Differential piezoelectric resonant pressure sensor, compensation system and preparation method

Abstract

The invention provides a differential piezoelectric resonant pressure sensor, a compensation system and a preparation method, and relates to the technical field of sensitive element and sensor manufacturing. The differential piezoelectric resonant pressure sensor comprises a piezoelectric assembly, a resonant film and a pressure resonant assembly. The piezoelectric assembly and the resonant film are matched to form a resonant assembly, the resonant assembly comprises a first resonator, a second resonator, a first structure and a second structure, the first structure and the second structure are arranged at an interval, and compared with the first resonator, the second resonator is arranged close to the edge of the differential piezoelectric resonant pressure sensor; a first end of the first resonator is connected to a first position of the first structure, a second end of the first resonator is connected to a second position of the first structure, a first end of the second resonator is connected to the first structure, and a second end of the second resonator is connected to the second structure. According to the differential piezoelectric resonant pressure sensor provided by the embodiment of the invention, the detection sensitivity and the detection precision of the differential piezoelectric resonant pressure sensor can be improved.

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 differential piezoelectric resonant pressure sensor, a compensation system and a preparation method. Background Art

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

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

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

[0005] Based on the structure of the existing differential piezoelectric resonant pressure sensor, the pressure detection sensitivity of the differential piezoelectric resonant pressure sensor is low, which may affect the detection accuracy of the differential piezoelectric resonant pressure sensor. Summary of the invention

[0006] The present application provides a differential piezoelectric resonant pressure sensor, which can improve the detection sensitivity and detection accuracy of the differential piezoelectric resonant pressure sensor.

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

[0008] Among them, the piezoelectric component and the resonant film cooperate to form a resonant component, and the resonant component includes a first resonator, a second resonator, and a first structure and a second structure arranged at intervals. Compared with the first resonator, the second resonator is arranged close to the edge of the differential piezoelectric resonant pressure sensor, the first end of the first resonator is connected to the first position of the first structure, the second end of the first resonator is connected to the second position of the first structure, the second position is spaced apart from the first position, the first end of the second resonator is connected to the first structure, and the second end of the second resonator is connected to the second structure.

[0009] Based on the differential piezoelectric resonant pressure sensor provided in the above example, the pressure cavity can receive the pressure to be detected. Since the pressure cavity is arranged on the side of the pressure resonance component away from the resonance film, and the resonance film and the pressure resonance component cooperate to form a resonance cavity, the pressure to be detected can be transmitted to the resonance film through the pressure resonance component. Since the piezoelectric component is arranged on one side of the resonance film, the pressure to be detected transmitted to the resonance film can be transmitted to the piezoelectric component, and the piezoelectric component can detect the pressure to be detected.

[0010] Since the first resonator is located on the inner side of the first structure and the second resonator is located on the outer side of the first structure, after the first structure is deformed under the action of the pressure to be detected, the force applied to the first resonator by the first structure is opposite to the force applied to the second resonator, so that the frequency change of the first resonator is opposite to the frequency change of the second resonator. The first resonator and the second resonator cooperate to form a differential structure, so that the deformation of the resonant component under the action of the same pressure to be detected is more obvious, which can improve the detection sensitivity of the differential piezoelectric resonant pressure sensor and improve the detection accuracy of the differential piezoelectric resonant pressure sensor.

[0011] In some possible implementations, the differential piezoelectric resonant pressure sensor further includes a deformation segment, one end of the deformation segment is connected to the first resonator via the first structure, and the other end of the deformation segment is connected to the second structure.

[0012] During the use of the differential piezoelectric resonant sensor, the first structure may be deformed under the action of the pressure to be detected, and the deformation of the first structure may drive the first resonator to deform. Because the deformation segment is connected to the first structure, the deformation segment can be deformed under the drive of the first structure. Since the deformation capacity of the deformation segment is higher than the deformation capacity of the first resonator, the setting of the deformation segment has little effect on the deformation amplitude of the first structure, thereby ensuring the performance of the first resonator.

[0013] In addition, since the first resonator is located on the inner side of the first structure, and the first end of the first resonator is connected to the first position of the first structure, and the second end of the first resonator is connected to the second position of the first structure, it is inconvenient for the electrode in the piezoelectric component corresponding to the first resonator to be connected to an external circuit. In the example of the present application, by setting one end of the deformation segment to be connected to the first structure, and one end of the first resonator to be connected to the first structure, the deformation segment can be connected to the first resonator through the first structure. And since the other end of the deformation segment is connected to the second structure, the electrode in the piezoelectric component corresponding to the first resonator can be led out to the second structure through the first structure and the deformation segment, which facilitates the electrical connection between the first resonator and the external circuit.

[0014] In some possible implementations, a plurality of second resonators are provided, and positions where different second resonators are connected to the first structure are spaced apart, and positions where different second resonators are connected to the second structure are spaced apart.

[0015] Since there are multiple second resonators and the multiple second resonators are arranged at intervals, the pressure to be detected can be transmitted to different second resonators through the first structure, so that different second resonators can detect the pressure to be detected from different positions, thereby improving the detection accuracy of the pressure to be detected.

[0016] In some possible implementations, the differential piezoelectric resonant pressure sensor includes a first groove and a second groove that are spaced apart, the second groove is disposed on a side of the first groove close to an edge of the differential piezoelectric resonant pressure sensor, and the notch of the first groove and the notch of the second groove are both disposed on a side of the piezoelectric component away from the resonant film. The first structure is provided with a first groove, and the second groove divides the resonant component into a first structure and a second structure that are spaced apart. The first end of the first resonator is connected to the first position, and the second end of the first resonator is connected to the second position. The first end of the second resonator is connected to a side of the first structure away from the first groove, and the second end of the second resonator is connected to a side of the second structure close to the second groove.

[0017] By setting the first groove, the contact area between the first structure and the pressure sensitive film can be reduced, so that the first structure undergoes a larger deformation under the same pressure to be detected, thereby causing a larger deformation of the first resonator, thereby improving the detection sensitivity and detection accuracy of the differential piezoelectric resonant pressure sensor.

[0018] By setting the second groove, the first structure and the second structure can be spaced apart, and the contact surface area between the second structure and the pressure sensitive film can be reduced, so that the second structure can be deformed more under the same pressure to be detected, thereby making the deformation of the second resonator larger, further improving the detection sensitivity and detection accuracy of the differential piezoelectric resonant pressure sensor.

[0019] In some possible implementations, the first structure is provided with at least one third groove, and the third groove connects the first groove and the second groove.

[0020] In some possible implementations, the piezoelectric component includes a first lead electrode group, a second lead electrode group, a first electrode group, a piezoelectric layer, and a second electrode group. The second electrode group is connected to a side of the resonant film away from the pressure resonant component, the piezoelectric layer is connected to a side of the second electrode group away from the resonant film, part of the second lead electrode group is arranged on a side of the piezoelectric layer away from the second electrode group, and the second lead electrode group is arranged through the piezoelectric layer and is electrically connected to the second electrode group.

[0021] The first electrode group is connected to a side of the piezoelectric layer away from the second electrode group, the first lead electrode group is arranged on a side of the first electrode group away from the piezoelectric layer, and the first lead electrode group is electrically connected to the first electrode group.

[0022] In some possible implementations, part of the resonant film is the first carrier, and part of the resonant film is the second carrier, and the first carrier is spaced apart from the second carrier; the first lead electrode group includes a first sub-lead electrode and a second sub-lead electrode, the first electrode group includes a first sub-electrode and a second sub-electrode, the first sub-electrode is arranged on the first carrier, the first sub-lead electrode is electrically connected to the first sub-electrode, the second sub-electrode is arranged on the second carrier, and the second sub-lead electrode is electrically connected to the second sub-electrode.

[0023] The second lead electrode group includes a third sub-lead electrode and a fourth sub-lead electrode, the second electrode group includes a third sub-electrode and a fourth sub-electrode, the third sub-electrode is arranged on the first carrier, the third sub-lead electrode is electrically connected to the third sub-electrode, the fourth sub-electrode is arranged on the second carrier, and the fourth sub-lead electrode is electrically connected to the fourth sub-electrode.

[0024] The first sub-electrode, the first sub-lead electrode, the third electrode, the third sub-lead electrode and the corresponding piezoelectric layer can cooperate to form a first resonator, and the second sub-electrode, the second sub-lead electrode, the fourth electrode, the fourth sub-lead electrode and the corresponding piezoelectric layer can cooperate to form a second resonator. Therefore, the differential piezoelectric resonant pressure sensor provided according to the example of the present application can simultaneously use the first resonator and the second resonator to detect the pressure to be detected.

[0025] In addition, since the first resonator and the second resonator are connected to two opposite sides of the first structure, the first stress transmitted to the first resonator through the first structure is in opposite directions to the second stress transmitted to the second resonator, so that the detection frequencies of the first resonator and the second resonator are opposite, so that the frequency change detected by the differential piezoelectric resonant pressure sensor under the same pressure to be detected is more obvious, thereby improving the detection sensitivity and detection accuracy of the differential piezoelectric resonant pressure sensor.

[0026] The second aspect of the present application provides a method for preparing a differential piezoelectric resonant pressure sensor, which is applicable to any of the differential piezoelectric resonant pressure sensors mentioned in the above examples, and the method is used to process a Si wafer and an SOI wafer into a differential piezoelectric resonant pressure sensor, wherein the SOI wafer includes a first device layer, a first buried oxide layer, and a first substrate layer. The method includes:

[0027] A Si wafer is taken, and a first structure and a second structure are formed on one side of the Si wafer. The first structure and the second structure cooperate to form a resonant cavity.

[0028] Take the SOI wafer, bond the SOI wafer and the Si wafer together, and seal the cavity opening of the resonant cavity with the first device layer.

[0029] The first buried oxide layer and the first substrate layer are removed, and the thickness of the first device layer is set to be the thickness of the resonant film.

[0030] A piezoelectric component is arranged on the side of the first device layer facing away from the Si wafer.

[0031] A pressure chamber is processed on the side of the Si wafer facing away from the first substrate layer.

[0032] A first resonator, a second resonator, and a first structure and a second structure spaced apart are formed on a side of the piezoelectric component away from the first device layer.

[0033] Part of the resonant cavity is arranged in the first structure, and part of the resonant cavity is arranged between the first structure and the second structure. The first end of the first resonator is connected to the first position of the first structure, and the second end of the first resonator is connected to the second position of the first structure. The second position is spaced apart from the first position. The first end of the second resonator is connected to the first structure, and the second end of the second resonator is connected to the second structure.

[0034] The third aspect of the present application provides a method for preparing a differential piezoelectric resonant pressure sensor, which is applicable to the differential piezoelectric resonant pressure sensor mentioned in any of the above examples, wherein the CSOI wafer includes a second device layer, a second buried oxide layer, and a second substrate layer. A first structure and a second structure are arranged at intervals on the side of the second substrate layer facing the second buried oxide layer, and the end of the first structure is connected to the middle of the second buried oxide layer, and the first structure, the second structure, and the second buried oxide layer cooperate to form a resonant cavity. The method includes:

[0035] Take the CSOI wafer and process the piezoelectric component on the side of the second device layer away from the second buried oxide layer.

