniaturization of the piezoelectric resonant pressure sensor is facilitated.
In some possible implementations, the pressure sensitive assembly further includes a resonant substrate, the pressure sensitive film cooperating with the resonant substrate to form a pressure cavity, the resonant substrate being located on a side of the pressure sensitive film facing away from the resonant assembly.
Through setting up the resonance substrate, resonance substrate and pressure sensitive film cooperation form the pressure chamber, and operating personnel can control fluid such as gas or liquid and exert pressure to the chamber wall in pressure chamber, can make the atress of pressure sensitive film comparatively concentrated through setting up the pressure chamber, and the operating personnel of being convenient for exerts the pressure of waiting to detect to the chamber wall in pressure chamber.
In some possible implementations, the pressure sensitive component is provided with a pressure chamber at a location where it encloses the resonant cavity. The resonant assembly comprises a connecting structure and a resonant film which are connected, the connecting structure and the resonant film are matched to form a resonant cavity, and the resonant film is positioned on one side of the connecting structure, which is away from the pressure sensitive assembly.
Because one side of the connecting structure is provided with the pressure sensitive film, the other side of the connecting structure is provided with the piezoelectric component. Based on the above, the pressure to be detected acting on the pressure sensitive film can be transferred to the piezoelectric component through the connecting structure and converted into stress on the piezoelectric component and the resonance component, so that the resonance frequency of the structure is changed. Because the resonant cavity is arranged on one side of the piezoelectric component, the resonant cavity can provide vibration space for vibration of the piezoelectric component, and the possibility of damage of the piezoelectric component caused by deformation of the piezoelectric component due to vibration is reduced.
The connecting structure can connect the pressure sensitive film and the piezoelectric component, and can change the acting direction of pressure to be detected, so that the pressure to be detected, which acts on the piezoelectric component vertically, is smaller, the possibility of damaging the piezoelectric component is further reduced, the pressure bearing capacity of the resonant film is improved, the detection range of the piezoelectric resonant pressure sensor is further enlarged, and the linearity of the piezoelectric resonant pressure sensor in the pressure detection range is ensured.
In some possible implementations, an anchor point is located on a side of the connection structure, which is close to the pressure sensitive component, and a distance between the anchor point and the resonant thin film is a first distance, and a distance between the anchor point and the pressure sensitive component is a second distance, where the first distance is greater than the second distance.
Through setting up first distance and being greater than the second distance, can make resonant film, pressure sensitive component and anchor point combined action form the lever, first distance is first lever arm, and the second distance is the second lever arm. Based on the lever principle, the connecting structure with the anchor point can amplify working stress generated by pressure to be detected, so that the detection sensitivity of the piezoelectric resonance type pressure sensor is improved.
In some possible implementations, the piezoelectric assembly includes a first lead electrode, a second lead electrode, a first electrode, a piezoelectric layer, and a second electrode. The second electrode is arranged on one side of the resonance component, which is away from the pressure sensitive component, and one side of the second electrode, which is towards the resonance component, is directly or indirectly connected with the resonance component.
The piezoelectric layer is arranged on one side of the second electrode, which is away from the resonance component, and one side of the piezoelectric layer, which is towards the second electrode, is connected with the second electrode.
The first electrode is arranged on one side of the piezoelectric layer, which is away from the second electrode, and one side of the piezoelectric layer, which is towards the first electrode, is connected with the first electrode.
The first lead electrode is arranged on one side of the first electrode, which is away from the piezoelectric layer, one end of the first lead electrode is connected with the first electrode, and the other end of the first lead electrode is connected with a first part of an external circuit. The second lead electrode is arranged on one side of the second electrode facing the piezoelectric layer, one end of the second lead electrode is connected with the second electrode, and the other end of the second lead electrode is connected with a second part of the external circuit.
Compared with the resistance detection type piezoelectric sensor which needs to be provided with a Wheatstone bridge and the capacitance detection type pressure sensor which needs to be provided with a capacitance bridge, the piezoelectric resonance type pressure sensor provided by the application does not need to be provided with an additional detection circuit, and has the advantages of simpler structure and lower manufacturing cost.
In some possible implementations, the piezoelectric resonant pressure sensor is provided with at least one groove, the groove being provided between the resonant membrane and the pressure sensitive membrane. Or the groove is arranged on one side of the resonant assembly, which is away from the resonant substrate, and the notch of the groove is arranged away from the resonant substrate.
The groove can enable the distance between the resonant substrate and the connecting structure to be kept, so that the cross-sectional area of the connecting structure is reduced, the working stress transferred to the pressure sensitive film through the connecting structure is concentrated, and the detection accuracy of the piezoelectric resonant pressure sensor is improved.
In some possible implementations, the piezoelectric resonant pressure sensor further includes a cover disposed on a side of the piezoelectric assembly facing away from the pressure sensitive assembly, the cover being directly or indirectly connected to the piezoelectric assembly.
In a vacuum environment, the cover may be used to encapsulate a piezoelectric resonator, which may include a resonant assembly and a piezoelectric assembly. The sealing cover can be arranged on one side of the piezoelectric component, which is away from the resonance component, so as to isolate the piezoelectric component from the atmospheric environment, ensure that the piezoelectric component is in a vacuum environment during working, further improve the numerical value corresponding to the quality factor of the piezoelectric resonance type pressure sensor and ensure the working performance of the piezoelectric resonance type pressure sensor.
A second aspect of the application provides a compensation system comprising a drive component, a detection component and a piezoelectric resonant pressure sensor as mentioned in any of the examples above, the at least two piezoelectric resonant pressure sensors comprising at least one pressure sensor and at least one compensation sensor.
According to the compensation system provided by the example of the application, when the detection component detects the resonant frequency of the pressure sensor and the compensation sensor, the influence of environmental factors can be eliminated and the detection accuracy of the compensation system to the pressure to be detected can be improved as long as the resonant frequency output by the pressure sensor is subtracted from the resonant frequency output by the compensation sensor and the final resonant frequency is extracted.
A third aspect of the present application provides a method of manufacturing a piezoelectric resonator pressure sensor, suitable for use in the piezoelectric resonator pressure sensor mentioned in any of the above examples, for processing the piezoelectric resonator pressure sensor from a first SOI wafer comprising a first device layer, a first buried oxide layer and a first substrate layer, and from a second SOI wafer comprising a second device layer, a second buried oxide layer and a second substrate layer.
The thickness of the first device layer is equal to the sum of the height of the resonant cavity and the thickness of the resonant film, and the thickness of the second device layer is equal to the thickness of the pressure sensitive film.
The method comprises the following steps: and taking the first SOI wafer, and processing the resonant cavity on the first device layer. And bonding the second device layer with the first device layer by taking the second SOI wafer, and sealing the resonant cavity by the second device layer, wherein an oxide layer is formed between the second device layer and the first device layer in the bonding process. And removing the first buried oxide layer and the first substrate layer, and taking part of the first device layer as a resonance film. A piezoelectric assembly is disposed on a side of the first device layer facing away from the second SOI wafer. And forming a pressure cavity on the second substrate layer and forming a pressure sensitive film, wherein at least part of the pressure sensitive film seals the resonant cavity.
Drawings
Fig. 1 is a schematic structural diagram of a piezoelectric resonant pressure sensor according to an example of the present application.
Fig. 2 is a top view of a piezoelectric resonant pressure sensor according to an example of the present application.
Fig. 3 is a cross-sectional view of A-A in fig. 2.
Fig. 4 is a cross-sectional view of B-B of fig. 2.
Fig. 5 is a schematic structural diagram of another piezoelectric resonant pressure sensor according to an example of the present application.
Fig. 6 is a top view of another piezoelectric resonant pressure sensor provided by an example of the present application.
Fig. 7 is a cross-sectional view of fig. 6C-C.
Fig. 8 is a schematic diagram illustrating an operation principle of a piezoelectric resonant pressure sensor according to an example of the present application.
Fig. 9 is a schematic diagram of a resonance principle of a piezoelectric resonant pressure sensor according to an example of the present application.
Fig. 10 is a schematic diagram of an internal structure of a piezoelectric resonant pressure sensor according to an example of the present application.
Fig. 11 is a schematic structural diagram of a piezoelectric resonant pressure sensor without a lead electrode and a protective layer according to an embodiment of the present application, where 4 lead bridges are provided.
Fig. 12 is a schematic structural diagram of a piezoelectric resonant pressure sensor without a lead electrode and a protective layer according to an embodiment of the present application, where 3 lead bridges are provided.
Fig. 13 is a schematic structural diagram of a piezoelectric resonant pressure sensor without a lead electrode and a protective layer according to an embodiment of the present application, where 2 lead bridges are provided.
Fig. 14 is a schematic structural diagram of a piezoelectric resonant pressure sensor without a lead electrode and a protective layer according to an embodiment of the present application, where 1 lead bridge is provided.
Fig. 15 is a schematic structural diagram of a piezoelectric resonant pressure sensor without a lead electrode and a protective layer according to an embodiment of the present application, where no lead bridge is provided.
Fig. 16 is a schematic structural diagram of another piezoelectric resonant pressure sensor according to an example of the present application.
Fig. 17 is a schematic flow chart of a method for manufacturing a piezoelectric resonant pressure sensor according to an example of the present application.
Fig. 18 is a schematic structural diagram of a first SOI wafer provided as an example of the present application when not processed.
Fig. 19 is a schematic structural diagram of a first SOI wafer fabricated resonator and a trench according to an exemplary embodiment of the present application.
