Piezoelectric resonant pressure sensor and compensation system

Abstract

The utility model provides a piezoelectric resonant pressure sensor and a compensation system, 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 and compensation system. Background Art

[0002] Pressure sensors are sensitive components that convert received pressure signals into electrical signals according to specific patterns and output these signals to other devices. They are widely used in defense, automotive, petroleum, aerospace, smart hardware, and other technical fields, belonging to the core technology areas of the electronics industry.

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

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

[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 range of the piezoelectric resonant pressure sensor. Utility Model Content

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

[0007] In a 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 facing 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 facing away from the resonant film. A pressure chamber is provided on the side of the pressure-sensitive component facing away from the connecting component, and the pressure chamber 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] In the piezoelectric resonant pressure sensor provided in this example, the pressure chamber can receive the pressure to be detected, which can be transmitted through the pressure-sensitive component to the connecting component and the resonant film, and then to the piezoelectric component. The pressure to be detected is detected based on the characteristics of the piezoelectric component.

[0010] Because the piezoelectric component is positioned on the side of the resonant film facing away from the connecting component, and the pressure-sensitive component is positioned on the side of the connecting component facing away from the resonant film, the piezoelectric component is separated from the pressure chamber that receives the pressure to be detected. Furthermore, because the connecting component and the resonant film cooperate to form a resonant cavity, when the piezoelectric component drives the resonant component to vibrate, the resonant cavity provides space for the piezoelectric component to deform, reducing the possibility of damage to the piezoelectric component caused by large deformation due to vibration.

[0011] When the possibility of damage to the piezoelectric component is reduced, the piezoelectric resonant pressure sensor provided in the example of this 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 scope of application 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, 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 thereby improve the detection accuracy of the piezoelectric resonant pressure sensor.

[0013] The second connection structure can connect the pressure-sensitive film and the piezoelectric component, and the second connection 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 a 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.

[0015] In the example of the present application, since 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 improving the measurement range of the piezoelectric resonant pressure sensor and expanding 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] Because the opening of the deformation groove is located on the side of the piezoelectric component facing away from the resonant film, the bottom of the deformation groove is located on the second connecting structure, and one end of the second connecting structure is connected to the middle of the resonant film, the provision of the deformation groove can create a gap in the middle of the resonant film and the piezoelectric component, reducing the cross-sectional area of the resonant film and the piezoelectric component. This makes 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 and detection accuracy of the piezoelectric resonant 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 spaced-apart sub-connection structures, 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 a second groove, the second connection structure can include multiple spaced 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 large deformation, 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 assembly 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 facing away from the connection assembly, the piezoelectric layer is connected to a side of the second electrode facing away from the resonant film, a portion of the second lead electrode is disposed on a side of the piezoelectric layer facing away from the second electrode, and the second lead electrode is disposed through the piezoelectric layer and 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. 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 this 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 facing away from the first connection structure. At least a portion of the resonant thin film serves as a carrier, the first electrode and at least a portion 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 this application, the carrier can provide a mounting support for at least a portion of the first electrode, the second electrode, and the piezoelectric layer. Because the first lead electrode and the second lead electrode are disposed on the first connection structure, and the first end of the carrier is connected to the first connection structure, the carrier facilitates connection between the first electrode and the first lead electrode, and between the second electrode and the second lead electrode. Furthermore, by adjusting the position of the first lead electrode, the reliability of the connection 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] Because a first groove is formed between the first and second connecting structures, and the second connecting structure is connected to the middle of the resonant film, the second connecting structure vibrates with a greater amplitude than the first connecting structure. Because the first and second lead electrodes are located on one side of the first connecting structure, the first and second lead electrodes deform less in response to the pressure to be detected. This reduces the impact of the pressure to be detected on the first and second lead electrodes, lowering the likelihood of vibration in response to the pressure to be detected, thereby ensuring the reliability of the piezoelectric resonant pressure sensor.

[0030] In the piezoelectric resonant pressure sensor provided by the above example, along the direction from the resonant film to the pressure sensitive component, the projection of at least part of the resonant cavity falls within the projection range of the pressure sensitive cavity.

[0031] In this example, a pressure-sensitive film is formed where the pressure-sensitive component defines the pressure cavity, and at least a portion of the pressure-sensitive film encloses the resonant cavity, allowing the resonant cavity and the pressure cavity to at least partially overlap. This reduces the volume of the resonant piezoelectric sensor, facilitating the miniaturization and integration of the piezoelectric resonant pressure sensor.

[0032] Based on the piezoelectric resonant pressure sensor provided in the above example, the piezoelectric resonant pressure sensor may further include a cover, which is provided on a side of the piezoelectric component away from the resonant film, and is directly or indirectly connected to the piezoelectric component.

[0033] In a vacuum environment, a cover can be used to encapsulate a piezoelectric resonant pressure sensor. The cover can be placed on the side of the piezoelectric component facing away from the resonant component to isolate the piezoelectric component from the atmosphere, ensuring that the piezoelectric component operates in a vacuum environment. This improves the quality factor of the piezoelectric resonant pressure sensor and ensures its performance.

[0034] The second 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.

[0035] According to the compensation system provided in the example of this 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

[0036] Figure 1 A schematic structural diagram of a piezoelectric resonant pressure sensor provided as an example in this application.

[0037] Figure 2 This is an electrode arrangement diagram of a piezoelectric resonant pressure sensor provided as an example in this application.

[0038] Figure 3 for Figure 2 Cross-sectional view along AA.

[0039] Figure 4 A schematic structural diagram of a piezoelectric resonant pressure sensor provided as an example in this application.

[0040] Figure 5 A top view of a piezoelectric resonant pressure sensor provided as an example of this application.

[0041] Figure 6 for Figure 5 Cross-sectional view along BB.

[0042] Figure 7 for Figure 5 Cross-sectional view along CC.

[0043] Figure 8This is an electrode arrangement diagram of a piezoelectric resonant pressure sensor provided as an example in this application.

[0044] Figure 9 for Figure 8 Cross-sectional view of DD.

[0045] Figure 10 A schematic diagram of the working principle of a piezoelectric resonant pressure sensor provided as an example in this application.

[0046] Figure 11 A schematic structural diagram of a piezoelectric resonant pressure sensor provided as an example in this application.

[0047] Figure 12 A schematic structural diagram of a piezoelectric resonant pressure sensor provided as an example in this application.

[0048] Figure 13 A schematic flow chart of a method for preparing a piezoelectric resonant pressure sensor provided as an example in this application.

[0049] Figure 14 A schematic diagram of the structure of an unprocessed Si wafer provided as an example in this application.

[0050] Figure 15 A schematic structural diagram of a Si wafer processing ring groove provided as an example in this application.