[0036] A pressure cavity is processed on a side of the second substrate layer away from the second buried oxide layer.

[0037] A first resonator and a second resonator are formed on a side of the piezoelectric component facing away from the second device layer. Compared with the first resonator, the second resonator is arranged closer to the edge of the differential piezoelectric resonant pressure sensor. The first end of the first resonator is connected to a first position of the first structure, and the second end of the first resonator is connected to a second position of the first structure. The second position is spaced apart from the first position, and the first end of the second resonator is connected to the first structure, and the second end of the second resonator is connected to the second structure.

[0038] The fourth aspect of the present application provides a compensation system, which includes an integrated driving component, a detection component and a differential piezoelectric resonant pressure sensor mentioned in any of the above examples, at least two differential piezoelectric resonant pressure sensors including at least one pressure sensor and at least one compensation sensor.

[0039] According to the compensation system provided in the example of the present application, when the detection component detects the resonant frequency of the pressure sensor and the compensation sensor, it only needs to subtract the resonant frequency output by the compensation sensor from the resonant frequency output by the pressure sensor and then extract the final resonant frequency, thereby eliminating the influence of environmental factors and improving the detection accuracy of the compensation system for the pressure to be detected. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 A schematic diagram of the structure of a differential piezoelectric resonant pressure sensor provided as an example in this application.

[0041] Figure 2 A top view of a differential piezoelectric resonant pressure sensor provided as an example of the present application.

[0042] Figure 3 for Figure 2 Section view along AA.

[0043] Figure 4 for Figure 2 Cross-sectional view along BB.

[0044] Figure 5 for Figure 2 Cross-sectional view along CC.

[0045] Figure 6 A schematic diagram of the working principle of a first resonator in a differential piezoelectric resonant pressure sensor provided as an example of the present application.

[0046] Figure 7 A schematic diagram of the working principle of the second resonator in a differential piezoelectric resonant pressure sensor provided as an example of the present application.

[0047] Figure 8 A schematic diagram of the structure of a differential piezoelectric resonant pressure sensor provided as an example in this application.

[0048] Fig. 9 A top view of a differential piezoelectric resonant pressure sensor provided as an example of the present application.

[0049] Fig.10 for Fig. 9 Cross-sectional view along DD.

[0050] Fig.11 A schematic diagram of the structure of a differential piezoelectric resonant pressure sensor provided as an example in this application.

[0051] Fig.12 A schematic flow chart of a method for preparing a differential piezoelectric resonant pressure sensor provided in an example of this application.

[0052] Fig.13 A schematic diagram of the structure of an unprocessed Si wafer provided as an example in this application.

[0053] Fig.14 A schematic diagram of the structure of a first structure and a second structure for Si wafer processing provided as an example in this application.

[0054] Fig.15 A schematic diagram of the structure of an unprocessed SOI wafer provided as an example in this application.

[0055] Fig.16 A method based on Fig.15 Schematic diagram of the structure of connecting Si wafer to SOI wafer.

[0056] Fig.17 Based on Fig.16 Schematic diagram of the structure after removing the first substrate layer and the first buried oxide layer.

[0057] Fig.18 A schematic diagram of a structure in which a piezoelectric component is deposited on the side of a first device layer facing away from a Si wafer is provided as an example of the present application.

[0058] Fig.19 A method based on Fig.18 Schematic diagram of the structure of the piezoelectric component after processing.

[0059] Fig. 20 A method based on Fig.19 Schematic diagram of the structure in which a protective layer is provided on the piezoelectric component away from the device layer.

[0060] Fig.21 A method based on Fig. 20 Schematic diagram of the structure of processing the second connecting hole from the protective layer.

[0061] Fig. 22 A method based on Fig. 20 or Fig.21 Schematic diagram of the structure of processing the first connecting hole from the protective layer.

[0062] Fig.23 A method based on Fig. 22 Schematic diagram of the structure of depositing a lead electrode layer on the side of the protection layer away from the device layer.

[0063] Fig.24 A method based on Fig.23 Schematic diagram of the structure of processing lead electrodes on the lead electrode layer.

[0064] Fig.25 A method based on Fig.24 Schematic diagram of the structure of processing a pressure chamber on the side of the Si wafer away from the first device layer.

[0065] Fig.26 A method based on Fig.25 Schematic diagram of the structure of processing the first resonator and the second resonator from the protective layer.

[0066] Fig. 27 A schematic diagram of the structure of a glass wafer provided as an example of this application.

[0067] Fig.28 A schematic diagram of a structure for processing a Ge layer on a glass wafer provided as an example of this application.

[0068] Fig.29 A method based on Fig.28 Structural schematic diagram of processing the second connecting piece.

[0069] Fig.30 A schematic diagram of a structure for machining a cavity on a glass wafer to form a cover is provided as an example of the present application.

[0070] Fig.31 A schematic diagram of a structure in which an adsorption structure is provided inside a cover provided as an example of the present application.

[0071] Fig.32 A schematic diagram of a structure in which a cover is connected to the side of a protective layer facing away from the piezoelectric layer, provided as an example of the present application.

[0072] Fig.33 A schematic flow chart of another method for preparing a differential piezoelectric resonant pressure sensor provided as an example of this application.

[0073] Fig.34 A schematic diagram of the structure of a compensation system provided for the example of this application.

[0074] Fig.35A schematic diagram of the working process of a compensation system provided as an example of this application.

[0075] Description of reference numerals:

[0076] 100, differential piezoelectric resonant pressure sensor; 110, piezoelectric component; 111, first electrode layer; 1111, first sub-electrode; 1112, second sub-electrode; 112, piezoelectric layer; 113, second electrode layer; 1131, third sub-electrode; 1132, fourth sub-electrode; 1141, first sub-lead electrode; 1142, second sub-lead electrode; 1143, first connection hole; 1151, fourth sub-lead electrode; 1152, second connection hole; 120, resonant film; 121, first bearing member; 122, second bearing member; 130, pressure resonance component; 131, first structure; 1311, sub-structure; 132, second structure; 133, first groove; 134, second groove; 135, third groove; 136, pressure chamber; 140, first resonator; 141, deformation section; 150, second resonator; 160, oxide layer; 170, protective layer; 181, first connecting member; 182, second connecting member; 190, cover; 191, adsorption structure; 200, Si wafer; 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

[0077] In order to make the purpose, technical solution and advantages of the examples of this application clearer, the technical solution in the examples of this application will be clearly and completely described below in conjunction with the drawings in the examples of this application. Obviously, the described examples are part of the examples of this application, not all of them. Based on the examples in this application, all other examples obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0078] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used in the specification of the application herein are only for the purpose of describing specific examples and are not intended to limit this application; the terms "including" and "having" in the specification, claims and drawings of this application and any variations thereof are intended to cover non-exclusive inclusions.

[0079] Reference to "examples" herein means that a particular feature, structure, or characteristic described in conjunction with the examples may be included in at least one example of the present application. The appearance of the phrase "example" in various locations in the specification does not necessarily refer to the same example, nor is it an independent or alternative example that is mutually exclusive with other examples. It is explicitly and implicitly understood by those skilled in the art that the examples described herein may be combined with other examples.

[0080] The term "and / or" in this article is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0081] The directional words appearing in the following description are all directions shown in the figures, and do not limit the specific structure of the differential piezoelectric resonant pressure sensor of the present application.

[0082] In addition, the terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects rather than to describe a specific order, and may explicitly or implicitly include one or more of the features.

[0083] In the description of the present application, unless otherwise specified, "plurality" means more than two (including two), and similarly, "multiple groups" means more than two groups (including two).

[0084] In the description of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, the "connection" or "connection" of a mechanical structure may refer to a physical connection. For example, the physical connection may be a fixed connection, such as a fixed connection through a barrier, such as a fixed connection through screws, bolts or other barrier; the physical connection may also be a detachable connection, such as a mutual snap-on or snap-fit ​​connection; the physical connection may also be an integral connection, such as a connection formed by welding, bonding or integral molding. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0085] Based on the above, the present application example provides a differential piezoelectric resonant pressure sensor, a compensation system and a preparation method.

[0086] The differential piezoelectric resonant pressure sensor mentioned in the example of this application can be combined with MEMS technology to achieve mass production of the differential piezoelectric resonant pressure sensor and improve the production efficiency of the differential piezoelectric resonant pressure sensor.

[0087] The differential 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.

[0088] In order to enable those skilled in the art to better understand the present application, the differential piezoelectric resonant pressure sensor, compensation system and preparation method provided by the example of the present application will be clearly and completely described below in conjunction with the accompanying drawings.

[0089] Exemplarily, the present application provides a differential piezoelectric resonant pressure sensor. Figure 1 A schematic diagram of a differential piezoelectric resonant pressure sensor provided as an example in this application. Figure 2 A top view of a differential piezoelectric resonant pressure sensor provided as an example of the present application, Figure 3 for Figure 2 The cross-sectional view along AA, Figure 4 for Figure 2 Cross-sectional view along BB, Figure 5 for Figure 2 Cross-sectional view along CC.

[0090] Please refer to Figure 1 to Figure 5 The differential piezoelectric resonant pressure sensor 100 may include a piezoelectric component 110, a resonant film 120, and a pressure resonant component 130. 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 pressure resonant component 130 is connected to the side of the resonant film 120 away from the piezoelectric component 110. The side of the pressure resonant component 130 facing the resonant film 120 cooperates with the resonant film 120 to form a resonant cavity. The side of the pressure resonant component 130 away from the resonant film 120 is provided with a pressure cavity 136, and the pressure cavity 136 is used to receive the pressure to be detected.

[0091] Among them, the piezoelectric component 110 and the resonant film 120 cooperate to form a resonant component, and the resonant component includes a first resonator 140, a second resonator 150, and a first structure 131 and a second structure 132 that are arranged at intervals. Compared with the first resonator 140, the second resonator 150 is arranged close to the edge of the differential piezoelectric resonant pressure sensor 100, and the first end of the first resonator 140 is connected to the first position of the first structure 131, and the second end of the first resonator 140 is connected to the second position of the first structure 131, and the second position is spaced apart from the first position. The first end of the second resonator 150 is connected to the first structure 131, and the second end of the second resonator 150 is connected to the second structure 132.

[0092] Based on the differential piezoelectric resonant pressure sensor 100 provided in the above example, the pressure chamber 136 can receive the pressure to be detected. Since the pressure chamber 136 is arranged on the side of the pressure resonance component 130 away from the resonance film 120, and the resonance film 120 and the pressure resonance component 130 cooperate to form a resonance chamber, the pressure to be detected can be transmitted to the resonance film 120 through the pressure resonance component 130. Since the piezoelectric component 110 is arranged on one side of the resonance film 120, the pressure to be detected transmitted to the resonance film 120 can be transmitted to the piezoelectric component 110, and the piezoelectric component 110 can detect the pressure to be detected.

[0093] Next, the structure of the differential piezoelectric resonance pressure sensor 100 is described in detail.

