A dual-diaphragm differential pressure resonant pressure sensor based on stepped silicon islands to amplify lateral displacement

Abstract

A dual-diaphragm differential pressure resonant pressure sensor based on a stepped silicon island to amplify lateral displacement relates to a pressure sensor. The sensor adopts electrostatic excitation piezoresistive detection and includes an upper membrane, an upper silicon island, an oxide layer, a resonant layer and a lower membrane island. Except for the oxide layer, the rest are made of silicon material. When the upper membrane is subjected to load pressure, the pressure diaphragm deforms, thereby driving the upper silicon island to produce displacement. The upper silicon island structure is stepped. The displacement generated by the rotation along the fulcrum amplifies the lateral displacement and transmits it to the resonator layer, thereby causing the resonant beam on the resonant layer to produce axial internal stress, causing the resonator resonant frequency to change, thereby realizing differential pressure measurement. The lower membrane island structure is an integrated structure, and the resonator can be vacuum-encapsulated. The lower membrane island structure of the sensor, the upper membrane and the upper silicon island structure jointly balance the static pressure, realizing application under high static pressure background.

Description

Technical Field

[0001] The present invention relates to a pressure sensor, in particular to a double-diaphragm differential pressure resonant pressure sensor based on a stepped silicon island for amplifying lateral displacement and a manufacturing method thereof. Background Art

[0002] Since the early 1980s, MEMS (Micro-Electro-Mechanical Systems) resonant pressure sensors have gradually become a key technology in the field of pressure measurement. Powered by MEMS technology, pressure sensors have achieved miniaturization, high precision, and low cost. However, with the continuous expansion of application areas, pressure sensors in extreme environments have attracted increasing attention, particularly in high-end equipment, military weaponry, aerospace, and deep-sea exploration. In these extreme environments, achieving micro differential pressure detection under high static pressure has become a major technical challenge for MEMS pressure sensors. MEMS pressure sensors can be categorized as differential, absolute, and gauge pressure depending on the reference pressure used for the test. Their core sensing mechanisms include piezoresistive, piezoelectric, and resonant. Resonant pressure sensors are widely favored in the pressure measurement field due to their high precision, high sensitivity, and stability, with an overall accuracy of better than 0.01% FS. However, for differential pressure sensors, achieving micro differential pressure detection under high static pressure remains a technical challenge. Improving the sensitivity of differential pressure sensors is crucial to improving their overall performance.

[0003] Against this backdrop, many companies and research teams, both domestically and internationally, began developing related products. Foreign companies such as Druck, YOKOGAWA, Paroscientific, and Thales began developing these products as early as the 1980s. Domestic research institutions and universities, such as the Institute of Electronics of the Chinese Academy of Sciences, Beijing University of Aeronautics and Astronautics, University of Electronic Science and Technology of China, Xiamen University, and Northwestern Polytechnical University, began research in this field in the 1990s.

[0004] The literature (Xiangguang Han, Mimi Huang, Zutang Wu, et al. Advances in high-performance MEMS pressure sensors: design, fabrication, and packaging. Microsystems & Nanoengineering. 2023; 9(1): 0-0. doi: 10.1038 / s41378-023-00620-1.) reviewed in detail the development and application status of MEMS pressure sensor technology, indicating that there are still huge technical challenges and room for development in the field of high static pressure and micro-differential pressure detection. Summary of the Invention

[0005] The present invention aims to provide a dual-diaphragm differential pressure resonant pressure sensor based on a stepped silicon island that amplifies lateral displacement, featuring a novel structure, high sensitivity, and superior measurement accuracy. Through its unique structural design and manufacturing process, it achieves highly sensitive detection of pressure changes.