[0051] Figure 16 A schematic diagram of the structure of an unprocessed SOI wafer provided as an example in this application.

[0052] Figure 17 A method based on Figure 15 Schematic diagram of the structure of the connection between Si wafer and SOI wafer.

[0053] Figure 18 Based on Figure 17 Schematic diagram of the structure after removing the first substrate layer and the first buried oxide layer.

[0054] Figure 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 this application.

[0055] Figure 20 A method based on Figure 19 Schematic diagram of the structure of the piezoelectric component after processing.

[0056] Figure 21 A method based on Figure 20 Schematic diagram of the structure of providing a protective layer on the piezoelectric component away from the device layer.

[0057] Figure 22A method based on Figure 21 Schematic diagram of the structure of processing the second connecting hole from the protective layer.

[0058] Figure 23 A method based on Figure 21 or Figure 22 Schematic diagram of the structure of processing the first connecting hole from the protective layer.

[0059] Figure 24 A method based on Figure 23 Schematic diagram of the structure of depositing the lead electrode layer on the side of the protection layer away from the device layer.

[0060] Figure 25 A method based on Figure 24 Schematic diagram of the structure of processing lead electrodes on the lead electrode layer.

[0061] Figure 26 A method based on Figure 25 Schematic diagram of the structure of processing the pressure chamber on the side of the Si wafer away from the device layer.

[0062] Figure 27 A method based on Figure 26 Schematic diagram of the structure of machining deformation groove from the protective layer.

[0063] Figure 28 A schematic diagram of the structure of a glass wafer provided as an example in this application.

[0064] Figure 29 A schematic diagram of the structure of processing a Ge layer on a glass wafer provided as an example of this application.

[0065] Figure 30 A method based on Figure 29 Schematic diagram of the structure for processing the second connecting piece.

[0066] Figure 31 A schematic diagram of a structure for processing a cavity on a glass wafer to form a cover is provided as an example of this application.

[0067] Figure 32 A schematic diagram of a structure in which an adsorption structure is provided inside a cover provided as an example in this application.

[0068] Figure 33 A schematic diagram of a structure in which a cover is connected to the side of the protective layer facing away from the piezoelectric layer, provided as an example of this application.

[0069] Figure 34 A schematic flow chart of another method for preparing a piezoelectric resonant pressure sensor provided as an example in this application.

[0070] Figure 35 A schematic diagram of the structure of a compensation system provided as an example in this application.

[0071] Figure 36 A schematic diagram of the workflow of a compensation system provided as an example in this application.

[0072] Description of reference numerals:

[0073] 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. Support; 130. Connecting component; 131. First connecting structure; 132. Second connecting structure; 1321. Sub-connecting 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. Ring 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

[0074] To make the purpose, technical solutions, and advantages of the examples of this application more clear, the technical solutions in the examples of this application will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the examples described are only 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 making any creative efforts are within the scope of protection of this application.

[0075] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein in the specification of the application are only for the purpose of describing specific examples and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification, claims and drawings of this application are intended to cover non-exclusive inclusions.

[0076] References to "examples" herein mean that a particular feature, structure, or characteristic described in connection with the examples may be included in at least one example of the present application. The appearance of the phrase "example" in various places in the specification does not necessarily refer to the same example, nor does it constitute an independent or alternative example that is mutually exclusive of other examples. It is understood, both explicitly and implicitly, by those skilled in the art that the examples described herein may be combined with other examples.

[0077] The term "and / or" in this document simply describes a relationship between related objects, indicating that three possible relationships exist. For example, "A and / or B" can mean: A exists, A and B exist, and B exists. Additionally, the character " / " in this document generally indicates that the related objects are in an "or" relationship.

[0078] The directional words appearing in the following description refer to the directions shown in the drawings and do not limit the specific structure of the piezoelectric resonant pressure sensor of the present application.

[0079] In addition, the terms "first", "second", etc. in the description 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 such features.

[0080] In the description of this application, unless otherwise specified, "plurality" means more than two (including two), and similarly, "multiple groups" means more than two (including two).

[0081] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, 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 connection or snap connection; the physical connection may also be an integral connection, such as a connection formed by welding, bonding, or integral molding. For those skilled in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0082] Based on the above, the present application example provides a piezoelectric resonant pressure sensor and compensation system.

[0083] The piezoelectric resonant pressure sensor mentioned in the examples 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.

[0084] 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.

[0085] In order to enable people skilled in the art to better understand the present application, the piezoelectric resonant pressure sensor and compensation system provided in the example of the present application will be clearly and completely described below in conjunction with the accompanying drawings.

[0086] Illustratively, the present application provides a piezoelectric resonant pressure sensor. Figure 1 This is a schematic diagram of the structure of a piezoelectric resonant pressure sensor provided as an example in this application. Figure 2 This is an electrode arrangement diagram of a piezoelectric resonant pressure sensor provided as an example in this application. Figure 3 for Figure 2 Cross-sectional view along AA.

[0087] Please refer to Figures 1 to 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 facing away from the piezoelectric component 110. 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 facing away from the resonant film 120. A pressure chamber 141 is provided on the side of the pressure-sensitive component 140 facing away from the connecting component 130. The pressure chamber 141 is used to receive the pressure to be detected.

[0088] Among them, the connecting component 130 includes a first connecting structure 131 and a second connecting structure 132 arranged at intervals, 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.

[0089] 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, the resonant film 120 and the connecting component 130 cooperate to form a resonant cavity 135. Therefore, 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.

[0090] Next, the structure of the piezoelectric resonant pressure sensor 100 is described in detail.

[0091] 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 the film in the pressure sensitive component 140 that mainly receives the pressure to be detected.

[0092] If the pressure-sensitive component 140 includes only a pressure-sensitive film, the pressure chamber 141 may be the space where the pressure-sensitive film faces away from the resonant component. If the pressure-sensitive component 140 includes a pressure-sensitive film and other structures connected to the pressure-sensitive film, the pressure chamber 141 may also be the space formed by the pressure-sensitive film and other structures connected to the pressure-sensitive film. This example does not impose any specific limitations on this.

[0093] 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 a fluid, and the fluid may be a liquid, a gas, or the like.

[0094] The connecting assembly 130 can be directly or indirectly connected to the side of the pressure-sensitive assembly 140 facing away from the pressure chamber 141. A resonant film 120 is provided on the side of the connecting assembly 130 facing away from the pressure-sensitive assembly 140. The resonant film 120 and the connecting structure cooperate to form a resonant cavity 135. A piezoelectric assembly 110 is provided on the side of the resonant film 120 facing away from the connecting assembly 130. The pressure to be detected acting on the pressure-sensitive assembly 140 can be transmitted to the piezoelectric assembly 110 via the connecting assembly 130 and the resonant film 120, and the piezoelectric assembly 110 can then detect the pressure to be detected.

