Piezoelectric resonant pressure sensor, compensation system and preparation method

Abstract

The invention provides a piezoelectric resonant pressure sensor, a compensation system and a preparation method, and relates to the technical field of sensitive element and sensor manufacturing. The piezoelectric resonant pressure sensor comprises a piezoelectric assembly, a resonant film, a connecting assembly and a pressure sensitive assembly. The resonant film is connected to one side of the piezoelectric assembly. The connecting assembly is connected to the side, away from the piezoelectric assembly, of the resonant film. The pressure-sensitive assembly is connected to the side, away from the resonant film, of the connecting assembly. The connecting assembly comprises a first connecting structure and a second connecting structure which are arranged at intervals, the end of the second connecting structure is connected to the middle of the resonant film, at least part of the resonant film is matched with part of the piezoelectric assembly to form a resonator, one end of the resonator is connected to the first connecting structure, and the second end of the resonator is connected to the second connecting structure. According to the piezoelectric resonant pressure sensor provided by the embodiment of the invention, the pressure detection range of the piezoelectric resonant pressure sensor can be expanded, and the application range of the piezoelectric resonant pressure sensor is expanded.

Description

Technical Field

[0001] The present application relates to the technical field of sensitive components and sensor manufacturing in the core electronics industry, and in particular to a piezoelectric resonant pressure sensor, a compensation system and a preparation method. Background Art

[0002] Pressure sensors can convert received pressure signals into electrical signals according to certain rules and output the electrical signals to other devices. They are sensitive components. Pressure sensors are widely used in defense, automobile, petroleum, aerospace, smart hardware and other technical fields, and belong to the core electronic industry technology field.

[0003] With the development of micro-electro-mechanical system (MEMS) technology, pressure sensors can be combined with MEMS technology to realize mass production of pressure sensors and improve the production efficiency of pressure sensors.

[0004] According to different working principles, pressure sensors can be divided into piezoelectric resonant pressure sensors, piezoresistive pressure sensors, capacitive pressure sensors, piezoelectric pressure sensors, etc. Among them, piezoelectric resonant pressure sensors have the advantages of good stability and high accuracy, and are widely used in technical fields with high precision requirements and harsh environments, such as aerospace, petroleum, etc.

[0005] Based on the structure of the existing piezoelectric resonant pressure sensor, the pressure detection range of the piezoelectric resonant pressure sensor is relatively small, which may affect the application scope of the piezoelectric resonant pressure sensor. Summary of the invention

[0006] The present application provides a piezoelectric resonant pressure sensor to expand the pressure detection range of the piezoelectric resonant pressure sensor, expand the application range of the piezoelectric resonant pressure sensor, and improve the pressure detection sensitivity and accuracy of the piezoelectric resonant pressure sensor.

[0007] In the first aspect, the present application provides an example of a piezoelectric resonant pressure sensor. The piezoelectric resonant pressure sensor includes a piezoelectric component, a resonant film, a connecting component, and a pressure-sensitive component. The piezoelectric component is connected to an external circuit. The resonant film is connected to one side of the piezoelectric component. The connecting component is connected to the side of the resonant film away from the piezoelectric component, and the connecting component and the resonant film cooperate to form a resonant cavity. The pressure-sensitive component is connected to the side of the connecting component away from the resonant film, and a pressure cavity is provided on the side of the pressure-sensitive component away from the connecting component, and the pressure cavity is used to receive the pressure to be detected.

[0008] Among them, the connecting component includes a first connecting structure and a second connecting structure arranged at intervals, the end of the second connecting structure is connected to the middle of the resonant film, at least part of the resonant film and part of the piezoelectric component cooperate to form a resonator, the first end of the resonator is connected to the first connecting structure, and the second end of the resonator is connected to the second connecting structure.

[0009] According to the piezoelectric resonant pressure sensor provided in the example of this application, the pressure chamber can receive the pressure to be detected, and the pressure to be detected can be transmitted to the connecting component and the resonant film through the pressure sensitive component, and then transmitted to the piezoelectric component. The pressure to be detected is detected by the characteristics of the piezoelectric component.

[0010] Since the piezoelectric component is arranged on the side of the resonant film away from the connecting component, and the pressure sensitive component is arranged on the side of the connecting component away from the resonant film, the piezoelectric component is separated from the pressure cavity that receives the pressure to be detected. And since the connecting component cooperates with the resonant film to form a resonant cavity, when the piezoelectric component drives the resonant component to vibrate, the resonant cavity can provide a deformation space for the piezoelectric component, thereby reducing the possibility of the piezoelectric component being damaged due to a large deformation amount caused by vibration.

[0011] When the possibility of damage to the piezoelectric component is reduced, the piezoelectric resonant pressure sensor provided in the example of the present application can withstand a larger pressure to be detected, thereby improving the pressure measurement range of the piezoelectric resonant pressure sensor, expanding the measurement range of the piezoelectric resonant pressure sensor, and expanding the application scope of the piezoelectric resonant pressure sensor, so that the piezoelectric resonant pressure sensor can be widely used in the core technology field of the electronics industry.

[0012] In addition, since in the example of the present application, the connecting component can realize the connection between the resonant film and the pressure sensitive component. The connecting component includes a first connecting structure and a second connecting structure arranged at intervals, and the end of the second connecting structure is connected to the middle of the resonant film. Therefore, at least part of the pressure to be detected can be transmitted to the resonator through the second connecting structure. The second connecting structure can move in a direction away from the pressure sensitive component under the action of the pressure to be detected, or the second connecting structure has a tendency to move in the opposite direction away from the pressure sensitive component under the action of the pressure to be detected. Since the second end of the resonator is connected to the second connecting structure, the resonator can be deformed under the action of the second connecting structure. Since the first connecting structure and the second connecting structure are arranged at intervals, and the first end of the resonator is connected to the first connecting structure, and the second end of the resonator is connected to the second connecting structure, therefore, under the action of the pressure to be detected, the deformation of the resonator in the example of the present application is more obvious, which can improve the detection sensitivity of the piezoelectric resonant pressure sensor, and thus improve the detection accuracy of the piezoelectric resonant pressure sensor.

[0013] The second connecting structure can connect the pressure-sensitive film and the piezoelectric component, and the second connecting structure can change the direction of action of the pressure to be detected, so that the pressure to be detected acting vertically on the piezoelectric component is smaller, further reducing the possibility of damage to the piezoelectric component, improving the pressure-bearing capacity of the resonant film, expanding the detection range of the piezoelectric resonant pressure sensor, and ensuring the linearity of the piezoelectric resonant pressure sensor within the pressure detection range.

[0014] In some possible implementations, along the direction from the resonance film to the connection component, the center line of the second connection structure is collinear with the center line of the resonance film.

[0015] In the example of the present application, the center line of the second connecting structure is collinear with the center line of the resonant film. Based on this, under the action of the pressure to be detected, the second connecting structure can move in the direction away from the pressure-sensitive component, that is, in the direction toward the piezoelectric component. Since the center line of the second connecting structure is collinear with the center line of the resonant film along the direction from the resonant film to the connecting component, the deformation of the resonant film caused by the second connecting structure is relatively uniform, so that the stress transmitted to the piezoelectric component by the pressure to be detected is relatively uniform, reducing the situation where some piezoelectric components are damaged due to uneven force, which is beneficial to improve the measurement range of the piezoelectric resonant pressure sensor and expand the scope of application of the piezoelectric resonant pressure sensor.

[0016] In some possible implementations, the piezoelectric resonant pressure sensor is provided with a deformation groove, the notch of the deformation groove is provided on a side of the piezoelectric component away from the resonant film, and the bottom of the deformation groove is provided on the second connecting structure.

[0017] Since the opening of the deformation groove is arranged on the side of the piezoelectric component away from the resonance film, and the bottom of the deformation groove is arranged on the second connection structure, and one end of the second connection structure is connected to the middle of the resonance film, therefore, by setting the deformation groove, a gap can be formed in the middle of the resonance film and the piezoelectric component, reducing the cross-sectional area of ​​the resonance film and the piezoelectric component, making it easier for the pressure-sensitive film and the piezoelectric component to deform under the action of the pressure to be detected, further improving the detection sensitivity of the piezoelectric resonance pressure sensor, and improving the detection accuracy of the piezoelectric resonance pressure sensor.

[0018] In some possible implementations, a first groove is formed between the first connection structure and the second connection structure. The second connection structure includes a plurality of sub-connection structures arranged at intervals, a second groove is formed between two adjacent sub-connection structures, and the second groove connects the deformation groove and the first groove.

[0019] By setting the second groove, the second connection structure can include a plurality of spaced-apart sub-connection structures, which can reduce the cross-sectional area of ​​the second connection structure, thereby increasing the deformation amplitude of the second connection structure under the action of the pressure to be detected, so that the deformation amplitude of the resonant film and the piezoelectric component connected to the second connection structure is larger, thereby improving the detection sensitivity and detection accuracy of the piezoelectric resonant pressure sensor.

[0020] In addition, a first groove is formed between the first connection structure and the second connection structure that are spaced apart. The second connection structure includes a plurality of sub-connection structures that are spaced apart, and a second groove is formed between two adjacent sub-connection structures, and the second groove connects the deformation groove and the first groove. In the case where the sub-connection structure is deformed, the resonant film and the piezoelectric component that cooperate with the sub-connection structure will also be deformed. The second groove, the first groove and the deformation groove can provide deformation space for the deformation of the sub-connection structure, the resonant film that cooperates with the sub-connection structure and the piezoelectric component, thereby reducing the possibility of damage to the piezoelectric component and the resonant film due to a large deformation amount, expanding the measurement range of the piezoelectric resonant pressure sensor, and expanding the scope of application of the piezoelectric resonant pressure sensor.

[0021] In some possible implementations, the plurality of sub-connection structures are evenly arranged.

[0022] By arranging multiple sub-connection structures evenly, the deformation amplitudes of different deformation structures under the same pressure to be detected can be relatively similar, and the deformation amounts transmitted to the piezoelectric component by different deformation structures can be relatively similar, thereby ensuring the detection accuracy of the piezoelectric resonant pressure sensor for the detection pressure.

[0023] In some possible implementations, the piezoelectric component includes a first lead electrode, a second lead electrode, a first electrode, a piezoelectric layer, and a second electrode. The second electrode is connected to a side of the resonant film away from the connection component, the piezoelectric layer is connected to a side of the second electrode away from the resonant film, a portion of the second lead electrode is disposed on a side of the piezoelectric layer away from the second electrode, and the second lead electrode is disposed through the piezoelectric layer and is electrically connected to the second electrode.

[0024] The first electrode is connected to a side of the piezoelectric layer away from the second electrode, the first lead electrode is arranged on a side of the first electrode away from the piezoelectric layer, and the first lead electrode is electrically connected to the first electrode.

[0025] Compared with the resistance detection type piezoelectric sensor which requires the setting of a Wheatstone bridge and the capacitance detection type pressure sensor which requires the setting of a capacitance bridge, the piezoelectric resonant pressure sensor provided in the example of the present application does not require the setting of an additional detection circuit, has a simpler structure and a lower manufacturing cost.

[0026] In some possible implementations, the first lead electrode and the second lead electrode are disposed on a side of the piezoelectric layer away from the first connection structure. At least part of the resonant film is a carrier, the first electrode and at least part of the second electrode are disposed on the carrier, a first end of the carrier is connected to the first connection structure, and a second end of the carrier is connected to the second connection structure.