Fig. 20 is a schematic diagram of a structure of a first SOI wafer flipped after processing a resonator and a trench according to an exemplary embodiment of the present application.
Fig. 21 is a schematic structural diagram of a second SOI wafer provided as an example of the present application when not processed.
Fig. 22 is a schematic structural diagram of bonding connection between a first SOI wafer and a second SOI wafer according to an exemplary embodiment of the present application.
Fig. 23 is a schematic structural diagram of a first SOI wafer and a second SOI wafer provided by an example of the present application after bonding connection and removal of the first substrate layer and the first buried oxide layer.
Fig. 24 is a schematic view of a structure for depositing a piezoelectric component on a side of a first device layer facing away from a second SOI wafer, in accordance with an exemplary embodiment of the present application.
Fig. 25 is a schematic structural diagram of a piezoelectric assembly after processing based on fig. 24 according to an example of the present application.
Fig. 26 is a schematic structural diagram of an exemplary embodiment of a protective layer disposed on a piezoelectric component facing away from a first device layer according to fig. 25.
Fig. 27 is a schematic structural view of processing a first connection hole from a protection layer based on fig. 26 according to an example of the present application.
Fig. 28 is a schematic structural view of processing a second connection hole from a protective layer based on fig. 27 according to an example of the present application.
Fig. 29 is a schematic structural view of a lead electrode layer deposited on the side of the protective layer facing away from the first device layer based on fig. 28, which is provided by an example of the present application.
Fig. 30 is a schematic view of a structure for processing a lead electrode layer based on fig. 29 according to an example of the present application.
Fig. 31 is a schematic structural diagram of a processing pressure chamber facing away from a first device layer on a second SOI wafer based on the embodiment of the present application as provided in fig. 30.
Fig. 32 is a schematic structural diagram of processing a trench from a protective layer based on fig. 31 according to an example of the present application.
Fig. 33 is a schematic structural diagram of a glass wafer according to an example of the present application.
Fig. 34 is a schematic view of a structure for forming a cover by processing a cavity on a glass wafer according to an embodiment of the present application.
Fig. 35 is a schematic structural diagram of a glass wafer connected to a side of a protective layer facing away from a piezoelectric layer according to an example of the present application.
Fig. 36 is a schematic structural diagram of a compensation system according to an example of the present application.
FIG. 37 is a schematic workflow diagram of a compensation system provided by an example of the present application.
Reference numerals illustrate:
100. A piezoelectric resonant pressure sensor; 110. a piezoelectric assembly; 111. a first lead electrode; 1111. a first connection hole; 112. a second lead electrode; 1121. a second connection hole; 113. a first electrode; 114. a piezoelectric layer; 115. a second electrode; 120. a resonant assembly; 121. a resonant cavity; 122. a resonant thin film; 123. a connection structure; 124. a resonant substrate; 130. a pressure sensitive component; 131. a pressure chamber; 132. a pressure sensitive membrane; 133. a resonant substrate; 140. a protective layer; 150. an oxide layer; 160. a cover; 170. a groove; 171. a lead bridge; 172. a beam structure; 200. a compensation system; 210. a pressure sensor; 220. compensating the sensor; 230. a driving part; 240. a detection section; 310. a first device layer; 320. a first buried oxide layer; 330. a first substrate layer; 410. a second device layer; 420. a second buried oxide layer; 430. a second substrate layer; 500. a glass wafer.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the present examples more apparent, the technical solutions in the present examples will be clearly and completely described below with reference to the accompanying drawings in the present examples, and it is apparent that the described examples are some, but not all examples of the present application. All other examples, which a person of ordinary skill in the art would obtain without undue burden based on the examples in this disclosure, are within the scope of this disclosure.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used in the description of the applications herein is for the purpose of describing particular examples only and is not intended to be limiting of the application; the terms "comprising" and "having" and any variations thereof in the description and claims of the application and in the description of the drawings are intended to cover a non-exclusive inclusion.
Reference herein to "an example" means that a particular feature, structure, or characteristic described in connection with the example may be included in at least one example of the application. The appearances of the phrase "in an example" in various places in the specification are not necessarily all referring to the same example, nor are separate or alternative examples mutually exclusive of other examples. Those skilled in the art will explicitly and implicitly understand that the examples described herein may be combined with other examples.
The term "and/or" is herein merely an association relationship describing an associated object, meaning that there may be three relationships, e.g., a and/or B, may represent: there are three cases, a, B, a and B simultaneously. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship.
The directional terms appearing in the following description are directions shown in the drawings, and do not limit the specific structure of the piezoelectric resonant pressure sensor of the present application.
Furthermore, the terms first, second and the like in the description and in the claims or in the above-described figures, are used for distinguishing between different objects and not for describing a particular sequential order, and may be used to improve one or more of these features either explicitly or implicitly.
In the description of the present application, unless otherwise indicated, the meaning of "plurality" means two or more (including two), and similarly, "plural sets" means two or more (including two).
In the description of the present application, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., the terms "connected" or "connected" of a mechanical structure may refer to a physical connection, e.g., the physical connection may be a fixed connection, e.g., by a spacer, such as by a screw, bolt, or other spacer; the physical connection may also be a detachable connection, such as a snap-fit or snap-fit connection; the physical connection may also be an integral connection, such as a welded, glued or integrally formed connection. The specific meaning of the above terms in the present application will be understood in specific cases by those of ordinary skill in the art.
The resonant pressure sensor indirectly measures the pressure to be detected through measuring the resonant frequency change of the structure, has the advantages of high precision and good stability, and is suitable for scenes with high precision requirements and severe environments such as aerospace, oil and gas exploration and the like. Existing resonant pressure sensors include electrostatic excitation-resistance detection type resonant pressure sensors, piezoelectric excitation-piezoelectric detection type resonant pressure sensors, electromagnetic driving-electromagnetic detection type resonant pressure sensors, optical driving-optical detection type resonant pressure sensors, piezoelectric resonant pressure sensors of quartz materials, and the like. The measurement structure may be a detection circuit or other structure capable of detecting the pressure to be detected.
The processing technology of the electrostatic excitation-resistance detection type resonant pressure sensor is simpler, but the circuit structure of the electrostatic excitation-resistance detection type resonant pressure sensor is more complex because the piezoresistance detection needs to use a Wheatstone bridge, and the processing requirements of the electrostatic excitation-resistance detection type resonant pressure sensor are higher for the consistency of piezoresistors.
The piezoelectric excitation-resistance detection type resonant pressure sensor is similar to the electrostatic excitation-resistance detection type, and the problems of complex circuit structure and higher consistency requirement of piezoresistors are also existed.
The electromagnetic drive-electromagnetic detection type resonant pressure sensor utilizes the periodic vibration generated by the time-varying Lorentz force of a harmonic oscillator in an excitation electromagnetic field, and then utilizes the inverse process of electromagnetic drive to detect the vibration. This approach requires the addition of sensor peripherals to provide the magnetic field due to the need for electromagnetic fields, and the sensor is not easily miniaturized.
Based on the above, the present disclosure provides a piezoelectric resonant pressure sensor, a compensation system and a method for manufacturing the same.
The piezoelectric resonant pressure sensor according to the example of the application can be combined with MEMS technology to realize mass production of the piezoelectric resonant pressure sensor and improve the production efficiency of the piezoelectric resonant pressure sensor.
The piezoelectric resonant pressure sensor provided by the example of the application can output corresponding electric signals based on the received pressure to be detected, and belongs to sensitive elements.
In order to better understand the solution of the present application, the following description will clearly and completely describe the piezoelectric resonant pressure sensor, the compensation system and the preparation method provided by the examples of the present application with reference to the accompanying drawings.
For example, fig. 1 is a schematic structural diagram of a piezoelectric resonant pressure sensor according to an embodiment of the present application, fig. 2 is a top view of the piezoelectric resonant pressure sensor according to an embodiment of the present application, fig. 3 is a cross-sectional view A-A of fig. 2, fig. 4 is a cross-sectional view B-B of fig. 2, and referring to fig. 1 to 4, the piezoelectric resonant pressure sensor 100 may include a piezoelectric component 110, a resonant component 120, and a pressure sensitive component 130.
The piezoelectric assembly 110 may be directly or indirectly connected to an external circuit. The resonant assembly 120 is disposed on one side of the piezoelectric assembly 110, and a resonant cavity 121 is disposed on a side of the resonant assembly 120 facing away from the piezoelectric assembly 110. The pressure sensitive component 130 is connected to one side of the resonant component 120, which is away from the piezoelectric component 110, and one side of the pressure sensitive component 130, which is away from the resonant component 120, is provided with a pressure cavity 131, where the pressure cavity 131 is used for receiving the pressure to be detected. The pressure sensitive element 130 forms a pressure sensitive film 132 at a position where the pressure cavity 131 is opened, and at least part of the pressure sensitive film 132 seals the resonant cavity 121.
Based on the piezoelectric resonant pressure sensor 100 provided in the above example, the pressure chamber 131 may receive the pressure to be detected, and since the pressure chamber 131 is disposed at a side of the pressure sensitive component 130 facing away from the resonant component 120 and the pressure sensitive component 130 is directly or indirectly connected with the resonant component 120, the pressure to be detected can be transmitted to the resonant component 120 through the pressure sensitive component 130. Since the resonant assembly 120 is disposed on one side of the piezoelectric assembly 110, the resonant assembly 120 is directly or indirectly connected to the piezoelectric assembly 110, and the pressure to be detected, which indirectly acts on the resonant assembly 120, can be transferred to the piezoelectric assembly 110.