[0094] A resonance groove may be provided on one side of the pressure resonance component 130, and the resonance groove may include a first groove and a second groove that are spaced apart. In this case, the first groove and the second groove cooperate with the resonance film 120 to form two resonance cavities that are spaced apart. The resonance groove may also include a first groove and a second groove that are connected. In this case, the first groove and the second groove cooperate with the resonance film 120 to form a resonance cavity.

[0095] A pressure-sensitive film may be formed on the side of the pressure resonance component 130 away from the resonance groove. In this case, the pressure cavity 136 refers to the space on the side of the pressure-sensitive component away from the resonance groove. The pressure resonance component 130 may also include a matching pressure-sensitive film and other structures, and the pressure-sensitive film and other structures cooperate to form a groove-shaped structure, which is the pressure cavity 136. The example of this application does not limit the specific implementation method of the pressure resonance component 130.

[0096] A piezoelectric component 110 is arranged on the side of the resonant film 120 facing away from the pressure resonance component 130. The pressure to be detected acting on the pressure resonance component 130 can indirectly act on the piezoelectric component 110 through the pressure resonance component 130 and the resonant film 120, and the pressure to be detected is detected by the piezoelectric component 110.

[0097] For example, the piezoelectric component 110 may include a piezoelectric layer 112 and an electrode. The piezoelectric layer 112 may be made of AlN, ScAlN, lead zirconate titanate, ZnO, LiNbO 3 The piezoelectric film material is made of piezoelectric thin film materials. Due to the piezoelectricity of the piezoelectric thin film material, when the piezoelectric layer 112 receives pressure, the two opposite sides of the piezoelectric layer 112 can generate charges to form a potential difference, that is, the positive piezoelectric effect; similarly, when the piezoelectric layer 112 is driven by voltage, it will deform, that is, the inverse piezoelectric effect. The positive piezoelectric effect and the inverse piezoelectric effect of the piezoelectric layer 112 are used to obtain the relevant parameters of the pressure to be detected.

[0098] The electrode can be directly electrically connected to an external circuit, or the electrode can be indirectly connected to an external circuit via a conductive member such as a wire.

[0099] The external circuit may be a circuit for detecting the magnitude of current, or a circuit for detecting the magnitude of voltage or a circuit for detecting the magnitude of charge. The present 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. The specific structure of the piezoelectric component 110 can be seen in the relevant description below.

[0100] The resonant film 120 may be directly or indirectly connected to the side of the pressure resonance component 130 away from the pressure cavity 136 , and the resonant film 120 may close the opening of the resonant groove. The resonant film 120 and the resonant groove may cooperate to form a resonant cavity.

[0101] The piezoelectric component 110 and the pressure resonance component 130 can cooperate to form a resonance component. The resonance component can specifically include a first resonator 140, a second resonator 150, and a first structure 131 and a second structure 132 that are spaced apart.

[0102] The structure of the first resonator 140 may be the same as or different from the structure of the second resonator 150. For example, the first resonator 140 may be in a straight line, a cross, a M, a tuning fork, a circle, or other shapes.

[0103] The first resonator 140 may be provided with one, and in this case, the second resonator 150 may be provided with one, or a plurality of second resonators 150 may be provided.

[0104] There may be multiple first resonators 140, and in this case, there may be only one second resonator 150, or there may be multiple second resonators 150. The present application example does not limit the specific structure and number of the first resonator 140 and the specific structure and number of the second resonator 150.

[0105] Along the direction from the piezoelectric component 110 to the resonant film 120, the projections of the first structure 131 and the second structure 132 can both be annular structures. The annular structure can be a circular ring or a square ring, and the inner projection of the annular structure can be circular. In this case, the outer projection of the annular structure can be polygonal. Alternatively, the inner projection of the annular structure can be polygonal, and the outer projection of the annular structure can be circular. The example of this application does not limit the specific implementation of the first structure 131 and the second structure 132.

[0106] For example, the projection of the first structure 131 may be in a square ring shape, in which case the projection of the second structure 132 may be in a square ring shape, or the projection of the second structure 132 may be in a circular ring shape. Alternatively, the projection of the first structure 131 may be in a circular ring shape, in which case the projection of the second structure 132 may be in a circular ring shape, or the projection of the second structure 132 may be in a square ring shape.

[0107] The first resonator 140 may include a first end and a second end, the first end of the first resonator 140 is connected to the first position of the first structure 131, and the second end of the first resonator 140 is connected to the second position of the first structure 131. When the first structure 131 is projected in a ring-shaped structure along the direction of the piezoelectric component 110 toward the resonant film 120, the first position and the second position may be positions close to the inner ring of the ring structure, and the line connecting the first position and the second position may intersect with the center line of the ring structure. The angle between the line connecting the first position and the second position and the center line of the ring structure may be any one of a right angle, an acute angle, or an obtuse angle, and the example of the present application does not specifically limit the first position and the second position.

[0108] The second resonator 150 may include a first end and a second end, the first end of the second resonator 150 being connected to the first structure 131 , and the second end of the second resonator 150 being connected to the second structure 132 .

[0109] Compared to the first resonator 140 , the second resonator 150 is disposed closer to the edge of the differential piezoelectric resonant pressure sensor 100 .

[0110] Along the direction of the piezoelectric component 110 toward the resonant film 120, the geometric center of the projection of the first resonator 140 can overlap with the geometric center of the projection of the pressure chamber 136, and the geometric center of the projection of the first resonator 140 can be separated from the geometric center of the projection of the pressure chamber 136. This example of the application does not impose any specific restrictions on this.

[0111] The first resonator 140 and the second resonator 150 each have a certain resonant frequency. The frequency of the first resonator 140 may be equal to the frequency of the second resonator 150 , or the frequency of the first resonator 140 may be different from the frequency of the second resonator 150 .

[0112] When the frequency of the voltage applied to the first resonator 140 is equal to the resonant frequency of the first resonator 140, and the frequency of the voltage applied to the second resonator 150 is equal to the resonant frequency of the second resonator 150, both the first resonator 140 and the second resonator 150 can resonate. Under the effect of the pressure to be detected, the frequency of the first resonator 140 and the frequency of the second resonator 150 will change, and the change of the corresponding resonant frequency of the first resonator 140 and the second resonator 150 can feedback the size of the pressure to be detected, thereby facilitating the operator to detect the pressure to be detected.

[0113] Figure 6 A schematic diagram of the working principle of the first resonator in a differential piezoelectric resonant pressure sensor provided as an example of this application, Figure 7 The schematic diagram of the working principle of the second resonator in a differential piezoelectric resonant pressure sensor provided in this application example is shown in FIG. Figure 6 and Figure 7 Since the resonant sensitive component cooperates with the piezoelectric component 110 to form a resonant component, the first structure 131 and the first resonator 140 both belong to the resonant component. Therefore, at least part of the pressure to be detected acting on the resonant sensitive component can be transmitted to the first resonator 140 through the first structure 131, and the first structure 131 can change the direction of the pressure to be detected. The pressure to be detected through the first structure 131 can have a first stress parallel to the pressure sensitive film, and the direction of the first stress is toward the edge of the differential piezoelectric resonant pressure sensor 100. Under the action of the first stress, the side of the first resonator 140 away from the pressure chamber 136 can expand and deform.

[0114] The second structure 132 and the second resonator 150 are also part of the resonant component. Therefore, at least part of the pressure to be detected acting on the resonant sensitive component can be transmitted to the second resonator 150 through the first structure 131, and the first structure 131 can change the direction of the pressure to be detected. The pressure to be detected through the first structure 131 can have a second stress parallel to the pressure sensitive film, and the direction of the second stress is opposite to the direction of the first stress. Under the action of the second stress, the side of the second resonator 150 away from the pressure chamber 136 can be compressed and deformed.

[0115] Based on the differential piezoelectric resonant pressure sensor 100 provided in the above example, the pressure chamber 136 can receive the pressure to be detected. Since the pressure chamber 136 is arranged on the side of the pressure resonance component 130 away from the resonance film 120, and the resonance film 120 and the pressure resonance component 130 cooperate to form a resonance chamber, the pressure to be detected can be transmitted to the resonance film 120 through the pressure resonance component 130. Since the piezoelectric component 110 is arranged on one side of the resonance film 120, the pressure to be detected transmitted to the resonance film 120 can be transmitted to the piezoelectric component 110, and the piezoelectric component 110 can detect the pressure to be detected.

[0116] Since the first resonator 140 is located on the inner side of the first structure 131 and the second resonator 150 is located on the outer side of the first structure 131, after the first structure 131 is deformed under the action of the pressure to be detected, the force applied to the first resonator 140 by the first structure 131 is opposite to the force applied to the second resonator 150, so that the frequency change of the first resonator 140 is opposite to the frequency change of the second resonator 150. The first resonator 140 and the second resonator 150 cooperate to form a differential structure, so that the deformation of the resonant component under the action of the same pressure to be detected is more obvious, which can improve the detection sensitivity of the differential piezoelectric resonant pressure sensor 100, thereby improving the detection accuracy of the differential piezoelectric resonant pressure sensor 100.

[0117] Based on the differential piezoelectric resonant pressure sensor 100 provided in the above example, please refer to Figure 1 The second resonator 150 may be provided in plurality, and positions where different second resonators 150 are connected to the first structure 131 are spaced apart, and positions where different second resonators 150 are connected to the second structure 132 are spaced apart.

[0118] Since the positions where different second resonators 150 are connected to the first structure 131 are spaced apart, and the positions where different second resonators 150 are connected to the second structure 132 are spaced apart, the different second resonators 150 may be disposed at intervals.

[0119] Different second resonators 150 may be arranged at an angle, and the angle between different second resonators 150 may be a right angle, an acute angle, or an obtuse angle. Alternatively, different second resonators 150 may also be parallel to each other, and this application example does not impose any specific limitation on this.

[0120] In the example of the present application, since there are multiple second resonators 150 and the multiple second resonators 150 are arranged at intervals, the pressure to be detected can be transmitted to different second resonators 150 through the first structure 131, so that different second resonators 150 can detect the pressure to be detected from different positions, thereby improving the detection accuracy of the pressure to be detected.

[0121] Based on the differential piezoelectric resonant pressure sensor 100 provided in the above example, the plurality of second resonators 150 may be evenly arranged.

[0122] In the case where the plurality of second resonators 150 are arranged at an angle, the plurality of second resonators 150 are arranged evenly, which can be understood as the angle between two adjacent second resonators 150 is equal.

[0123] In the case where the plurality of second resonators 150 are arranged in parallel, the plurality of second resonators 150 are arranged uniformly, which can be understood as the distance between two adjacent second resonators 150 is equal.

[0124] In the example of the present application, the multiple second resonators 150 are evenly arranged, so that the stress transmitted to different second resonators 150 through the first structure 131 can be relatively uniform, thereby reducing the possibility that some second resonators 150 may be damaged due to receiving a large pressure to be detected.

[0125] Based on the differential piezoelectric resonant pressure sensor 100 provided in the above example, Figure 8 A schematic diagram of a differential piezoelectric resonant pressure sensor provided as an example in this application. Fig. 9 A top view of a differential piezoelectric resonant pressure sensor provided as an example of the present application, Fig.10 for Fig. 9 For the cross-sectional view at the middle edge DD, please refer to Figure 8 to Figure 10 The differential piezoelectric resonant pressure sensor 100 further includes a deformation section 141 , one end of the deformation section 141 is connected to the first resonator 140 through the first structure 131 , and the other end of the deformation section 141 is connected to the second structure 132 .