[0027] In the example of the present application, the carrier can provide a mounting carrier for at least part of the first electrode, the second electrode and the piezoelectric layer. Since the first lead electrode and the second lead electrode are arranged on the first connection structure, and the first end of the carrier is connected to the first connection structure, it is easy to achieve the connection between the first electrode and the first lead electrode, and the connection between the second electrode and the second lead electrode by setting the carrier. In addition, by adjusting the setting position of the first lead electrode, the connection reliability between the first lead electrode and the first electrode can be ensured.

[0028] Since the first end of the carrier is connected to the first connecting structure, the second end of the carrier is connected to the second connecting structure, and the first connecting structure and the second connecting structure are spaced apart, the pressure to be detected transmitted to the second connecting structure can easily cause the carrier to deform, thereby making the deformation of the piezoelectric layer larger, thereby improving the detection sensitivity and detection accuracy of the piezoelectric resonant pressure sensor.

[0029] Since a first groove is formed between the first connection structure and the second connection structure, and the second connection structure is connected to the middle of the resonant film, the vibration amplitude of the second connection structure is larger than that of the first connection structure. Since the first lead electrode and the second lead electrode are arranged on one side of the first connection structure, the deformation amplitude of the first lead electrode and the second lead electrode under the pressure to be detected is smaller, which can reduce the influence of the pressure to be detected on the first lead electrode and the second lead electrode, and reduce the possibility of the first lead electrode and the second lead electrode vibrating under the pressure to be detected, thereby ensuring the reliability of the piezoelectric resonant pressure sensor.

[0030] The second aspect of the present application provides a method for preparing a piezoelectric resonant pressure sensor, which is applicable to the piezoelectric resonant pressure sensor mentioned in any of the above examples, and the method is used to process a Si wafer and an SOI wafer into a piezoelectric resonant pressure sensor, and the SOI wafer includes a first device layer, a first buried oxide layer, and a first substrate layer. The method includes:

[0031] Take a Si wafer, process a ring groove on one side of the Si wafer to form a first connection structure on the outer side of the ring groove and a second connection structure on the inner side of the ring groove, and the first connection structure and the second connection structure cooperate to form a resonant cavity; take an SOI wafer, remove the first buried oxide layer and the first substrate layer, and set the thickness of the first device layer to be the thickness of the resonant film; bond the SOI wafer and the Si wafer, and the first device layer closes the cavity opening of the resonant cavity; set a piezoelectric component on the side of the first device layer away from the Si wafer; process a pressure cavity on the side of the Si wafer away from the first device layer; wherein the second connection structure is connected to the middle of the first device layer on the side facing the first device layer.

[0032] The third aspect of the present application provides a method for preparing a piezoelectric resonant pressure sensor, which is applicable to the piezoelectric resonant pressure sensor mentioned in any of the above examples. The method is used to process a CSOI wafer into a piezoelectric resonant pressure sensor, and the CSOI wafer includes a second device layer, a second buried oxide layer and a second substrate layer.

[0033] The second substrate layer is provided with a second connection structure and a second connection structure spaced apart on one side facing the second buried oxide layer, the end of the second connection structure is connected to the middle of the second buried oxide layer, and the second connection structure, the second connection structure and the second buried oxide layer cooperate to form a resonant cavity. The method includes:

[0034] A piezoelectric component is arranged on the side of the second device layer away from the second buried oxide layer, and a pressure cavity is processed on the side of the second substrate layer away from the second buried oxide layer.

[0035] The fourth aspect of the present application provides a compensation system, which includes an integrated driving component, a detection component and a piezoelectric resonant pressure sensor mentioned in any of the above examples, at least two piezoelectric resonant pressure sensors including at least one pressure sensor and at least one compensation sensor.

[0036] According to the compensation system provided in the example of the present application, when the detection component detects the resonant frequency of the pressure sensor and the compensation sensor, it only needs to subtract the resonant frequency output by the compensation sensor from the resonant frequency output by the pressure sensor and then extract the final resonant frequency, thereby eliminating the influence of environmental factors and improving the detection accuracy of the compensation system for the pressure to be detected. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A schematic diagram of the structure of a piezoelectric resonant pressure sensor provided as an example in this application.

[0038] Figure 2 An electrode arrangement diagram of a piezoelectric resonant pressure sensor provided as an example of the present application.

[0039] Figure 3 for Figure 2 Sectional view along AA.

[0040] Figure 4 A schematic diagram of the structure of a piezoelectric resonant pressure sensor provided as an example in this application.

[0041] Figure 5 A top view of a piezoelectric resonant pressure sensor provided as an example of the present application.

[0042] Figure 6 for Figure 5 Cross-sectional view along BB.

[0043] Figure 7 for Figure 5 Cross-sectional view along CC.

[0044] Figure 8 An electrode arrangement diagram of a piezoelectric resonant pressure sensor provided as an example of the present application.

[0045] Fig. 9 for Figure 8 Cross-sectional view of DD.

[0046] Fig.10 A schematic diagram of the working principle of a piezoelectric resonant pressure sensor provided as an example in this application.

[0047] Fig.11 A schematic diagram of the structure of a piezoelectric resonant pressure sensor provided as an example in this application.

[0048] Fig.12 A schematic diagram of the structure of a piezoelectric resonant pressure sensor provided as an example in this application.

[0049] Fig.13 A schematic flow chart of a method for preparing a piezoelectric resonant pressure sensor provided as an example in this application.

[0050] Fig.14 A schematic diagram of the structure of an unprocessed Si wafer provided as an example in this application.

[0051] Fig.15 A schematic structural diagram of a Si wafer processing ring groove provided as an example in this application.

[0052] Fig.16 A schematic diagram of the structure of an unprocessed SOI wafer provided as an example in this application.

[0053] Fig.17 A method based on Fig.15 Schematic diagram of the structure of connecting Si wafer to SOI wafer.

[0054] Fig.18 Based on Fig.17Schematic diagram of the structure after removing the first substrate layer and the first buried oxide layer.

[0055] Fig.19 A schematic diagram of a structure in which a piezoelectric component is deposited on the side of the device layer facing away from the Si wafer is provided as an example of the present application.

[0056] Fig. 20 A method based on Fig.19 Schematic diagram of the structure of the piezoelectric component after processing.

[0057] Fig.21 A method based on Fig. 20 Schematic diagram of the structure in which a protective layer is provided on the piezoelectric component away from the device layer.

[0058] Fig. 22 A method based on Fig.21 Schematic diagram of the structure of processing the second connecting hole from the protective layer.

[0059] Fig.23 A method based on Fig.21 or Fig. 22 Schematic diagram of the structure of processing the first connecting hole from the protective layer.

[0060] Fig.24 A method based on Fig.23 Schematic diagram of the structure of depositing a lead electrode layer on the side of the protection layer away from the device layer.

[0061] Fig.25 A method based on Fig.24 Schematic diagram of the structure of processing lead electrodes on the lead electrode layer.

[0062] Fig.26 A method based on Fig.25 Schematic diagram of the structure of processing the pressure chamber on the side of the Si wafer away from the device layer.

[0063] Fig. 27 A method based on Fig.26 Schematic diagram of the structure of machining deformation groove from the protective layer.

[0064] Fig.28 A schematic diagram of the structure of a glass wafer provided as an example of this application.

[0065] Fig.29 A schematic diagram of a structure for processing a Ge layer on a glass wafer provided as an example of this application.

[0066] Fig.30 A method based on Fig.29 Structural schematic diagram of processing the second connecting piece.

[0067] Fig.31 A schematic diagram of a structure for machining a cavity on a glass wafer to form a cover is provided as an example of the present application.

[0068] Fig.32 A schematic diagram of a structure in which an adsorption structure is provided inside a cover provided as an example of the present application.

[0069] Fig.33 A schematic diagram of a structure in which a cover is connected to the side of a protective layer facing away from the piezoelectric layer, provided as an example of the present application.

[0070] Fig.34 A schematic flow chart of another method for preparing a piezoelectric resonant pressure sensor provided as an example in this application.

[0071] Fig.35 A schematic diagram of the structure of a compensation system provided for the example of this application.

[0072] Fig.36 A schematic diagram of the working process of a compensation system provided as an example of this application.

[0073] Description of reference numerals:

[0074] 100, piezoelectric resonant pressure sensor; 110, piezoelectric component; 111, first electrode; 112, piezoelectric layer; 113, second electrode; 114, first lead electrode; 1141, first connection hole; 115, second lead electrode; 1151, second connection hole; 120, resonant film; 121, carrier; 130, connection component; 131, first connection structure; 132, second connection structure; 1321, sub-connection structure; 133, deformation groove; 134, second groove; 135, resonant cavity; 140, pressure sensitive component; 141. pressure chamber; 142. resonant substrate; 150. resonator; 160. oxide layer; 171. first connector; 172. second connector; 180. protective layer; 190. cover; 191. adsorption structure; 200. Si wafer; 210. annular groove; 300. SOI wafer; 310. first device layer; 320. first buried oxide layer; 330. first substrate layer; 400. glass wafer; 500. compensation system; 510. pressure sensor; 520. compensation sensor; 530. driving component; 540. detection component. DETAILED DESCRIPTION

[0075] In order to make the purpose, technical solution and advantages of the examples of this application clearer, the technical solution in the examples of this application will be clearly and completely described below in conjunction with the drawings in the examples of this application. Obviously, the described examples are part of the examples of this application, not all of them. Based on the examples in this application, all other examples obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0076] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used in the specification of the application herein are only for the purpose of describing specific examples and are not intended to limit this application; the terms "including" and "having" in the specification, claims and drawings of this application and any variations thereof are intended to cover non-exclusive inclusions.

[0077] Reference to "examples" herein means that a particular feature, structure, or characteristic described in conjunction with the examples may be included in at least one example of the present application. The appearance of the phrase "example" in various locations in the specification does not necessarily refer to the same example, nor is it an independent or alternative example that is mutually exclusive with other examples. It is explicitly and implicitly understood by those skilled in the art that the examples described herein may be combined with other examples.

[0078] The term "and / or" in this article is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0079] The directional words appearing in the following description are all directions shown in the figures, and do not limit the specific structure of the piezoelectric resonant pressure sensor of the present application.

[0080] In addition, the terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects rather than to describe a specific order, and may explicitly or implicitly include one or more of the features.

[0081] In the description of the present application, unless otherwise specified, "plurality" means more than two (including two), and similarly, "multiple groups" means more than two groups (including two).

[0082] In the description of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, the "connection" or "connection" of a mechanical structure may refer to a physical connection. For example, the physical connection may be a fixed connection, such as a fixed connection through a barrier, such as a fixed connection through screws, bolts or other barrier; the physical connection may also be a detachable connection, such as a mutual snap-on or snap-fit ​​connection; the physical connection may also be an integral connection, such as a connection formed by welding, bonding or integral molding. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0083] Based on the above, the present application example provides a piezoelectric resonant pressure sensor, a compensation system and a preparation method.

[0084] The piezoelectric resonant pressure sensor mentioned in the example of this application can be combined with MEMS technology to achieve mass production of piezoelectric resonant pressure sensors and improve the production efficiency of piezoelectric resonant pressure sensors.

[0085] The piezoelectric resonant pressure sensor mentioned in the example of this application can output a corresponding electrical signal based on the received pressure to be detected, and is a sensitive element.

[0086] In order to enable those skilled in the art to better understand the present application, the piezoelectric resonant pressure sensor, compensation system and preparation method provided by the example of the present application will be clearly and completely described below in conjunction with the accompanying drawings.

[0087] Exemplarily, the present application provides a piezoelectric resonant pressure sensor. Figure 1 A schematic diagram of the structure of a piezoelectric resonant pressure sensor provided as an example of this application, Figure 2 The electrode arrangement diagram of a piezoelectric resonant pressure sensor provided as an example of this application is Figure 3 for Figure 2 Section view along AA.

