A design and manufacturing method of a resonant differential pressure sensor based on eutectic bonding process

Abstract

The present invention designs a design and production method of a resonant differential pressure sensor based on a eutectic bonding process, uses photolithography, DRIE, and HF release processes to complete the production of a pressure sensitive film and a resonator on SOI, and uses a eutectic bonding process to bond a pure silicon wafer and SOI together to achieve vacuum packaging of the resonator. The resonant differential pressure sensor designed by the present invention can measure differential pressure, and the geometrically symmetrical dual-resonator differential output can make the sensor have higher sensitivity, smaller temperature coefficient and static pressure error. Compared with selective epitaxial growth, sacrificial layer etching, polysilicon process and silicon-silicon bonding process, the eutectic bonding process greatly reduces the difficulty of the process.

Description

Technical Field

[0001] The present invention relates to the field of silicon resonant pressure sensors, and in particular to a design and manufacturing method of a silicon resonant differential pressure sensor, specifically a design and manufacturing method of a resonant differential pressure sensor based on a eutectic bonding process. Background Art

[0002] Micro-electro-mechanical system (MEMS) is a cutting-edge interdisciplinary subject developed on the basis of microelectronics technology. It combines the electrical and mechanical movable structure characteristics of the chip, and uses two MEMS processing technologies, bulk silicon processing and surface processing, to achieve interaction with external electrical, thermal, optical, acoustic, force and other signals on a micro scale. Therefore, MEMS technology is widely used in modern sensor technology. Resonant MEMS differential pressure sensor is based on the principle that the resonant frequency of the resonator changes with the differential pressure. The differential pressure can be measured by detecting the resonant frequency of the resonator. It is widely used in oil exploration, industrial control, aerospace and other fields, and has excellent characteristics such as high precision, good long-term stability, digital output, and strong anti-interference ability.

[0003] The resonant differential pressure sensor mainly adopts an integrated structure of a resonator and a pressure sensitive membrane. The resonator is placed on the pressure sensitive membrane. When the pressure sensitive membrane is subjected to differential pressure, the resonator is subjected to stress, which causes a change in the resonant frequency. The magnitude of the differential pressure is inferred by detecting the resonant frequency through a closed-loop control circuit. Since the resonant frequency is a direct variable that directly reflects the magnitude of the measured differential pressure, the resonant frequency of the resonator should only be affected by the differential pressure. Therefore, in order to avoid the influence of external factors such as temperature, humidity, dust, and air pressure on the resonant frequency, it is very necessary to vacuum package the resonator. In addition, vacuum packaging can ensure that the resonant differential pressure sensor has a higher Q value, which can make the resonant differential pressure sensor have a higher detection resolution and a faster system response speed.

[0004] In the existing resonant differential pressure sensor vacuum packaging technology, Yokogawa Electric Corporation of Japan uses selective epitaxial growth and selective etching of sacrificial layers to achieve vacuum sealing of resonators. This process is complex and lacks flexibility, and is difficult to implement. The University of Wisconsin and Honeywell in the United States use LPCVD deposition of polysilicon and sacrificial layer release and other processes to achieve vacuum sealing of polysilicon double-ended clamped beams. This process needs to consider the adhesion of the substrate to polysilicon. In addition, polysilicon is not as good as single crystal silicon in terms of material aging, hysteresis, fatigue, creep, yielding, etc.; The University of Twente in the Netherlands uses silicon-silicon bonding and other processes to achieve vacuum packaging of resonators. However, silicon-silicon bonding is quite harsh on the flatness and roughness of the wafer and the temperature conditions during bonding, which is relatively difficult to implement. Therefore, the present invention proposes a design and production of a resonant differential pressure sensor based on eutectic bonding technology. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] The main purpose of the present invention is to provide a design and manufacturing method of a resonant differential pressure sensor based on a eutectic bonding process, so as to ensure that the resonant differential pressure sensor has good performance on the basis of realizing differential pressure measurement.

[0007] (II) Technical solution

[0008] The invention provides a design and manufacturing method of a resonant differential pressure sensor based on a eutectic bonding process.