[0095] The connecting component 130 may be directly connected to the resonant film 120 , or the connecting component 130 may be indirectly connected to the resonant film 120 via other connecting structures, which is not specifically limited in this example of the present application.

[0096] 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.

[0097] There may be one pressure chamber 141 or multiple pressure chambers 141 spaced apart. There may also be only one resonant cavity 135 or multiple resonant cavities 135 , which is not limited in this example.

[0098] Along the direction of 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.

[0099] Exemplarily, the piezoelectric component 110 may include a piezoelectric layer 112 and electrodes. The piezoelectric layer 112 may be made of a piezoelectric thin film material such as AlN, ScAlN, lead zirconate titanate, ZnO, or LiNbO3. Due to the piezoelectricity of the piezoelectric thin film material, when the piezoelectric layer 112 receives pressure, charges are generated on the two opposite sides of the piezoelectric layer 112, thereby forming an electric potential difference, which is known as the positive piezoelectric effect. Similarly, when the piezoelectric layer 112 is driven by a voltage, it deforms, which is known as the inverse piezoelectric effect. The positive and inverse piezoelectric effects of the piezoelectric layer 112 are used to determine the relevant parameters of the pressure to be detected.

[0100] 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 detailed description can be found below.

[0101] The electrodes can be directly electrically connected to an external circuit, or indirectly connected to an external circuit via conductive members such as wires.

[0102] The external circuit can be a circuit for detecting current or voltage. This application example 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.

[0103] The connecting assembly 130 may include a first connecting structure 131 and a second connecting structure 132 that are spaced apart.

[0104] There may be one or more first connection structures 131. The connection position between the first connection structure 131 and the resonant film 120 may be close to the outer wall of the resonant film 120. The outer wall of the first connection structure 131 may be flush with the outer wall of the resonant film 120, or a certain distance may be provided between the outer wall of the first connection structure 131 and the outer wall of the resonant film 120.

[0105] The second connection structure 132 may be cylindrical, prismatic, or other columnar structures. There may be one or more second connection structures 132. This application example does not limit the specific implementation of the first connection structure 131 and the second connection structure 132.

[0106] One end of the second connecting structure 132 can be connected to the middle of the resonant film 120. The middle of the resonant film 120 can refer to an area near the center line of the resonant film 120 along the direction from the resonant film 120 to the connecting component 130, and spaced apart from the position where the first connecting structure 131 is connected to the resonant film 120.

[0107] Because 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. Because 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 piezoelectric component 110 to vibrate, reducing the possibility of damage to the piezoelectric component 110 due to deformation caused by vibration.

[0108] 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 multiple resonators 150 spaced apart. The piezoelectric component 110 in the resonator 150 can detect the pressure to be detected.

[0109] Based on the above, according to the piezoelectric resonant pressure sensor 100 provided by the example of this 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 based on the characteristics of the piezoelectric component 110.

[0110] Because the piezoelectric component 110 is disposed on the side of the resonant film 120 facing away from the connecting component 130, and the pressure-sensitive component 140 is disposed on the side of the connecting component 130 facing away from the resonant film 120, the piezoelectric component 110 is separated from the pressure chamber 141 that receives the pressure to be detected. Furthermore, 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 provides space for the piezoelectric component 110 to deform, reducing the possibility of damage to the piezoelectric component 110 caused by large deformation due to vibration.

[0111] 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 scope of application 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.

[0112] 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 spaced apart. 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. Under the action of the pressure to be detected, the second connecting structure 132 can move in a direction away from the pressure sensitive component 140, 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.

[0113] Based on the piezoelectric resonant pressure sensor 100 provided in the above example, along the direction from the resonant film 120 to the connecting assembly 130 , the center line of the second connecting structure 132 is collinear with the center line of the resonant film 120 .

[0114] 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. It can be understood that one end of the second connecting structure 132 is connected to the center of the resonant film 120, and the other end of the second connecting structure 132 can be connected to the center of the pressure-sensitive film.

[0115] In the example of the present application, the center line of the second connecting structure 132 is collinear with the center line of the resonant film 120. Based on this, under the action of the pressure to be detected, the second connecting structure 132 can move in a direction away from the pressure sensitive component 140, that is, in a direction toward the piezoelectric component 110. Since the center line of the second connecting structure 132 is collinear with the center line of the resonant film 120 along the direction from the resonant film 120 to the connecting component 130, the deformation of the resonant film 120 caused by the second connecting structure 132 is relatively uniform, so that the stress transmitted to the piezoelectric component 110 by the pressure to be detected is relatively uniform, reducing the possibility of partial damage of the piezoelectric component 110 due to uneven force, 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.

[0116] Based on the piezoelectric resonant pressure sensor 100 provided in the above example, Figure 4 This is a schematic diagram of the structure of a piezoelectric resonant pressure sensor provided as an example in this application. Figure 5 A top view of a piezoelectric resonant pressure sensor provided as an example in this application. Figure 6 for Figure 5 Cross-sectional view along BB, Figure 7 for Figure 5 Cross-sectional view along CC, Figure 8 This is an electrode arrangement diagram of a piezoelectric resonant pressure sensor provided as an example in this application. Figure 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 connecting structure 132 .

[0117] The location of the deformation groove 133 may correspond to the location of the second connection structure 132 .

[0118] For example, the deformation groove 133 may penetrate the piezoelectric component 110 and the resonant film 120 and extend to the second connection structure 132. The bottom of the deformation groove 133 may be located in the middle of the second connection structure 132 or on a side of the second connection structure 132 close to the pressure sensitive component 140, and this example is not specifically limited to this.

[0119] 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 a direction from the resonance film 120 toward the connection assembly 130 .

[0120] Along the direction from the resonant film 120 to the connecting component 130 , the projection of the deformation groove 133 may be a regular shape such as a circle, an ellipse, a polygon, etc. The projection of the deformation groove 133 may also be an irregular shape, which is not specifically limited in this example of the present application.

[0121] The second connection structure 132 can connect the resonant film 120 directly or indirectly to one side of the pressure sensitive film. Figure 10 The working principle diagram of a piezoelectric resonant pressure sensor provided for this application example is shown in FIG. Figure 10 , the second connection structure 132 can change the direction of action of the pressure to be detected.

[0122] For example, 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 whose action direction has an angle with the action direction of the pressure to be detected.