[0088] Please refer to Figure 1 to Figure 3 The piezoelectric resonant pressure sensor 100 includes a piezoelectric component 110, a resonant film 120, a connecting component 130 and a pressure sensitive component 140. The piezoelectric component 110 is connected to an external circuit. The resonant film 120 is connected to one side of the piezoelectric component 110. The connecting component 130 is connected to the side of the resonant film 120 away from the piezoelectric component 110, and the connecting component 130 and the resonant film 120 cooperate to form a resonant cavity 135. The pressure sensitive component 140 is connected to the side of the connecting component 130 away from the resonant film 120, and a pressure cavity 141 is provided on the side of the pressure sensitive component 140 away from the connecting component 130, and the pressure cavity 141 is used to receive the pressure to be detected.

[0089] Among them, the connecting component 130 includes a first connecting structure 131 and a second connecting structure 132 which are arranged at intervals, and the end of the second connecting structure 132 is connected to the middle of the resonant film 120. At least part of the resonant film 120 and part of the piezoelectric component 110 cooperate to form a resonator 150. The first end of the resonator 150 is connected to the first connecting structure 131, and the second end of the resonator 150 is connected to the second connecting structure 132.

[0090] Based on the piezoelectric resonant pressure sensor 100 provided in the above example, the pressure chamber 141 can receive the pressure to be detected. Since the pressure chamber 141 is arranged on the side of the pressure sensitive component 140 away from the connecting component 130, and the pressure sensitive component 140 is connected to the resonant film 120 through the connecting component 130, and the resonant film 120 and the connecting component 130 cooperate to form a resonant chamber 135, the pressure to be detected can be transmitted to the connecting component 130 through the pressure sensitive component 140, and then transmitted to the resonant film 120 through the connecting component 130. Since the piezoelectric component 110 is arranged on one side of the resonant film 120, the pressure to be detected transmitted to the resonant film 120 can be transmitted to the piezoelectric component 110, and the piezoelectric component 110 can detect the pressure to be detected.

[0091] Next, the structure of the piezoelectric resonant pressure sensor 100 is described in detail.

[0092] The pressure sensitive component 140 may include only a pressure sensitive film, or may include a pressure sensitive film and other structures connected to the pressure sensitive film. The pressure sensitive film refers to a film in the pressure sensitive component 140 that mainly receives the pressure to be detected.

[0093] In the case where the pressure sensitive component 140 only includes a pressure sensitive film, the pressure cavity 141 may be a space where the pressure sensitive film is away from the resonant component. In the case where the pressure sensitive component 140 includes a pressure sensitive film and other structures connected to the pressure sensitive film, the pressure cavity 141 may also be a space formed by the pressure sensitive film and other structures connected to the pressure sensitive film, which is not specifically limited in this example of the present application.

[0094] The pressure to be detected received by the pressure sensitive component 140 may be the pressure applied directly or indirectly to the pressure sensitive component 140 by the fluid, and the fluid may be liquid, gas, etc.

[0095] The connecting component 130 can be directly or indirectly connected to the side of the pressure sensitive component 140 away from the pressure chamber 141. The side of the connecting component 130 away from the pressure sensitive component 140 is provided with a resonant film 120, and the resonant film 120 cooperates with the connecting structure to form a resonant cavity 135. The side of the resonant film 120 away from the connecting component 130 is provided with a piezoelectric component 110. The pressure to be detected acting on the pressure sensitive component 140 can be transmitted to the piezoelectric component 110 through the connecting component 130 and the resonant film 120, and then the pressure to be detected is detected by the piezoelectric component 110.

[0096] The connection component 130 may be directly connected to the resonance film 120 , or the connection component 130 may be indirectly connected to the resonance film 120 via other connection structures, which is not specifically limited in this example of the present application.

[0097] The pressure sensitive component 140 and the connecting component 130 may be integrally formed, or the pressure sensitive component 140 and the connecting component 130 may be connected together via a connecting structure.

[0098] There may be one pressure chamber 141 or multiple pressure chambers 141 may be provided at intervals. There may also be only one resonance chamber 135 or multiple resonance chambers 135 may be provided, and this application example does not limit this.

[0099] Along the direction from the resonant film 120 toward the pressure sensitive component 140, the projection of the resonant cavity 135 may also fall within the projection range of the pressure cavity 141, the projection of part of the resonant cavity 135 may also fall within the projection range of the pressure cavity 141, and the projection of the resonant cavity 135 may also be separated from the projection of the pressure cavity 141. The example of this application does not specifically limit the positional relationship between the resonant cavity 135 and the pressure cavity 141.

[0100] Exemplarily, the piezoelectric component 110 may include a piezoelectric layer 112 and an electrode. The piezoelectric layer 112 may be made of piezoelectric thin film materials such as AlN, ScAlN, lead zirconate titanate, ZnO, and LiNbO3. Due to the piezoelectricity of the piezoelectric thin film material, when the piezoelectric layer 112 receives pressure, the two opposite sides of the piezoelectric layer 112 can generate charges to form a potential difference, that is, the positive piezoelectric effect; similarly, the piezoelectric layer 112 will deform when driven by a voltage, that is, the inverse piezoelectric effect. The positive piezoelectric effect and the inverse piezoelectric effect of the piezoelectric layer 112 are used to obtain the relevant parameters of the pressure to be detected.

[0101] The relevant parameters may include the numerical value of the pressure to be detected and the direction parameter of the pressure to be detected, etc., and a specific description may be found below.

[0102] The electrode can be directly electrically connected to an external circuit, or the electrode can be indirectly connected to an external circuit via a conductive member such as a wire.

[0103] The external circuit can be a circuit for detecting current or voltage. The example of this application does not limit the specific type of the external circuit, as long as the external circuit can detect the electrical signal output by the piezoelectric component 110.

[0104] The connection assembly 130 may include a first connection structure 131 and a second connection structure 132 that are spaced apart from each other.

[0105] There may be one or more first connection structures 131. The connection position between the first connection structure 131 and the resonance film 120 may be close to the outer wall of the resonance film 120. The outer wall of the first connection structure 131 may be flush with the outer wall of the resonance film 120, or a certain distance may be set between the outer wall of the first connection structure 131 and the outer wall of the resonance film 120.

[0106] The second connection structure 132 may be cylindrical, prism-shaped or other columnar structures. There may be one or more second connection structures 132. The present application example does not limit the specific implementation of the first connection structure 131 and the second connection structure 132.

[0107] One end of the second connecting structure 132 can be connected to the middle of the resonance film 120. The middle of the resonance film 120 can refer to a region near the center line of the resonance film 120 along the direction from the resonance film 120 to the connecting component 130, and spaced apart from the position where the first connecting structure 131 is connected to the resonance film 120.

[0108] Since the pressure sensitive component 140 is disposed on one side of the second connection structure 132, and the pressure sensitive film is disposed on the other side of the second connection structure 132, the pressure to be detected acting on the pressure sensitive component 140 can be transmitted to the resonant film 120 and the piezoelectric component 110 through the second connection structure 132, generating stress in the resonant film 120 and the piezoelectric component 110, thereby causing a change in the vibration frequency of the resonant film 120 and the piezoelectric component 110. Since the resonant cavity 135 is disposed on one side of the piezoelectric component 110, the resonant cavity 135 can provide a vibration space for the vibration of the piezoelectric component 110, thereby reducing the possibility of the piezoelectric component 110 being damaged due to deformation of the piezoelectric component 110 due to vibration.

[0109] Part of the resonant film 120 and part of the piezoelectric component 110 cooperate to form a resonator 150. The resonator 150 may be provided with one or a plurality of resonators 150 arranged at intervals. The piezoelectric component 110 in the resonator 150 can detect the pressure to be detected.

[0110] Based on the above, according to the piezoelectric resonant pressure sensor 100 provided by the example of the present application, the pressure chamber 141 can receive the pressure to be detected, and the pressure to be detected can be transmitted to the connecting component 130 and the resonant film 120 through the pressure sensitive component 140, and then transmitted to the piezoelectric component 110. The pressure to be detected is detected by the characteristics of the piezoelectric component 110.

[0111] Since the piezoelectric component 110 is arranged on the side of the resonant film 120 away from the connecting component 130, and the pressure sensitive component 140 is arranged on the side of the connecting component 130 away from the resonant film 120, the piezoelectric component 110 and the pressure chamber 141 receiving the pressure to be detected are separated. And since the connecting component 130 and the resonant film 120 cooperate to form a resonant cavity 135. When the piezoelectric component 110 drives the resonant component to vibrate, the resonant cavity 135 can provide a deformation space for the piezoelectric component 110, thereby reducing the possibility that the piezoelectric component 110 is damaged due to a large deformation amount caused by vibration.

[0112] When the possibility of damage to the piezoelectric component 110 is reduced, the piezoelectric resonant pressure sensor 100 provided in the example of the present application can withstand a larger pressure to be detected, thereby improving the pressure measurement range of the piezoelectric resonant pressure sensor 100, expanding the measurement range of the piezoelectric resonant pressure sensor 100, and expanding the application scope of the piezoelectric resonant pressure sensor 100, so that the piezoelectric resonant pressure sensor 100 can be widely used in the core technology field of the electronics industry.

[0113] In addition, in the example of the present application, the connecting component 130 can realize the connection between the resonant film 120 and the pressure sensitive component 140. The connecting component 130 includes a first connecting structure 131 and a second connecting structure 132 which are arranged at intervals, and the end of the second connecting structure 132 is connected to the middle of the resonant film 120. Therefore, at least part of the pressure to be detected can be transmitted to the resonator 150 through the second connecting structure 132. The second connecting structure 132 can move in a direction away from the pressure sensitive component 140 under the action of the pressure to be detected, or the second connecting structure 132 has a tendency to move in the opposite direction away from the pressure sensitive component 140 under the action of the pressure to be detected. Since the second end of the resonator 150 is connected to the second connecting structure 132, the resonator 150 can be deformed under the action of the second connecting structure 132. Since the first connecting structure 131 and the second connecting structure 132 are spaced apart, and the first end of the resonator 150 is connected to the first connecting structure 131, and the second end of the resonator 150 is connected to the second connecting structure 132, under the action of the pressure to be detected, the deformation of the resonator 150 in the example of the present application is more obvious, which can improve the detection sensitivity of the piezoelectric resonant pressure sensor 100, and thereby improve the detection accuracy of the piezoelectric resonant pressure sensor 100.

[0114] Based on the piezoelectric resonant pressure sensor 100 provided in the above example, along the direction from the resonant film 120 to the connecting component 130 , the center line of the second connecting structure 132 is collinear with the center line of the resonant film 120 .

[0115] Along the direction from the resonance film 120 to the connection component 130, the center line of the second connection structure 132 is colinear with the center line of the resonance film 120. It can be understood that one end of the second connection structure 132 is connected to the center of the resonance film 120, and the other end of the second connection structure 132 can be connected to the center of the pressure sensitive film.

[0116] In the example of the present application, the center line of the second connection structure 132 is collinear with the center line of the resonance film 120. Based on this, under the action of the pressure to be detected, the second connection structure 132 can move in the direction away from the pressure sensitive component 140, that is, in the direction toward the piezoelectric component 110. Since the center line of the second connection structure 132 is collinear with the center line of the resonance film 120 along the direction from the resonance film 120 to the connection component 130, the deformation of the resonance film 120 driven by the second connection structure 132 is relatively uniform, so that the stress transmitted to the piezoelectric component 110 by the pressure to be detected is relatively uniform, and the situation that the piezoelectric component 110 is partially damaged due to uneven force is reduced, which is conducive to improving the measurement range of the piezoelectric resonant pressure sensor 100 and expanding the scope of application of the piezoelectric resonant pressure sensor 100.