Next, the structure of the piezoelectric resonant pressure sensor 100 will be described in detail.
Pressure sensitive component 130 may include only a pressure sensitive membrane, and pressure sensitive component 130 may include a pressure sensitive membrane and other structures coupled to a pressure sensitive membrane.
In the case where the pressure sensitive component 130 comprises only a pressure sensitive membrane, the pressure chamber 131 may be the space where the pressure sensitive membrane faces away from the resonant component 120. Where pressure sensitive assembly 130 includes a pressure sensitive membrane and other structures coupled to the pressure sensitive membrane, pressure chamber 131 may also be a space formed by the pressure sensitive membrane and other structures coupled to the pressure sensitive membrane in conjunction, as examples of the application are not limited in particular.
The pressure to be sensed received by the pressure sensitive component 130 may be the pressure applied directly or indirectly to the pressure sensitive component 130 by a fluid, which may be a liquid, a gas, or the like.
The resonance component 120 may be directly or indirectly connected to a side of the pressure sensitive component 130 facing away from the pressure cavity 131, where the side of the resonance component 120 facing away from the pressure sensitive component 130 is provided with the piezoelectric component 110, and the pressure to be detected acting on the pressure sensitive component 130 may be transferred to the piezoelectric component 110 through the pressure sensitive component 130 and the resonance component 120, and the pressure to be detected may be detected through the piezoelectric component 110.
The pressure chamber 131 may be formed on a side of the pressure sensitive component 130 facing away from the resonant component 120, and the pressure sensitive component 130 is formed with a pressure sensitive film 132 at a position where the pressure chamber 131 is formed. It will be appreciated that the projection of at least a portion of resonant cavity 121 falls within the projection of pressure cavity 131 in the direction of resonant assembly 120 to pressure sensitive assembly 130.
For example, the projection of the resonant cavity 121 may completely fall within the projection range of the pressure cavity 131, and at this time, the geometric center of the projection of the resonant cavity 121 may overlap with the geometric center of the projection of the pressure cavity 131, and the geometric center of the resonant cavity 121 may also be spaced from the geometric center of the pressure cavity 131.
For example, the projection of part of the resonant cavity 121 may fall within the projection range of the pressure cavity 131, that is, the projection of the resonant cavity 121 coincides with the projection part of the pressure cavity 131.
The shape of the pressure chamber 131 may be the same as the shape of the resonant chamber 121, and the shape of the pressure chamber 131 may be different from the shape of the resonant chamber 121. The inventive examples are described herein with reference to pressure chamber 131 only. For example, the shape of the pressure chamber 131 may be cylindrical, the shape of the pressure chamber 131 may be prismatic, or the shape of the pressure chamber 131 may be irregular.
The pressure chambers 131 may be provided in one, or the pressure chambers 131 may be provided in plural at intervals. The resonator 121 may be provided with only one, or the resonator 121 may be provided with a plurality of resonators, which is not limited by the present example.
The positional relationship between the resonant cavity 121 and the pressure cavity 131 is not particularly limited in the present embodiment, so long as the projection of at least part of the resonant cavity 121 coincides with the projection of the pressure cavity 131, so as to ensure that the pressure to be detected received by the pressure cavity 131 can be transmitted to the piezoelectric component 110 through the resonant cavity 121, and the pressure to be detected can be detected through the piezoelectric component 110.
Illustratively, the piezoelectric assembly 110 may include a piezoelectric layer 114 and electrodes, and the piezoelectric layer 114 may be made of a thin film material such as AlN, scAlN, PZT (piezoelectric ceramic), znO, liNbO 3, or the like. Due to piezoelectricity of the piezoelectric film material, under the condition that the piezoelectric layer 114 receives pressure, potential difference can be generated on two sides of the piezoelectric layer 114 which are oppositely arranged, and relevant parameters of the pressure to be detected can be known by utilizing positive piezoelectric effect and inverse piezoelectric effect of the piezoelectric layer 114, wherein the relevant parameters can include numerical value of the pressure to be detected, direction parameters of the pressure to be detected and the like, and specific description can be seen below.
The electrode can be directly and electrically connected with the external circuit, and the electrode can be indirectly connected with the external circuit through conducting pieces such as wires.
The external circuit can be a circuit for detecting the current and a circuit for detecting the voltage. The specific type of the external circuit is not limited by the present example, as long as the external circuit is guaranteed to be able to detect the electrical signal output by the piezoelectric assembly 110.
Based on the above, according to the piezoelectric resonant pressure sensor 100 provided by the example of the present application, the pressure chamber 131 can receive the pressure to be detected, and the pressure to be detected can be transmitted to the piezoelectric assembly 110 and the resonant assembly 120 through the pressure sensitive assembly 130, and the pressure to be detected is detected through the characteristics of the piezoelectric assembly 110. Since the piezoelectric assembly 110 is disposed on a side of the resonant assembly 120 facing away from the pressure sensitive assembly 130, the piezoelectric assembly 110 is disposed separately from the pressure chamber 131 that receives the pressure to be detected. And since the resonant assembly 120 is provided with the resonant cavity 121. Under the condition that the piezoelectric component 110 drives the resonant component 120 to vibrate, the resonant cavity 121 can provide a deformation space for the piezoelectric component 110, so that the deformation of the piezoelectric component 110 due to vibration is reduced, and the possibility of breakage of the piezoelectric component 110 is further reduced.
Under the condition that the possibility of breakage of the piezoelectric component 110 is reduced, the piezoelectric resonant pressure sensor 100 provided by the example of the application can bear larger pressure to be detected, so that the range of pressure measurement of the piezoelectric resonant pressure sensor 100 is increased, the measuring range of the piezoelectric resonant pressure sensor 100 is enlarged, the application range of the piezoelectric resonant pressure sensor 100 is enlarged, and the piezoelectric resonant pressure sensor 100 can be widely applied to the technical field of electronic core industry.
Furthermore, in the present example, since the pressure sensitive member 130 forms the pressure sensitive film 132 at a position where the pressure chamber 131 is opened, and at least part of the pressure sensitive film 132 encloses the resonant cavity 121, the resonant cavity 121 at least partially coincides with the pressure chamber 131. Based on this, the volume of the resonant piezoelectric sensor can be reduced, which is advantageous for miniaturization of the piezoelectric resonant pressure sensor 100 and for the development of integration of the piezoelectric resonant pressure sensor 100.
Based on the piezoelectric resonant pressure sensor 100 provided in the above example, referring to fig. 3, a pressure chamber 131 is disposed at a position where the pressure sensitive component 130 seals the resonant cavity 121.
Since the pressure sensitive film 132 is formed at the position where the pressure sensitive component 130 opens the pressure cavity 131, at least part of the pressure sensitive film 132 seals the resonant cavity 121, it can be known that the projection of the resonant cavity 121 coincides with the projection of the pressure cavity along the direction from the resonant cavity 121 to the pressure cavity 131. Because the pressure sensitive component 130 is provided with the pressure cavity 131 at the position where the resonant cavity 121 is sealed, based on this, it can be known that along the direction from the resonant cavity 121 to the pressure cavity 131, the projection of the resonant cavity 121 can completely fall into the projection range of the pressure cavity 131, so that the volume of the piezoelectric resonant pressure sensor 100 can be further reduced, which is beneficial to miniaturization of the piezoelectric resonant pressure sensor 100 and integration development of the piezoelectric resonant pressure sensor 100.
Based on the piezoelectric resonant pressure sensor 100 provided by the above example, the pressure sensitive component 130 may further include a resonant substrate 133, and the pressure sensitive film 132 may form the pressure cavity 131 in cooperation with the resonant substrate 133, where the resonant substrate 133 is located on a side of the pressure sensitive film 132 facing away from the resonant component 120.
The resonator substrate 133 may be of unitary construction with the pressure sensitive membrane 132, in which case the pressure chamber 131 may be a cavity formed by a block-like structure with intermediate portions removed. The pressure sensitive membrane 132 may be a partial block structure corresponding to the bottom of the pressure chamber 131. The resonant substrate 133 may be a partial block structure corresponding to a sidewall of the pressure chamber 131.
The resonant substrate 133 may also be bonded or otherwise coupled to the pressure sensitive membrane 132, in which case the resonant substrate 133 may include a plurality of different resonant substrates 133 capable of being coupled to the sidewalls of the corresponding pressure sensitive membranes 132. In this case, the pressure sensitive film 132 may serve as a bottom wall of the pressure chamber 131, the resonant substrate 133 may serve as a side wall of the pressure chamber 131, and the pressure sensitive film 132 and the resonant substrate 133 may jointly enclose the pressure chamber 131.
Through setting up resonant substrate 133, resonant substrate 133 and pressure sensitive film 132 cooperation form pressure chamber 131, and operating personnel can control fluid such as gas or liquid and exert pressure to the chamber wall of pressure chamber 131, can make the atress of pressure sensitive film 132 comparatively concentrated through setting up pressure chamber 131, and the operating personnel of being convenient for exerts the pressure of waiting to detect to the chamber wall of pressure chamber 131.
Based on the piezoelectric resonant pressure sensor 100 provided by the above example, fig. 5 is a schematic structural diagram of another piezoelectric resonant pressure sensor provided by the example of the present application, fig. 6 is a top view of another piezoelectric resonant pressure sensor provided by the example of the present application, fig. 7 is a cross-sectional view of C-C in fig. 6, and referring to fig. 5 to 7, the resonant assembly 120 may include a connecting structure 123 and a resonant film 122, where the connecting structure 123 and the resonant film 122 cooperate to form a resonant cavity 121, and the resonant film 122 is located on a side of the connecting structure 123 facing away from the pressure sensitive assembly 130.