[0123] Based on the above, since the opening of the deformation groove 133 is located on the side of the piezoelectric component 110 facing away from the resonant film 120, the bottom of the deformation groove 133 is located on the second connecting structure 132, and one end of the second connecting structure 132 is connected to the middle of the resonant film 120, the provision of the deformation groove 133 can create a gap in the middle of the resonant film 120 and the piezoelectric component 110, reducing the cross-sectional area of the resonant film 120 and the piezoelectric component 110. This makes it easier for the pressure-sensitive film and the piezoelectric component 110 to deform under the action of the pressure to be detected, further improving the detection sensitivity of the piezoelectric resonant pressure sensor 100 and improving the detection accuracy of the piezoelectric resonant pressure sensor 100.

[0124] 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, further reducing the possibility of damage to the piezoelectric component 110, improving the pressure-bearing capacity of the resonant film 120, expanding the detection range of the piezoelectric resonant pressure sensor 100, and ensuring the linearity of the piezoelectric resonant pressure sensor 100 within the pressure detection range.

[0125] Based on the piezoelectric resonant pressure sensor 100 provided in the above example, Figure 11 The working principle diagram of a piezoelectric resonant pressure sensor provided in this application example is shown in FIG. Figure 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 spaced sub-connection structures 1321. A second groove 134 is formed between two adjacent sub-connection structures 1321. The second groove 134 connects the deformation groove 133 and the first groove.

[0126] 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 .

[0127] The projection of the first groove along the direction from the resonant film 120 toward the connecting assembly 130 can be a circular ring structure, a square ring structure, or another ring structure. Alternatively, the first groove can include multiple spaced-apart sub-grooves, which can cooperate to form a ring structure. This example of the present application does not impose any specific restrictions on the implementation of the first sub-grooves.

[0128] The opening of the first groove may be located on a side of the second connection structure 132 facing the resonant film 120 , or may be located on a side of the piezoelectric component 110 facing away from the resonant film 120 .

[0129] 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 can be the same, or the specifications and shapes of the plurality of sub-connection structures 1321 can be different, or some of the plurality of sub-connection structures 1321 can have the same size specifications.

[0130] The number of the resonators 150 may be equal to the number of the sub-connection structures 1321 , and the resonators 150 and the sub-connection structures 1321 may correspond one to one.

[0131] 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 intersect at one intersection. The example of this application does not limit the specific setting of the sub-connection structure 1321.

[0132] The shapes and specifications of different second grooves 134 can be the same, or they can be different. This example of the present application does not impose any specific limitation on this.

[0133] The opening of the second groove 134 may be located on a side of the second connection structure 132 facing the resonant film 120 , or may be located on a side of the piezoelectric component 110 facing away from the resonant film 120 .

[0134] 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.

[0135] In addition, a first groove is formed between the first connecting structure 131 and the second connecting structure 132, which are spaced apart. The second connecting structure 132 includes a plurality of spaced-apart sub-connecting structures 1321. A second groove 134 is formed between two adjacent sub-connecting structures 1321. The second groove 134 connects the deformation groove 133 and the first groove. When the sub-connecting structure 1321 deforms, the resonant film 120 and the piezoelectric component 110 that cooperate with the sub-connecting structure 1321 also deform. The second groove 134, the first groove, and the deformation groove 133 all provide deformation space for the sub-connecting structure 1321, the resonant film 120 that cooperates with the sub-connecting structure 1321, and the piezoelectric component 110 to deform. This reduces the possibility of damage to the piezoelectric component 110 and the resonant film 120 due to large deformation, expands the measurement range of the piezoelectric resonant pressure sensor 100, and expands the scope of application of the piezoelectric resonant pressure sensor 100.

[0136] Based on the piezoelectric resonant pressure sensor 100 provided in the above example, the plurality of sub-connection structures 1321 are evenly arranged.

[0137] When the plurality of sub-connection structures 1321 are arranged crosswise, the center lines of the plurality of sub-connection structures 1321 may intersect at one point, and the uniform arrangement of the plurality of sub-connection structures 1321 may mean that the angles between two adjacent sub-connection structures 1321 are equal.

[0138] 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 this example of the application does not specifically limit the arrangement of the sub-connection structures 1321.

[0139] In the example of the present application, by arranging multiple sub-connection structures 1321 in a uniform arrangement, 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.

[0140] 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.

[0141] The anchor point is the main force bearing point of the connecting component 130.

[0142] By setting the first distance 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, with the first distance representing the first lever arm and the second distance representing the second lever arm. Based on the principle of leverage, 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.

[0143] Based on the piezoelectric resonant pressure sensor 100 provided in the above example, please refer to Figure 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 that faces away from the connecting component 130, the piezoelectric layer 112 is connected to a side of the second electrode 113 that faces away from the resonant film 120, a portion of the second lead electrode 115 is disposed on a side of the piezoelectric layer 112 that faces 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.

[0144] 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 .

[0145] The second electrode 113 can be disposed on a side of the resonant component facing away from the pressure-sensitive component 140. The side of the second electrode 113 facing the resonant component can be directly or indirectly connected to the resonant component. The piezoelectric layer 112 can be disposed on a side of the second electrode 113 facing away from the resonant component. The side of the piezoelectric layer 112 facing the second electrode 113 can be connected to the second electrode 113. The first electrode 111 can be disposed on a side of the piezoelectric layer 112 facing away from the second electrode 113. The side of the piezoelectric layer 112 facing the first electrode 111 can be connected to the first electrode 111.

[0146] 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 can be connected to the first electrode 111 , and the other end of the first lead electrode 114 can be connected to a first portion of an external circuit.

[0147] 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 can be connected to the second electrode 113 , and the other end of the second lead electrode 115 can be connected to a second portion of the external circuit.

[0148] The first electrode 111, the second electrode 113, the first lead electrode 114, and the second lead electrode 115 can all be made of a conductive material, such as molybdenum, aluminum, copper, or gold. The number of first lead electrodes 114 can correspond to the number of first electrodes 111. There can be at least one second lead electrode 115, or there can be multiple second lead electrodes 115. The multiple second lead electrodes 115 can be connected to different positions of the second electrode 113.

[0149] 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, prismatic, or any other regular shape, or may be an irregular shape.

[0150] 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 used as an example for description.

[0151] 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 being connected to the first electrode 111, and one end of the second connection portion being 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. This example of the present 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.

[0152] The second electrode 113 may be a conductive layer provided on the side of the resonant film 120 away from the resonant cavity 135 , and only one second electrode 113 may be provided. The second electrode 113 may be used to achieve grounding of the piezoelectric resonant pressure sensor 100 .

[0153] A piezoelectric layer 112 may be provided on a side of the second electrode 113 facing away from the resonant component. The piezoelectric layer 112 may be made of a piezoelectric film material.

[0154] The first electrode 111 can be disposed on a side of the piezoelectric layer 112 facing away from the second electrode 113. At least two first electrodes 111 can be provided. The first electrode 111 can 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.