[0126] The deformation section 141 may be at least one of a folded line structure, a curved line structure, and an annular structure. The annular structure may be a circular ring, an elliptical ring, a polygonal ring, or other annular structures. The deformation section 141 may be a combination of a folded line structure and a curved line structure. The deformation section 141 may also be a combination of a folded line structure and an annular structure. The deformation section 141 may also be other structures. This application example does not impose specific restrictions on this.

[0127] The deformation capacity of the deformation section 141 can be higher than the deformation capacity of the first resonator 140. The deformation capacity of the deformation section 141 can be higher than the deformation capacity of the first resonator 140 by setting the structural features of the deformation section 141 to be different from the structural features of the first resonator 140 or other methods. This example of the present application does not make any specific limitation on this.

[0128] In the example of the present application, during the use of the differential piezoelectric resonant pressure sensor 100, the first structure 131 may be deformed under the action of the pressure to be detected, and the deformation of the first structure 131 may drive the first resonator 140 to deform. Because the deformation section 141 is connected to the first structure 131, the deformation section 141 can be deformed under the drive of the first structure 131. Since the deformation capacity of the deformation section 141 is higher than the deformation capacity of the first resonator 140, the deformation amplitude of the first structure 131 is less affected by the setting of the deformation section 141, thereby ensuring the performance of the first resonator 140.

[0129] In addition, since the first resonator 140 is located inside the first structure 131, and the first end of the first resonator 140 is connected to the first position of the first structure 131, and the second end of the first resonator 140 is connected to the second position of the first structure 131, it is inconvenient for the electrode in the piezoelectric component 110 corresponding to the first resonator 140 to be connected to the external circuit. In the example of the present application, by setting one end of the deformation segment 141 to be connected to the first structure 131, and one end of the first resonator 140 to be connected to the first structure 131, the deformation segment 141 can be connected to the first resonator 140 through the first structure 131. And since the other end of the deformation segment 141 is connected to the second structure 132, the electrode in the piezoelectric component 110 corresponding to the first resonator 140 can be led out to the second structure 132 through the first structure 131 and the deformation segment 141, so as to facilitate the electrical connection between the first resonator 140 and the external circuit.

[0130] Based on the differential piezoelectric resonant pressure sensor 100 provided in the above example, please refer to Figure 1 or Figure 8 , the differential piezoelectric resonant pressure sensor 100 may include a first groove 133 and a second groove 134 arranged at intervals, the second groove 134 is arranged on a side of the first groove 133 close to the edge of the differential piezoelectric resonant pressure sensor 100, and the notch of the first groove 133 and the notch of the second groove 134 are both arranged on the side of the piezoelectric component 110 away from the resonant film 120. The second groove 134 divides the resonant component into a first structure 131 and a second structure 132 arranged at intervals, the first structure 131 is provided with a first groove 133, and the second groove 134 is arranged between the first structure 131 and the second structure 132. The first end of the first resonator 140 is connected to the first position, and the second end of the first resonator 140 is connected to the second position. The first end of the second resonator 150 is connected to the side of the first structure 131 away from the first groove 133, and the second end of the second resonator 150 is connected to the side of the second structure 132 close to the second groove 134.

[0131] The first groove 133 is disposed in the first structure 131 . The first groove 133 may be a circular groove, a square groove, or a groove in other shapes, so that the first structure 131 is an annular structure.

[0132] The second groove 134 is arranged outside the first groove 133. Compared with the first groove 133, the second groove 134 is arranged near the edge of the piezoelectric differential resonant pressure sensor. The second groove 134 is arranged between the first structure 131 and the second structure 132. The second groove 134 can be an annular groove structure, the inner side of the annular groove is the first structure 131, and the outer side of the annular groove is the second structure 132. The second groove 134 can be a circular annular groove, a square annular groove or an annular groove of other shapes. The example of this application does not limit the specific shapes of the first groove 133 and the second groove 134.

[0133] The notch of the first groove 133 and the notch of the second groove 134 are both opened on the side of the piezoelectric component 110 away from the resonance film 120. Along the direction from the piezoelectric component 110 to the resonance film 120, the depth of the first groove 133 and the depth of the second groove 134 can be the same or different, and this example of the application does not impose specific limitations on this.

[0134] The first resonator 140 may be connected to two positions spaced apart in the first groove 133. For example, the first end of the first resonator 140 is connected to the first position, and the second end of the first resonator 140 is connected to the second position. The first position and the second position may be groove sidewalls of the first groove 133, and the first position and the second position may be disposed near the notch of the first groove 133. The line connecting the first position and the second position may intersect with the center line of the first groove 133.

[0135] The second resonator 150 may include a first end and a second end. The first end of the second resonator 150 is connected to a side of the first structure 131 away from the first groove 133 , and the second end of the second resonator 150 is connected to the second structure 132 .

[0136] In the example of the present application, by setting the first groove 133, the contact area between the first structure 131 and the pressure sensitive film can be reduced, so that the first structure 131 undergoes a larger deformation under the same pressure to be detected, thereby causing the first resonator 140 to undergo a larger deformation, thereby improving the detection sensitivity and detection accuracy of the differential piezoelectric resonant pressure sensor 100.

[0137] By setting the second groove 134, the first structure 131 and the second structure 132 can be spaced apart, and the contact area between the second structure 132 and the pressure sensitive film can be reduced, so that the second structure 132 can be deformed more under the same pressure to be detected, thereby making the second resonator 150 deformed more, further improving the detection sensitivity and detection accuracy of the differential piezoelectric resonant pressure sensor 100.

[0138] Based on the differential piezoelectric resonant pressure sensor 100 provided in the above example, please refer to Figure 1 or Figure 8 The first structure 131 is provided with at least one third groove 135 , and the third groove 135 connects the first groove 133 and the second groove 134 .

[0139] The notch of the third groove 135 may be disposed on a side of the piezoelectric component 110 facing away from the resonant film 120 .

[0140] There may be one third groove 135 , or there may be a plurality of third grooves 135 .

[0141] When there are multiple third grooves 135 , two adjacent third grooves 135 may cooperate to form a non-zero angle, and two adjacent third grooves 135 may also be substantially parallel.

[0142] The fact that two adjacent third grooves 135 are substantially parallel can be understood as that the angle formed between the two adjacent third grooves 135 is greater than or equal to zero degree and less than 10 degrees.

[0143] Along the direction from the piezoelectric component 110 toward the resonant film 120 , the depth of the third groove 135 may be the same as the depth of the first groove 133 , or may be different from the depth of the first groove 133 , and this example of the application does not impose any specific limitation on this.

[0144] In the example of the present application, the third groove 135 is provided in the first structure 131, and the third groove 135 connects the first groove 133 and the second groove 134. Therefore, by providing the third groove 135, the first structure 131 can be divided into a plurality of substructures 1311, thereby further reducing the contact area between the first structure 131 and the pressure-sensitive film, so that the deformation amplitude of the first structure 131 under the same pressure to be detected is larger, which is beneficial to further improve the detection sensitivity and detection accuracy of the differential piezoelectric resonant pressure sensor 100.

[0145] Based on the differential piezoelectric resonant pressure sensor 100 provided in the above example, please refer to Figure 1 or Figure 8 There may be a plurality of third grooves 135 , and the plurality of third grooves 135 are evenly distributed.

[0146] In the case where two adjacent third grooves 135 are arranged at an angle, the uniform distribution of the plurality of third grooves 135 can be understood as that the angle formed between the two adjacent third grooves 135 is equal.

[0147] When two adjacent third grooves 135 are substantially parallel, the uniform distribution of the plurality of third grooves 135 can be understood as the distance between two adjacent third grooves 135 being equal. Based on different configurations of the third grooves 135, the uniform distribution of the third grooves 135 can also be understood in other ways, and this application example does not specifically limit this.

[0148] In the example of the present application, since the third groove 135 is provided in the first structure 131, by arranging a plurality of third grooves 135 to be evenly distributed, the third groove 135 can divide the first structure 131 into a plurality of evenly arranged substructures 1311, so that the deformation amplitudes of different substructures 1311 under the same pressure to be detected are relatively similar, and thus the stresses transmitted to the first resonator 140 and the second resonator 150 by different substructures 1311 are relatively similar, thereby ensuring the detection accuracy of the differential piezoelectric resonant pressure sensor 100.

[0149] Based on the differential piezoelectric resonant pressure sensor 100 provided in the above example, the side of the first structure 131 close to the pressure sensitive film 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 film is a second distance, and the first distance is greater than the second distance.

[0150] The anchor point is the main stress point of the first structure 131 .

[0151] By setting the first distance to be greater than the second distance, the resonant film 120, the pressure sensitive film and the anchor point can work together to form a lever, the first distance is the first lever arm, and the second distance is the second lever arm. Based on the lever principle, the first structure 131 with the anchor point can amplify the working stress generated by the pressure to be detected, thereby improving the detection sensitivity of the differential piezoelectric resonant pressure sensor 100.

[0152] Based on the differential piezoelectric resonant pressure sensor 100 provided in the above example, the piezoelectric component 110 may include a first lead electrode group, a second lead electrode group, a first electrode group, a piezoelectric layer 112 and a second electrode group.

[0153] Among them, the second electrode group is connected to the side of the resonant film 120 away from the pressure resonance component 130, the piezoelectric layer 112 is connected to the side of the second electrode group away from the resonant film 120, part of the second lead electrode group is arranged on the side of the piezoelectric layer 112 away from the second electrode group, and the second lead electrode group passes through the piezoelectric layer 112 and is electrically connected to the second electrode group.

[0154] The first electrode group is connected to a side of the piezoelectric layer 112 away from the second electrode group. The first lead electrode group is disposed on a side of the first electrode group away from the piezoelectric layer 112. The first lead electrode group is electrically connected to the first electrode group.

[0155] The characteristics of the piezoelectric layer 112 can be found in the above description.

[0156] The first lead electrode group and the second lead electrode group can be connected to different positions of the external circuit respectively. Since the first lead electrode is connected to the first electrode group and the second lead electrode group is connected to the second electrode group, the electrical connection between the differential piezoelectric resonant pressure sensor 100 and the external circuit can be achieved through the coordination of the first lead electrode group and the first electrode group, and the coordination of the second lead electrode group and the second electrode group.

[0157] Based on the differential piezoelectric resonant pressure sensor 100 provided in the above example, please refer to Figure 4 Part of the resonant film 120 is the first carrier 121 , and part of the resonant film 120 is the second carrier 122 . The first carrier 121 is spaced from the second carrier 122 .

[0158] The first lead electrode group includes a first sub-lead electrode 1141 and a second sub-lead electrode 1142. The first electrode group includes a first sub-electrode 1111 and a second sub-electrode 1112. The first sub-electrode 1111 is disposed on the first carrier 121, and the first sub-lead electrode 1141 is electrically connected to the first sub-electrode 1111. The second sub-electrode 1112 is disposed on the second carrier 122, and the second sub-lead electrode 1142 is electrically connected to the second sub-electrode 1112.