[0006] The dual-membrane differential pressure resonant pressure sensor based on a stepped silicon island to amplify lateral displacement comprises a lower membrane island, a pressure-sensitive membrane, a resonant layer, an oxide layer, an upper membrane, and an upper silicon island, which are arranged in sequence from bottom to top;

[0007] The upper silicon island includes a stepped silicon island, which adopts a design of a first-order rotation fulcrum, a second-order matching step, and a third-order membrane island bonding domain to achieve amplification of lateral displacement, thereby improving the sensitivity of the sensor;

[0008] The upper membrane and the upper silicon island are tightly bonded together by bonding technology. Four electrode holes are symmetrically distributed below the upper membrane for achieving precise electrical connection with the electrodes of the resonance layer. The membrane cavity of the upper membrane is located on one side, and the membrane cavity design matches the position of the stepped silicon island structure of the upper silicon island, ensuring that the four electrode holes correctly correspond to the electrodes of the resonance layer and are distributed on one side of the membrane cavity of the upper membrane to achieve precise electrical connection.

[0009] The oxide layer is located between the upper silicon island and the resonant layer. As a key layer for releasing the movable structure of the resonant layer in the SOI process, it plays a vital role in the performance and stability of the sensor.

[0010] The resonant layer includes a resonant main beam, a resonant sub-beam, a Chinese-shaped beam at the bend, a resonant layer cover, a detection piezoresistive beam, a detection electrode and a ground electrode, forming the core resonant structure of the sensor, and realizing balanced force-electricity conversion through its symmetrical distribution; the resonant main beam and the resonant sub-beam are connected to each other through the Chinese-shaped beam at the bend to form a stable resonant structure, the resonant end moving tooth is integrated with the resonant sub-beam and connected to the resonant main beam, and the driving end fixed tooth is connected to the driving electrode; the resonant sub-beam is connected to the piezoresistive detection beam and the ground electrode through the end; one end of the resonant main beam is connected to the step through the resonant layer cover The oxide layer cover plate below the stepped silicon island is connected, and the other end of the resonant main beam is connected to the Chinese-shaped beam at the bend of the resonator; the Chinese-shaped beam at the bend is located in the center of the resonator, and only one end is connected to the stepped silicon island cover plate, and the other end is not fixed; the oxide layer cover plate is connected to the bottom of the stepped silicon island, and the oxide layer cover plate is connected to the resonator; the piezoresistive strips are symmetrically distributed and connected, and are all connected to the detection electrode; the resonant layer cover plate is used to fix the stepped silicon island to ensure its stable operation under pressure; the detection piezoresistive beam and the detection electrode are used to convert mechanical stress into electrical signals to realize pressure detection.

[0011] The pressure-sensitive membrane is located in the central area of ​​the lower membrane island and is used to sense changes in external pressure and transmit the pressure to the resonant layer;

[0012] The lower membrane island is an integrated structure of a pressure-sensitive membrane and a silicon island. One side of the structure is a silicon island connected to the resonant layer cover plate, and the other side is a pressure-sensitive membrane structure that works together with the upper membrane to balance the static pressure and improve measurement accuracy.

[0013] The shape of the pressure-sensitive film is rectangular or oblong to adapt to different installation requirements and application scenarios.

[0014] The upper film is bonded to the upper silicon island.

[0015] Silicon oxide is connected between the upper silicon island and the resonance layer, and the movable structure of the resonator is released by the silicon oxide.

[0016] An oxide layer is sandwiched between the upper silicon island and the resonance layer, and the three-layer structure is made of SOI.

[0017] The resonant main beam, the resonant sub-beam and the detection piezoresistive strips are symmetrically distributed on both sides of the resonator.

[0018] The two ends of the resonant main beam are respectively connected to the resonant layer cover and the U-shaped beam at the bend. Only one side of the U-shaped beam at the bend is connected to the stepped silicon island cover, and the other side is not fixed to a resonator structure similar to a single-ended clamp.

[0019] The lower membrane island structure is an integrated structure of a pressure-sensitive membrane and a silicon island. One side of the structure is a pressure-sensitive membrane for balancing static pressure, and the other side is a silicon island structure for transmitting deformation stress of the pressure-sensitive membrane and amplifying the stress.

[0020] The sensor of the present invention not only improves measurement accuracy and sensitivity through the above-mentioned structural design and manufacturing process, but also achieves miniaturization and integration through SOI processing technology, and is suitable for various high-precision pressure measurement fields such as aerospace, medical equipment, environmental monitoring, etc.