[0009] A design and manufacturing method of a resonant differential pressure sensor based on a eutectic bonding process, comprising:

[0010] Step S1: constructing a three-dimensional model of a resonant differential pressure sensor;

[0011] Step S2: performing finite element simulation on the three-dimensional model of the resonant differential pressure sensor to solve the problems of modal interference and dual resonator sensitivity matching;

[0012] Step S3: drawing a photolithography mask for the resonant differential pressure sensor; preferably, drawing the photolithography mask for the resonant differential pressure sensor is performed in MEMS pro;

[0013] Step S4: using photolithography, DRIE and HF release processes to manufacture a resonator, a pressure sensitive film, a lead hole and an electrode structure on a piece of SOI;

[0014] Step S5: vacuum-packaging the pure silicon wafer and the processed SOI using a eutectic bonding process to obtain a eutectic bonded wafer;

[0015] Step S6: etching the pressure sensitive film area on the front side of the eutectic bonded wafer to obtain a sensor chip;

[0016] Step S7: Assemble the sensor chip obtained in step S6 and the glass by anodic bonding.

[0017] Specifically, the present invention provides a design and manufacturing method of a resonant differential pressure sensor based on a eutectic bonding process, including: step S1: constructing a three-dimensional model of a resonant differential pressure sensor; step S2: performing finite element simulation on the three-dimensional model of the resonant differential pressure sensor to solve the problems of modal interference and dual resonator sensitivity matching; step S3: drawing a photolithography mask of the resonant differential pressure sensor in MEMS pro; step S4: constructing a resonator, a pressure sensitive membrane, a lead hole and an electrode structure on a piece of SOI by using processes such as photolithography, DRIE and HF release; step S5: vacuum packaging a pure silicon wafer and a processed SOI by using a eutectic bonding process; step S6: etching a pressure sensitive membrane area on the front of the wafer after eutectic bonding. Step S7: assembling the vacuum packaged sensor chip with glass BF33 by using anodic bonding; step S8: assembling the sensor chip.

[0018] Preferably, the step S1 includes: sub-step S1a: performing finite element simulation on the first resonator and the second resonator at different positions on the pressure sensitive membrane, and adjusting the positions of the dual resonators to achieve the purpose of matching the sensitivities; sub-step S1b: simulating the change in the differential pressure sensitivity of the resonant differential pressure sensor under conditions of different pressure sensitive membrane thicknesses, and determining the thickness of the pressure sensitive membrane; sub-step S1c: optimizing the geometric symmetry design of the resonant differential pressure sensor structure by simulating the static pressure sensitivity of the sensor.

[0019] Preferably, step S2 includes: performing finite element simulation on the differential pressure characteristics and static pressure characteristics of the resonant differential pressure sensor within the working range (differential pressure range is -100kPa to 100kPa, static pressure range is 10kPa to 350kPa) to facilitate mutual verification with subsequent test results.

[0020] Preferably, the step S4 comprises: sub-step S4a: performing DRIE twice on the SOI substrate layer using a composite mask composed of ZnO and AZ4620 photoresist to form lead holes and a pressure sensitive film; sub-step S4b: performing DRIE twice on the SOI device layer using a composite mask composed of ZnO and AZ4620 photoresist to form a resonator and an electrode; sub-step S4c: using gaseous HF to release the buried oxide layer under the H-type resonant beam.

[0021] Preferably, the step S5 comprises: sub-step S5a: sputtering a certain thickness of Cr / Au on the back side of the pure silicon wafer as an intermediate layer for eutectic bonding; sub-step S5b: placing the processed SOI and the pure silicon wafer into a suss sb6e bonding machine to form a certain bonding system, evacuating the chamber, and applying a certain pressure and temperature to bond the two wafers.

[0022] Preferably, the step S7 comprises: sub-step S7a: cutting an air guide hole on the glass BF33 by laser processing; sub-step S7b: placing the glass BF33 and the manufactured sensor chip into a bonding machine and applying pressure, temperature and voltage for anodic bonding.

[0023] Preferably, step S8 includes: fixing the glass BF33 assembly layer of the sensor chip on the Kovar alloy base through silicone rubber, processing a through hole in the Kovar alloy base for connecting one of the pressure sources, and interconnecting the electrodes on the substrate layer of the sensor chip with the pins on the Kovar alloy base through gold wires.