[0159] The second lead electrode group includes a third sub-lead electrode and a fourth sub-lead electrode 1151, the second electrode group includes a third sub-electrode 1131 and a fourth sub-electrode 1132, the third sub-electrode 1131 is arranged on the first carrier 121, the third sub-lead electrode is electrically connected to the third sub-electrode 1131, the fourth sub-electrode 1132 is arranged on the second carrier 122, and the fourth sub-lead electrode 1151 is electrically connected to the fourth sub-electrode 1132.

[0160] The number of first sub-electrodes 1111 may be greater than the number of first resonators 140, and each first resonator 140 may correspond to two first sub-electrodes 1111, one of which may be a driving electrode, and the other may be a detection electrode. At least two first sub-lead electrodes 1141 may be provided, and the first sub-lead electrodes 1141 are connected to the corresponding first sub-electrodes 1111, and the first sub-electrode 1111 may be connected to an external circuit through the first sub-lead electrodes 1141.

[0161] The number of the third sub-electrodes 1131 may be equal to the number of the first resonators 140, and the third sub-electrodes 1131 correspond one to one with the first resonators 140. There may be at least one third sub-lead electrode, and the number of the third sub-lead electrodes may be equal to the number of the third sub-electrodes 1131, or the number of the third sub-lead electrodes may be different from the number of the third sub-electrodes 1131. This example of the present application does not specifically limit this, as long as the third sub-lead electrode can realize the electrical connection between the third sub-electrode 1131 and the external circuit.

[0162] The first sub-electrode 1111 , the third electrode, and the corresponding piezoelectric layer 112 may cooperate to form a first resonator 140 .

[0163] The number of second sub-electrodes 1112 may be greater than the number of second resonators 150, and each second resonator 150 may correspond to two second sub-electrodes 1112, one of which is an excitation electrode, and the other second sub-electrode 1112 is a detection electrode. At least two second sub-lead electrodes 1142 may be provided, and the second sub-lead electrodes 1142 are connected to the corresponding second sub-electrodes 1112. The second sub-lead electrodes 1142 may be electrically connected to the external circuit.

[0164] The number of the fourth sub-electrodes 1132 may be equal to the number of the second resonators 150, and the fourth sub-electrodes 1132 correspond to the second resonators 150 one by one. There may be at least one fourth sub-lead electrode 1151, and the number of the fourth sub-lead electrodes 1151 may be equal to the number of the fourth sub-electrodes 1132, or the number of the fourth sub-lead electrodes 1151 may be different from the number of the fourth sub-electrodes 1132, and this example of the present application does not specifically limit this, as long as the fourth sub-lead electrode 1151 can achieve electrical connection between the fourth sub-electrode 1132 and the external circuit.

[0165] The second sub-electrode 1112 , the fourth electrode, and the corresponding piezoelectric layer 112 may cooperate to form a second resonator 150 .

[0166] In the above example, the first sub-electrode 1111, the third electrode and the corresponding piezoelectric layer 112 can cooperate to form a first resonator 140, and the second sub-electrode 1112, the fourth electrode and the corresponding piezoelectric layer 112 can cooperate to form a second resonator 150. Therefore, the differential piezoelectric resonant pressure sensor 100 provided according to the example of the present application can simultaneously use the first resonator 140 and the second resonator 150 to detect the pressure to be detected.

[0167] In addition, since the first resonator 140 and the second resonator 150 are connected to two opposite sides of the first structure 131, the first stress transmitted to the first resonator 140 through the first structure 131 is opposite to the second stress transmitted to the second resonator 150, so that the detection frequencies of the first resonator 140 and the second resonator 150 are opposite, so that the frequency change detected by the differential piezoelectric resonant pressure sensor 100 under the same pressure to be detected is more obvious, thereby improving the detection sensitivity and detection accuracy of the differential piezoelectric resonant pressure sensor 100.

[0168] Next, in combination with the specific structure of the piezoelectric component 110 , taking the example that both the first resonator 140 and the second resonator 150 are circular, the principle of the differential piezoelectric resonant pressure sensor 100 is further introduced.

[0169] When any of the first sub-electrodes 1111 receives a voltage, stress is generated in the piezoelectric layer 112 based on the inverse piezoelectric effect of the piezoelectric layer 112. At this time, since the neutral layer of the piezoelectric layer 112 deviates from the geometric center position of the piezoelectric layer 112, the piezoelectric layer 112 will be deformed, and the deformation of the piezoelectric layer 112 drives the entire first resonator 140 to be deformed.

[0170] When an alternating voltage having the same resonant frequency as the first resonator 140 is applied to any first sub-electrode 1111, the entire structure will resonate, and the resonant frequency is:

[0171]

[0172] In the formula, f r1 is the resonant frequency of the first resonator 140, μ n is the constant set when solving the Bessel function, t 1 is the thickness of the first resonator 140, r 1 is the radius of the first resonator 140, E is Young's modulus, ρ 1 is the density of the first resonator 140, and δ is the Poisson's ratio.

[0173] When the pressure chamber 136 receives the pressure to be detected, the pressure sensitive film will deform and generate working stress under the action of the pressure to be detected. The first structure 131 can transfer the deformation and working stress of the pressure sensitive film to the first resonator 140, specifically to the piezoelectric layer 112. During the transmission process of the first structure 131, the first structure 131 can change the direction of action of the pressure to be detected, reducing the possibility of damage to the resonant film 120. The anchor point can use the lever principle to amplify the working stress and increase the measurement range of the differential piezoelectric resonant pressure sensor 100.

[0174] Since the first resonator 140 is provided with at least two first sub-electrodes 1111, when one of the first sub-electrodes 1111 drives the piezoelectric layer 112 to vibrate, the other first sub-electrode 1111 detects the vibration of the first resonator 140. The first sub-electrode 1111 that receives a voltage may be a driving electrode, and the first sub-electrode 1111 that detects vibration may be a detecting electrode.

[0175] 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 piezoelectric resonator.

[0176] Assume that the working stress generated by the pressure to be detected on the first resonator 140 is σ, and the resonant frequency of the piezoelectric resonator is:

[0177]

[0178] The resonant frequency of the first resonator 140 changes to:

[0179] Δf 1 =f r1 -f′ r1

[0180] It can be seen from the above formula that the pressure value can be determined when the frequency change of the first resonator is detected.

[0181] When an alternating voltage having the same resonant frequency as the second resonator 150 is applied to any second sub-electrode 1112, the entire structure will resonate, and the resonant frequency is:

[0182]

[0183] In the formula, f r2 is the resonant frequency of the second resonator 150, μ n is the constant set when solving the Bessel function, t 2 is the thickness of the second resonator 150, r 2 is the radius of the second resonator 150, E is Young's modulus, ρ 2 is the density of the second resonator 150, and δ is the Poisson's ratio.

[0184] When the pressure chamber 136 receives the pressure to be detected, the pressure-sensitive film will deform and generate working stress under the action of the pressure to be detected. The first structure 131 can transfer the deformation and working stress of the pressure-sensitive film to the second resonator 150, specifically to the piezoelectric layer 112. During the transmission process of the first structure 131, the first structure 131 can change the direction of action of the pressure to be detected, reducing the possibility of damage to the resonant film 120. The anchor point can use the lever principle to amplify the working stress and increase the measurement range of the differential piezoelectric resonant pressure sensor 100.

[0185] Since the second resonator 150 is provided with at least two second sub-electrodes 1112, when one of the second sub-electrodes 1112 drives the piezoelectric layer 112 to vibrate, the other second sub-electrode 1112 detects the vibration of the second resonator 150. The second sub-electrode 1112 that receives the voltage may be a driving electrode, and the second sub-electrode 1112 that detects the vibration may be a detection electrode.

[0186] 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 piezoelectric resonator.

[0187] Assume that the working stress generated by the pressure to be detected on the second resonator 150 is -σ, and the resonant frequency of the piezoelectric resonator is:

[0188]

[0189] The resonant frequency of the first resonator 140 changes to:

[0190] Δf 2 =f r2 -f′ r2

[0191] It can be seen from the above formula that the pressure value can be determined when the frequency change of the second resonator is detected.

[0192] It can be seen from the above formula that before and after the pressure chamber 136 receives the pressure to be detected, the resonant frequencies of the first resonator 140 and the second resonator 150 change in opposite directions, so that differentiation can be achieved. At this time, the resonant frequency change caused by the pressure to be detected is:

[0193] Δf=Δf 1 -Δf 2

[0194] It can be seen from the above formula that, under the same pressure to be detected, the frequency change detected by the differential piezoelectric resonant pressure sensor 100 is more obvious, and thus the detection sensitivity and detection accuracy of the differential piezoelectric resonant pressure sensor 100 are higher.

[0195] When the piezoelectric layer 112 is deformed, the portion of the piezoelectric layer 112 close to the resonance film 120 is squeezed by the pressure to be detected, and the portion of the piezoelectric layer 112 away from the resonance film 120 is stretched by the pressure to be detected. On the cross section of the piezoelectric layer 112, the transition layer between the stretched portion of the piezoelectric layer 112 and the squeezed portion of the piezoelectric layer 112, which is neither stretched nor compressed and has almost zero stress, is the above-mentioned neutral layer.

[0196] Compared with the resistance detection type piezoelectric sensor which needs to set up a Wheatstone bridge and the capacitance detection type pressure sensor which needs to set up a capacitance bridge, the differential piezoelectric resonant pressure sensor 100 provided in the example of the present application does not require the setting of an additional detection circuit, has a simpler structure, and has a lower manufacturing cost.

[0197] Based on the differential piezoelectric resonant pressure sensor 100 provided in the above example, the piezoelectric component 110 may further include a seed layer, and the seed layer is disposed between the piezoelectric component 110 and the resonant film 120 , and specifically, may be disposed between the second electrode and the resonant film 120 .

[0198] 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 differential piezoelectric resonant pressure sensor 100 .

[0199] Based on the differential piezoelectric resonant pressure sensor 100 provided in the above example, the resonant film 120 can be processed from an SOI wafer 300 (silicon on insulator wafer), and the piezoelectric resonant component can be processed from an Si wafer 200 .

[0200] Based on the differential piezoelectric resonant pressure sensor 100 provided in the above example, an oxide layer 160 is provided between the piezoelectric resonant component and the resonant film 120 .

[0201] 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 .

[0202] The oxide layer 160 can ensure the insulation between the piezoelectric resonance component and the resonance film 120 , reduce the possibility of leakage of the differential piezoelectric resonance pressure sensor 100 , and ensure the safety of the differential piezoelectric resonance pressure sensor 100 .

[0203] Based on the differential piezoelectric resonant pressure sensor 100 provided in the above example, Fig.11 For a schematic diagram of a differential piezoelectric resonant pressure sensor provided in this application example, please refer to Fig.11The differential 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 pressure sensitive component. The cover 190 is directly or indirectly connected to the piezoelectric component 110 .

[0204] 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.