[0021] The beneficial effects of the present invention are:

[0022] 1. High sensitivity and high precision: By adopting a resonant sensor structure and utilizing the change of resonant frequency to measure pressure, high sensitivity and high precision measurement can be achieved.

[0023] 2. Wide range adjustment capability: The sensor design allows the pressure measurement range to be adjusted within a wide range, such as 0.5kPa to 100MPa, while ensuring measurement accuracy better than 0.01%.

[0024] 3. High reliability and long life: Double-sided symmetrical etching and highly symmetrical chip structure design are adopted, internal stress is evenly dispersed, combined with vacuum packaging to improve the reliability and service life of the sensor.

[0025] 4. Wide temperature operating range: Utilizing silicon-glass anodic bonding technology and taking into account the matching of the thermal expansion coefficients of silicon and borosilicate glass, the sensor can operate stably in the temperature range of -55°C to 125°C, meeting the needs of high-end applications such as aerospace.

[0026] 5. Process compatibility and mass production potential: The preparation method uses photolithography, etching and thin film processes, which are compatible with CMOS processes, conducive to mass production and cost reduction.

[0027] 6. Strong anti-interference ability: The resonant differential pressure sensor has quasi-digital output characteristics, which makes it have good anti-interference ability and suitable for a variety of industrial environments.

[0028] 7. Reduce temperature drift: By designing Si-SiO2 composite resonant beams and applying dual resonators to offset thermal stress, the sensitivity temperature drift of the sensor is reduced.

[0029] 8. Simplified manufacturing process: Using simplified SOI-MEMS technology to improve the manufacturing efficiency and consistency of the sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the overall structure of the high differential pressure sensitivity dual-membrane resonant pressure sensor based on the stepped silicon island structure described in the present invention.

[0031] Figure 2 for Figure 1 An exploded view of the three-layer structure of the high differential pressure sensitivity dual-film resonant pressure sensor based on the stepped silicon island structure.

[0032] Figure 3 for Figure 1 A front view of the upper silicon island structure of the high differential pressure sensitivity dual-film resonant pressure sensor based on the stepped silicon island structure.

[0033] Figure 4 for Figure 1 A front view of the oxide layer structure of the high differential pressure sensitivity dual-film resonant pressure sensor based on the stepped silicon island structure.

[0034] Figure 5 for Figure 1 A front view of the stepped silicon island layer resonant layer structure of the high differential pressure sensitivity dual-film resonant pressure sensor based on the stepped silicon island structure.

[0035] Figure 6 for Figure 1 A front view of the lower membrane island structure of the high differential pressure sensitivity dual-membrane resonant pressure sensor based on the stepped silicon island structure.

[0036] Figure 7 for Figure 1 A simulated cross-sectional view of the stress distribution of the overall structure of the high differential pressure sensitivity dual-membrane resonant pressure sensor based on the stepped silicon island structure under two pressure states: static pressure and differential pressure.

[0037] Figure 8 for Figure 1 A structural simulation modal cross-sectional view of the resonant layer of the high differential pressure sensitivity dual-membrane resonant pressure sensor based on the stepped silicon island structure during differential pressure operation.

[0038] Figure 9 for Figure 1 The working modes of the main beam and the auxiliary beam of the resonant layer of the high differential pressure sensitivity dual-film resonant pressure sensor based on the stepped silicon island structure when they are in operation.

[0039] Figure 10 This is a diagram of the lateral displacement transmitted to the resonant layer cover plate of the present invention.