[0155] The external circuit may be a detection circuit for detecting the electrical signal output by the piezoelectric resonant pressure sensor 100 .

[0156] Next, the principle of the piezoelectric resonant pressure sensor 100 is further introduced in conjunction with the specific structure of the piezoelectric component 110 .

[0157] The resonant 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.

[0158] When any of the first electrodes 111 receives a voltage, stress is generated in the piezoelectric layer 112 due to the inverse piezoelectric effect. At this time, since the neutral layer of the piezoelectric layer 112 deviates from the geometric center of the piezoelectric layer 112, the piezoelectric layer 112 deforms, and the deformation of the piezoelectric layer 112 causes the entire resonator 150 to deform.

[0159] When an alternating voltage having the same resonant frequency as the resonator 150 is applied to any one of the first electrodes 111, the entire structure will resonate. At this time, the resonant frequency is:

[0160]

[0161] Where, f r is the resonant frequency, μ n These are the constants set when solving the Bessel function, t is the thickness, r is the radius, E is the Young's modulus, ρ is the density, and δ is the Poisson's ratio.

[0162] When pressure chamber 141 receives the pressure to be detected, the pressure-sensitive film deforms and generates operating stress under the influence of the pressure. The connecting structure can transmit the deformation and operating stress of the pressure-sensitive film to resonator 150, specifically to piezoelectric layer 112. During this transmission process, the connecting structure can change the direction of the pressure to be detected, reducing the possibility of damage to resonant film 120. The anchor point can amplify the operating stress by leveraging the principle of leverage, thereby increasing the measurement range of piezoelectric resonant pressure sensor 100.

[0163] Because the resonator 150 has 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 that receives voltage may be a driving electrode, and the first electrode 111 that detects vibration may be a detecting electrode.

[0164] 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 .

[0165] 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:

[0166]

[0167] 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.

[0168] When the piezoelectric layer 112 deforms, the portion of the piezoelectric layer 112 near the resonant component is compressed by the pressure to be detected, while the portion of the piezoelectric layer 112 away from the resonant component is stretched by the pressure to be detected. In the cross section of the piezoelectric layer 112, the transition layer between the stretched and squeezed portions of the piezoelectric layer 112, which is neither tensile nor compressive and has almost zero stress, is the aforementioned neutral layer.

[0169] Compared with the resistance detection type piezoelectric sensor that requires a Wheatstone bridge and the capacitance detection type pressure sensor that requires a capacitance bridge, the piezoelectric resonant pressure sensor 100 provided in the example of this application does not require an additional detection circuit, has a simpler structure, and has a lower manufacturing cost.

[0170] Based on the piezoelectric resonant pressure sensor 100 provided in the above example, please refer to Figure 9 The first lead electrode 114 and the second lead electrode 115 are disposed on a side of the piezoelectric layer 112 facing away from the first connection structure 131. At least a portion of the resonant film 120 may be a carrier 121. The first electrode 111 and at least a portion 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.

[0171] 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 .

[0172] 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.

[0173] 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.

[0174] The carrier 121 can be integrally formed with the resonant film 120. In this 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 this case, the carrier 121 can be a structure independent of the resonant film 120.

[0175] There can be only one supporting member 121, or a plurality of supporting members 121 can be provided at intervals. The plurality of supporting members 121 can be arranged in a cross shape, a 'M' shape, a straight shape or other irregular shapes.

[0176] 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.

[0177] In the example of the present application, the carrier 121 can provide a mounting support for at least a portion of the first electrode 111, the second electrode 113, and the piezoelectric layer 112. Because the first lead electrode 114 and the second lead electrode 115 are disposed on the first connection structure 131, and the first end of the carrier 121 is connected to the first connection structure 131, the provision of the carrier 121 facilitates the connection between the first electrode 111 and the first lead electrode 114, as well as the connection between the second electrode 113 and the second lead electrode 115. Furthermore, by adjusting the position of the first lead electrode 114, the reliability of the connection between the first lead electrode 114 and the first electrode 111 can be ensured.

[0178] Since the first end of the supporting member 121 is connected to the first connecting structure 131, the second end of the supporting member 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 supporting member 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.

[0179] Because a first groove is formed between the first connecting structure 131 and the second connecting structure 132, and the second connecting structure 132 is connected to the middle portion of the resonant film 120, the vibration amplitude of the second connecting structure 132 is greater than that of the first connecting structure 131. Because the first lead electrode 114 and the second lead electrode 115 are located on one side of the first connecting structure 131, the deformation amplitude of the first lead electrode 114 and the second lead electrode 115 in response to the pressure to be detected is smaller. This can reduce the impact 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.

[0180] 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.

[0181] There are many ways to ensure that the projection of at least a portion of the resonant cavity 135 falls within the projection range of the pressure cavity 141 along the direction from the resonant film 120 to the pressure sensitive component 140 .

[0182] For example, the projection of the resonant 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 resonant cavity 135 can overlap with the geometric center of the projection of the pressure cavity 141, and the geometric center of the resonant cavity 135 can be spaced apart from the geometric center of the pressure cavity 141.

[0183] For example, the projection of part of the resonant cavity 135 may fall within the projection range of the pressure cavity 141 , that is, the projection of the resonant cavity 135 partially overlaps with the projection of the pressure cavity 141 .

[0184] The shape of the pressure chamber 141 can be the same as that of the resonant cavity 135, or it can be different from that of the resonant cavity 135. This application example only uses the pressure chamber 141 as an example for description. For example, the shape of the pressure chamber 141 can be cylindrical, prismatic, or irregular.

[0185] In the example of the present application, a pressure-sensitive film is formed where the pressure-sensitive component 140 defines the pressure chamber 141, and at least a portion of the pressure-sensitive film seals the resonant cavity 135, so that the resonant cavity 135 and the pressure chamber 141 at least partially overlap. This reduces the volume of the resonant piezoelectric sensor, facilitating miniaturization and integration of the piezoelectric resonant pressure sensor 100.

[0186] 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 , specifically between the second electrode 113 and the resonant film 120 .

[0187] 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 .

[0188] 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 .

[0189] In 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.

[0190] 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 .

[0191] The oxide layer 160 can ensure the insulation between the pressure sensitive component 140 and the resonant component, reduce the possibility of leakage of the piezoelectric resonant pressure sensor 100, and ensure the safety of the piezoelectric resonant pressure sensor 100.

[0192] Based on the piezoelectric resonant pressure sensor 100 provided in the above example, Figure 12 For a schematic diagram of the structure of a piezoelectric resonant pressure sensor provided as an example in this application, please refer to Figure 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 .

[0193] 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.