The connection structure 123 may have a cylindrical shape, a prismatic shape, a truncated cone shape, or other shapes. The connection structure 123 may be provided with at least one, and the connection structure 123 may be provided with two, three, or even more.
The connection structure 123 may be a unitary structure with the resonant film 122, in which case the resonant cavity 121 may be a cavity formed by removing a middle portion of a block-shaped structural member. The resonant thin film 122 may be a partial block structure corresponding to the bottom of the resonant cavity 121. The connection structure 123 may be a partial block structure corresponding to a sidewall of the resonant cavity 121.
The connection structure 123 may be bonded or otherwise connected to the resonant thin film 122, and in this case, the connection structure 123 may include a plurality of connection structures 123, and different connection structures 123 may be connected to sidewalls of the corresponding resonant thin film 122. In this case, the resonant film 122 may be used as a bottom wall of the resonant cavity 121, the connection structure 123 may be used as a side wall of the resonant cavity 121, and the resonant film 122 and the connection structure 123 may jointly enclose the resonant cavity 121.
Since one side of the connection structure 123 is provided with the pressure sensitive film 132, the other side of the connection structure 123 is provided with the piezoelectric assembly 110. Based on this, the pressure to be detected acting on the pressure sensitive film 132 can be transmitted to the resonant film 122 and the piezoelectric element 110 through the connection structure 123, and stress is generated in the resonant film 122 and the piezoelectric element 110, thereby causing a change in the vibration frequency of the resonant film 122 and the piezoelectric element 110. Since the resonant cavity 121 is disposed on one side of the piezoelectric element 110, the resonant cavity 121 can provide a vibration space for the vibration of the piezoelectric element 110, and reduce the possibility of damage to the piezoelectric element 110 caused by deformation of the piezoelectric element 110 due to the vibration.
The connection structure 123 may directly or indirectly connect the resonant film 122 to one side of the pressure sensitive film 132, and fig. 8 is a schematic diagram illustrating the working principle of a piezoelectric resonant pressure sensor provided by the example of the present application, referring to fig. 8, the connection structure 123 can change the acting direction of the pressure to be detected.
Illustratively, the pressure to be detected acts on the pressure sensitive film 132 along a direction perpendicular to the pressure sensitive film 132, the pressure to be detected acting on the pressure sensitive film 132 can be transferred to the resonant film 122 through the connection structure 123, and the connection structure 123 can convert the pressure to be detected perpendicular to the pressure sensitive film 132 into an operating stress having an included angle between an acting direction and an acting direction of the pressure to be detected.
In summary, the resonant cavity 121 can provide a vibration space for the vibration of the piezoelectric assembly 110, so as to reduce the possibility of damage to the piezoelectric assembly 110 caused by deformation of the piezoelectric assembly 110 due to the vibration. The connection structure 123 can connect the pressure sensitive film 132 and the piezoelectric assembly 110, and the connection structure 123 can change the acting direction of the pressure to be detected, so that the pressure to be detected acting on the piezoelectric assembly 110 vertically is smaller, the possibility of damaging the piezoelectric assembly 110 is further reduced, the pressure bearing capacity of the resonant film 122 is improved, the detection range of the piezoelectric resonant pressure sensor 100 is enlarged, and the linearity of the piezoelectric resonant pressure sensor 100 in the pressure detection range is ensured.
The cavity 121 mentioned in the above example may be kept vacuum, and may be filled with a medium.
The piezoelectric resonant pressure sensor 100 may be an absolute pressure sensor, for example. The absolute pressure sensor is used for measuring absolute pressure, and can convert the absolute pressure of gas or liquid into equivalent electric signal output.
Illustratively, the piezoelectric resonant pressure sensor 100 may be a relative pressure sensor. The relative pressure sensor is measured based on the atmospheric pressure, and therefore, the measurement result of the relative pressure sensor is relative to the atmospheric pressure. Therefore, a relative pressure sensor may be used to measure the difference in relative pressure.
A user may select an appropriate absolute pressure sensor or a relative pressure sensor according to the needs, and the embodiment of the present application does not limit whether the medium is injected into the cavity of the piezoelectric resonator type pressure sensor 100.
Based on the piezoelectric resonant pressure sensor 100 provided in the above example, the side of the connection structure 123 near the pressure sensitive component 130 may be an anchor point, where the distance between the anchor point and the resonant thin film 122 is a first distance, and the distance between the anchor point and the pressure sensitive component 130 is a second distance, where the first distance is greater than the second distance.
The anchor point is the primary stress point of the connection structure 123.
By setting the first distance to be greater than the second distance, the resonant membrane 122, the pressure sensitive component 130, and the anchor point may cooperate to form a lever, the first distance being a first lever arm and the second distance being a second lever arm. Based on the lever principle, the connection structure 123 with the anchor point can amplify the working stress generated by the pressure to be detected, thereby improving the detection sensitivity of the piezoelectric resonant pressure sensor 100.
Based on the piezoelectric resonant pressure sensor 100 provided by the above example, fig. 9 is a schematic diagram of a resonance principle of the piezoelectric resonant pressure sensor provided by the example of the present application, and referring to fig. 1 to 5 and fig. 9, the piezoelectric assembly 110 may include a first lead electrode 111, a second lead electrode 112, a first electrode 113, a piezoelectric layer 114 and a second electrode 115.
The second electrode 115 may be disposed on a side of the resonant assembly 120 facing away from the pressure sensitive assembly 130, and a side of the second electrode 115 facing toward the resonant assembly 120 may be directly or indirectly connected to the resonant assembly 120. The piezoelectric layer 114 may be disposed on a side of the second electrode 115 facing away from the resonant assembly 120, and a side of the piezoelectric layer 114 facing the second electrode 115 may be connected to the second electrode 115. The first electrode 113 may be disposed on a side of the piezoelectric layer 114 facing away from the second electrode 115, and a side of the piezoelectric layer 114 facing the first electrode 113 may be connected to the first electrode 113.
The first lead electrode 111 is disposed on a side of the first electrode 113 facing away from the piezoelectric layer 114, one end of the first lead electrode 111 may be connected to the first electrode 113, and the other end of the first lead electrode 111 may be connected to a first portion of an external circuit.
The second lead electrode 112 is disposed on a side of the second electrode 115 facing the piezoelectric layer 114, one end of the second lead electrode 112 may be connected to the second electrode 115, and the other end of the second lead electrode 112 may be connected to a second portion of the external circuit.
The first electrode 113, the second electrode 115, the first lead electrode 111, and the second lead electrode 112 may be made of a conductive material, such as aluminum, copper, or gold. The number of the first lead electrodes 111 may correspond to the number of the first electrodes 113, the second lead electrodes 112 may be provided with at least one, the second lead electrodes 112 may be provided with a plurality, and the plurality of second lead electrodes 112 may be connected with different positions of the second electrodes 115.
The first electrode 113 and the second electrode 115 may have the same shape or different shapes. The present example is described using the first electrode 113 as an example, and the first electrode 113 may have any of other regular shapes such as a cylindrical shape, a prismatic shape, and the like, or may have an irregular shape.
The first lead electrode 111 and the second lead electrode 112 may have the same shape or different shapes. Only the first lead electrode 111 will be described here as an example.
Illustratively, the first lead electrode 111 may include a first connection portion and a second connection portion connected to each other, one end of the first connection portion being connected to the first electrode 113, and one end of the second connection portion being connected to an external circuit. The cross-sectional shapes of the first connecting portion and the second connecting portion may be the same or different, for example, the cross-sectional shape of the first connecting portion may be circular, elliptical, polygonal or irregular. The present example is not limited to a specific implementation of the first electrode 113, the second electrode 115, and the first lead electrode 111 and the second lead electrode 112.
The second electrode 115 may be a conductive layer laid on the side of the resonator film 122 facing away from the resonator 121, and the second electrode 115 may be provided with only one. The second electrode 115 may be used to implement the ground of the piezoelectric resonant pressure sensor 100.
The side of the second electrode 115 facing away from the resonant assembly 120 may be provided with a piezoelectric layer 114. The piezoelectric layer 114 may be made of a piezoelectric thin film material.
The first electrode 113 may be provided at a side of the piezoelectric layer 114 facing away from the second electrode 115, and the first electrode 113 may be provided with at least two. The first electrode 113 may include at least one driving electrode and at least one detecting electrode. The driving electrode is used for driving the piezoelectric layer 114 to vibrate, and the detecting electrode is used for detecting the vibration of the piezoelectric layer 114.
The external circuit may be a detection circuit for detecting an output electric signal of the piezoelectric resonant pressure sensor 100.
Next, referring to fig. 8 and 9, the principle of the piezoelectric resonant pressure sensor 100 will be further described with reference to the specific structure of the piezoelectric assembly 110.
The resonant assembly 120 and the piezoelectric assembly 110 cooperate to form a piezoelectric resonator, which may include other structures.
When any one of the first electrodes 113 receives a voltage, stress is generated in the piezoelectric layer 114 due to the inverse piezoelectric effect of the piezoelectric layer 114. At this time, the neutral layer of the piezoelectric layer 114 deviates from the geometric center position of the piezoelectric layer 114, which will cause the piezoelectric layer 114 to deform, and the deformation of the piezoelectric layer 114 drives the entire piezoelectric resonator to deform.