[0040] exist Figures 1 to 6 In the , each mark is:

[0041] 1: Upper membrane electrode hole, 2: Upper pressure-sensitive membrane; 3: Upper membrane, 4: Upper silicon island, 5: Oxide layer, 6: Resonance layer, 7: Lower membrane island; 8: First-order rotation fulcrum, 9: Second-order matching step, 10: Third-order membrane island bonding domain, 11: Upper silicon island electrode hole; 12: Oxide layer cover plate, 13: Oxide layer mass block, 14: Oxide layer electrode hole; 15: Resonance layer cover plate, 16: Driving electrode, 17: Resonance layer mass block, 18: Resonance main beam, 19: Resonance sub-beam, 20: Ground electrode, 21: Detection electrode; 22: Lower membrane island silicon island, 23: Lower membrane island mass block, 24: Lower membrane island movable structure release groove, 25: Lower pressure-sensitive membrane. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the following embodiments will be further described in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0043] See also Figures 1 to 6The high differential pressure sensitivity dual-film resonant pressure sensor based on a stepped silicon island structure includes an upper membrane 3, an upper silicon island 4, an oxide layer 5, a resonant layer 6, and a lower membrane island 7. The upper membrane 3 is located at the top of the sensor. One side of the upper membrane 3 is the upper pressure-sensing membrane 2. The upper membrane electrode holes 1 are symmetrically distributed below the upper membrane 3 for connecting the electrodes. The upper membrane 3 corresponds to the resonant layer cover 15 of the resonant layer 6. The upper silicon island 4, the oxide layer 5, and the resonant layer 6 are processed as a whole using an SOI wafer and manufactured using an SOI process to ensure the stability and reliability of the sensor in long-term applications. The outer side of the upper membrane island 4 is made of a first-order rotation fulcrum 8, a second-order matching step 9, and a third-order membrane island bonding domain 10 by wet etching, and the electrode holes of the upper silicon island 4 are made by dry etching. The oxide layer 5 is located between the upper silicon island 4 and the resonant layer 6, and has an oxide layer cover 12 on the oxide layer 5; the resonant layer 6 includes a resonant layer cover 15 for receiving and transmitting stress. After etching, the lower membrane island 7 is formed into a lower membrane silicon island 22. Dry etching is then used to form a lower membrane mass block 23 and a lower membrane movable structure release groove 24. Finally, the lower membrane is connected to the resonant layer 6 via silicon-silicon bonding. Through the interaction with the upper membrane electrode hole 1, the electrode hole 11 of the upper silicon island 4, and the electrode hole 14 of the oxide layer 5, the drive electrode 16 and the detection electrode 21 corresponding to the resonant layer 6 are led out using wires. The upper pressure-sensitive membrane 2 directly senses changes in external pressure and transmits the sensed pressure in the form of stress to the third-order membrane island bonding domain 10 of the upper silicon island 4. The upper silicon island 4 amplifies this stress and transmits the amplified stress to the resonant layer cover plate 15 of the resonant layer 6 via the oxide layer cover plate 12 of the oxide layer 5. The resonant layer cover plate 15 transmits this stress in the form of tensile stress, resulting in a lateral displacement to the resonant main beam 18, thereby causing the resonant layer to generate an operating modal output frequency.

[0044] The resonant layer 6 is provided with a resonant layer cover plate 15 , a driving electrode 16 , a ground electrode 20 , a detection electrode 21 , a resonant layer mass block 17 , a resonant main beam 18 , and a resonant sub-beam 19 .

[0045] Driven by an external power supply, the driving electrode 16 generates an excitation signal to cause the resonant main beam 18 to vibrate; when the resonant main beam 18 vibrates, it drives the resonant sub-beam 19 to vibrate, and the resonant sub-beam 19 vibrates in the plane around the bottom support point, driving the detection electrode 21 connected to the resonant sub-beam 19 to vibrate. The detection electrode 21 is a beam structure. During the vibration process, it is continuously compressed and stretched, resulting in periodic changes in its resistance value. In this case, the natural frequency of the resonant main beam 18 and the resonant sub-beam 19 decreases as the pressure increases, and the vibration frequency of the detection electrode 21 decreases accordingly, and the frequency of the periodic change of the resistance value also decreases. By detecting the change in electrical quantity caused by the change in the resistance value of the piezoresistive strip, the corresponding resonant frequency is obtained.