[0194] In a vacuum environment, the cover 190 can be used to encapsulate the piezoelectric resonant pressure sensor 100. The cover 190 can be placed on the side of the piezoelectric component 110 facing away from the resonant component to isolate the piezoelectric component 110 from the atmospheric environment, ensuring that the piezoelectric component 110 operates in a vacuum environment. This improves the value corresponding to the quality factor of the piezoelectric resonant pressure sensor 100 and ensures the operating performance of the piezoelectric resonant pressure sensor 100.

[0195] In this example, the cover 190 may be bonded to the side of the piezoelectric component 110 facing away from the resonant film 120 , and the cover 190 may close the opening of the deformation groove 133 , the opening of the first groove, and the opening of the second groove 134 .

[0196] The bonding method can be anodic bonding, or metal bonding such as Al-Ge, Au-Au, or other bonding methods.

[0197] 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.

[0198] 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.

[0199] 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.

[0200] For example, 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. Absolute pressure sensors measure absolute pressure and can convert the absolute pressure of a gas or liquid into an equivalent electrical signal for output.

[0201] For example, the piezoelectric resonant pressure sensor 100 can be a relative pressure sensor. In this case, the cover 190 can be bonded to the side of the piezoelectric component 110 facing away from the resonant film 120 under a certain pressure environment. A relative pressure sensor measures pressure based on the intracavity pressure. The measurement result of a relative pressure sensor is relative to the intracavity pressure, so a relative pressure sensor can be used to measure relative pressure differences.

[0202] Users can select a suitable absolute pressure sensor or relative pressure sensor according to their needs. This application example does not limit whether a medium is injected into the cavity of the piezoelectric resonant pressure sensor 100.

[0203] 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 or other moisture-proof materials.

[0204] The protective layer 180 can isolate the piezoelectric component 110 from the atmospheric environment and provide a moisture-proof function, thereby keeping the piezoelectric resonant pressure sensor 100 as dry as possible and ensuring the operational reliability of the piezoelectric resonant pressure sensor 100. The protective layer 180 can also provide temperature compensation during the operation of the piezoelectric resonant pressure sensor 100.

[0205] 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. This application example does not impose any restrictions on this.

[0206] Illustratively, the present application 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.

[0207] In the example of this application, the piezoelectric resonant pressure sensor 100 can be fabricated from multiple 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. This example of the application only uses the piezoelectric resonant pressure sensor 100 fabricated from an SOI wafer 300 and a Si wafer 200 as an example for illustration.

[0208] Figure 13 For a flow chart of a piezoelectric resonant pressure sensor preparation method provided in this application example, please refer to Figure 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:

[0209] S110, take Si wafer 200, process an annular groove 210 on one side of Si wafer 200, form a first connecting structure 131 outside the annular groove 210 and a second connecting structure 132 inside the annular groove 210, and the first connecting structure 131 and the second connecting structure 132 cooperate to form a resonant cavity 135. Figure 14 and Figure 1514 is a schematic structural diagram of an unprocessed Si wafer provided in an example of this application. Figure 15 A schematic structural diagram of a Si wafer processing ring groove provided as an example in this application.

[0210] The ring groove 210 can be formed on one side of the Si wafer 200 by etching, sputtering or other processing methods. The ring groove 210 can be a circular ring groove, a square ring groove or a ring groove 210 of other shapes. The specific shape of the ring groove 210 is not limited in this application example.

[0211] The protruding structure outside the annular groove 210 may be the first connecting structure 131 , and the protruding structure inside the annular groove 210 may be the second connecting structure 132 . A resonant cavity 135 is formed between the first connecting structure 131 and the second connecting structure 132 , that is, the annular groove 210 is the resonant cavity 135 .

[0212] 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.

[0213] 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 Figure 16 and Figure 17 16 is a schematic diagram of the structure of an unprocessed SOI wafer provided in an example of this application, Figure 17 A method based on Figure 15 Schematic diagram of the structure of the connection between Si wafer and SOI wafer.

[0214] By flipping the SOI wafer 300, the first device layer 310 can be oriented toward the Si wafer 200, facilitating bonding between the first device layer 310 and the Si wafer 200, so that the first device layer 310 seals the opening of the resonant cavity 135. The bonding method can be anodic bonding, fusion bonding, or other bonding methods.

[0215] 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 the thickness of the resonant film 120. Figure 18 , Figure 18 Based on Figure 17 Schematic diagram of the structure after removing the first substrate layer and the first buried oxide layer.

[0216] The first buried oxide layer 320 and the first substrate layer 330 can be removed by physical removal, chemical removal or other methods. The present application example does not impose any specific limitation on the removal method of the first buried oxide layer 320 and the first substrate layer 330.

[0217] In the example of the present application, the sum of the thicknesses of the first device layer 310 and the first buried oxide layer 320 can be set equal to the thickness of the resonant film 120, or the sum of the thicknesses 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 any specific restrictions on this.

[0218] S140 , disposing a piezoelectric component 110 on a side of the first device layer 310 facing away from the Si wafer 200 .

[0219] 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:

[0220] S141, sequentially deposit the second electrode layer, the piezoelectric layer 112 and the first electrode layer, see Figure 19 , Figure 19 This is a schematic diagram of a structure in which a piezoelectric component is deposited on the side of the first device layer facing away from the Si wafer, as provided in an example of this application.

[0221] S142, patterning the first electrode layer to form at least two first electrodes 111, please refer to Figure 20 , Figure 20 A method based on Figure 19 Schematic diagram of the structure of the piezoelectric component after processing.

[0222] In some possible implementations, after S142, the following steps may be further included:

[0223] S143, depositing a protective layer 180, please refer to Figure 21 , Figure 21 A method based on Figure 20 Schematic diagram of the structure in which a protective layer is provided on the piezoelectric component away from the first device layer.

[0224] Because the first electrode 111 has been patterned before depositing the protective layer 180 , which exposes part of the piezoelectric layer 112 , part of the protective layer 180 may contact the first electrode 111 , and another part of the protective layer 180 may contact the piezoelectric layer 112 .

[0225] S144, a second connection hole 1151 is processed at the position where the second electrode 113 is connected. The connector is passed through the second connection hole 1151 and can be connected to the second electrode 113. Please refer to Figure 22 , Figure 22 A method based on Figure 21 Schematic diagram of the structure of processing the second connecting hole from the protective layer.

[0226] The second connection hole 1151 can be processed to the side of the second electrode 113 away from the resonant component, and part of the hole wall of the second connection hole 1151 can also be set 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, this application example does not impose any specific restrictions on this.

[0227] S145, a first connection hole 1141 is processed at a position connected to the first electrode 111, and a conductive structure is provided through the first connection hole 1141 to be connected to the first electrode 111, please refer to Figure 23 , Figure 23 A method based on Figure 21 or Figure 22 Schematic diagram of the structure of processing the first connecting hole from the protective layer.