[0117] Based on the piezoelectric resonant pressure sensor 100 provided in the above example, Figure 4 A schematic diagram of the structure of a piezoelectric resonant pressure sensor provided as an example of this application, Figure 5 A top view of a piezoelectric resonant pressure sensor provided as an example of the present application, Figure 6 for Figure 5 The cross-sectional view along BB, Figure 7 for Figure 5 Cross-sectional view along CC, Figure 8 The electrode arrangement diagram of a piezoelectric resonant pressure sensor provided as an example of this application is Fig. 9 for Figure 8 For the cross-sectional view of DD, please refer to Figures 4 to 9 The piezoelectric resonant pressure sensor 100 is provided with a deformation groove 133 , the notch of the deformation groove 133 is provided on the side of the piezoelectric component 110 away from the resonant film 120 , and the bottom of the deformation groove 133 is provided on the second connection structure 132 .

[0118] The arrangement position of the deformation groove 133 may correspond to the arrangement position of the second connection structure 132 .

[0119] For example, the deformation groove 133 may penetrate the piezoelectric component 110 and the resonant film 120 to the second connection structure 132. The bottom of the deformation groove 133 may be arranged in the middle of the second connection structure 132, or may be arranged on one side of the second connection structure 132 close to the pressure sensitive component 140, and this application example does not impose any specific limitation on this.

[0120] The middle portion of the second connection structure 132 refers to a portion between a side of the second connection structure 132 facing the resonance film 120 and a side of the second connection structure 132 facing the pressure sensitive film along the direction from the resonance film 120 to the connection assembly 130 .

[0121] Along the direction from the resonant film 120 to the connecting component 130 , the projection of the deformation groove 133 may be in a regular shape such as a circle, an ellipse, a polygon, etc. The projection of the deformation groove 133 may also be in an irregular shape, which is not specifically limited in this example of the present application.

[0122] The second connection structure 132 can directly or indirectly connect the resonant film 120 to one side of the pressure sensitive film. Fig.10 A schematic diagram of the working principle of a piezoelectric resonant pressure sensor provided for this application example, please refer to Fig.10 , the second connection structure 132 can change the direction of action of the pressure to be detected.

[0123] Exemplarily, the pressure to be detected acts on the pressure sensitive film in a direction perpendicular to the pressure sensitive film. The pressure to be detected acting on the pressure sensitive film can be transmitted to the resonant film 120 through the second connecting structure 132. The second connecting structure 132 can convert the pressure to be detected perpendicular to the pressure sensitive film into a working stress having an angle between the direction of action and the direction of action of the pressure to be detected.

[0124] Based on the above, since the opening of the deformation groove 133 is arranged on the side of the piezoelectric component 110 away from the resonance film 120, and the bottom of the deformation groove 133 is arranged on the second connection structure 132, and one end of the second connection structure 132 is connected to the middle of the resonance film 120. Therefore, by providing the deformation groove 133, a gap can be provided in the middle of the resonance film 120 and the piezoelectric component 110, and the cross-sectional area of ​​the resonance film 120 and the piezoelectric component 110 can be reduced, so that the pressure sensitive film and the piezoelectric component 110 are more likely to deform under the action of the pressure to be detected, and the detection sensitivity of the piezoelectric resonance pressure sensor 100 is further improved, and the detection accuracy of the piezoelectric resonance pressure sensor 100 is improved.

[0125] The second connecting structure 132 can connect the pressure-sensitive film and the piezoelectric component 110, and the second connecting structure 132 can change the direction of action of the pressure to be detected, so that the pressure to be detected acting vertically on the piezoelectric component 110 is smaller, which further reduces the possibility of damage to the piezoelectric component 110, improves the pressure-bearing capacity of the resonant film 120, expands the detection range of the piezoelectric resonant pressure sensor 100, and ensures the linearity of the piezoelectric resonant pressure sensor 100 within the pressure detection range.

[0126] Based on the piezoelectric resonant pressure sensor 100 provided in the above example, Fig.11 The working principle diagram of a piezoelectric resonant pressure sensor provided in this application example is shown in Fig.11 A first groove is formed between the first connection structure 131 and the second connection structure 132. The second connection structure 132 includes a plurality of sub-connection structures 1321 arranged at intervals, and a second groove 134 is formed between two adjacent sub-connection structures 1321, and the second groove 134 connects the deformation groove 133 and the first groove.

[0127] A first trench may be formed between the first connection structure 131 and the second connection structure 132 that are spaced apart from each other, and the first trench may be a resonator 150 .

[0128] Along the direction from the resonant film 120 to the connecting component 130, the projection of the first groove may be a circular ring structure, a square ring structure or other ring structure. Alternatively, the first groove may include a plurality of spaced-apart sub-grooves, which may cooperate to form a ring structure. The example of the present application does not specifically limit the implementation of the first sub-grooves.

[0129] The opening of the first groove may be disposed on a side of the second connection structure 132 facing the resonance film 120 , or the opening of the first groove may be disposed on a side of the piezoelectric component 110 facing away from the resonance film 120 .

[0130] The second connection structure 132 includes a plurality of sub-connection structures 1321 arranged at intervals. The specifications and shapes of the plurality of sub-connection structures 1321 may be the same, or the specifications and shapes of the plurality of sub-connection structures 1321 may be different, or some of the plurality of sub-connection structures 1321 may have the same size specifications.

[0131] The number of resonators 150 may be equal to the number of sub-connection structures 1321 , and the resonators 150 correspond to the sub-connection structures 1321 one by one.

[0132] A second groove 134 is formed between two adjacent sub-connection structures 1321. The center lines of the multiple sub-connection structures 1321 can be roughly parallel to each other. The center lines of the multiple sub-connection structures 1321 can also intersect at multiple intersections, or at one intersection. The example of this application does not limit the specific setting of the sub-connection structure 1321.

[0133] The shapes and specifications of different second grooves 134 can be the same, or the shapes and specifications of different second grooves 134 can be different, and this example of the application does not impose any specific limitation on this.

[0134] The notch of the second groove 134 may be disposed on a side of the second connection structure 132 facing the resonance film 120 , or the notch of the second groove 134 may be disposed on a side of the piezoelectric component 110 facing away from the resonance film 120 .

[0135] In the example of the present application, by setting the second groove 134, the second connection structure 132 can include a plurality of spaced sub-connection structures 1321, which can reduce the cross-sectional area of ​​the second connection structure 132, thereby increasing the deformation amplitude of the second connection structure 132 under the action of the pressure to be detected, so that the deformation amplitude of the resonant film 120 and the piezoelectric component 110 connected to the second connection structure 132 is larger, thereby improving the detection sensitivity and detection accuracy of the piezoelectric resonant pressure sensor 100.

[0136] In addition, a first groove is formed between the first connection structure 131 and the second connection structure 132 which are arranged at intervals. The second connection structure 132 includes a plurality of sub-connection structures 1321 which are arranged at intervals, and a second groove 134 is formed between two adjacent sub-connection structures 1321, and the second groove 134 connects the deformation groove 133 and the first groove. In the case where the sub-connection structure 1321 is deformed, the resonant film 120 and the piezoelectric component 110 which cooperate with the sub-connection structure 1321 will also be deformed, and the second groove 134, the first groove and the deformation groove 133 can provide deformation space for the deformation of the sub-connection structure 1321, the resonant film 120 and the piezoelectric component 110 which cooperate with the sub-connection structure 1321, thereby reducing the possibility of damage of the piezoelectric component 110 and the resonant film 120 due to the large deformation, expanding the measurement range of the piezoelectric resonant pressure sensor 100, and expanding the application range of the piezoelectric resonant pressure sensor 100.

[0137] Based on the piezoelectric resonant pressure sensor 100 provided in the above example, a plurality of sub-connection structures 1321 are evenly arranged.

[0138] When the plurality of sub-connection structures 1321 are cross-arranged, center lines of the plurality of sub-connection structures 1321 may intersect at one point, and uniform arrangement of the plurality of sub-connection structures 1321 may mean that the angles between two adjacent sub-connection structures 1321 are equal.

[0139] When the plurality of sub-connection structures 1321 are substantially parallel, the uniform arrangement of the plurality of sub-connection structures 1321 may mean that the distance between two adjacent sub-connection structures 1321 is equal. Of course, the plurality of sub-connection structures 1321 may also be uniformly arranged in other ways, and the present application example does not specifically limit the arrangement of the sub-connection structures 1321.

[0140] In the example of the present application, by setting up multiple sub-connection structures 1321 in an evenly arranged manner, the deformation amplitudes of different deformation structures under the action of the same pressure to be detected can be relatively similar, and thus the deformation amounts transmitted to the piezoelectric component 110 by different deformation structures can be relatively similar, thereby ensuring the detection accuracy of the piezoelectric resonant pressure sensor 100 for the detection pressure.

[0141] Based on the piezoelectric resonant pressure sensor 100 provided in the above example, the side of the connecting component 130 close to the pressure sensitive component 140 can be an anchor point, the distance between the anchor point and the resonant film 120 is a first distance, and the distance between the anchor point and the pressure sensitive component 140 is a second distance, and the first distance is greater than the second distance.

[0142] The anchor point is the main force bearing point of the connecting component 130 .

[0143] By setting the first distance to be greater than the second distance, the resonant film 120, the pressure sensitive component 140 and the anchor point can work together to form a lever, the first distance is the first lever arm, and the second distance is the second lever arm. Based on the lever principle, the connecting component 130 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.

[0144] Based on the piezoelectric resonant pressure sensor 100 provided in the above example, please refer to Fig. 9 The piezoelectric component 110 may include a first lead electrode 114, a second lead electrode 115, a first electrode 111, a piezoelectric layer 112, and a second electrode 113. The second electrode 113 is connected to a side of the resonant film 120 away from the connecting component 130, the piezoelectric layer 112 is connected to a side of the second electrode 113 away from the resonant film 120, a portion of the second lead electrode 115 is disposed on a side of the piezoelectric layer 112 away from the second electrode 113, and the second lead electrode 115 penetrates the piezoelectric layer 112 and is electrically connected to the second electrode 113.

[0145] The first electrode 111 is connected to a side of the piezoelectric layer 112 away from the second electrode 113 . The first lead electrode 114 is disposed on a side of the first electrode 111 away from the piezoelectric layer 112 . The first lead electrode 114 is electrically connected to the first electrode 111 .

[0146] The second electrode 113 may be disposed on a side of the resonant component away from the pressure sensitive component 140, and the side of the second electrode 113 facing the resonant component may be directly or indirectly connected to the resonant component. The piezoelectric layer 112 may be disposed on a side of the second electrode 113 away from the resonant component, and the side of the piezoelectric layer 112 facing the second electrode 113 may be connected to the second electrode 113. The first electrode 111 may be disposed on a side of the piezoelectric layer 112 away from the second electrode 113, and the side of the piezoelectric layer 112 facing the first electrode 111 may be connected to the first electrode 111.

[0147] The first lead electrode 114 is disposed on a side of the first electrode 111 away from the piezoelectric layer 112 , one end of the first lead electrode 114 may be connected to the first electrode 111 , and the other end of the first lead electrode 114 may be connected to a first portion of an external circuit.

[0148] The second lead electrode 115 is disposed on a side of the second electrode 113 facing the piezoelectric layer 112 , one end of the second lead electrode 115 may be connected to the second electrode 113 , and the other end of the second lead electrode 115 may be connected to a second portion of the external circuit.

[0149] The first electrode 111, the second electrode 113, the first lead electrode 114 and the second lead electrode 115 may all be made of a conductive material, such as molybdenum, aluminum, copper or gold, etc. The number of the first lead electrodes 114 may correspond to the number of the first electrodes 111, at least one second lead electrode 115 may be provided, or a plurality of second lead electrodes 115 may be provided, and the plurality of second lead electrodes 115 may be connected to different positions of the second electrode 113.