[0046] The specific implementation scheme for the stepped silicon island transmission effect involves the synergistic effect of the upper silicon island 4, oxide layer 5, and resonant layer 6. When the upper membrane 3 is deformed by external pressure, the stress generated by the deformation is transmitted to the various layers of the cover structure. Driven by the three-layer cover structure of the upper silicon island 4, oxide layer 5, and resonant layer 6, a certain rotational displacement is generated. This rotational displacement amplifies the lateral displacement transmission caused by the stepped silicon island deformation, thereby improving the differential pressure sensitivity of the sensor. The lower pressure-sensing membrane 25 of the lower membrane island 7 and the upper pressure-sensing membrane 2 of the upper membrane 3 work simultaneously to achieve a balance between the upper and lower static pressures. This balancing mechanism ensures that the sensor achieves zero displacement of all intermediate layers under high pressure environments, thereby enabling the differential pressure sensor to operate stably even in extreme environments, increasing its application potential in various harsh environments.

[0047] The lower membrane island 7 is bonded to the resonant layer 6 to ensure a stable connection between the two layers. A movable structure release groove 24 is provided on the bonding surface between the lower membrane island 7 and the resonant layer 6. This design allows the resonant main beam 18, resonant sub-beam 19, and detection electrode 21 on the resonant layer 6 to vibrate freely, ensuring that these movable structures can vibrate freely without constraints, thereby achieving precise sensing.

[0048] The upper membrane 3 is connected to the upper silicon island 4 via silicon-silicon bonding. An upper membrane electrode hole 1 is formed in the upper membrane 3. This upper membrane electrode hole 1 connects to the resonant layer 6 through the upper silicon island electrode hole 11. The upper membrane electrode hole 1 is also connected to the drive electrode 16, the ground electrode 20, and the detection electrode 21, respectively. This allows electrical signals to be effectively transmitted from the upper membrane 3 to the resonant layer 6, thereby driving and detecting the resonant structure. The resonant differential pressure sensor has a quasi-digital output characteristic, giving it excellent anti-interference capabilities.

[0049] The upper and lower pressure-sensitive films 2 and 25 have a predetermined thickness and are rectangular in shape. Their thickness can be adjusted within the permitted process range based on the required range and sensitivity. The design utilizes double-sided symmetrical etching and a highly symmetrical chip structure, ensuring uniform internal stress distribution. This, combined with vacuum packaging, enhances the sensor's reliability and service life.

[0050] The entire structure can be bonded and fixed to glass, allowing it to be installed in different tube shells for application. The sensor design takes into account the matching of the thermal expansion coefficients of silicon and borosilicate glass, enabling it to operate stably in the temperature range of -55°C to 125°C.

[0051] See also Figures 7-10The present invention utilizes a stepped silicon island structure to amplify tiny displacements caused by pressure, significantly improving the sensor's differential pressure sensitivity. This is demonstrated through simulation cross-sectional views and operating modal diagrams, which show the stress distribution and modal changes of the sensor under different pressure conditions. The dual-membrane structure and symmetrical electrode design effectively improve measurement accuracy. This effect is demonstrated in the detailed description, supported by the structural details shown in the figure. Specifically:

[0052] Figure 7 The stress distribution of the overall structure of the dual-film resonant pressure sensor based on the stepped silicon island structure is shown under two pressure states: static pressure and differential pressure. Figure 7 The figure shows the stress distribution of various sensor components under pressure, the stress state of the upper membrane 3 and upper silicon island 4 under static and differential pressure, and the stress distribution of the oxide layer 5, which is the key layer for releasing the movable structure of the resonant layer in the SOI process.

[0053] Figure 8 The diagram shows the structural modes of the resonant layer under differential pressure. A mode refers to the vibration pattern of a structure at a specific frequency. The diagram shows the vibration modes of the resonant layer 6 under differential pressure, which helps us understand how the resonant frequency changes with pressure. The vibration modes of the resonant main beam 18 and secondary beam 19 are also shown, which are key components of the sensor's resonant frequency variation.

[0054] Figure 9 Demonstrate the operating modes of the main beam 18 and auxiliary beam 19 of the resonant layer. This includes the vibration patterns of the main beam and auxiliary beam, which are directly related to the sensor's resonant frequency. Also, demonstrate how these vibration modes affect the sensor's output signal, enabling detection of pressure changes.