[0228] The first connection hole 1141 can be processed to the side of the first electrode 111 away from the resonant component, and part of the hole wall of the first connection hole 1141 can also be set 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, this application example does not impose any specific restrictions on this.

[0229] 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 may be performed first and then S113 . This example of the present application does not impose any specific limitation on this.

[0230] 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 Figure 24 , Figure 24 A method based on Figure 23 Schematic diagram of the structure of depositing a lead electrode layer on the side of the protective layer away from the first device layer.

[0231] 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 Figure 25 , Figure 25 A method based on Figure 24 Schematic diagram of the structure of processing lead electrodes on the lead electrode layer.

[0232] The side of the first lead electrode 114 closest to the first electrode 111 is connected to the first electrode 111, and the side of the first lead electrode 114 facing away from the first electrode 111 can be connected to a first portion of an external circuit. The side of the second lead electrode 115 closest to the second electrode 113 is connected to the second electrode 113, and the side of the second lead electrode 115 facing away from the second electrode 113 can be connected to a second portion of an external circuit. The second lead electrode 115 is the conductive structure described in the above example. This structure enables connection between the piezoelectric resonant pressure sensor 100 and an external circuit.

[0233] S150, processing the pressure cavity 141 on the side of the Si wafer 200 away from the first device layer 310, please refer to Figure 26 , Figure 26 A method based on Figure 25 Schematic diagram of the structure of processing a pressure chamber on the side of the Si wafer away from the first device layer.

[0234] 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.

[0235] In the piezoelectric resonant pressure sensor 100 manufactured using the above method, the pressure chamber 141 can receive the pressure to be detected. 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 based on the characteristics of the piezoelectric component 110.

[0236] Because the piezoelectric component 110 is disposed on the side of the resonant film 120 facing away from the connecting component 130, and the pressure-sensitive component 140 is disposed on the side of the connecting component 130 facing away from the resonant film 120, the piezoelectric component 110 is separated from the pressure chamber 141 that receives the pressure to be detected. Furthermore, 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 provides space for the piezoelectric component 110 to deform, reducing the possibility of damage to the piezoelectric component 110 caused by large deformation due to vibration.

[0237] 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 scope of application 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.

[0238] 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 spaced apart. 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. Under the action of the pressure to be detected, the second connecting structure 132 can move in a direction away from the pressure sensitive component 140, 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.

[0239] 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, further reducing the possibility of damage to the piezoelectric component 110, improving the pressure-bearing capacity of the resonant film 120, expanding the detection range of the piezoelectric resonant pressure sensor 100, and ensuring the linearity of the piezoelectric resonant pressure sensor 100 within the pressure detection range.

[0240] 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, step S147 may further include:

[0241] S148, processing the deformation groove 133 from the side of the protection layer 180 away from the first device layer 310, please refer to Figure 27 , Figure 27 A method based on Figure 26 Schematic diagram of the structure of machining deformation groove from the protective layer.

[0242] 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 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.

[0243] In some possible implementations, the piezoelectric resonant pressure sensor 100 includes a second groove 134. The second groove 134 is positioned corresponding to the second connection structure 132. 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 simultaneously, or process the second groove 134 after processing the deformation groove 133. This example of the present application does not impose any specific limitations on this.

[0244] The processing method of the second groove 134 is similar to that of the annular groove 210 , and will not be described in detail in this example.

[0245] The second groove 134 may be processed before or after the pressure chamber 141 is processed, and this example of the application does not impose any specific limitation on this.

[0246] In some possible implementations, the piezoelectric resonant pressure sensor 100 may further include a cover 190, which is bonded to the piezoelectric assembly 110. The bonding method may be anodic bonding, metal bonding such as Al-Ge or Au-Au, or other bonding methods. The following describes the bonding method between the cover 190 and the piezoelectric assembly 110, using Al-Ge bonding as an example.

[0247] Based on the above-mentioned method for manufacturing the piezoelectric resonant pressure sensor 100 , after patterning the lead electrode layer to form at least one first lead electrode 114 and at least one second lead electrode 115 in S147 , the method further includes:

[0248] S1471, in addition to forming at least one first lead electrode 114 and at least one second lead electrode 115 on the patterned electrode layer, a first connecting member 171 is also formed. Figure 26 , Figure 26 and Figure 25 The cross-sectional directions are different.

[0249] The first connecting member 171 can be roughly in the shape of a circular ring, a square ring or other structures. The first connecting member 171 can be a sealed ring structure. The first connecting member 171 can also be composed of multiple spaced segments. This application example does not impose specific restrictions on this.

[0250] S160 , taking a glass wafer 400 , and etching a cavity to form a cover 190 , which may specifically include:

[0251] S161, depositing a Ge layer on one side of the glass wafer 400, refer to Figure 28 and Figure 29 , Figure 28 A schematic diagram of the structure of a glass wafer provided as an example in this application, Figure 29 A schematic diagram of the structure of processing a Ge layer on a glass wafer provided as an example of this application.

[0252] S162, etching the Ge layer to form a second connecting member 172, please refer to Figure 30 , Figure 30 A method based on Figure 29 Schematic diagram of the structure for processing the second connecting piece.

[0253] The shape of the second connecting member 172 can be the same as or different from the shape of the first connecting member 171. This application example does not impose any specific restrictions 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.

[0254] S163, a cavity is formed by etching on the side of the glass wafer 400 where the second connector 172 is provided. The opening of the cavity is set toward the side of the glass wafer 400 where the second connector 172 is provided. Figure 31 , Figure 31 A schematic diagram of a structure for processing a cavity on a glass wafer to form a cover is provided as an example of this application.

[0255] In some possible implementations, the piezoelectric resonant pressure sensor 100 may further include an adsorption structure 191 .

[0256] Based on the above-mentioned method for manufacturing the piezoelectric resonant pressure sensor 100 , in S140 , after taking a glass wafer 400 and etching a cavity to form a cover 190 , the following steps may also be included:

[0257] S164, an adsorption structure 191 is provided on the cavity wall, please refer to Figure 32 , Figure 32 A schematic diagram of a structure in which an adsorption structure is provided inside a cover provided as an example in this application.

[0258] 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 impose any specific restrictions on this.

[0259] S170, bonding the cover 190 and the piezoelectric component 110, please refer to Figure 33 , Figure 33 A schematic diagram of a structure in which a cover is connected to the side of the protective layer facing away from the piezoelectric layer, provided as an example of this application.

[0260] The bonding connection between the cover 190 and the piezoelectric component 110 can be performed in a vacuum environment or in an environment with a certain pressure, and this example of the application does not impose any specific limitation on this.