When an alternating voltage having the same resonant frequency as the piezoelectric resonator is applied to any one of the first electrodes 113, the entire structure will resonate, and the resonant frequency is:
Where fr is the resonance frequency, μn is a constant set when solving the Bessel function, t is the thickness, r is the radius, E is the Young's modulus, ρ is the density, and δ is the Poisson's ratio.
In the case that the pressure chamber 131 receives the pressure to be detected, the pressure sensitive film 132 deforms under the action of the pressure to be detected and generates working stress. The connection structure 123 may transfer the deformation and resulting operating stress of the pressure sensitive membrane 132 to the piezoelectric resonator, and in particular to the piezoelectric layer 114. During the transmission of the connection structure 123, the connection structure 123 can change the acting direction of the pressure to be detected, and the possibility of damage to the resonant thin film 122 is reduced. The anchor point can amplify the working stress by using the lever principle, and improves the measurement range of the piezoelectric resonant pressure sensor 100.
Since the piezoelectric resonator is provided with at least two first electrodes 113, in the case where one of the first electrodes 113 drives the piezoelectric layer 114 to vibrate, the other first electrode 113 detects the vibration of the piezoelectric resonator. The first electrode 113 receiving the voltage may be a driving electrode, and the first electrode 113 detecting the vibration may be a detecting electrode.
The detection electrode will generate an electrical signal due to the positive piezoelectric effect of the piezoelectric film material. The electrical signal may be used to detect the resonant frequency of the piezoelectric resonator.
Let the working stress of the pressure to be detected on the piezoelectric resonator be sigma, at this time, the resonance frequency of the piezoelectric resonator is:
From the above formula, the pressure value can be determined when the frequency change of the piezoelectric resonator is detected.
In the case of deformation of the piezoelectric layer 114, a portion of the piezoelectric layer 114 adjacent to the resonant assembly 120 is pressed by the pressure to be detected, and a portion of the piezoelectric layer 114 away from the resonant assembly 120 is stretched by the pressure to be detected. The transition layer, which is present between the piezoelectric layer 114 of the tensile portion and the piezoelectric layer 114 of the compressive portion and is neither in tension nor in compression, with almost zero stress, is the neutral layer mentioned above in the cross section of the piezoelectric layer 114.
Compared with the resistance detection type piezoelectric sensor which needs to be provided with a Wheatstone bridge and the capacitance detection type pressure sensor which needs to be provided with a capacitance bridge, the piezoelectric resonance type pressure sensor 100 provided by the example of the application does not need to be provided with an extra detection circuit, and has simpler structure and lower manufacturing cost.
Based on the piezoelectric resonant pressure sensor 100 provided by the above example, fig. 10 is a schematic diagram of an internal structure of the piezoelectric resonant pressure sensor provided by the example of the present application, and referring to fig. 7 or 10, fig. 3, 7 and 10 are schematic diagrams of internal structures of the piezoelectric resonant pressure sensor 100 respectively showing different structures. Fig. 3 is a view for illustrating an internal structure of the piezoelectric resonator type pressure sensor 100 when the piezoelectric resonator type pressure sensor 100 is not provided with a groove, fig. 7 is a view for illustrating an internal structure of the piezoelectric resonator type pressure sensor 100 when the piezoelectric resonator type pressure sensor 100 is provided with one groove, and fig. 10 is a view for illustrating an internal structure of the piezoelectric resonator type pressure sensor 100 when the piezoelectric resonator type pressure sensor 100 is provided with another groove.
The piezoelectric resonant pressure sensor 100 is provided with at least one groove 170. The groove 170 may be disposed between the resonant film 122 and the pressure sensitive film 132. Alternatively, the groove 170 may be disposed on a side of the resonant assembly 120 facing away from the resonant substrate 133, and a notch of the groove 170 may be opened facing away from the resonant substrate 133.
For example, referring to fig. 10, the resonant assembly 120 may further include a resonant substrate 124, where the resonant substrate 124 is disposed on a side of the pressure sensitive assembly 130 facing away from the pressure chamber 131. The groove 170 may be disposed between the resonant film 122 and the pressure sensitive film 132 in a direction in which the resonant assembly 120 faces the pressure sensitive assembly 130. The groove 170 is provided between the resonant substrate 124 and the connection structure 123 in the direction of the cross section of the resonant cavity 121.
The groove 170 can keep a distance between the resonant substrate 124 and the connection structure 123, so as to reduce the cross-sectional area of the connection structure 123, and make the working stress transferred to the pressure sensitive film 132 through the connection structure 123 more concentrated, which is beneficial to improving the detection accuracy of the piezoelectric resonant pressure sensor 100.
For example, referring to fig. 7, the resonant assembly 120 may further include a resonant substrate 124, where the resonant substrate 124 is disposed in a manner similar to the resonant substrate 124 mentioned in the previous example, and the present examples are not described herein.
The groove 170 may also be disposed on a side of the resonant assembly 120 facing away from the resonant substrate 133, and a notch of the groove 170 may be opened facing away from the resonant substrate 133.
The grooves 170 in the present embodiment can maintain a distance between the resonant substrate 124 and the connection structure 123, thereby reducing the cross-sectional area of the connection structure 123, so that the working stress transferred to the pressure sensitive film 132 through the connection structure 123 is concentrated, which is beneficial to improving the detection accuracy of the piezoelectric resonant pressure sensor 100.
Furthermore, since the opening of the groove 170 is facing away from the resonant substrate 133, the notch of the groove 170 may be opened to the position where the piezoelectric element 110 is located, and in particular, may be opened to the side of the piezoelectric element 110 facing away from the resonant element 120. Based on this, the resonator assembly 120 may divide the piezoelectric layer 114 into at least two parts, and along the direction from the resonator cavity 121 to the pressure cavity 131, the projection of the groove 170 is located between the projection of the at least one lead electrode and the projection of the resonator cavity 121, i.e., the groove 170 may divide the piezoelectric assembly 110 into a part that vibrates under the action of the pressure to be detected, and a part that hardly vibrates under the action of the pressure to be detected, and the at least one lead electrode may be located in the part of the piezoelectric assembly 110 that hardly vibrates. In this way, the influence of the pressure to be detected on the lead electrode can be reduced, the possibility of vibration of the lead electrode under the action of the pressure to be detected is reduced, and the use reliability of the piezoelectric resonant pressure sensor 100 is further ensured.
In the case where only one groove is provided, the piezoelectric resonant pressure sensor 100 may be provided with or without the lead bridge 171.
In the case where at least two grooves 170 are provided, a lead bridge 171 may be formed between adjacent two grooves 170, and the lead bridge 171 may be provided with one, two, three, four, or more. The plurality of lead bridges can be arranged in a cross shape, a rice shape, a straight shape or other irregular shapes in a matched manner.
The number of the lead bridges 171 may be equal to and one-to-one corresponding to the number of the first lead electrodes 111, and the number of the lead bridges 171 may be less than the number of the first lead bridges 171, which is not limited by the present example. Referring specifically to fig. 11 to 15, fig. 11 is a schematic structural diagram of a piezoelectric resonant pressure sensor without a lead electrode and a protective layer according to an example of the present application, where the structure is provided with 4 lead bridges. Fig. 12 is a schematic structural diagram of a piezoelectric resonant pressure sensor without a lead electrode and a protective layer according to an embodiment of the present application, where 3 lead bridges are provided. Fig. 13 is a schematic structural diagram of a piezoelectric resonant pressure sensor without a lead electrode and a protective layer according to an embodiment of the present application, where 2 lead bridges are provided. Fig. 14 is a schematic structural diagram of a piezoelectric resonant pressure sensor without a lead electrode and a protective layer according to an embodiment of the present application, where 1 lead bridge is provided. Fig. 15 is a schematic structural diagram of a piezoelectric resonant pressure sensor without a lead electrode and a protective layer according to an embodiment of the present application, where no lead bridge is provided.
By providing the lead bridge 171, a setting position can be provided for a lead wire connecting the first lead electrode 111 and the first electrode 113, and the setting position of the first lead electrode 111 is adjusted, so that the connection reliability of the first lead electrode 111 and the first electrode 113 is ensured.
Referring to fig. 11, a beam structure 172 may be disposed at a location where the first electrode 113 is disposed, and one or more beam structures 172 may be disposed.
An angle may be formed between beam structure 172 and lead bridge 171.
Illustratively, the included angle between the beam structure 172 and the lead bridge 171 may be equal to zero, i.e., the connection electrode between the first lead electrode 111 and the first electrode 113 may be linear, and the connection electrode may be provided to the lead bridge 171 to electrically connect the first lead electrode 111 and the first electrode 113. At this time, the number of beam structures 172 may be equal to or different from the number of lead bridges 171. For example, in the case where the number of beam structures 172 and the number of lead bridges 171 are equal, the beam structures 172 and the lead bridges 171 may cooperate to form a straight-line structure, a cross-shaped structure, a rice-shaped structure, or other structures.
Illustratively, the angle between the beam structure 172 and the lead bridge 171 may also be a non-zero angle, i.e., the connection electrode between the first lead electrode 111 and the first electrode 113 is in the shape of a meander. At this time, the number of beam structures 172 may be equal to or unequal to the number of lead bridges 171. The present examples are not limited to the specific implementation of beam structure 172 and lead bridge 171.