[0024] Preferably, the method further comprises: machining a through hole on the top of the metal pipe cap for connecting another pressure source, and welding and sealing the machined metal pipe cap and the Kovar alloy base, so that the two pressure sources can be isolated from each other.

[0025] (III) Beneficial effects

[0026] The present invention realizes bonding between SOI and silicon wafer through eutectic bonding process, realizes vacuum packaging of resonator, ensures that resonator works in vacuum environment, and reduces process complexity. In addition, the present invention makes the static pressure error of resonant differential pressure sensor very small through reasonable design, and improves the measurement accuracy of resonant differential pressure sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Resonant differential pressure sensor prototype;

[0028] Figure 2 Dimensional diagram of H-shaped double-end clamped beam;

[0029] Figure 3 Schematic diagram of the SOI device layer structure;

[0030] Figure 4 A schematic diagram of the three-dimensional structure of the resonant differential pressure sensor designed by the present invention;

[0031] Figure 5 A schematic diagram of the assembly method of the resonant differential pressure sensor designed by the present invention;

[0032] Figure 6 Process flow chart of the resonant differential pressure sensor designed by the present invention;

[0033] Figure 7 Schematic diagram of the back structure of the resonant differential pressure sensor designed by the present invention.

[0034] in:

[0035] 100-sensor sensitive unit; 130-substrate layer; 120-buried oxide layer; 110-device layer; 140-first resonator; 150-second resonator; 132-first pressure sensitive film; 221-second pressure sensitive film; 131-lead hole; 151, 152, 153, 154, 155, 156, 157, 158-electrodes; 200-packaging cover; 210-glass layer; 220-silicon layer. DETAILED DESCRIPTION

[0036] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0037] The resonator of the resonant differential pressure sensor designed by the present invention is an H-shaped double-end fixed-support beam, and a double resonator is constructed to be located in different stress areas of the pressure sensitive membrane. Here, the double resonator is respectively called the first resonator and the second resonator. The first resonator is placed in the middle of the pressure sensitive membrane, and the second resonator is placed on the edge of the pressure sensitive membrane. Whether the pressure sensitive membrane is deformed upward or downward, the stresses on the H-shaped resonant beam on the membrane are opposite. Figure 5 As shown, when the stress (P1) on the first sensitive film is greater than the stress (P2) on the second sensitive film, the middle area of ​​the pressure sensitive film is a tensile stress area, at this time, the first resonance beam is subjected to tensile stress, which increases the resonance frequency; the edge area of ​​the pressure sensitive film is a compressive stress area, at this time, the second resonance beam is subjected to compressive stress, which reduces the resonance frequency. When the stress (P1) on the first sensitive film is less than the stress (P2) on the second sensitive film, the middle area of ​​the pressure sensitive film is a compressive stress area, at this time, the first resonance beam is subjected to compressive stress, which reduces the resonance frequency; the edge area of ​​the pressure sensitive film is a tensile stress area, at this time, the second resonance beam is subjected to tensile stress, which increases the resonance frequency. The frequency differential output of the dual resonator is used to characterize the magnitude of the differential pressure. On the one hand, it increases the sensitivity of the resonant differential pressure sensor. On the other hand, since the theoretical design of the dual resonator is the same, the influence of temperature and static pressure on it is theoretically the same. However, the actual dual resonator will produce deviations during the process of manufacturing, so the dual resonator is not exactly the same, but the differential output can still greatly reduce the temperature and static pressure errors.

[0038] The design method of a resonant differential pressure sensor based on a eutectic bonding process includes:

[0039] Step S1: constructing a three-dimensional model of a resonant differential pressure sensor;

[0040] Step S2: performing finite element simulation on the three-dimensional model of the resonant differential pressure sensor to solve the problems of modal interference and dual resonator sensitivity matching;

[0041] Step S3: Drawing the photolithography mask of the resonant differential pressure sensor. Preferably, drawing the photolithography mask of the resonant differential pressure sensor is performed in MEMS pro.