[0205] In a vacuum environment, the cover 190 can be used to encapsulate the piezoelectric resonator. The cover 190 can be set on the side of the piezoelectric component 110 away from the resonant component to isolate the piezoelectric component 110 from the atmospheric environment, ensure that the piezoelectric component 110 is in a vacuum environment when working, and then improve the value corresponding to the quality factor of the differential piezoelectric resonant pressure sensor 100, and ensure the working performance of the differential piezoelectric resonant pressure sensor 100.

[0206] In this example of the present application, the cover 190 may be bonded to a side of the piezoelectric component 110 that is away from the resonant film 120 , and the cover 190 may close the notch of the first groove 133 and the notch of the second groove 134 .

[0207] The bonding method may be anodic bonding, or metal bonding such as Al-Ge, Au-Au, or other bonding methods.

[0208] Based on the differential piezoelectric resonant pressure sensor 100 provided in the above example, please refer to Fig.11 The cover 190 may be provided with an adsorption structure 191 on one side facing the piezoelectric component 110. The adsorption structure 191 may be a thin film getter or other structure capable of maintaining a vacuum inside the differential piezoelectric resonant pressure sensor 100.

[0209] The adsorption structure 191 can adsorb the gas or other substances inside the differential piezoelectric resonant pressure sensor 100, so that the inside of the differential piezoelectric resonant pressure sensor 100 is maintained in a vacuum state, thereby ensuring the measurement accuracy and sensitivity of the differential piezoelectric resonant pressure sensor 100 and extending the service life of the differential piezoelectric resonant pressure sensor 100.

[0210] Based on the differential piezoelectric resonant pressure sensor 100 provided in the above example, the differential piezoelectric resonant pressure sensor 100 may be an absolute pressure sensor, or the differential piezoelectric resonant pressure sensor 100 may be a relative pressure sensor.

[0211] Exemplarily, the differential piezoelectric resonant pressure sensor 100 may be an absolute pressure sensor. In this case, the cover 190 may be bonded to the side of the piezoelectric component 110 facing away from the resonant film 120 under a vacuum environment. The absolute pressure sensor is used to measure absolute pressure and can convert the absolute pressure of a gas or liquid into an equivalent electrical signal output.

[0212] Exemplarily, the differential piezoelectric resonant pressure sensor 100 may be a relative pressure sensor. In this case, the cover 190 may be bonded to the side of the piezoelectric component 110 away from the resonant film 120 under a certain pressure environment. The relative pressure sensor is measured based on the intracavity pressure, and the measurement result of the relative pressure sensor is relative to the intracavity pressure, so the relative pressure sensor can be used to measure the difference in relative pressure.

[0213] Users can select a suitable absolute pressure sensor or relative pressure sensor according to their needs. The present application example does not limit whether a medium is injected into the cavity of the differential piezoelectric resonant pressure sensor 100.

[0214] Based on the differential piezoelectric resonant pressure sensor 100 provided in the above example, a protective layer 170 may be provided on the side of the piezoelectric component 110 facing away from the resonant component. The protective layer 170 may be made of silicon dioxide material or other moisture-proof material.

[0215] The protective layer 170 can isolate the piezoelectric component 110 from the atmospheric environment, and the protective layer 170 can play a role in moisture-proofing, so that the differential piezoelectric resonant pressure sensor 100 is kept in a dry state as much as possible, ensuring the working reliability of the differential piezoelectric resonant pressure sensor 100. The protective layer 170 can also play a role in temperature compensation during the operation of the differential piezoelectric resonant pressure sensor 100.

[0216] During the use of the differential piezoelectric resonant pressure sensor 100, only the cover 190 may be provided, or only the protective layer 170 may be provided, or both the cover 190 and the protective layer 170 may be provided, or neither the cover 190 nor the protective layer 170 may be provided, and this application example does not impose any limitation on this.

[0217] Exemplarily, the present application provides a method for preparing a differential piezoelectric resonant pressure sensor 100. Fig.12 For a flow chart of a differential piezoelectric resonant pressure sensor preparation method provided in this application example, please refer to Fig.12 The method is applicable to the differential piezoelectric resonant pressure sensor 100 provided in any of the above examples. The following processing method can be completed by MEMS processing equipment.

[0218] In the example of the present application, the differential piezoelectric resonant pressure sensor 100 can be processed from multiple SOI wafers, or from a CSOI (buried cavity SOI) wafer and an SOI wafer, or from an SOI wafer 300 and an Si wafer 200, or from a CSOI wafer. The example of the present application only takes the differential piezoelectric resonant pressure sensor 100 processed from an SOI wafer 300 and an Si wafer 200 as an example for explanation.

[0219] The method is used to process a Si wafer 200 and an SOI wafer 300 into a differential piezoelectric resonant pressure sensor 100, wherein the SOI wafer 300 includes a first device layer 310, a first buried oxide layer 320, and a first substrate layer 330. The method includes:

[0220] S110, take the Si wafer 200, process the first structure 131 and the second structure 132 on one side of the Si wafer 200, the first structure 131 and the second structure 132 cooperate to form a resonant cavity; for details, please refer to Fig.13 and Fig.14 , Fig.13 A schematic diagram of the structure of an unprocessed Si wafer provided as an example of this application, Fig.14 A schematic diagram of the structure of a first structure and a second structure for Si wafer processing provided as an example in this application.

[0221] The first structure 131 and the second structure 132 can be formed on one side of the Si wafer 200 by etching, sputtering or other processing methods. The first structure 131 and the second structure 132 cooperate to form at least a partial resonant cavity, which can be a circular ring groove, a square ring groove or a ring groove of other shapes. The partial resonant cavity can be located inside the first structure 131, and the specific shape of the resonant cavity is not limited in the example of the present application.

[0222] A second trench is formed between the first structure 131 and the second structure 132 .

[0223] 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.

[0224] S120, take the SOI wafer 300, bond the SOI wafer 300 and the Si wafer 200, and seal the cavity opening of the resonant cavity with the first device layer 310. Fig.15 and Fig.16 , Fig.15 A schematic diagram of the structure of an unprocessed SOI wafer provided as an example of this application, Fig.16 A method based on Fig.15 Schematic diagram of the structure of connecting Si wafer to SOI wafer.

[0225] By flipping the SOI wafer 300, the first device layer 310 can be directed toward the Si wafer 200, so as to facilitate bonding between the first device layer 310 and the Si wafer 200, so that the first device layer 310 closes the cavity opening of the resonant cavity. The bonding method can be anodic bonding, melt bonding or other bonding methods.

[0226] S130, removing the first buried oxide layer 320 and the first substrate layer 330, and setting the thickness of the first device layer 310 to be the same as the thickness of the resonant film 120. For details, please refer to Fig.17 , Fig.17 Based on Fig.16 Schematic diagram of the structure after removing the first substrate layer and the first buried oxide layer.

[0227] The first buried oxide layer 320 and the first substrate layer 330 may be removed by physical removal, chemical removal or other methods. The present application example does not specifically limit the removal method of the first buried oxide layer 320 and the first substrate layer 330 .

[0228] In the example of the present application, the sum of the thickness of the first device layer 310 and the first buried oxide layer 320 can also be set equal to the thickness of the resonant film 120, and the sum of the thickness of part of the first substrate layer 330, the oxide layer 160 and the intermediate layer can also be set equal to the thickness of the resonant film 120. The example of the present application does not make any specific restrictions on this.

[0229] S140 , disposing a piezoelectric component 110 on a side of the first device layer 310 facing away from the Si wafer 200 .

[0230] In some possible implementations, the piezoelectric component 110 includes a first lead electrode group, a second lead electrode group, a first electrode group, a piezoelectric layer 112, and a second electrode group. S140 specifically includes the following steps:

[0231] S141, sequentially depositing the second electrode layer 113, the piezoelectric layer 112 and the first electrode layer 111, for details, please refer to Fig.18 , Fig.18 A schematic diagram of a structure in which a piezoelectric component is deposited on the side of a first device layer facing away from a Si wafer is provided as an example of the present application.

[0232] S142, patterning the first electrode layer 111 to form at least a first electrode group. The first electrode group may include a plurality of first electrodes. For details, see Fig.19 , Fig.19 A method based on Fig.18 Schematic diagram of the structure of the piezoelectric component after processing.

[0233] In some possible implementations, after S142, the following steps may be further included:

[0234] S143, depositing a protective layer 170, please refer to Fig. 20 , Fig. 20 A method based on Fig.19 Schematic diagram of the structure in which a protective layer is provided on the piezoelectric component away from the device layer.

[0235] Because the first electrode has been patterned before depositing the protection layer 170 , which causes a portion of the piezoelectric layer 112 to be exposed, a portion of the protection layer 170 may be in contact with the first electrode, and another portion of the protection layer 170 may be in contact with the piezoelectric layer 112 .

[0236] S144, a second connection hole 1152 is processed at a position where the second electrode is connected. The connection member is inserted through the second connection hole 1152 and can be connected to the second electrode group. The second electrode group may include at least one second electrode. Please refer to Fig.21 , Fig.21 A method based on Fig. 20 Schematic diagram of the structure of processing the second connecting hole from the protective layer.

[0237] The second connection hole 1152 can be processed to the side of the second electrode away from the resonance component, and part of the hole wall of the second connection hole 1152 can also be set on the second electrode. As long as the conductive structure passing through the second connection hole 1152 can be connected to the second electrode, the example of this application does not make any specific restrictions on this.

[0238] S145, processing a first connection hole 1143 at a position connected to the first electrode, and the conductive structure is arranged through the first connection hole 1143 to be connected to the first electrode, please refer to Fig. 22 , Fig. 22 A method based on Fig. 20 or Fig.21 Schematic diagram of the structure of processing the first connecting hole from the protective layer.

[0239] The first connection hole 1143 can be processed to the side of the first electrode away from the resonance film 120, and part of the hole wall of the first connection hole 1143 can also be arranged on the first electrode. As long as the conductive structure passing through the first connection hole 1143 can be connected to the first electrode, the example of this application does not make any specific restrictions on this.

[0240] During the manufacturing process of the differential piezoelectric resonant pressure sensor 100 , the first connection hole 1143 may be processed first and then the second connection hole 1152 , that is, S145 may be performed first and then S144 , and this example of the present application does not impose any specific limitation on this.

[0241] S146, depositing a lead electrode layer, part of the lead electrode layer may be located in the second connection hole 1152 and connected to the second electrode, please refer to Fig.23 , Fig.23A method based on Fig. 22 Schematic diagram of the structure of depositing a lead electrode layer on the side of the protection layer away from the device layer.

[0242] S147, patterning the lead electrode layer to form a first lead electrode group corresponding to the first electrode group and a second lead electrode group corresponding to the second electrode group, please refer to Fig.24 , Fig.24 A method based on Fig.23 Schematic diagram of the structure of processing lead electrodes on the lead electrode layer.

[0243] The side of the first lead electrode group close to the first electrode group is connected to the first electrode group, and the side of the first lead electrode group away from the first electrode group can be connected to the first part of the external circuit. The side of the second lead electrode group close to the second electrode group is connected to the second electrode group, and the side of the second lead electrode group away from the second electrode group can be connected to the second part of the external circuit. The second lead electrode group is the conductive structure mentioned in the above example. Based on this, the connection between the differential piezoelectric resonant pressure sensor 100 and the external circuit can be achieved.