Based on the piezoelectric resonant pressure sensor 100 provided in the above example, the piezoelectric component 110 may further include a seed layer, where the seed layer is disposed between the piezoelectric component 110 and the resonant component 120, and in particular may be disposed between the second electrode 115 and the resonant component 120.
By providing the seed layer, the operation performance of the piezoelectric component 110 can be ensured, and thus the operation performance of the piezoelectric resonant pressure sensor 100 can be ensured.
Based on the piezoelectric resonant pressure sensor 100 provided by the above example, the resonant assembly 120 can be fabricated from a first SOI wafer (silicon on insulator) and the pressure sensitive assembly 130 can be fabricated from a second SOI wafer.
Next, a second SOI wafer is taken as an example, and the structure of the second SOI wafer is briefly described in connection with the pressure sensitive device 130.
The second SOI wafer may include a second device layer, a second buried oxide layer, and a second substrate layer connected. The pressure cavity 131 may be processed on a side of the second substrate layer facing away from the second device layer, and the bottom wall of the pressure cavity 131 may be a side of the second oxygen-buried layer facing toward the second substrate layer 430, and the bottom wall of the pressure cavity 131 may also be a side of the second oxygen-buried layer facing away from the second substrate layer.
Referring to fig. 10, referring to the piezoelectric resonant pressure sensor 100 provided by the above example, an oxide layer 150 is disposed between the pressure sensitive component 130 and the resonant component 120.
The oxide layer 150 may be an oxide layer 150 formed during the process of connecting the first SOI wafer and the second SOI wafer, and the oxide layer 150 may be an oxide layer 150 purposely provided between the first SOI wafer and the second SOI wafer.
By providing the oxide layer 150, insulation between the pressure sensitive component 130 and the resonant component 120 can be ensured, the possibility of leakage of the piezoelectric resonant pressure sensor 100 is reduced, and the use safety of the piezoelectric resonant pressure sensor 100 is ensured.
In addition, since the pressure sensitive film 132 is located at one side of the trench 170, the processing depth of the trench 170 can be ensured by providing the oxide layer 150, and the possibility of damage to the pressure sensitive film 132 when the trench 170 is processed can be reduced.
Based on the piezoelectric resonant pressure sensor 100 provided in the above example, referring to fig. 10, the pressure sensitive component 130 may further include a second oxygen-buried layer 420, where a sidewall of the second oxygen-buried layer 420 cooperates with a sidewall of the resonant substrate 133 to form a sidewall of the pressure cavity 131.
By arranging the second oxygen burying layer 420, the processing depth of the pressure cavity 131 can be ensured, the thickness of the pressure sensitive film 132 is further ensured, the strength of the pressure sensitive film 132 is ensured, and the possibility of damage of the pressure sensitive film 132 due to the impact of the pressure to be detected is reduced.
Based on the piezoelectric resonant pressure sensor 100 provided by the above example, fig. 16 is a schematic structural diagram of another piezoelectric resonant pressure sensor provided by the example of the present application, referring to fig. 16, the piezoelectric resonant pressure sensor 100 may further include a cover 160, where the cover 160 is disposed on a side of the piezoelectric component 110 facing away from the pressure sensitive component 130, and the cover 160 is directly or indirectly connected to the piezoelectric component 110.
The cover 160 may be made of a silicon wafer, a glass wafer, an inorganic semiconductor material, or other amorphous inorganic nonmetallic material.
The cover 160 may be used to encapsulate the piezoelectric resonator in a vacuum environment. The cover 160 may be disposed on a side of the piezoelectric assembly 110 away from the resonant assembly 120, so as to isolate the piezoelectric assembly 110 from the atmospheric environment, ensure that the piezoelectric assembly 110 is in a vacuum environment during operation, further improve the value corresponding to the quality factor of the piezoelectric resonant pressure sensor 100, and ensure the working performance of the piezoelectric resonant pressure sensor 100.
Based on the piezoelectric resonant pressure sensor 100 provided in the above example, referring to fig. 10, a side of the piezoelectric assembly 110 facing away from the resonant assembly 120 may be provided with a protective layer 140, and the protective layer 140 may be made of a silicon dioxide material or other material capable of preventing moisture.
The protective layer 140 can isolate the piezoelectric assembly 110 from the atmospheric environment, and the protective layer 140 can play a role in moisture prevention, so that the piezoelectric resonant pressure sensor 100 is maintained in a dry state as much as possible, and the working reliability of the piezoelectric resonant pressure sensor 100 is ensured. The protective layer 140 may also function as temperature compensation during operation of the piezoelectric resonant pressure sensor 100.
In the use of the piezoelectric resonant pressure sensor 100, only the cover 160 may be provided, only the protective layer 140 may be provided, both the cover 160 and the protective layer 140 may be provided, or neither the cover 160 nor the protective layer 140 may be provided, which is not particularly limited by the present application.
Illustratively, the present examples provide a method of manufacturing a piezoelectric resonant pressure sensor 100, which is applicable to the piezoelectric resonant pressure sensor 100 provided in any of the above examples, and the following processing method may be accomplished by a MEMS processing device. The method is used to process a piezoelectric resonant pressure sensor 100 from a first SOI wafer and a second SOI wafer.
The first SOI wafer includes a first device layer 310, a first buried oxide layer 320, and a first substrate layer 330, and the second SOI wafer includes a second device layer 410, a second buried oxide layer 420, and a second substrate layer 430. The thickness of the first device layer 310 is equal to the sum of the height of the resonant cavity 121 and the thickness of the resonant thin film 122, and the thickness of the second device layer 410 is equal to the thickness of the pressure sensitive thin film 132. Fig. 17 is a schematic flow chart of a method for manufacturing a piezoelectric resonant pressure sensor according to an embodiment of the present application, please refer to fig. 17, the method specifically includes the following steps:
s201, taking the first SOI wafer, processing the resonator 121 on the first device layer 310. Fig. 18 is a schematic structural diagram of a first SOI wafer provided by the present application when not processed, and fig. 19 is a schematic structural diagram of a first SOI wafer provided by the present application when processed with a resonant cavity and a trench, specifically referring to fig. 18 and 19.
The resonant cavity 121 may be formed by etching, sputtering or other processing on the side of the first device layer 310 facing away from the first buried oxide layer 320. The thickness of the first device layer 310 is equal to the sum of the thickness of the resonant thin film 122 and the height of the resonant cavity 121. The etching may include dry etching including, but not limited to, xenon difluoride and plasma etching, and wet etching including, but not limited to, HF etching and electrochemical etching.
The thickness of the first device layer 310, the thickness of the resonant film 122, and the height of the resonant cavity 121 refer to the dimension corresponding to the first device layer 310, the dimension corresponding to the resonant film 122, and the dimension corresponding to the resonant cavity 121 along the direction from the first buried oxide layer 320 to the first device layer 310.
In some possible implementations, the piezoelectric resonant pressure sensor 100 includes a groove 170, and the groove 170 may be formed by a plurality of methods.
Illustratively, based on the preparation method provided in the above example, in S201, taking the first SOI wafer, when the resonant cavity 121 is processed on the first device layer 310, the preparation method may further include:
In S2011, at least one first trench is processed in the first device layer 310, referring to fig. 19, fig. 19 is a schematic structural diagram of a first SOI wafer processed resonant cavity and trench provided in an example of the present application.
The depth of the first groove may be the same as or different from the height of the resonant cavity 121. The first groove and the resonator 121 may be simultaneously processed, the first groove may be processed before the resonator 121 is processed, or the first groove may be processed after the resonator 121 is processed, which is not limited by the present example.
In the case of processing the first trench, the second device layer 410 may close the notch of the first trench while bonding the first device layer 310 and the second device layer 410.
In some possible implementations, where the first device layer 310 processes at least one first trench, the method of preparing may further include:
s2013, processing a second groove from the piezoelectric assembly 110 based on the arrangement position of the first groove, wherein the second groove is communicated with the first groove to form a groove 170.
S202, taking the second SOI wafer, bonding the second device layer 410 to the first device layer 310, where the second device layer 410 seals the resonant cavity 121, and where the oxide layer 150 is formed between the second device layer 410 and the first device layer 310 during the bonding process. Fig. 20 is a schematic diagram of a structure of a first SOI wafer turned over after a resonant cavity and a trench are processed according to an exemplary embodiment of the present application, fig. 21 is a schematic diagram of a structure of a second SOI wafer provided according to an exemplary embodiment of the present application when the second SOI wafer is not processed, and fig. 22 is a schematic diagram of a structure of bonding connection between the first SOI wafer and the second SOI wafer according to an exemplary embodiment of the present application, which can be seen in fig. 20 to 22.
The first SOI wafer may also enable the first device layer 310 to face the second device layer 410, so that bonding between the first device layer 310 and the second device layer 410 is facilitated, and the second device layer 410 seals the cavity opening of the resonant cavity 121.
By flipping the second SOI wafer, the second device layer 410 may be oriented towards the first device layer 310, facilitating bonding of the first device layer 310 to the second device layer 410, such that the second device layer 410 closes the cavity mouth of the resonator 121. Bonding may be anodic bonding, fusion bonding or other bonding means.
S203, removing the first buried oxide layer 320 and the first substrate layer 330, and a portion of the first device layer 310 serves as the resonant film 122. Fig. 23 is a schematic structural view of a first SOI wafer and a second SOI wafer provided as an example of the present application after bonding connection and removal of the first substrate layer and the first buried oxide layer, and fig. 23 may be referred to specifically.
The present example does not specifically limit the removal manner of the first buried oxide layer 320 and the oxide layer 150.