[0042] Wherein, the step S1 includes: sub-step S1a: performing finite element simulation on the differential pressure sensitivity when the first resonator and the second resonator are located at different positions on the pressure sensitive membrane, and adjusting the positions of the dual resonators to achieve the purpose of matching the sensitivities; sub-step S1b: simulating the change in the differential pressure sensitivity of the resonant differential pressure sensor under conditions of different pressure sensitive membrane thicknesses, and determining the thickness of the pressure sensitive membrane; sub-step S1c: optimizing the geometric symmetry design of the resonant differential pressure sensor structure by simulating the static pressure sensitivity of the sensor.

[0043] Step S2 includes: using ANSYS software to perform finite element simulation on the differential pressure characteristics and static pressure characteristics of the resonant differential pressure sensor within the working range; wherein the working range of the resonant differential pressure sensor includes a differential pressure range and a static pressure range, the differential pressure range is -100kPa to 100kPa, and the static pressure range is 10kPa to 350kPa.

[0044] The resonant differential pressure sensor design prototype provided by the present invention is as follows Figure 1 As shown, it uses the correlation between the resonant frequency of the resonator and the differential pressure, uses the SOI substrate layer as a pressure sensitive film, uses the SOI device layer to build the resonator, the SOI buried oxide layer is used as an electrical insulation layer and anchor point, and the pure silicon wafer is used as a sealing cover for vacuum packaging. The length of the resonator is set to 1140um, the width is set to 12um, the middle connecting block is 36um long and 12um wide, as shown Figure 2 As shown. Theoretically calculated, its natural frequency is 69.48kHZ. The size of the pressure sensitive film is set to 7000um×7000um, the size of the electrode on the device layer is 1000um×1000um, and the diameter of the lead hole in the SOI substrate layer is 600um. The problem of lead interconnection in the sensor vacuum packaging is solved by etching the back hole in the SOI substrate layer.

[0045] like Figure 1-7As shown, the structure of the resonant differential pressure sensor includes: a sensor sensitive unit 100, the sensor sensitive unit SOI is composed of a device layer 110, a buried oxide layer 120, and a substrate layer 130. A first pressure sensitive film 132 and a lead hole 131 are provided on the substrate layer. A first resonator 140 and a second resonator 150 are provided on the device layer 110, and the first resonator 140 and the second resonator 150 are respectively located in the middle and edge regions of the pressure sensitive film. The first resonator 140 and the second resonator 150 are respectively coupled to the substrate layer 130 through anchor points located on the buried oxide layer 120. A package cover plate 200 of the sensor, the package cover plate of the sensor is composed of a silicon layer 220 and a glass layer 210, and a second pressure sensitive film 221 is provided on the silicon layer 220. The sensor sensitive unit and the package cover plate are vacuum packaged by eutectic bonding, and the glass and the silicon wafer are connected by anodic bonding.

[0046] For the resonant differential pressure sensor, static pressure will cause the cross-section of the diaphragm protected by the cap to deform, and this deformation will cause the resonant frequency of the resonant beam to shift. In order to make the first-order effect of the ambient pressure the same for each resonator, the effect of static pressure after the difference frequency output will be greatly reduced. Therefore, when designing the device layer structure, the present invention designs the size and shape of the electrodes and the electrical connection parts of the first resonator and the second resonator into a geometrically symmetrical structure, such as Figure 3-4 Except for the different positions of the two resonators on the pressure sensitive membrane, the anchor points and electrodes 151, 152, 153, 154, 155, 156, 157, 158 of the two resonators are all geometrically symmetrical.

[0047] In the design of the resonator, it is also necessary to continuously adjust the positions of the first resonator and the second resonator on the pressure sensitive membrane through finite element analysis to achieve the purpose of matching the sensitivities of the first resonator and the second resonator. The sensitivity matching of the dual resonators will enable the resonant differential pressure sensor of the present invention to have better differential output and static pressure compensation performance. Finally, it is determined that the dual resonators are located at 1100um and -2760um on the pressure sensitive membrane respectively.

[0048] The manufacturing method of the resonant differential pressure sensor provided by the present invention is as follows Figure 6 shown.