[0244] S150, processing the pressure chamber 136 on the side of the Si wafer 200 away from the first substrate layer 330, please refer to Fig.25 , Fig.25 A method based on Fig.24 Schematic diagram of the structure of processing a pressure chamber on the side of the Si wafer away from the first device layer.

[0245] The pressure chamber 136 can be formed by etching or other processing methods on the side of the Si wafer 200 away from the first substrate layer 330. 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.

[0246] S160, forming a first resonator 140, a second resonator 150, and a first structure 131 and a second structure 132 which are spaced apart on a side of the piezoelectric component 110 away from the first device layer 310; wherein a portion of the resonant cavity is disposed in the first structure 131, and a portion of the resonant cavity is disposed between the first structure 131 and the second structure 132, a first end of the first resonator 140 is connected to a first position of the first structure 131, a second end of the first resonator 140 is connected to a second position of the first structure 131, the second position is spaced apart from the first position, a first end of the second resonator 150 is connected to the first structure 131, and a second end of the second resonator 150 is connected to the second structure 132, please refer to Fig.26 , Fig.26 A method based on Fig.25Schematic diagram of the structure of processing the first resonator and the second resonator from the protective layer.

[0247] The first resonator 140 , the second resonator 150 , and the first structure 131 and the second structure 132 that are spaced apart may be formed by etching or other processing methods.

[0248] In the process of forming the first resonator 140 and the second resonator 150, the first sub-electrode 1111, the third sub-electrode 1131, the first lead sub-electrode and the third sub-lead electrode corresponding to the first resonator 140 can be formed, and the second sub-electrode 1112, the fourth sub-electrode 1132, the second lead sub-electrode and the fourth sub-lead electrode corresponding to the second resonator 150 can be formed at the same time.

[0249] The first structure 131 may be processed with a first groove 133 so that the first structure 131 is annular, so that both ends of the first resonator 140 can be connected to the inner wall of the first groove 133 to achieve the connection between the first structure 131 and the first resonator 140 .

[0250] The first trench 133 can be formed by etching or other processing methods.

[0251] In the differential piezoelectric resonant pressure sensor 100 formed by the above method, the pressure chamber 136 can receive the pressure to be detected. Since the pressure chamber 136 is arranged on the side of the pressure resonance component 130 away from the resonance film 120, and the resonance film 120 and the pressure resonance component 130 cooperate to form a resonance chamber, the pressure to be detected can be transmitted to the resonance film 120 through the pressure resonance component 130. Since the piezoelectric component 110 is arranged on one side of the resonance film 120, the pressure to be detected transmitted to the resonance film 120 can be transmitted to the piezoelectric component 110, and the piezoelectric component 110 can detect the pressure to be detected.

[0252] Since the first resonator 140 is located on the inner side of the first structure 131 and the second resonator 150 is located on the outer side of the first structure 131, after the first structure 131 is deformed under the action of the pressure to be detected, the force applied to the first resonator 140 by the first structure 131 is opposite to the force applied to the second resonator 150, so that the frequency change of the first resonator 140 is opposite to the frequency change of the second resonator 150. The first resonator 140 and the second resonator 150 cooperate to form a differential structure, so that the deformation of the resonant component under the action of the same pressure to be detected is more obvious, which can improve the detection sensitivity of the differential piezoelectric resonant pressure sensor 100 and improve the detection accuracy of the differential piezoelectric resonant pressure sensor 100.

[0253] In some possible implementations, the differential piezoelectric resonant pressure sensor 100 includes a third groove 135 , which is disposed in the first structure 131 . There may be at least one third groove 135 , and the third groove 135 may divide the first structure 131 into a plurality of substructures 1311 .

[0254] 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.

[0255] In some possible implementations, the differential piezoelectric resonant pressure sensor 100 includes a third groove 135, the location of the third groove 135 corresponds to the location of the second structure 132, and the third groove 135 can divide the second structure 132 into a plurality of substructures 1311. In this case, S148 can process the deformation groove and the third groove 135 at the same time, or process the third groove 135 after processing the deformation groove, and this application example does not impose specific restrictions on this.

[0256] The third groove 135 may connect the first groove 133 and the second groove 134 , and at least one third groove 135 may be provided.

[0257] The processing method of the third groove 135 is similar to that of the first groove 133 , and is not described in detail in this example of the present application.

[0258] The third groove 135 may be processed before or after the pressure chamber 136 is processed, and this example of the present application does not impose any specific limitation on this.

[0259] In some possible implementations, the differential piezoelectric resonant pressure sensor 100 may further include a cover 190, and the cover 190 is bonded to the piezoelectric component 110. The bonding method may be anodic bonding, or metal bonding such as Al-Ge, Au-Au, or other bonding methods. Next, the bonding method of the cover 190 and the piezoelectric component 110 is described by taking the Al-Ge bonding connection between the cover 190 and the piezoelectric component 110 as an example.

[0260] Based on the above-mentioned method for manufacturing the differential piezoelectric resonant pressure sensor 100, in S147, after patterning the lead electrode layer to form at least one first lead electrode and at least one second lead electrode, the method further includes:

[0261] S1471, in addition to forming at least one first lead electrode and at least one second lead electrode on the patterned electrode layer, a first connecting member 181 is also formed. Please refer to Fig.26 , Fig.26 and Fig.25 The cross-sectional directions are different.

[0262] The first connecting member 181 may be roughly in the shape of a circular ring, a square ring or other structures. The first connecting member 181 may be a sealed ring structure. The first connecting member 181 may also be composed of a plurality of spaced segments. This application example does not impose any specific limitation on this.

[0263] S170, taking a glass wafer 400, and etching a cavity to form a cover 190 may specifically include:

[0264] S171, depositing a Ge layer on one side of the glass wafer 400, refer to Fig. 27 and Fig.28 , Fig. 27 A schematic diagram of the structure of a glass wafer 400 provided as an example of this application, Fig.28 A schematic diagram of a structure for processing a Ge layer on a glass wafer 400 provided as an example of the present application.

[0265] S162, etching the Ge layer to form a second connecting member 182, please refer to Fig.29 , Fig.29 A method based on Fig.28 Structural schematic diagram of processing the second connecting piece.

[0266] The shape of the second connecting member 182 can be the same as or different from the shape of the first connecting member 181. This application example does not impose any specific restrictions on this. As long as the first connecting member 181 can be connected to the second connecting member 182, the connection between the cover 190 and the piezoelectric component 110 can be achieved.

[0267] S173, a cavity is formed by etching on the side of the glass wafer 400 where the second connecting member 182 is provided, and the opening of the cavity is arranged toward the side of the glass wafer 400 where the second connecting member 182 is provided. Fig.30 , Fig.30 A schematic diagram of a structure for machining a cavity on a glass wafer to form a cover is provided as an example of the present application.

[0268] In some possible implementations, the differential piezoelectric resonant pressure sensor 100 may further include an adsorption structure 191 .

[0269] Based on the above-mentioned method for manufacturing the differential piezoelectric resonant pressure sensor 100, in S173, after taking a glass wafer 400 and etching the cavity to form a cover, the following steps may also be included:

[0270] S174, an adsorption structure 191 is provided on the cavity wall, please refer to Fig.31 , Fig.31 A schematic structural diagram of a cover 190 provided as an example of the present application, wherein an adsorption structure 191 is disposed inside.

[0271] Specifically, the connection between the adsorption structure 191 and the cover 190 can be achieved through a vacuum coating process or other processing methods, and this application example does not make any specific restrictions on this.

[0272] S180, bonding the cover 190 and the piezoelectric component 110, please refer to Fig.32 , Fig.32 A schematic diagram of a structure in which a cover is connected to the side of a protective layer facing away from the piezoelectric layer, provided as an example of the present application.

[0273] The bonding connection between the cover 190 and the piezoelectric component 110 can be performed in a vacuum environment or in an environment of a certain pressure, and this example of the application does not impose any specific limitation on this.

[0274] Exemplarily, the present application provides a method for preparing a differential piezoelectric resonant pressure sensor 100. Fig.33 For a flow chart of another method for preparing a differential piezoelectric resonant pressure sensor provided in this application example, please refer to Fig.33 The method is applicable to the differential piezoelectric resonant pressure sensor 100 provided in any of the above examples. The following processing method can be completed by MEMS processing equipment.

[0275] In the example of the present application, the method is used to process a CSOI wafer into a differential piezoelectric resonant pressure sensor 100 , and the CSOI wafer includes a second device layer, a second buried oxide layer, and a second substrate layer.

[0276] Among them, the second substrate layer is provided with a first structure 131 and a second structure 132 spaced apart on one side facing the second buried oxide layer, the end of the second structure 132 is connected to the middle of the second buried oxide layer, and the first structure 131, the second structure 132 and the second buried oxide layer cooperate to form a resonant cavity; in the example of the present application, the structure of the CSOI wafer is similar to the structure formed by bonding the Si wafer 200 and the SOI wafer 300 mentioned above, and the specific structure can be referred to Fig.17 The structure shown, Fig.17 The Si wafer 200 processed in the middle is equivalent to the second substrate layer in the example of this application. Fig.17 The oxide layer 160 in the embodiment is equivalent to the second buried oxide layer in the present application, and the first device layer 310 is equivalent to the second device layer in the present application. The method includes:

[0277] S210 , disposing a piezoelectric component 110 on a side of the second device layer away from the second buried oxide layer.

[0278] In the example of the present application, the method for setting the piezoelectric component 110 is similar to the method for setting the piezoelectric component 110 when the differential 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 18 to Figure 24The structure shown.

[0279] S220, processing a pressure cavity 136 on a side of the second substrate layer away from the second buried oxide layer.

[0280] In the example of the present application, the processing method of the pressure chamber 136 is similar to the processing method of the pressure chamber 136 when the differential piezoelectric resonant pressure sensor 100 is processed from the Si wafer 200 and the SOI wafer 300. For details, please refer to the relevant description above and Fig.25 The structure shown.

[0281] The differential piezoelectric resonant pressure sensor 100 formed by the method provided in the example of this application is similar in structure and function to the differential piezoelectric resonant pressure sensor 100 formed by processing the Si wafer 200 and the SOI wafer 300, and is not described in detail in this application.

[0282] By processing the differential piezoelectric resonant pressure sensor 100 according to the method provided in the example of the present application, during the manufacturing process of the differential piezoelectric resonant pressure sensor 100, the processing of the first structure 131 and the second structure 132 can be reduced, thereby reducing the processing steps of the differential piezoelectric resonant pressure sensor 100 and reducing the processing cost of the differential piezoelectric resonant pressure sensor 100.

[0283] The differential piezoelectric resonant pressure sensor 100 processed according to the method provided in the example of the present application may also include a third groove 135. The structure and processing method of the third groove 135 are similar to the processing method of the third groove 135 when the differential piezoelectric resonant pressure sensor 100 is processed from a Si wafer 200 and an SOI wafer 300, and the examples of the present application are not repeated here.