Removing the first buried oxide layer 320 and the first substrate layer 330 may expose the first device layer 310 for subsequent processing.
In S204, the piezoelectric component 110 is disposed on a side of the first device layer 310 facing away from the second SOI wafer, and referring specifically to fig. 24, fig. 24 is a schematic structural diagram of a piezoelectric component deposited on a side of the first device layer facing away from the second SOI wafer according to an example of the present application.
The piezoelectric assembly 110 may be deposited or otherwise disposed on a side of the first device layer 310 facing away from the second SOI wafer.
In some possible implementations, the piezoelectric assembly 110 includes a lead electrode, a first electrode 113, a piezoelectric layer 114, and a second electrode 115. S204 specifically comprises the following steps:
s2041, a second electrode layer, a piezoelectric layer 114, and a first electrode layer are sequentially deposited, with particular reference to fig. 24.
S2042, patterning the first electrode layer to form at least two first electrodes 113, refer to fig. 25, and fig. 25 is a schematic structural diagram of the piezoelectric assembly after processing based on fig. 24 according to an example of the present application.
In some possible implementations, after S2042, the following steps may be further included:
S2411, depositing a protective layer 140, and referring specifically to fig. 26, fig. 26 is a schematic structural diagram of an example of the present application provided by fig. 25, where the protective layer is disposed on a piezoelectric assembly facing away from a first device layer.
Since patterning of the first electrode 113 has been performed before depositing the protective layer 140, resulting in exposure of a portion of the piezoelectric layer 114, a portion of the protective layer 140 may be in contact with the first electrode 113 and another portion of the protective layer 140 may be in contact with the piezoelectric layer 114.
S2412, machining a first connection hole 1111 at a position where the first electrode 113 is connected, wherein the conductive structure is disposed through the first connection hole 1111 and is capable of being connected to the first electrode 113. Referring specifically to fig. 27, fig. 27 is a schematic structural diagram of processing a first connection hole from a protective layer based on fig. 26 according to an example of the present application.
The first connection hole 1111 may be machined to a side of the first electrode 113 facing away from the resonant assembly 120, and a portion of a hole wall of the first connection hole 1111 may be disposed on the first electrode 113, so long as it is ensured that the conductive structure penetrates through the first connection hole 1111 and can be connected to the first electrode 113.
S2413, machining a second connection hole 1121 at a position where the second electrode 115 is connected, wherein the connector is inserted through the second connection hole 1121 and may be connected to the second electrode 115. Referring specifically to fig. 28, fig. 28 is a schematic structural view of a second connection hole formed in a protective layer according to fig. 27 according to an example of the present application, and fig. 28 is different from fig. 27 in a cross-sectional direction.
The second connection hole 1121 may be machined to a side of the second electrode 115 facing away from the resonant assembly 120, and a portion of a hole wall of the second connection hole 1121 may be disposed on the second electrode 115, so long as it is ensured that the conductive structure penetrates through the second connection hole 1121 and can be connected to the second electrode 115, which is not particularly limited in the present embodiment.
S2043, depositing a lead electrode layer, where a portion of the lead electrode layer may be located in the second connection hole 1121 and connected to the second electrode 115, and referring specifically to fig. 29, fig. 29 is a schematic structural diagram of depositing a lead electrode layer on a side of the protective layer facing away from the first device layer based on fig. 28 according to an example of the present application.
S2044, patterning the lead electrode layer to form at least one first lead electrode 111 and at least one second lead electrode 112, and referring specifically to fig. 30, fig. 30 is a schematic structural diagram of processing the lead electrode layer based on fig. 29 according to an example of the present application.
The side of the first lead electrode 111 near the first electrode 113 is connected to the first electrode 113, and the side of the first lead electrode 111 facing away from the first electrode 113 may be connected to a first portion of an external circuit. The side of the second lead electrode 112 near the second electrode 115 is connected to the second electrode 115, and the side of the second lead electrode 112 facing away from the second electrode 115 may be connected to a second portion of the external circuit. The second lead electrode 112 is a conductive structure mentioned in the above example. Based on this, connection between the piezoelectric resonant pressure sensor 100 and an external circuit can be achieved.
S205, a pressure cavity 131 is formed on the second substrate layer 430, and a pressure sensitive film 132 is formed, where at least a portion of the pressure sensitive film 132 seals the resonant cavity 121, and referring to fig. 31, fig. 31 is a schematic structural diagram of a processing pressure cavity on the second SOI wafer away from the first device layer based on fig. 30 according to an example of the present application.
The pressure chamber 131 is processed in a manner similar to that of the resonant chamber 121, and the description of the present example will not be repeated.
The pressure chamber 131 may be formed on a side of the pressure sensitive component 130 facing away from the resonant component 120, and the pressure sensitive component 130 is formed with a pressure sensitive film 132 at a position where the pressure chamber 131 is formed. It will be appreciated that the projection of at least a portion of resonant cavity 121 falls within the projection of pressure cavity 131 in the direction of resonant assembly 120 to pressure sensitive assembly 130.
For example, the projection of the resonant cavity 121 may fall entirely within the projection range of the pressure cavity 131, in which case the geometric center of the projection of the resonant cavity 121 may overlap with the geometric center of the projection of the pressure cavity 131, and the geometric center of the resonant cavity 121 may also be spaced from the geometric center of the pressure cavity 131.
For example, the projection of part of the resonant cavity 121 may fall within the projection range of the pressure cavity 131, that is, the projection of the resonant cavity 121 coincides with the projection part of the pressure cavity 131.
The positional relationship between the resonant cavity 121 and the pressure cavity 131 is not particularly limited in the present embodiment, so long as the projection of at least part of the resonant cavity 121 coincides with the projection of the pressure cavity 131, so as to ensure that the pressure to be detected received by the pressure cavity 131 can be transmitted to the piezoelectric component 110 through the resonant cavity 121, and the pressure to be detected can be detected through the piezoelectric component 110.
Illustratively, at S205, after the pressure chamber 131 is opened on the second substrate layer 430 and the pressure sensitive film 132 is formed, the method may further include:
S2014, processing a groove 170 on a side of the piezoelectric assembly 110 away from the first device layer 310, where the groove 170 is spaced from the resonant cavity 121, and referring specifically to fig. 32, fig. 32 is a schematic structural diagram of processing a groove from a protective layer based on fig. 31 according to an example of the present application.
In this embodiment, the notch of the trench 170 may be opened away from the resonant substrate 133, the bottom of the trench 170 may be at least part of the oxide layer 150, the bottom of the trench 170 may be at least part of the second device layer 410, and the bottom of the trench 170 may be at least part of other structures.
Based on the piezoelectric resonant pressure sensor 100 processed by the above preparation method, the pressure cavity 131 can receive the pressure to be detected, the pressure to be detected can be transmitted to the piezoelectric component 110 and the resonant component 120 through the pressure sensitive component 130, and the pressure to be detected is detected through the characteristics of the piezoelectric component 110. Since the piezoelectric assembly 110 is disposed on a side of the resonant assembly 120 facing away from the pressure sensitive assembly 130, the piezoelectric assembly 110 is disposed separately from the pressure chamber 131 that receives the pressure to be detected. And since the resonant assembly 120 is provided with the resonant cavity 121. Under the condition that the piezoelectric component 110 drives the resonant component 120 to vibrate, the resonant cavity 121 can provide a deformation space for the piezoelectric component 110, so that the deformation of the piezoelectric component 110 due to vibration is reduced, and the possibility of breakage of the piezoelectric component 110 is further reduced.
Under the condition that the possibility of breakage of the piezoelectric component 110 is reduced, the piezoelectric resonant pressure sensor 100 provided by the example of the application can bear larger pressure to be detected, so that the range of pressure measurement of the piezoelectric resonant pressure sensor 100 is increased, the measuring range of the piezoelectric resonant pressure sensor 100 is enlarged, the application range of the piezoelectric resonant pressure sensor 100 is enlarged, and the piezoelectric resonant pressure sensor 100 can be widely applied to the technical field of electronic core industry.
Furthermore, in the present example, since the pressure sensitive member 130 forms the pressure sensitive film 132 at a position where the pressure chamber 131 is opened, and at least part of the pressure sensitive film 132 encloses the resonant cavity 121, the resonant cavity 121 at least partially coincides with the pressure chamber 131. Based on this, the volume of the resonant piezoelectric sensor can be reduced, which is advantageous for miniaturization of the piezoelectric resonant pressure sensor 100 and for the development of integration of the piezoelectric resonant pressure sensor 100.
In some possible implementations, the piezoelectric resonant pressure sensor 100 may further include a cover, and the preparation method may further include:
S206, taking a glass wafer 500, etching the cavity to form the cover 160. Referring to fig. 33 and 34, fig. 33 is a schematic structural view of a glass wafer according to an example of the present application, and fig. 34 is a schematic structural view of a processing cavity forming cover on a glass wafer according to an example of the present application.
S207, in a vacuum environment, the cover 160 and the piezoelectric assembly are bonded and connected, and referring to FIG. 35, FIG. 35 is a schematic structural diagram of a glass wafer connected to a side of the protective layer facing away from the piezoelectric layer according to an example of the present application. The bonding mode can be anodic bonding, metal bonding such as Al-Ge, au-Au, or other bonding modes.
The above reference numerals do not limit the order of the steps of the above method, and in the specific implementation process of the preparation method, the implementation steps of the above method may be adaptively adjusted based on actual situations.