[0055] Figure 10 The amplification effect of the lateral displacement transmitted to the resonant layer cover plate in the present invention is demonstrated. The figure includes: a schematic diagram of the lateral displacement, which contains two curves, representing the surface lateral displacement of the upper surface (curve 94 in the figure) and the lower surface (curve 46 in the figure) of the resonant layer cover plate under different pressure conditions. The increase in the lateral displacement value indicates that the sensitivity of the sensor has been significantly improved. The introduction of the stepped silicon island amplification mechanism explains how to amplify the displacement through this structural design, thereby improving the sensitivity of the sensor. The double membrane structure and symmetrical electrode design, these designs help to improve the measurement accuracy. The application of SOI technology ensures the long-term stability and reliability of the sensor. The present invention can further amplify the lateral displacement transmitted to the resonant layer cover plate, and the lateral displacement value can be increased by an order of magnitude. The present invention significantly improves the sensitivity of the sensor through the stepped silicon island amplification mechanism. The double membrane structure and symmetrical electrode design effectively improve the measurement accuracy. The application of SOI technology ensures the long-term stability and reliability of the sensor.

[0056] The working principle of the present invention is given below:

[0057] When external pressure acts on the pressure-sensitive membrane, the pressure felt by the upper pressure-sensitive membrane 2 is transmitted in the form of stress to the third-order membrane island bonding domain 10 of the upper silicon island 4. The upper silicon island 4 amplifies this stress and transmits it to the resonant layer cover 15 of the resonant layer 6 through the oxide layer cover 12 of the oxide layer 5. The resonant layer cover 15 transmits the amplified stress in the form of tensile stress to the resonant main beam 18, causing the resonant layer to generate an operating modal output frequency. When the resonant main beam 18 vibrates, it drives the resonant sub-beam 19 to vibrate. The resonant sub-beam 19 vibrates in-plane around the bottom support, driving the detection electrode 21 to vibrate. The resistance of the detection electrode 21 changes periodically, and its vibration frequency decreases as pressure increases. The corresponding resonant frequency is obtained by detecting the change in the electrical quantity generated by the change in the resistance of the detection electrode 21, thereby achieving pressure measurement. The present invention amplifies the tiny deformation of the resonant layer through a stepped silicon island amplification mechanism, causing the detection piezoresistive beam and the detection electrode to generate corresponding electrical signal changes. By detecting and processing these electrical signals, high-precision measurement of external pressure can be achieved.

[0058] Based on microelectromechanical systems (MEMS) technology, the present invention effectively amplifies minute pressure changes through a combination of a multilayer membrane structure and a silicon island structure, achieving highly sensitive detection of minute pressure changes. The dual-membrane structure and symmetrical electrode design improve measurement accuracy and ensure high sensor sensitivity. The use of SOI technology ensures the long-term stability and reliability of the sensor. The present invention effectively amplifies and transmits stress, ultimately obtaining accurate pressure measurements by detecting changes in the electrodes.

[0059] The above embodiments are only preferred embodiments of the present invention and should not be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent of the present invention.