[0049] Step a: prepare a piece of SOI, whose substrate layer is 300um, buried oxide layer is 2um, and device layer is 40um. After cleaning, sputter Cr on the front side to protect the device layer;

[0050] Step b: Deep etching (DRIE) the SOI substrate layer using a composite mask composed of ZnO and AZ4620 photoresist. This step requires two etchings. In the first etching, the photoresist is used as an etching mask, the etching pattern is the lead hole, and the etching depth is 170um. After the first etching is completed, acetone alcohol is used to remove the photoresist mask; in the second etching, ZnO is used as an etching mask, the etching pattern is the lead hole and the pressure sensitive film, and the etching depth is 150um. After the second etching is completed, NH 4 The ZnO mask was removed by Cl solution. After two etchings, the pressure sensitive film was etched to a position of 150 μm in the vertical direction, while the lead hole was etched to the buried oxide layer due to the self-stop of etching.

[0051] Step c: Use a composite mask composed of ZnO and AZ4620 photoresist to deeply etch (DRIE) the SOI device layer to etch out the resonant beam. This step requires two etchings. In the first etching, the photoresist is used as an etching mask, the etching pattern is the isolation groove, and the etching depth is 35um. After the first etching is completed, acetone alcohol is used to remove the photoresist mask; in the second etching, ZnO is used as an etching mask, and the etching pattern is the isolation groove, resonator and electrode. The etching depth is 10um. After the second etching is completed, NH4Cl solution is used to remove the ZnO mask. After two etchings, the resonator and electrode are etched to a position of 10um in the vertical direction, and the isolation groove is etched to the buried oxide layer due to the self-stop of etching;

[0052] Step d: Gaseous HF releases the resonant beam. Here, a two-step method is used to release the resonant beam. Gaseous HF is used to remove the buried oxide layer at the resonant beam, and then isopropyl alcohol is used to remove the water vapor on the surface. The resonator is released after several cycles.

[0053] Step e: prepare a 300um P-type (100) crystalline silicon wafer and clean it;

[0054] Step f: sputtering a metal layer of 30 nm Cr and 50 nm Au on the back side of the silicon wafer;

[0055] Step g: eutectic bonding the metal-sputtered silicon wafer to the SOI. Before bonding, gaseous HF is used to remove the natural oxide layer on the surface of the SOI device layer. The eutectic bonding adopts a sandwich bonding system, and a silicon wafer is added above and below the SOI and silicon wafer to ensure uniform force on the entire wafer area.

[0056] Step h: using a ZnO mask to DRIE-etch 270 μm on the front side of the eutectic-bonded wafer to etch out an action area of ​​another pressure source;

[0057] Step i: using gaseous HF to etch the buried oxide layer in the area where the lead hole is located on the back side of the SOI;

[0058] Step j: sputtering electrodes in the lead holes using a hard mask;

[0059] Step k: prepare 1000um glass BF33, and use laser processing technology to cut a circular hole with a radius of 800um as a pressure-conducting hole;

[0060] Step 1: Perform single-chip anodic bonding on the glass BF33 and the prepared silicon wafer.

[0061] After the resonant differential pressure sensor chip is completed, it needs to be assembled. For the assembly of the resonant differential pressure sensor, we need to isolate the upper and lower pressure sources of the pressure sensitive membrane from each other, and also ensure its electrical connection with the outside world. Therefore, the present invention provides such Figure 5 In the assembly method shown, the sensor chip is connected to the base of the Kovar alloy through silicone rubber, a pressure through hole is processed on the Kovar alloy base, connected to a pressure source, the electrode connection lead on the SOI substrate layer is connected to the pin on the Kovar alloy base, the pin realizes the electrical connection between the outside world and the sensor chip in the metal cap, the metal cap and the Kovar alloy base are welded together to achieve sealing, and a through hole is processed on the metal cap to connect to another pressure source.

[0062] So far, the embodiments of the present invention have been described in detail in conjunction with the accompanying drawings. Based on the above description, those skilled in the art should have a clear understanding of the design and manufacture of the resonant differential pressure sensor of the present invention.