[0150] The shapes of the first electrode 111 and the second electrode 113 may be the same or different. This application example only takes the first electrode 111 as an example for description. For example, the first electrode 111 may be cylindrical, prism or any other regular shape, or may be irregular.

[0151] The shapes of the first lead electrode 114 and the second lead electrode 115 may be the same or different. Here, only the first lead electrode 114 is taken as an example for description.

[0152] Exemplarily, the first lead electrode 114 may include a first connection portion and a second connection portion connected to each other, one end of the first connection portion is connected to the first electrode 111, and one end of the second connection portion is connected to an external circuit. The cross-sectional shapes of the first connection portion and the second connection portion may be the same or different, for example, the cross-sectional shape of the first connection portion may be circular, elliptical, polygonal or irregular. The example of this application does not limit the specific implementation of the first electrode 111, the second electrode 113, the first lead electrode 114 and the second lead electrode 115.

[0153] The second electrode 113 may be a conductive layer laid on the side of the resonance film 120 away from the resonance cavity 135 , and only one second electrode 113 may be provided. The second electrode 113 may be used to achieve grounding of the piezoelectric resonance pressure sensor 100 .

[0154] A piezoelectric layer 112 may be disposed on a side of the second electrode 113 facing away from the resonance component. The piezoelectric layer 112 may be made of a piezoelectric film material.

[0155] The first electrode 111 may be disposed on a side of the piezoelectric layer 112 away from the second electrode 113, and at least two first electrodes 111 may be provided. The first electrode 111 may include at least one driving electrode and at least one detecting electrode. The driving electrode is used to drive the piezoelectric layer 112 to vibrate, and the detecting electrode is used to detect the vibration of the piezoelectric layer 112.

[0156] The external circuit may be a detection circuit for detecting the output electrical signal of the piezoelectric resonance pressure sensor 100 .

[0157] Next, the principle of the piezoelectric resonant pressure sensor 100 is further introduced in combination with the specific structure of the piezoelectric component 110 .

[0158] The resonance component and the piezoelectric component 110 cooperate with each other to form a resonator 150. The resonator 150 may also include other structures. This application only describes the resonator 150 as a circular structure.

[0159] When any of the first electrodes 111 receives a voltage, stress is generated in the piezoelectric layer 112 based on the inverse piezoelectric effect of the piezoelectric layer 112. At this time, since the neutral layer of the piezoelectric layer 112 deviates from the geometric center position of the piezoelectric layer 112, the piezoelectric layer 112 will be deformed, and the deformation of the piezoelectric layer 112 drives the entire resonator 150 to deform.

[0160] When an alternating voltage having the same resonant frequency as the resonator 150 is applied to any first electrode 111, the entire structure will resonate, and the resonant frequency is:

[0161]

[0162] In the formula, f r is the resonant frequency, μ n are the constants set when solving the Bessel function, t is the thickness, t is the radius, E is the Young's modulus, ρ is the density, and δ is the Poisson's ratio.

[0163] When the pressure chamber 141 receives the pressure to be detected, the pressure sensitive film will deform and generate working stress under the action of the pressure to be detected. The connection structure can transfer the deformation and working stress of the pressure sensitive film to the resonator 150, specifically to the piezoelectric layer 112. During the transmission process of the connection structure, the connection structure can change the direction of action of the pressure to be detected, reducing the possibility of damage to the resonant film 120. The anchor point can use the lever principle to amplify the working stress and increase the measurement range of the piezoelectric resonant pressure sensor 100.

[0164] Since the resonator 150 is provided with at least two first electrodes 111, when one of the first electrodes 111 drives the piezoelectric layer 112 to vibrate, the other first electrode 111 detects the vibration of the resonator 150. The first electrode 111 receiving the voltage may be a driving electrode, and the first electrode 111 detecting the vibration may be a detecting electrode.

[0165] Due to the positive piezoelectric effect of the piezoelectric film material, the detection electrode will generate an electrical signal, which can be used to detect the resonant frequency of the resonator 150 .

[0166] Assume that the working stress generated by the pressure to be detected on the piezoelectric resonator is σ, and the resonant frequency of the piezoelectric resonator is:

[0167]

[0168] From the above formula, it can be seen that the pressure value can be determined when the frequency change of the piezoelectric resonator is detected.

[0169] When the piezoelectric layer 112 is deformed, the portion of the piezoelectric layer 112 close to the resonant component is squeezed by the pressure to be detected, and the portion of the piezoelectric layer 112 away from the resonant component is stretched by the pressure to be detected. On the cross section of the piezoelectric layer 112, the transition layer between the stretched portion of the piezoelectric layer 112 and the squeezed portion of the piezoelectric layer 112, which is neither stretched nor compressed and has almost zero stress, is the above-mentioned neutral layer.

[0170] Compared with the resistance detection type piezoelectric sensor which needs to set up a Wheatstone bridge and the capacitance detection type pressure sensor which needs to set up a capacitance bridge, the piezoelectric resonant pressure sensor 100 provided in the example of the present application does not require the setting of an additional detection circuit, has a simpler structure, and has a lower manufacturing cost.

[0171] Based on the piezoelectric resonant pressure sensor 100 provided in the above example, please refer to Fig. 9The first lead electrode 114 and the second lead electrode 115 are disposed on the side of the piezoelectric layer 112 away from the first connection structure 131. At least part of the resonant film 120 may be a carrier 121, the first electrode 111 and at least part of the second electrode 113 are disposed on the carrier 121, a first end of the carrier 121 is connected to the first connection structure 131, and a second end of the carrier 121 is connected to the second connection structure 132.

[0172] The pressure sensitive component 140 may include a resonant substrate 142, and the resonant substrate 142 and the pressure sensitive film may cooperate to form a pressure chamber 141. The location of the resonant substrate 142 may correspond to the location of the first connection structure 131.

[0173] Based on this, when the pressure to be detected acts on the pressure sensitive component 140 , the pressure to be detected mainly acts on the pressure sensitive film, and then is transmitted to the piezoelectric component 110 through the second connection structure 132 , and the pressure to be detected is detected by the piezoelectric component 110 .

[0174] At least part of the second electrode 113, the piezoelectric layer 112 and the first electrode 111 can be disposed on a side of the carrier 121 away from the pressure sensitive component 140. The second electrode 113, the piezoelectric layer 112, the first electrode 111 and the carrier 121 can cooperate to form a resonator 150.

[0175] The carrier 121 can be integrally formed with the resonant film 120, in which case the carrier 121 can be a part of the resonant film 120. The carrier 121 can also be connected to the resonant film 120 via a connecting structure (not shown in the figure), in which case the carrier 121 can be a structure independent of the resonant film 120.

[0176] There can be one supporting member 121, or multiple supporting members 121 can be arranged at intervals. The multiple supporting members 121 can be arranged in a cross shape, a cross shape, a straight shape, or other irregular shapes.

[0177] The number of the carriers 121 may be equal to and correspond to the number of the first lead electrodes 114 , or the number of the carriers 121 may be different from the number of the first lead electrodes 114 , which is not limited in this example of the present application.

[0178] In the example of the present application, the carrier 121 can provide a mounting carrier for at least part of the first electrode 111, the second electrode 113, and the piezoelectric layer 112. Since the first lead electrode 114 and the second lead electrode 115 are arranged on the first connection structure 131, and the first end of the carrier 121 is connected to the first connection structure 131, the connection between the first electrode 111 and the first lead electrode 114, and the connection between the second electrode 113 and the second lead electrode 115 can be easily achieved by setting the carrier 121. In addition, by adjusting the setting position of the first lead electrode 114, the connection reliability between the first lead electrode 114 and the first electrode 111 can be ensured.

[0179] Since the first end of the carrier 121 is connected to the first connecting structure 131, the second end of the carrier 121 is connected to the second connecting structure 132, and the first connecting structure 131 and the second connecting structure 132 are spaced apart, the pressure to be detected transmitted to the second connecting structure 132 can easily cause the carrier 121 to deform, thereby making the deformation of the piezoelectric layer 112 larger, thereby improving the detection sensitivity and detection accuracy of the piezoelectric resonant pressure sensor 100.

[0180] Since a first groove is formed between the first connection structure 131 and the second connection structure 132, and the second connection structure 132 is connected to the middle of the resonant film 120, the vibration amplitude of the second connection structure 132 is larger than that of the first connection structure 131. Since the first lead electrode 114 and the second lead electrode 115 are arranged on one side of the first connection structure 131, the deformation amplitude of the first lead electrode 114 and the second lead electrode 115 under the pressure to be detected is smaller, which can reduce the influence of the pressure to be detected on the first lead electrode 114 and the second lead electrode 115, and reduce the possibility of the first lead electrode 114 and the second lead electrode 115 vibrating under the pressure to be detected, thereby ensuring the reliability of the piezoelectric resonant pressure sensor 100.

[0181] Based on the piezoelectric resonant pressure sensor 100 provided in the above example, along the direction from the resonant film 120 to the pressure sensitive component 140 , the projection of at least part of the resonant cavity 135 falls within the projection range of the pressure sensitive cavity.

[0182] There are many ways to achieve that the projection of at least a portion of the resonance cavity 135 falls within the projection range of the pressure cavity 141 along the direction from the resonance film 120 to the pressure sensitive component 140 .

[0183] For example, the projection of the resonance cavity 135 can completely fall within the projection range of the pressure cavity 141. At this time, the geometric center of the projection of the resonance cavity 135 can overlap with the geometric center of the projection of the pressure cavity 141, and the geometric center of the resonance cavity 135 can be spaced apart from the geometric center of the pressure cavity 141.

[0184] For example, the projection of part of the resonance cavity 135 may fall within the projection range of the pressure cavity 141 , that is, the projection of the resonance cavity 135 partially overlaps with the projection of the pressure cavity 141 .

[0185] The shape of the pressure chamber 141 may be the same as the shape of the resonance chamber 135, or the shape of the pressure chamber 141 may be different from the shape of the resonance chamber 135. The present application example is described here only by taking the pressure chamber 141 as an example. For example, the shape of the pressure chamber 141 may be cylindrical, the shape of the pressure chamber 141 may be prismatic, or the shape of the pressure chamber 141 may be irregular.

[0186] In the example of the present application, since the pressure sensitive component 140 forms a pressure sensitive film at the position where the pressure cavity 141 is opened, and at least part of the pressure sensitive film closes the resonance cavity 135, the resonance cavity 135 and the pressure cavity 141 at least partially overlap. Based on this, the volume of the resonant piezoelectric sensor can be reduced, which is conducive to the miniaturization of the piezoelectric resonant pressure sensor 100 and the integrated development of the piezoelectric resonant pressure sensor 100.

[0187] Based on the piezoelectric resonant pressure sensor 100 provided in the above example, the piezoelectric component 110 may further include a seed layer, which is disposed between the piezoelectric component 110 and the resonant film 120 , and specifically between the second electrode 113 and the resonant film 120 .

[0188] By providing the seed layer, the quality of the piezoelectric layer 112 during processing can be improved, thereby ensuring the working performance of the piezoelectric component 110 and further ensuring the working performance of the piezoelectric resonant pressure sensor 100 .

[0189] Based on the piezoelectric resonant pressure sensor 100 provided in the above example, the resonant component can be processed from an SOI wafer 300 (silicon on insulator wafer), and the pressure sensitive component 140 can be processed from an Si wafer 200 .

[0190] Based on the piezoelectric resonant pressure sensor 100 provided in the above example, an oxide layer 160 is provided between the pressure sensitive component 140 and the resonant component.