[0261] For example, the present application provides a method for preparing a piezoelectric resonant pressure sensor 100. Figure 34 For a flow chart of another method for preparing a piezoelectric resonant pressure sensor provided as an example in this application, please refer to Figure 34 This 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.

[0262] In the example of the present application, the method is used to process a CSOI wafer into a piezoelectric resonant pressure sensor 100 , where the CSOI wafer includes a second device layer, a second buried oxide layer, and a second substrate layer.

[0263] Among them, the side of the second substrate layer facing the second buried oxide layer is provided with a first connection structure and a second connection structure spaced apart, 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 this application example, 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 Figure 18 The structure shown, Figure 18 The Si wafer 200 after the processing is equivalent to the second substrate layer in the example of this application. Figure 18 The oxide layer 160 in the embodiment of the present application is equivalent to the second buried oxide layer, and the first device layer 310 is equivalent to the second device layer in the embodiment of the present application. The method includes:

[0264] S210 , disposing a piezoelectric component 110 on a side of the second device layer away from the second buried oxide layer.

[0265] In the example of this 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 Figures 19 to 25 The structure shown.

[0266] S220 , processing a pressure cavity 141 on a side of the second substrate layer away from the second buried oxide layer.

[0267] In this example, 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 Figure 26 The structure shown.

[0268] The piezoelectric resonant pressure sensor 100 formed by the method provided in the example of this application is similar in structure to the piezoelectric resonant pressure sensor 100 formed by processing the Si wafer 200 and the SOI wafer 300, and plays a similar role, so this application will not describe it in detail.

[0269] By processing the piezoelectric resonant pressure sensor 100 according to the method provided in the example of this application, the processing of the first connecting structure and the second connecting structure can be reduced during the manufacturing process of the piezoelectric resonant pressure sensor 100, thereby reducing the processing steps of the piezoelectric resonant pressure sensor 100 and reducing the processing cost of the piezoelectric resonant pressure sensor 100.

[0270] 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 relevant description above. Figure 27 The structure shown in this application example will not be described in detail here.

[0271] The piezoelectric resonant pressure sensor 100 processed according to the method provided in the example of this 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 the Si wafer 200 and the SOI wafer 300. The examples of this application are not repeated here.

[0272] The piezoelectric resonant pressure sensor 100 processed according to the method provided in the example of this 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 relevant description above and Figures 28 to 33 The structure shown in this application example will not be described in detail here.

[0273] In this example, a suction structure 191 may also be provided in the cover 190. For details on the specific configuration of the suction structure 191 and the function of the suction structure 191, please refer to the above description.

[0274] 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.

[0275] During the testing 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 in turn affect the detection results of the piezoelectric resonant pressure sensor 100. Environmental factors may include temperature, vibration, shock, etc. Based on this, it is necessary to compensate the piezoelectric resonant pressure sensor 100.

[0276] Exemplarily, the present application provides a compensation system 500, Figure 35 For a structural diagram of a compensation system provided for this application example, please refer to Figure 35 The 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.

[0277] When only one pressure sensor 510 is provided, only one or more compensation sensors 520 may be provided.

[0278] 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.

[0279] Multiple compensation sensors 520 and detection sensors may be provided, and the number of compensation sensors 520 may be equal to or different from the number of detection sensors.

[0280] The pressure sensor 510 is used to detect the pressure to be detected, and the compensation sensor 520 is used to compensate for the effects 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. 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.

[0281] 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.

[0282] 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 for the pressure to be detected.

[0283] Figure 36 For a schematic diagram of the compensation system provided for this application example, please refer to Figure 36 , the working process of the compensation sensor 520 is as follows:

[0284] S310 , the driving component 530 is used to drive the pressure sensor 510 and the compensation sensor 520 .

[0285] S320 , the detection component 540 is configured 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 .

[0286] S330: The calculation module is configured to calculate a difference between the first resonant frequency and the second resonant frequency to obtain a target resonant frequency.

[0287] S340, the calculation module may also calculate the pressure value of the pressure to be detected based on the resonant frequency.

[0288] The calculation module can be a part of the detection component 540, or it can be a module independent of the detection component 540, and this application example does not limit this.

[0289] Based on the compensation system 500 described in the above example, during operation of the compensation system 500, the pressure to be detected can act on the pressure chamber 141 of the pressure sensor, while the pressure to be detected does not act on the compensation sensor 520. Therefore, the structure of the pressure sensor 510 and the structure of the compensation sensor 520 can be completely identical. The structures of the pressure sensor 510 and the compensation sensor 520 can also be different. For example, the compensation sensor 520 may not be provided with the pressure sensitive component 140. The examples of this application do not limit the specific structures of the pressure sensor 510 and the compensation sensor 520.

[0290] In summary, according to the compensation system 500 provided in the example of this 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, thereby eliminating the influence of environmental factors and improving the detection accuracy of the compensation system 500 for the pressure to be detected.

[0291] Finally, it should be noted that the above embodiments are merely specific implementations of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection 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 facing away from the piezoelectric component, wherein the connecting component cooperates with the resonant film to form a resonant cavity; a pressure sensitive component connected to a side of the connecting component away from the resonant film, wherein 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; In which, 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, wherein: Along a 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, wherein: The piezoelectric resonant pressure sensor is provided with a deformation groove, the notch of the deformation groove is provided on the side of the piezoelectric component away from the resonant film, and the bottom of the deformation groove is provided on the second connecting structure.

4. The piezoelectric resonant pressure sensor according to claim 3, wherein: 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, wherein: The plurality of sub-connection structures are evenly arranged.

6. The piezoelectric resonant pressure sensor according to claim 1, wherein: 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 facing away from the connecting component, the piezoelectric layer is connected to a side of the second electrode facing away from the resonant film, a portion of the second lead electrode is provided on a side of the piezoelectric layer facing away from the second electrode, and the second lead electrode is provided 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 provided on a side of the first electrode away from the piezoelectric layer. The first lead electrode is electrically connected to the first electrode.

7. The piezoelectric resonant pressure sensor according to claim 6, wherein: 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 provided 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. The piezoelectric resonant pressure sensor according to claim 1, wherein: Along the direction from the resonant film to the pressure sensitive component, at least a portion of the projection of the resonant cavity falls within the projection range of the pressure sensitive cavity.

9. The piezoelectric resonant pressure sensor according to claim 1, wherein: The device further comprises a cover, which is arranged on a side of the piezoelectric component away from the resonant film, and is directly or indirectly connected to the piezoelectric component.

10. A compensation system, characterized in that: The invention comprises an integrated driving component, a detection component and at least two piezoelectric resonant pressure sensors according to any one of claims 1 to 9, wherein the at least two piezoelectric resonant pressure sensors comprise at least one pressure sensor and at least one compensation sensor.

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