Claims

1. A dual-diaphragm differential pressure resonant pressure sensor based on a stepped silicon island to amplify lateral displacement, characterized by It includes a lower membrane island, a pressure-sensitive membrane, a resonant layer, an oxide layer, an upper membrane, and an upper silicon island arranged successively from bottom to top; The upper silicon island includes a stepped silicon island, and the stepped silicon island adopts a design of a first-order rotating fulcrum, a second-order matching step, and a third-order membrane island bonding domain to achieve amplification of lateral displacement, thereby improving the sensitivity of the sensor; The upper membrane and the upper silicon island are tightly bonded together through a bonding technology. Four electrode holes are symmetrically distributed below the upper membrane for precise electrical connection with the electrodes of the resonant layer; the membrane cavity of the upper membrane is located on one side, and the design of the membrane cavity matches the position of the stepped silicon island of the upper silicon island structure, ensuring that the four electrode holes correctly correspond to the electrodes of the resonant layer and are distributed on one side of the membrane cavity of the upper membrane to achieve precise electrical connection; The oxide layer is located between the upper silicon island and the resonant layer. As the key layer for releasing the movable structure of the resonant layer in the SOI process, it plays a crucial role in the performance and stability of the sensor; The resonant layer includes a resonant main beam, a resonant sub-beam, a middle-shaped beam at the bending part, a resonant layer cover plate, a detection piezoresistive beam, a detection electrode, and a grounding electrode, forming the core resonant structure of the sensor, and achieving balanced force-electricity conversion through its symmetric distribution; The resonant main beam and the resonant sub-beam are connected to each other through the middle-shaped beam at the bending part to form a stable resonant structure. The movable teeth at the resonant end are integrated with the resonant sub-beam and connected to the resonant main beam, and the fixed teeth at the driving end are connected to the driving electrode; The resonant sub-beam is connected to the piezoresistive detection beam and the grounding electrode through its end; One end of the resonant main beam is connected to the oxide layer cover plate below the stepped silicon island through the resonant layer cover plate, and the other end of the resonant main beam is connected to the middle-shaped beam at the bending part of the resonator; the middle-shaped beam at the bending part is located at the center of the resonator, and one end is connected to the stepped silicon island cover plate; the stepped silicon island is connected to the oxide layer cover plate below, and the oxide layer cover plate is connected to the resonator; the piezoresistive strips are symmetrically distributed and connected, and are all connected to the detection electrode; the resonant layer cover plate is used to fix the stepped silicon island to ensure its stable operation under pressure; the detection piezoresistive beam and the detection electrode are used to convert mechanical stress into an electrical signal to achieve pressure detection; The pressure-sensitive membrane is located in the central area of the lower membrane island, used to sense external pressure changes and transmit the pressure to the resonant layer; The lower membrane island is an integrated structure of the pressure-sensitive membrane and the silicon island. One side of this structure is the silicon island, which is connected to the resonant layer cover plate, and the other side is the pressure-sensitive membrane structure, which works together with the upper membrane to balance the static pressure and improve the measurement accuracy.

2. A dual-diaphragm differential pressure resonant pressure sensor based on a stepped silicon island amplifying lateral displacement according to claim 1, characterized in that The shape of the pressure-sensitive membrane is rectangular or square to adapt to different installation requirements and application scenarios.

3. A dual-diaphragm differential pressure resonant pressure sensor based on a stepped silicon island amplifying lateral displacement as claimed in claim 1, characterized in that There is silicon oxide connected between the upper silicon island and the resonant layer, and the movable structure of the resonator is released through the silicon oxide.

4. A dual-diaphragm differential pressure resonant pressure sensor based on a stepped silicon island amplifying lateral displacement as claimed in claim 1, characterized in that There is an oxide layer sandwiched between the upper silicon island and the resonant layer, and the three-layer structure is processed by SOI.

5. A dual-diaphragm differential pressure resonant pressure sensor based on a stepped silicon island amplifying lateral displacement as claimed in claim 1, characterized in that The resonant main beam, the resonant sub-beam, and the detection piezoresistive strips are symmetrically distributed on both sides of the resonator.

6. A dual-diaphragm differential pressure resonant pressure sensor based on a stepped silicon island amplifying lateral displacement as claimed in claim 1, characterized in that Both ends of the resonant main beam are respectively connected to the resonant layer cover plate and the middle-shaped beam at the bending part. The middle-shaped beam at the bending part is only connected to the stepped silicon island cover plate on one side, and there is no fixed structure similar to a single-end fixed support on the other side.

7. A dual-diaphragm differential pressure resonant pressure sensor based on a stepped silicon island for amplifying lateral displacement according to claim 1, characterized in that The lower membrane island structure is an integrated structure of a pressure-sensitive membrane and a silicon island. One side of the structure is a pressure-sensitive membrane for balancing static pressure, and the other side is a silicon island structure for transmitting deformation stress of the pressure-sensitive membrane and amplifying the stress.

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