[0191] The oxide layer 160 may be an oxide layer 160 formed during the connection process between the SOI wafer 300 and the Si wafer 200 , or the oxide layer 160 may be an oxide layer 160 intentionally disposed between the SOI wafer 300 and the Si wafer 200 .

[0192] By providing the oxide layer 160 , the insulation between the pressure sensitive component 140 and the resonant component can be ensured, the possibility of leakage of the piezoelectric resonant pressure sensor 100 can be reduced, and the safety of the piezoelectric resonant pressure sensor 100 can be ensured.

[0193] Based on the piezoelectric resonant pressure sensor 100 provided in the above example, Fig.12 For a schematic diagram of the structure of a piezoelectric resonant pressure sensor provided in this application example, please refer to Fig.12 The piezoelectric resonant pressure sensor 100 may further include a cover 190 . The cover 190 is disposed on a side of the piezoelectric component 110 away from the resonant film 120 . The cover 190 is directly or indirectly connected to the piezoelectric component 110 .

[0194] The cover 190 may be made of a silicon wafer, a glass wafer 400 , an inorganic semiconductor material, or other amorphous inorganic non-metallic materials.

[0195] In a vacuum environment, the cover 190 can be used to encapsulate the piezoelectric resonant pressure sensor 100. The cover 190 can be disposed on the side of the piezoelectric component 110 away from the resonant component to isolate the piezoelectric component 110 from the atmospheric environment, ensuring that the piezoelectric component 110 is in a vacuum environment when working, thereby improving the value corresponding to the quality factor of the piezoelectric resonant pressure sensor 100 and ensuring the working performance of the piezoelectric resonant pressure sensor 100.

[0196] In this example of the present application, the cover 190 may be bonded to a side of the piezoelectric component 110 facing away from the resonant film 120 , and the cover 190 may close the notch of the deformation groove 133 , the notch of the first groove, and the notch of the second groove 134 .

[0197] The bonding method may be anodic bonding, or metal bonding such as Al-Ge, Au-Au, or other bonding methods.

[0198] Based on the piezoelectric resonant pressure sensor 100 provided in the above example, a suction structure 191 may be provided on the side of the cover 190 facing the piezoelectric component 110. The suction structure 191 may be a thin film getter or other structure capable of maintaining a vacuum inside the piezoelectric resonant pressure sensor 100.

[0199] The adsorption structure 191 can adsorb the gas or other substances inside the piezoelectric resonant pressure sensor 100 so that the inside of the piezoelectric resonant pressure sensor 100 is maintained in a vacuum state, thereby ensuring the measurement accuracy and sensitivity of the piezoelectric resonant pressure sensor 100 and extending the service life of the piezoelectric resonant pressure sensor 100.

[0200] Based on the piezoelectric resonant pressure sensor 100 provided in the above example, the piezoelectric resonant pressure sensor 100 may be an absolute pressure sensor, or the piezoelectric resonant pressure sensor 100 may be a relative pressure sensor.

[0201] Exemplarily, the piezoelectric resonant pressure sensor 100 may be an absolute pressure sensor. In this case, the cover 190 may be bonded to the side of the piezoelectric component 110 facing away from the resonant film 120 under a vacuum environment. The absolute pressure sensor is used to measure absolute pressure and can convert the absolute pressure of a gas or liquid into an equivalent electrical signal output.

[0202] Exemplarily, the piezoelectric resonant pressure sensor 100 may be a relative pressure sensor. In this case, the cover 190 may be bonded to the side of the piezoelectric component 110 that is away from the resonant film 120 under a certain pressure environment. The relative pressure sensor is measured based on atmospheric pressure, and the measurement result of the relative pressure sensor is relative to the atmospheric pressure, so the relative pressure sensor can be used to measure the difference in relative pressure.

[0203] Users can select a suitable absolute pressure sensor or relative pressure sensor according to their needs. The present application example does not limit whether a medium is injected into the cavity of the piezoelectric resonant pressure sensor 100.

[0204] Based on the piezoelectric resonant pressure sensor 100 provided in the above example, a protective layer 180 may be provided on the side of the piezoelectric component 110 facing away from the resonant component. The protective layer 180 may be made of silicon dioxide material or other moisture-proof material.

[0205] The protective layer 180 can isolate the piezoelectric component 110 from the atmospheric environment, and the protective layer 180 can play a role in moisture-proofing, so that the piezoelectric resonant pressure sensor 100 is kept in a dry state as much as possible, thereby ensuring the working reliability of the piezoelectric resonant pressure sensor 100. The protective layer 180 can also play a role in temperature compensation during the operation of the piezoelectric resonant pressure sensor 100.

[0206] During the use of the piezoelectric resonant pressure sensor 100, only the cover 190 may be provided, only the protective layer 180 may be provided, both the cover 190 and the protective layer 180 may be provided, or neither the cover 190 nor the protective layer 180 may be provided, and this application example does not impose any limitation on this.

[0207] Illustratively, the present application example provides a method for preparing a piezoelectric resonant pressure sensor 100 , which is applicable to the piezoelectric resonant pressure sensor 100 provided in any of the above examples. The following processing method can be completed by MEMS processing equipment.

[0208] In the example of the present application, the piezoelectric resonant pressure sensor 100 can be processed from a plurality of SOI wafers 300, or from a CSOI (buried cavity SOI) wafer and an SOI wafer 300, or from an SOI wafer 300 and a Si wafer 200, or from a CSOI wafer. The example of the present application only takes the piezoelectric resonant pressure sensor 100 processed from an SOI wafer 300 and an Si wafer 200 as an example for explanation.

[0209] Fig.13 For a schematic diagram of a method for preparing a piezoelectric resonant pressure sensor provided in this application example, please refer to Fig.13 The method is used to process a Si wafer 200 and an SOI wafer 300 into a piezoelectric resonant pressure sensor 100, wherein the SOI wafer 300 includes a first device layer 310, an oxide layer, and a first substrate layer 330. The method specifically includes the following steps:

[0210] S110, take the Si wafer 200, process the annular groove 210 on one side of the Si wafer 200, form the first connecting structure 131 outside the annular groove 210 and the second connecting structure 132 inside the annular groove 210, the first connecting structure 131 and the second connecting structure 132 cooperate to form a resonant cavity 135. For details, please refer to Fig.14 and Fig.15 14 is a schematic diagram of the structure of an unprocessed Si wafer provided in the example of this application, Fig.15 A schematic structural diagram of a Si wafer processing ring groove provided as an example in this application.

[0211] The annular groove 210 can be formed on one side of the Si wafer 200 by etching, sputtering or other processing methods. The annular groove 210 can be a circular annular groove, a square annular groove or annular groove 210 of other shapes. The specific shape of the annular groove 210 is not limited in the present application example.

[0212] The protruding structure outside the annular groove 210 may be the first connection structure 131 , and the protruding structure inside the annular groove 210 may be the second connection structure 132 . A resonance cavity 135 is formed between the first connection structure 131 and the second connection structure 132 , that is, the annular groove 210 is the resonance cavity 135 .

[0213] Etching may include dry etching and wet etching, wherein dry etching includes but is not limited to xenon difluoride and plasma etching, and wet etching includes but is not limited to HF etching and electrochemical etching.

[0214] S120, take the SOI wafer 300, bond the SOI wafer 300 and the Si wafer 200, the first device layer 310 closes the cavity opening of the resonant cavity 135, and the second connection structure 132 is connected to the middle of the first device layer 310 on one side facing the first device layer 310, please refer to Fig.16 and Fig.17 , 16 is a schematic diagram of the structure of an unprocessed SOI wafer provided in an example of this application, Fig.17 A method based on Fig.15 Schematic diagram of the structure of connecting Si wafer to SOI wafer.

[0215] By flipping the SOI wafer 300, the first device layer 310 can be directed toward the Si wafer 200, so as to facilitate bonding between the first device layer 310 and the Si wafer 200, so that the first device layer 310 closes the cavity opening of the resonant cavity 135. The bonding method can be anodic bonding, melt bonding or other bonding methods.

[0216] S130, removing the first buried oxide layer 320 and the first substrate layer 330, and setting the thickness of the first device layer 310 to be the same as the thickness of the resonant film 120. Fig.18 , Fig.18 Based on Fig.17 Schematic diagram of the structure after removing the first substrate layer and the first buried oxide layer.

[0217] The first buried oxide layer 320 and the first substrate layer 330 may be removed by physical removal, chemical removal or other methods. The present application example does not specifically limit the removal method of the first buried oxide layer 320 and the first substrate layer 330 .

[0218] In the example of the present application, the sum of the thickness of the first device layer 310 and the first buried oxide layer 320 can also be set equal to the thickness of the resonant film 120, or the sum of the thickness of part of the first substrate layer 330, the oxide layer and the intermediate layer can be set equal to the thickness of the resonant film 120. The example of the present application does not impose specific restrictions on this.

[0219] S140 , disposing a piezoelectric component 110 on a side of the first device layer 310 facing away from the Si wafer 200 .

[0220] In some possible implementations, the piezoelectric component 110 includes a lead electrode, a first electrode 111, a piezoelectric layer 112, and a second electrode 113. S140 specifically includes the following steps:

[0221] S141, sequentially deposit the second electrode layer, the piezoelectric layer 112 and the first electrode layer, please refer to Fig.19 , Fig.19 A schematic diagram of a structure in which a piezoelectric component is deposited on the side of a first device layer facing away from a Si wafer is provided as an example of the present application.

[0222] S142, patterning the first electrode layer to form at least two first electrodes 111, please refer to Fig. 20 , Fig. 20 A method based on Fig.19Schematic diagram of the structure of the piezoelectric component after processing.

[0223] In some possible implementations, after S142, the following steps may be further included:

[0224] S143, depositing a protective layer 180, please refer to Fig.21 , Fig.21 A method based on Fig. 20 Schematic diagram of a structure in which a protective layer is provided on a piezoelectric component away from a first device layer.

[0225] Because the first electrode 111 has been patterned before the protective layer 180 is deposited, which causes a portion of the piezoelectric layer 112 to be exposed, a portion of the protective layer 180 may contact the first electrode 111 , and another portion of the protective layer 180 may contact the piezoelectric layer 112 .

[0226] S144, a second connection hole 1151 is processed at a position connected to the second electrode 113, and a connecting member is inserted through the second connection hole 1151 to be connected to the second electrode 113, please refer to Fig. 22 , Fig. 22 A method based on Fig.21 Schematic diagram of the structure of processing the second connecting hole from the protective layer.

[0227] The second connection hole 1151 can be processed to the side of the second electrode 113 away from the resonance component, and part of the hole wall of the second connection hole 1151 can also be arranged on the second electrode 113. As long as the conductive structure passing through the second connection hole 1151 can be connected to the second electrode 113, the example of this application does not make any specific restrictions on this.

[0228] S145, processing a first connection hole 1141 at a position connected to the first electrode 111, and the conductive structure is arranged through the first connection hole 1141 to be connected to the first electrode 111, please refer to Fig.23 , Fig.23 A method based on Fig.21 or Fig. 22 Schematic diagram of the structure of processing the first connecting hole from the protective layer.

[0229] The first connection hole 1141 can be processed to the side of the first electrode 111 away from the resonance component, and part of the hole wall of the first connection hole 1141 can also be arranged on the first electrode 111. As long as the conductive structure passing through the first connection hole 1141 can be connected to the first electrode 111, the example of this application does not make any specific restrictions on this.

[0230] During the manufacturing process of the piezoelectric resonant pressure sensor 100 , the first connection hole 1141 may be processed first, and then the second connection hole 1151 , that is, S114 is performed first, and then S113 , and this example of the present application does not impose any specific limitation on this.