In the detection process of the piezoelectric resonant pressure sensor 100, the detection of the piezoelectric resonant pressure sensor 100 is easily affected by environmental factors, and thus the detection result of the piezoelectric resonant pressure sensor 100 may be affected. The environmental factors may be temperature, vibration, shock, etc. Based on this, the piezoelectric resonant pressure sensor 100 needs to be compensated.
As an example, the present application provides a compensation system 200, and fig. 36 is a schematic structural diagram of the compensation system provided by the example of the present application, referring to fig. 36, the compensation system 200 may include a driving component 230, a detecting component 240 and at least two piezoelectric resonant pressure sensors 100 mentioned in the foregoing embodiments, where the at least two piezoelectric resonant pressure sensors 100 include at least one pressure sensor 210 and at least one compensation sensor 220.
In the case where the pressure sensor 210 is provided in one, the compensation sensor 220 may be provided in only one, or the compensation sensor 220 may be provided in plurality.
In the case where one compensation sensor 220 is provided, one detection sensor may be provided, and a plurality of detection sensors may be provided.
The number of the compensation sensors 220 and the number of the detection sensors may be equal to each other, and the number of the compensation sensors 220 may be different from the number of the detection sensors.
The pressure sensor 210 is used for detecting the pressure to be detected, and the compensation sensor 220 is used for compensating the influence of environmental factors on the pressure sensor 210. The driving part 230 is connected to the driving electrode of the pressure sensor 210 and to the driving electrode of the compensation sensor 220, and the driving part 230 is used to drive the detection sensor and the compensation sensor 220 to vibrate. The detecting part 240 is connected to the detecting electrode of the pressure sensor 210 and to the detecting electrode of the compensation sensor 220. The detecting unit 240 is used for detecting the resonant frequencies of the pressure sensor 210 and the compensation sensor 220.
Since the pressure sensor 210 and the compensation sensor 220 are integrated together, having the same resonant assembly 120, environmental factors such as temperature, vibration, shock, etc. may have the same influence on the pressure sensor 210 and the resonant assembly 120 of the compensation sensor 220, so that the pressure sensor 210 and the resonant assembly 120 of the compensation sensor 220 may have the same output based on the influence of the environmental factors.
Based on this, when the detecting unit 240 detects the resonant frequencies of the pressure sensor 210 and the compensation sensor 220, the resonant frequency output by the compensation sensor 220 is subtracted from the resonant frequency output by the pressure sensor 210, and the final resonant frequency is extracted, so that the influence of environmental factors can be eliminated, and the accuracy of detecting the pressure to be detected by the compensation system 200 can be improved.
Fig. 37 is a schematic workflow diagram of a compensation system provided by an example of the present application, referring to fig. 37, the workflow of the compensation sensor 220 is specifically as follows:
S101, the driving part 230 is used to drive the pressure sensor 210 and the compensation sensor 220.
S102, the detecting unit 240 is configured to detect and output a first resonant frequency corresponding to the pressure sensor 210 and a second resonant frequency corresponding to the compensation sensor 220.
And S103, a calculation module is used for calculating the difference value between the first resonant frequency and the second resonant frequency to obtain the target resonant frequency.
And S104, the calculation module can also calculate a pressure value of the pressure to be detected based on the resonance frequency.
The calculation module may be part of the detecting unit 240, or may be a module independent of the detecting unit 240, which is not limited by the present example.
Based on the compensation system 200 mentioned in the above example, during operation of the compensation system 200, the pressure to be detected can act on the pressure chamber 131 of the pressure sensor, and the pressure to be detected does not act on the compensation sensor 220. Based on this, the structure of the pressure sensor 210 and the structure of the compensation sensor 220 may be completely identical. The structures of the pressure sensor 210 and the compensation sensor 220 may also be inconsistent, for example, the compensation sensor 220 may not be provided with the pressure sensitive component 130. The specific structures of the pressure sensor 210 and the compensation sensor 220 are not limited by the present example.
In summary, according to the compensation system 200 provided in the present embodiment, when the detecting component 240 detects the resonant frequencies of the pressure sensor 210 and the compensation sensor 220, the resonant frequency output by the compensation sensor 220 is subtracted from the resonant frequency output by the pressure sensor 210, and then the final resonant frequency is extracted, so that the influence of environmental factors can be eliminated, and the accuracy of detecting the pressure to be detected by the compensation system 200 is improved.
Finally, it should be noted that: the above embodiments are merely specific embodiments of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions within the technical scope of the present application should be covered by the scope of the present application. Therefore, the protection scope of the application is subject to the protection scope of the claims.
Claims (10)
1. A piezoelectric resonant pressure sensor for use in the electronics core industry, comprising:
The piezoelectric component is directly or indirectly connected with the external circuit;
The resonant assembly is arranged on one side of the piezoelectric assembly, and a resonant cavity is formed on one side of the resonant assembly, which faces away from the piezoelectric assembly;
The pressure sensitive component is connected to one side of the resonance component, which is away from the piezoelectric component, and one side of the pressure sensitive component, which is away from the resonance component, is provided with a pressure cavity for receiving pressure to be detected;
and a pressure sensitive film is formed at the position where the pressure sensitive component is provided with the pressure cavity, and at least part of the pressure sensitive film seals the resonant cavity.
2. The piezoelectric resonant pressure sensor of claim 1, wherein the pressure sensitive component is provided with the pressure chamber at a location where it encloses the resonant cavity.
3. The piezoelectric resonant pressure sensor of claim 1, wherein the pressure sensitive component further comprises a resonant substrate, the pressure sensitive membrane cooperating with the resonant substrate to form the pressure cavity, the resonant substrate being located on a side of the pressure sensitive membrane facing away from the resonant component.
4. A piezoelectric resonant pressure sensor according to claim 3, wherein the resonant assembly comprises a connecting structure and a resonant membrane connected, the connecting structure and the resonant membrane cooperating to form the resonant cavity, the resonant membrane being located on a side of the connecting structure facing away from the pressure sensitive assembly.
5. The piezoelectric resonant pressure sensor of claim 4, wherein a side of the connection structure proximate to the pressure sensitive component is an anchor point, a distance between the anchor point and the resonant membrane is a first distance, a distance between the anchor point and the pressure sensitive component is a second distance, and the first distance is greater than the second distance.
6. The piezoelectric resonant pressure sensor of claim 1, wherein the piezoelectric assembly comprises a first lead electrode, a second lead electrode, a first electrode, a piezoelectric layer, and a second electrode; wherein,
The second electrode is arranged on one side of the resonance component, which is away from the pressure sensitive component, and one side of the second electrode, which is towards the resonance component, is directly or indirectly connected with the resonance component;
The piezoelectric layer is arranged on one side of the second electrode, which is away from the resonance component, and one side of the piezoelectric layer, which is towards the second electrode, is connected with the second electrode;
the first electrode is arranged on one side of the piezoelectric layer, which is away from the second electrode, and one side of the piezoelectric layer, which is towards the first electrode, is connected with the first electrode;
the piezoelectric device comprises a piezoelectric layer, a first lead electrode, a second electrode, a first electrode and a second electrode, wherein the first lead electrode is arranged on one side of the first electrode, which is away from the piezoelectric layer, one end of the first lead electrode is connected with the first electrode, the other end of the first lead electrode is connected with a first part of an external circuit, the second lead electrode is arranged on one side of the second electrode, which faces the piezoelectric layer, one end of the second lead electrode is connected with the second electrode, and the other end of the second lead electrode is connected with a second part of the external circuit.
7. The piezoelectric resonant pressure sensor of claim 4, wherein the piezoelectric resonant pressure sensor is provided with at least one groove, the groove being provided between the resonant thin film and the pressure sensitive thin film; or alternatively
The groove is formed in one side, away from the resonant substrate, of the resonant assembly, and a notch of the groove is formed away from the resonant substrate.
8. The piezoelectric resonant pressure sensor of claim 1, further comprising a cover disposed on a side of the piezoelectric assembly facing away from the pressure sensitive assembly, the cover being directly or indirectly connected to the piezoelectric assembly.
9. A compensation system comprising a drive component, a detection component, and at least two piezoelectric resonant pressure sensors according to any one of claims 1-8, wherein at least two of the piezoelectric resonant pressure sensors comprise at least one pressure sensor and at least one compensation sensor.
10. A method for manufacturing a piezoelectric resonator pressure sensor, which is applicable to the piezoelectric resonator pressure sensor according to any one of claims 1 to 8, wherein the method is used for processing a first SOI wafer and a second SOI wafer, the first SOI wafer comprising a first device layer, a first oxygen-buried layer and a first substrate layer, the second SOI wafer comprising a second device layer, a second oxygen-buried layer and a second substrate layer; the thickness of the first device layer is equal to the sum of the height of the resonant cavity and the thickness of the resonant film, and the thickness of the second device layer is equal to the thickness of the pressure sensitive film;
The method comprises the following steps:
Taking a first SOI wafer, and processing a resonant cavity on the first device layer;
Bonding the second device layer and the first device layer by taking a second SOI wafer, wherein the second device layer seals the resonant cavity, and an oxide layer is formed between the second device layer and the first device layer in the bonding process;
removing the first oxygen-buried layer and the first substrate layer, and taking part of the first device layer as a resonance film;
A piezoelectric component is arranged on one side of the first device layer, which is away from the second SOI wafer;
And forming a pressure cavity on the second substrate layer, and forming a pressure sensitive film, wherein at least part of the pressure sensitive film seals the resonant cavity.
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