[0284] The differential piezoelectric resonant pressure sensor 100 processed according to the method provided in the example of the present application may also include a cover 190. The structure and processing method of the cover 190 are similar to the processing method of the cover 190 when the differential piezoelectric resonant pressure sensor 100 is processed from the Si wafer 200 and the SOI wafer 300. For details, please refer to the above related description and Figure 27 to Figure 32 The structure shown in this application example will not be repeated here.

[0285] In the present application example, a suction structure 191 may also be provided in the cover 190. For the specific configuration of the suction structure 191 and the role played by the suction structure 191, please refer to the above related description.

[0286] 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.

[0287] During the detection process of the differential piezoelectric resonant pressure sensor 100, the detection of the differential piezoelectric resonant pressure sensor 100 is easily affected by environmental factors, which may affect the detection result of the differential piezoelectric resonant pressure sensor 100. Environmental factors may be temperature, vibration, shock, etc. Based on this, the differential piezoelectric resonant pressure sensor 100 needs to be compensated.

[0288] Exemplarily, the present application provides a compensation system 500, Fig.34 For a schematic diagram of a compensation system 500 provided in this application example, please refer to Fig.34 The compensation system 500 may include an integrated driving component 530, a detection component 540 and at least two differential piezoelectric resonant pressure sensors 100 mentioned in the above embodiments, and the at least two differential piezoelectric resonant pressure sensors 100 include at least one pressure sensor 510 and at least one compensation sensor 520.

[0289] When only one pressure sensor 510 is provided, only one or more compensation sensors 520 may be provided.

[0290] 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.

[0291] Multiple compensation sensors 520 and detection sensors may be provided, and the number of compensation sensors 520 may be equal to the number of detection sensors, or the number of compensation sensors 520 may be different from the number of detection sensors.

[0292] The pressure sensor 510 is used to detect the pressure to be detected, and the compensation sensor 520 is used to compensate for the influence of environmental factors on the pressure sensor 510. The driving component 530 is connected to the driving electrode of the pressure sensor 510 and the driving electrode of the compensation sensor 520, and the driving component 530 is used to drive the detection sensor and the compensation sensor 520 to vibrate. The detection component 540 is connected to the detection electrode of the pressure sensor 510 and the detection electrode of the compensation sensor 520. The detection component 540 is used to detect the resonant frequency of the pressure sensor 510 and the compensation sensor 520.

[0293] 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.

[0294] Based on this, when the detection component 540 detects the resonant frequency of the pressure sensor 510 and the compensation sensor 520, it only needs to subtract the resonant frequency output by the compensation sensor 520 from the resonant frequency output by the pressure sensor 510 and then extract the final resonant frequency, thereby eliminating the influence of environmental factors and improving the detection accuracy of the compensation system 500 on the pressure to be detected.

[0295] Fig.35 For a schematic diagram of the working process of a compensation system 500 provided as an example of this application, please refer to Fig.35 , the working process of the compensation sensor 520 is as follows:

[0296] S310 , the driving component 530 is used to drive the pressure sensor 510 and the compensation sensor 520 .

[0297] S320 , the detection component 540 is used to detect and output a first resonant frequency corresponding to the pressure sensor 510 and a second resonant frequency corresponding to the compensation sensor 520 .

[0298] S330, a calculation module is used to calculate the difference between the first resonant frequency and the second resonant frequency to obtain a target resonant frequency.

[0299] S340, the calculation module may also calculate the pressure value of the pressure to be detected based on the resonance frequency.

[0300] The calculation module may be a part of the detection component 540 , or a module independent of the detection component 540 , which is not limited in this example of the present application.

[0301] Based on the compensation system 500 mentioned in the above example, during the operation of the compensation system 500, the pressure to be detected can act on the pressure chamber 136 of the pressure sensor, and the pressure to be detected does not act on the compensation sensor 520. Based on this, the structure of the pressure sensor 510 and the structure of the compensation sensor 520 can be completely consistent. The structures of the pressure sensor 510 and the compensation sensor 520 may also be inconsistent, for example, the compensation sensor 520 may not be provided with a pressure sensitive component. The example of this application does not limit the specific structures of the pressure sensor 510 and the compensation sensor 520.

[0302] In summary, according to the compensation system 500 provided in the example of the present application, when the detection component 540 detects the resonant frequency of the pressure sensor 510 and the compensation sensor 520, it only needs to subtract the resonant frequency output by the compensation sensor 520 from the resonant frequency output by the pressure sensor 510 and then extract the final resonant frequency. This can eliminate the influence of environmental factors and improve the detection accuracy of the compensation system 500 for the pressure to be detected.

[0303] Finally, it should be noted that the above embodiments are only specific implementation methods of the present application, but the protection scope of the present application is not limited thereto, and any changes or substitutions within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A differential 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 pressure resonance component is connected to the side of the resonance film away from the piezoelectric component, the side of the pressure resonance component facing the resonance film cooperates with the resonance film to form a resonance cavity, and a pressure cavity is provided on the side of the pressure resonance component away from the resonance film, and the pressure cavity is used to receive the pressure to be detected; Among them, the piezoelectric component and the resonant film cooperate to form a resonant component, and the resonant component includes a first resonator, a second resonator, and a first structure and a second structure arranged at intervals. Compared with the first resonator, the second resonator is arranged close to the edge of the differential piezoelectric resonant pressure sensor, the first end of the first resonator is connected to the first position of the first structure, the second end of the first resonator is connected to the second position of the first structure, the second position is arranged at intervals from the first position, the first end of the second resonator is connected to the first structure, and the second end of the second resonator is connected to the second structure.

2. The differential piezoelectric resonant pressure sensor according to claim 1, characterized in that: It also includes a deformation section, one end of which is connected to the first resonator through the first structure, and the other end of which is connected to the second structure.

3. The differential piezoelectric resonant pressure sensor according to claim 1, characterized in that: There are a plurality of second resonators, and positions where different second resonators are connected to the first structure are spaced apart, and positions where different second resonators are connected to the second structure are spaced apart.

4. The differential piezoelectric resonant pressure sensor according to any one of claims 1 to 3, characterized in that: The differential piezoelectric resonant pressure sensor comprises a first groove and a second groove which are arranged at intervals, wherein the second groove is arranged on a side of the first groove close to an edge of the differential piezoelectric resonant pressure sensor, and the notch of the first groove and the notch of the second groove are both arranged on a side of the piezoelectric component away from the resonant film; The first structure is provided with the first groove, and the second groove divides the resonant component into the first structure and the second structure which are spaced apart; A first end of the first resonator is connected to the first location, and a second end of the first resonator is connected to the second location; A first end of the second resonator is connected to a side of the first structure away from the first groove, and a second end of the second resonator is connected to a side of the second structure close to the second groove.

5. The differential piezoelectric resonant pressure sensor according to claim 4, characterized in that: The first structure is provided with at least one third groove, and the third groove communicates with the first groove and the second groove.

6. The differential piezoelectric resonant pressure sensor according to any one of claims 1 to 3, characterized in that: The piezoelectric assembly includes a first lead electrode group, a second lead electrode group, a first electrode group, a piezoelectric layer and a second electrode group; The second electrode group is connected to a side of the resonant film away from the pressure resonant component, the piezoelectric layer is connected to a side of the second electrode group away from the resonant film, part of the second lead electrode group is arranged on a side of the piezoelectric layer away from the second electrode group, and the second lead electrode group is arranged through the piezoelectric layer and is electrically connected to the second electrode group; The first electrode group is connected to a side of the piezoelectric layer away from the second electrode group, the first lead electrode group is arranged on a side of the first electrode group away from the piezoelectric layer, and the first lead electrode group is electrically connected to the first electrode group.

7. The differential piezoelectric resonant pressure sensor according to claim 6, characterized in that: Part of the resonant film is a first carrier, and part of the resonant film is a second carrier, and the first carrier is spaced from the second carrier; The first lead electrode group includes a first sub-lead electrode and a second sub-lead electrode, the first electrode group includes a first sub-electrode and a second sub-electrode, the first sub-electrode is disposed on the first carrier, the first sub-lead electrode is electrically connected to the first sub-electrode, the second sub-electrode is disposed on the second carrier, and the second sub-lead electrode is electrically connected to the second sub-electrode; The second lead electrode group includes a third sub-lead electrode and a fourth sub-lead electrode, the second electrode group includes a third sub-electrode and a fourth sub-electrode, the third sub-electrode is arranged on the first carrier, the third sub-lead electrode is electrically connected to the third sub-electrode, the fourth sub-electrode is arranged on the second carrier, and the fourth sub-lead electrode is electrically connected to the fourth sub-electrode.

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

9. A method for preparing a differential piezoelectric resonant pressure sensor, characterized in that: Applicable to the differential piezoelectric resonant pressure sensor according to any one of claims 1 to 7, the method is used to process a Si wafer and an SOI wafer into the differential piezoelectric resonant pressure sensor, the SOI wafer comprising a first device layer, a first buried oxide layer and a first substrate layer; The method comprises: Taking the Si wafer, processing one side of the Si wafer to form a first structure and a second structure, wherein the first structure and the second structure cooperate to form a resonant cavity; Taking the SOI wafer, bonding the SOI wafer to the Si wafer, and sealing the cavity opening of the resonant cavity with the first device layer; removing the first buried oxide layer and the first substrate layer, and setting the thickness of the first device layer to be the thickness of the resonance film; Disposing a piezoelectric component on a side of the first device layer away from the Si wafer; Processing a pressure chamber on a side of the Si wafer away from the first substrate layer; Processing a first resonator, a second resonator, and a first structure and a second structure spaced apart on a side of the piezoelectric component away from the first device layer; Part of the resonant cavity is arranged in the first structure, and part of the resonant cavity is arranged between the first structure and the second structure, the first end of the first resonator is connected to the first position of the first structure, the second end of the first resonator is connected to the second position of the first structure, the second position is spaced apart from the first position, the first end of the second resonator is connected to the first structure, and the second end of the second resonator is connected to the second structure.

10. A method for preparing a differential piezoelectric resonant pressure sensor, characterized in that: Applicable to the differential piezoelectric resonant pressure sensor according to any one of claims 1 to 7, the method is used to process a CSOI wafer into the differential piezoelectric resonant pressure sensor, the CSOI wafer comprising a second device layer, a second buried oxide layer and a second substrate layer; A first structure and a second structure are provided at intervals on one side of the second substrate layer facing the second buried oxide layer, an end of the first structure is connected to the middle of the second buried oxide layer, and the first structure, the second structure and the second buried oxide layer cooperate to form a resonant cavity; The method comprises: Taking the CSOI wafer, processing a piezoelectric component on a side of the second device layer away from the second buried oxide layer; Processing a pressure cavity on a side of the second substrate layer away from the second buried oxide layer; A first resonator and a second resonator are formed on a side of the piezoelectric component facing away from the second device layer. Compared with the first resonator, the second resonator is arranged closer to the edge of the differential piezoelectric resonant pressure sensor. The first end of the first resonator is connected to a first position of the first structure, and the second end of the first resonator is connected to a second position of the first structure. The second position is spaced apart from the first position, and the first end of the second resonator is connected to the first structure, and the second end of the second resonator is connected to the second structure.

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