[0231] S146, depositing a lead electrode layer, part of the lead electrode layer may be located in the second connection hole 1151 and connected to the second electrode 113, please refer to Fig.24 , Fig.24 A method based on Fig.23 Schematic diagram of the structure of depositing a lead electrode layer on the side of the protection layer away from the first device layer.

[0232] S147, patterning the lead electrode layer to form at least one first lead electrode 114 and at least one second lead electrode 115, please refer to Fig.25 , Fig.25 A method based on Fig.24 Schematic diagram of the structure of processing lead electrodes on the lead electrode layer.

[0233] The side of the first lead electrode 114 close to the first electrode 111 is connected to the first electrode 111, and the side of the first lead electrode 114 away from the first electrode 111 can be connected to the first part of the external circuit. The side of the second lead electrode 115 close to the second electrode 113 is connected to the second electrode 113, and the side of the second lead electrode 115 away from the second electrode 113 can be connected to the second part of the external circuit. The second lead electrode 115 is the conductive structure mentioned in the above example. Based on this, the connection between the piezoelectric resonant pressure sensor 100 and the external circuit can be realized.

[0234] S150, processing the pressure cavity 141 on the side of the Si wafer 200 away from the first device layer 310, please refer to Fig.26 , Fig.26 A method based on Fig.25 Schematic diagram of the structure of processing a pressure chamber on the side of the Si wafer away from the first device layer.

[0235] The pressure chamber 141 can be formed by etching or other processing methods on the side of the first substrate layer 330 away from the first buried oxide layer 320. Etching can include dry etching and wet etching, wherein dry etching includes but is not limited to xenon difluoride and plasma etching, and wet etching includes but is not limited to HF etching and electrochemical etching.

[0236] In the piezoelectric resonant pressure sensor 100 processed by the above method, the pressure chamber 141 can receive the pressure to be detected, and the pressure to be detected can be transmitted to the connecting component 130 and the resonant film 120 through the pressure sensitive component 140, and then transmitted to the piezoelectric component 110. The pressure to be detected is detected by the characteristics of the piezoelectric component 110.

[0237] Since the piezoelectric component 110 is arranged on the side of the resonant film 120 away from the connecting component 130, and the pressure sensitive component 140 is arranged on the side of the connecting component 130 away from the resonant film 120, the piezoelectric component 110 and the pressure chamber 141 receiving the pressure to be detected are separated. And since the connecting component 130 and the resonant film 120 cooperate to form a resonant cavity 135. When the piezoelectric component 110 drives the resonant component to vibrate, the resonant cavity 135 can provide a deformation space for the piezoelectric component 110, thereby reducing the possibility that the piezoelectric component 110 is damaged due to a large deformation amount caused by vibration.

[0238] When the possibility of damage to the piezoelectric component 110 is reduced, the piezoelectric resonant pressure sensor 100 provided in the example of the present application can withstand a larger pressure to be detected, thereby improving the pressure measurement range of the piezoelectric resonant pressure sensor 100, expanding the measurement range of the piezoelectric resonant pressure sensor 100, and expanding the application scope of the piezoelectric resonant pressure sensor 100, so that the piezoelectric resonant pressure sensor 100 can be widely used in the core technology field of the electronics industry.

[0239] In addition, in the example of the present application, the connecting component 130 can realize the connection between the resonant film 120 and the pressure sensitive component 140. The connecting component 130 includes a first connecting structure 131 and a second connecting structure 132 which are arranged at intervals, and the end of the second connecting structure 132 is connected to the middle of the resonant film 120. Therefore, at least part of the pressure to be detected can be transmitted to the resonator 150 through the second connecting structure 132. The second connecting structure 132 can move in a direction away from the pressure sensitive component 140 under the action of the pressure to be detected, or the second connecting structure 132 has a tendency to move in the opposite direction away from the pressure sensitive component 140 under the action of the pressure to be detected. Since the second end of the resonator 150 is connected to the second connecting structure 132, the resonator 150 can be deformed under the action of the second connecting structure 132. Since the first connecting structure 131 and the second connecting structure 132 are spaced apart, and the first end of the resonator 150 is connected to the first connecting structure 131, and the second end of the resonator 150 is connected to the second connecting structure 132, under the action of the pressure to be detected, the deformation of the resonator 150 in the example of the present application is more obvious, which can improve the detection sensitivity of the piezoelectric resonant pressure sensor 100, and thereby improve the detection accuracy of the piezoelectric resonant pressure sensor 100.

[0240] The second connecting structure 132 can connect the pressure-sensitive film and the piezoelectric component 110, and the second connecting structure 132 can change the direction of action of the pressure to be detected, so that the pressure to be detected acting vertically on the piezoelectric component 110 is smaller, which further reduces the possibility of damage to the piezoelectric component 110, improves the pressure-bearing capacity of the resonant film 120, expands the detection range of the piezoelectric resonant pressure sensor 100, and ensures the linearity of the piezoelectric resonant pressure sensor 100 within the pressure detection range.

[0241] In some possible implementations, the piezoelectric resonant pressure sensor 100 includes a deformation groove 133. In this case, after patterning the lead electrode layer to form at least one first lead electrode 114 and at least one second lead electrode 115, S147 may further include:

[0242] S148, processing the deformation groove 133 from the side of the protection layer 180 away from the first device layer 310, please refer to Fig. 27 , Fig. 27 A method based on Fig.26 Schematic diagram of the structure of machining deformation groove from the protective layer.

[0243] The deformation groove 133 is formed by etching or other processing methods on the side of the protection layer 180 away from the first device layer 310. The etching may include dry etching and wet etching, wherein dry etching includes but is not limited to xenon difluoride and plasma etching, and wet etching includes but is not limited to HF etching and electrochemical etching.

[0244] In some possible implementations, the piezoelectric resonant pressure sensor 100 includes a second groove 134, the second groove 134 is disposed at a position corresponding to the second connection structure 132, and the second groove 134 can divide the second connection structure 132 into a plurality of sub-connection structures 1321. In this case, S148 can process the deformation groove 133 and the second groove 134 at the same time, or process the second groove 134 after processing the deformation groove 133, and this application example does not impose specific restrictions on this.

[0245] The processing method of the second groove 134 is similar to the processing method of the annular groove 210 , and is not described in detail in this example.

[0246] The second groove 134 may be processed before or after the pressure chamber 141 is processed, and this example of the present application does not impose any specific limitation on this.

[0247] In some possible implementations, the piezoelectric resonant pressure sensor 100 may further include a cover 190, and the cover 190 is bonded to the piezoelectric component 110. The bonding method may be anodic bonding, or metal bonding such as Al-Ge, Au-Au, or other bonding methods. Next, the bonding method of the cover 190 and the piezoelectric component 110 is described by taking the Al-Ge bonding connection between the cover 190 and the piezoelectric component 110 as an example.

[0248] Based on the above-mentioned method for manufacturing the piezoelectric resonant pressure sensor 100, in S147, after patterning the lead electrode layer to form at least one first lead electrode 114 and at least one second lead electrode 115, the method further includes:

[0249] S1471, in the patterned electrode layer, in addition to forming at least one first lead electrode 114 and at least one second lead electrode 115, a first connecting member 171 is also formed. Fig.26 , Fig.26 and Fig.25 The cross-sectional directions are different.

[0250] The first connecting member 171 may be roughly in the shape of a circular ring, a square ring or other structures. The first connecting member 171 may be a sealed ring structure. The first connecting member 171 may also be composed of a plurality of spaced segments. This application example does not impose any specific limitation on this.

[0251] S160, taking a glass wafer 400, and etching a cavity to form a cover 190 may specifically include:

[0252] S161, depositing a Ge layer on one side of the glass wafer 400, refer to Fig.28 and Fig.29 , Fig.28 A schematic diagram of the structure of a glass wafer provided as an example of this application, Fig.29 A schematic diagram of a structure for processing a Ge layer on a glass wafer provided as an example of this application.

[0253] S162, etching the Ge layer to form a second connecting member 172, please refer to Fig.30 , Fig.30 A method based on Fig.29 Structural schematic diagram of processing the second connecting piece.

[0254] The shape of the second connecting member 172 can be the same as or different from the shape of the first connecting member 171. The example of the present application does not impose any specific limitation on this. As long as the first connecting member 171 can be connected to the second connecting member 172, the connection between the cover 190 and the piezoelectric component 110 can be achieved.

[0255] S163, a cavity is formed by etching on the side of the glass wafer 400 where the second connecting member 172 is provided, and the opening of the cavity is arranged toward the side of the glass wafer 400 where the second connecting member 172 is provided. Fig.31 , Fig.31 A schematic diagram of a structure for machining a cavity on a glass wafer to form a cover is provided as an example of the present application.

[0256] In some possible implementations, the piezoelectric resonant pressure sensor 100 may further include an adsorption structure 191 .

[0257] Based on the above-mentioned method for manufacturing the piezoelectric resonant pressure sensor 100, in S140, after taking a glass wafer 400 and etching the cavity to form the cover 190, the following steps may also be included:

[0258] S164, an adsorption structure 191 is provided on the cavity wall, please refer to Fig.32 , Fig.32 A schematic diagram of a structure in which an adsorption structure is provided inside a cover provided as an example of the present application.

[0259] Specifically, the connection between the adsorption structure 191 and the cover 190 can be achieved through a vacuum coating process or other processing methods, and this application example does not make any specific restrictions on this.

[0260] S170, bonding the cover 190 and the piezoelectric component 110, please refer to Fig.33 , Fig.33 A schematic diagram of a structure in which a cover is connected to the side of a protective layer facing away from the piezoelectric layer, provided as an example of the present application.

[0261] The bonding connection between the cover 190 and the piezoelectric component 110 can be performed in a vacuum environment or in an environment of a certain pressure, and this example of the application does not impose any specific limitation on this.

[0262] Exemplarily, the present application provides a method for preparing a piezoelectric resonant pressure sensor 100. Fig.34 For a flow chart of another method for preparing a piezoelectric resonant pressure sensor provided in this application example, please refer to Fig.34 The method is applicable to the piezoelectric resonant pressure sensor 100 provided in any of the above examples, and the following processing method can be completed by MEMS processing equipment.

[0263] In the example of the present application, the method is used to process a CSOI wafer into a piezoelectric resonant pressure sensor 100 , and the CSOI wafer includes a second device layer, a second buried oxide layer, and a second substrate layer.

[0264] The second substrate layer is provided with a first connection structure and a second connection structure spaced apart on one side facing the second buried oxide layer, the end of the second connection structure is connected to the middle of the second buried oxide layer, and the first connection structure, the second connection structure and the second buried oxide layer cooperate to form a resonant cavity. In the example of this application, the structure of the CSOI wafer is similar to the structure formed by bonding the Si wafer and the SOI wafer mentioned above. For details, please refer to Fig.18 The structure shown, Fig.18 The Si wafer 200 processed in the middle is equivalent to the second substrate layer in the example of this application. Fig.18 The oxide layer 160 in the embodiment is equivalent to the second buried oxide layer in the present application, and the first device layer 310 is equivalent to the second device layer in the present application. The method includes:

[0265] S210 , disposing a piezoelectric component 110 on a side of the second device layer away from the second buried oxide layer.

[0266] In the example of the present application, the method for setting the piezoelectric component 110 is similar to the method for setting the piezoelectric component when the piezoelectric resonant pressure sensor 100 is processed from the Si wafer 200 and the SOI wafer 300. For details, please refer to the relevant description above and Figure 19 to Figure 25 The structure shown.

[0267] S220, processing a pressure cavity 141 on a side of the second substrate layer away from the second buried oxide layer.

[0268] In the example of the present application, the processing method of the pressure chamber 141 is similar to the processing method of the pressure chamber 141 when the piezoelectric resonant pressure sensor 100 is processed from the Si wafer 200 and the SOI wafer 300. For details, please refer to the relevant description above and Fig.26 The structure shown.

[0269] The piezoelectric resonant pressure sensor 100 formed by the method provided in the example of this application is similar in structure and function to the piezoelectric resonant pressure sensor 100 formed by the Si wafer 200 and the SOI wafer 300, and will not be described in detail in this application.

[0270] By processing the piezoelectric resonant pressure sensor 100 according to the method provided in the example of the present application, during the manufacturing process of the piezoelectric resonant pressure sensor 100, the processing of the first connecting structure and the second connecting structure can be reduced, thereby reducing the processing steps of the piezoelectric resonant pressure sensor 100 and reducing the processing cost of the piezoelectric resonant pressure sensor 100.

[0271] In addition, the piezoelectric resonant pressure sensor 100 processed according to the method provided in the example of the present application may also include a deformation groove 133. The structure and processing method of the deformation groove 133 are similar to the processing method of the deformation groove 133 when the piezoelectric resonant pressure sensor 100 is processed from the Si wafer 200 and the SOI wafer 300. The structure and function of the deformation groove 133 can be found in the above description, and Fig. 27 The structure shown in this application example will not be repeated here.

[0272] The piezoelectric resonant pressure sensor 100 processed according to the method provided in the example of the present application may also include a second groove 134. The structure and processing method of the second groove 134 are similar to the processing method of the second groove 134 when the piezoelectric resonant pressure sensor 100 is processed from a Si wafer 200 and an SOI wafer 300, and the examples of the present application are not repeated here.

[0273] The piezoelectric resonant pressure sensor 100 processed by the method provided in the example of the present application may also include a cover 190. The structure and processing method of the cover 190 are similar to the processing method of the cover 190 when the piezoelectric resonant pressure sensor 100 is processed from a Si wafer and an SOI wafer. For details, please refer to the above related description and Figure 28 to Figure 33 The structure shown in this application example will not be repeated here.

[0274] In the present application example, a suction structure 191 may also be provided in the cover 190. For the specific configuration of the suction structure 191 and the role played by the suction structure 191, please refer to the above related description.

[0275] The above-mentioned numbers do not limit the order of the steps of the above-mentioned method. During the specific implementation of the preparation method, the implementation steps of the above-mentioned method can be adaptively adjusted based on actual conditions.

[0276] During 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, which may affect the detection result of the piezoelectric resonant pressure sensor 100. Environmental factors may be temperature, vibration, impact, etc. Based on this, the piezoelectric resonant pressure sensor 100 needs to be compensated.

[0277] Exemplarily, the present application provides a compensation system 500, Fig.35 For a schematic diagram of the compensation system provided for this application example, please refer to Fig.35The compensation system 500 may include an integrated driving component 530, a detection component 540 and at least two piezoelectric resonant pressure sensors 100 mentioned in the above embodiments, and the at least two piezoelectric resonant pressure sensors 100 include at least one pressure sensor 510 and at least one compensation sensor 520.

[0278] When only one pressure sensor 510 is provided, only one or more compensation sensors 520 may be provided.

[0279] In the case where only one compensation sensor 520 is provided, only one detection sensor may be provided, or a plurality of detection sensors may be provided.

[0280] Multiple compensation sensors 520 and detection sensors may be provided, and the number of compensation sensors 520 may be equal to the number of detection sensors, or the number of compensation sensors 520 may be different from the number of detection sensors.

[0281] The pressure sensor 510 is used to detect the pressure to be detected, and the compensation sensor 520 is used to compensate for the influence of environmental factors on the pressure sensor 510. The driving component 530 is connected to the driving electrode of the pressure sensor 510 and the driving electrode of the compensation sensor 520, and the driving component 530 is used to drive the detection sensor and the compensation sensor 520 to vibrate. The detection component 540 is connected to the detection electrode of the pressure sensor 510 and the detection electrode of the compensation sensor 520. The detection component 540 is used to detect the resonant frequency of the pressure sensor 510 and the compensation sensor 520.

[0282] Since the pressure sensor 510 and the compensation sensor 520 are integrated together, environmental factors such as temperature, vibration, and shock will have the same impact on the resonant components of the pressure sensor 510 and the compensation sensor 520, so that the resonant components of the pressure sensor 510 and the compensation sensor 520 can have the same output based on the influence of environmental factors.

[0283] Based on this, when the detection component 540 detects the resonant frequency of the pressure sensor 510 and the compensation sensor 520, it only needs to subtract the resonant frequency output by the compensation sensor 520 from the resonant frequency output by the pressure sensor 510 and then extract the final resonant frequency, thereby eliminating the influence of environmental factors and improving the detection accuracy of the compensation system 500 on the pressure to be detected.

[0284] Fig.36 For a schematic diagram of the working process of a compensation system provided for this application example, please refer to Fig.36 , the working process of the compensation sensor 520 is as follows:

[0285] S310 , the driving component 530 is used to drive the pressure sensor 510 and the compensation sensor 520 .

[0286] S320 , the detection component 540 is used to detect and output a first resonant frequency corresponding to the pressure sensor 510 and a second resonant frequency corresponding to the compensation sensor 520 .

[0287] S330, a calculation module is used to calculate the difference between the first resonant frequency and the second resonant frequency to obtain a target resonant frequency.

[0288] S340, the calculation module may also calculate the pressure value of the pressure to be detected based on the resonance frequency.

[0289] The calculation module may be a part of the detection component 540 , or a module independent of the detection component 540 , which is not limited in this example of the present application.

[0290] Based on the compensation system 500 mentioned in the above example, during the operation of the compensation system 500, the pressure to be detected can act on the pressure chamber 141 of the pressure sensor, and the pressure to be detected does not act on the compensation sensor 520. Based on this, the structure of the pressure sensor 510 and the structure of the compensation sensor 520 can be completely consistent. The structures of the pressure sensor 510 and the compensation sensor 520 may also be inconsistent, for example, the compensation sensor 520 may not be provided with a pressure sensitive component 140. The example of this application does not limit the specific structures of the pressure sensor 510 and the compensation sensor 520.

[0291] In summary, according to the compensation system 500 provided in the example of the present application, when the detection component 540 detects the resonant frequency of the pressure sensor 510 and the compensation sensor 520, it only needs to subtract the resonant frequency output by the compensation sensor 520 from the resonant frequency output by the pressure sensor 510 and then extract the final resonant frequency. This can eliminate the influence of environmental factors and improve the detection accuracy of the compensation system 500 for the pressure to be detected.

[0292] Finally, it should be noted that the above embodiments are only specific implementation methods of the present application, but the protection scope of the present application is not limited thereto, and any changes or substitutions within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A piezoelectric resonant pressure sensor, characterized in that: include: A piezoelectric component connected to an external circuit; A resonant film connected to one side of the piezoelectric component; A connecting component connected to a side of the resonant film away from the piezoelectric component, wherein the connecting component cooperates with the resonant film to form a resonant cavity; A pressure sensitive component is connected to a side of the connecting component away from the resonant film, and a pressure chamber is provided on the side of the pressure sensitive component away from the connecting component, and the pressure chamber is used to receive a pressure to be detected; Among them, the connecting component includes a first connecting structure and a second connecting structure arranged at intervals, the end of the second connecting structure is connected to the middle of the resonant film, at least part of the resonant film and part of the piezoelectric component cooperate to form a resonator, the first end of the resonator is connected to the first connecting structure, and the second end of the resonator is connected to the second connecting structure.

2. The piezoelectric resonant pressure sensor according to claim 1, characterized in that: Along the direction from the resonant film to the connecting component, a center line of the second connecting structure is collinear with a center line of the resonant film.

3. The piezoelectric resonant pressure sensor according to claim 1, characterized in that: The piezoelectric resonant pressure sensor is provided with a deformation groove, the notch of the deformation groove is arranged on the side of the piezoelectric component away from the resonant film, and the bottom of the deformation groove is arranged on the second connecting structure.

4. The piezoelectric resonant pressure sensor according to claim 3, characterized in that: A first groove is formed between the first connecting structure and the second connecting structure; The second connection structure includes a plurality of sub-connection structures arranged at intervals, a second groove is formed between two adjacent sub-connection structures, and the second groove communicates with the deformation groove and the first groove.

5. The piezoelectric resonant pressure sensor according to claim 4, characterized in that: The plurality of sub-connection structures are evenly arranged.

6. The piezoelectric resonant pressure sensor according to claim 1, characterized in that: The piezoelectric component includes a first lead electrode, a second lead electrode, a first electrode, a piezoelectric layer and a second electrode; wherein, The second electrode is connected to a side of the resonant film away from the connecting component, the piezoelectric layer is connected to a side of the second electrode away from the resonant film, a portion of the second lead electrode is arranged on a side of the piezoelectric layer away from the second electrode, and the second lead electrode is arranged through the piezoelectric layer and is electrically connected to the second electrode; The first electrode is connected to a side of the piezoelectric layer away from the second electrode, the first lead electrode is arranged on a side of the first electrode away from the piezoelectric layer, and the first lead electrode is electrically connected to the first electrode.

7. The piezoelectric resonant pressure sensor according to claim 6, characterized in that: The first lead electrode and the second lead electrode are arranged on a side of the piezoelectric layer away from the first connection structure; At least part of the resonant film is a carrier, the first electrode and at least part of the second electrode are arranged on the carrier, a first end of the carrier is connected to the first connection structure, and a second end of the carrier is connected to the second connection structure.

8. A compensation system, characterized in that: It comprises an integrated driving component, a detection component and at least two piezoelectric resonant pressure sensors according to any one of claims 1 to 7, wherein the at least two piezoelectric resonant pressure sensors comprise at least one pressure sensor and at least one compensation sensor.

9. A method for preparing a piezoelectric resonant pressure sensor, characterized in that: Applicable to the piezoelectric resonant pressure sensor according to any one of claims 1 to 7, the method is used to process a Si wafer and an SOI wafer into the piezoelectric resonant pressure sensor, the SOI wafer comprising a first device layer, a first buried oxide layer and a first substrate layer; The method comprises: Take the Si wafer, process a ring groove on one side of the Si wafer, form a first connection structure on the outer side of the ring groove and a second connection structure on the inner side of the ring groove, the first connection structure and the second connection structure cooperate to form a resonant cavity; Taking the SOI wafer, bonding the SOI wafer and the Si wafer, the first device layer closing the cavity opening of the resonant cavity, and the second connection structure connecting to the middle of the first device layer on one side facing the first device layer; removing the first buried oxide layer and the first substrate layer, and setting the thickness of the first device layer to be the thickness of the resonance film; Disposing a piezoelectric component on a side of the first device layer away from the Si wafer; A pressure cavity is fabricated on a side of the Si wafer facing away from the first device layer.

10. A method for preparing a piezoelectric resonant pressure sensor, characterized in that: Applicable to the piezoelectric resonant pressure sensor according to any one of claims 1 to 7, the method is used to process a CSOI wafer into the piezoelectric resonant pressure sensor, the CSOI wafer comprising a second device layer, a second buried oxide layer and a second substrate layer; A first connection structure and a second connection structure are provided at intervals on one side of the second substrate layer facing the second buried oxide layer, an end of the second connection structure is connected to the middle of the second buried oxide layer, and the first connection structure, the second connection structure and the second buried oxide layer cooperate to form a resonant cavity; The method comprises: Disposing a piezoelectric component on a side of the second device layer away from the second buried oxide layer; A pressure cavity is processed on a side of the second substrate layer away from the second buried oxide layer.

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