[0063] It should be noted that the implementation methods not shown or described in the drawings or the text of the specification are all forms known to ordinary technicians in the relevant technical field and are not described in detail. In addition, the above definitions of each element are not limited to the various methods mentioned in the embodiments, and ordinary technicians in the field can simply change or replace them, for example:

[0064] (1) Directional terms such as “upper”, “lower”, “front”, “back”, “left”, “right”, etc. mentioned in the embodiments are only used to refer to the directions of the drawings and are not intended to limit the scope of protection of the present invention;

[0065] (2) The above embodiments can be used in combination with each other or with other embodiments based on design and reliability considerations. That is, the technical features in different embodiments can be freely combined to form more embodiments.

[0066] The specific embodiments described above have detailed descriptions of the objectives, technical solutions and beneficial effects of the present invention. It should be understood that the above descriptions are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A design and manufacturing method of a resonant differential pressure sensor based on eutectic bonding process, characterized in that: The resonator of the resonant differential pressure sensor is an H-shaped double-end fixed-support beam, and a dual resonator is constructed to be located in different stress areas of the pressure sensitive membrane. Here, the dual resonators are respectively a first resonator and a second resonator. The first resonator is placed in the middle of the pressure sensitive membrane, and the second resonator is placed on the edge of the pressure sensitive membrane. Whether the pressure sensitive membrane is deformed upward or downward, the stresses on the H-shaped resonant beam on the membrane are opposite in the middle area and the membrane edge area. The frequency differential output of the dual resonator is used to characterize the magnitude of the differential pressure. The method comprises: Step S1: constructing a three-dimensional model of a resonant differential pressure sensor; Step S2: performing finite element simulation on the three-dimensional model of the resonant differential pressure sensor to solve the problems of modal interference and dual resonator sensitivity matching; Step S3: drawing a photolithography mask for the resonant differential pressure sensor; Step S4: using photolithography, DRIE and HF release processes to manufacture a resonator, a pressure sensitive film, a lead hole and an electrode structure on a piece of SOI; Step S5: vacuum packaging the pure silicon wafer and the processed SOI using a eutectic bonding process to obtain a eutectic bonded wafer; the step S5 includes: Sub-step S5a: sputtering Cr and Au on the back side of the pure silicon wafer as an intermediate layer for eutectic bonding; Sub-step S5b: placing the processed SOI and the pure silicon wafer into a bonding machine to form a bonding system, evacuating the chamber, and applying pressure and temperature to bond the pure silicon wafer and the SOI; Step S6: etching the pressure sensitive film area on the front side of the eutectic bonded wafer to obtain a sensor chip; Step S7: Assemble the sensor chip obtained in step S6 and the glass BF33 by anodic bonding.

2. The design and production method according to claim 1, characterized in that: The step S1 comprises: Sub-step S1a: performing finite element simulation on the differential pressure sensitivity when the first resonator and the second resonator are located at different positions on the pressure sensitive membrane, and adjusting the positions of the dual resonators to achieve the purpose of matching the sensitivities; Sub-step S1b: simulating the change of the differential pressure sensitivity of the resonant differential pressure sensor under conditions of different pressure sensitive film thicknesses to determine the thickness of the pressure sensitive film; Sub-step S1c: Optimizing the geometric symmetry design of the resonant differential pressure sensor structure by simulating the static pressure sensitivity of the sensor.

3. The design and production method according to claim 1, characterized in that: Step S2 includes: using ANSYS software to perform finite element simulation on the differential pressure characteristics and static pressure characteristics of the resonant differential pressure sensor within the working range of the resonant differential pressure sensor; wherein the working range of the resonant differential pressure sensor includes a differential pressure range and a static pressure range, the differential pressure range is -100kPa~100kPa, and the static pressure range is 10kPa~350kPa.

4. The design and production method according to claim 1, characterized in that: The step S4 comprises: Sub-step S4a: performing DRIE twice on the SOI substrate layer using a composite mask composed of ZnO and photoresist to form a lead hole and a pressure sensitive film; Sub-step S4b: performing DRIE twice on the SOI device layer using a composite mask composed of ZnO and photoresist to form a resonator and an electrode; Sub-step S4c: using gaseous HF to release the buried oxide layer under the H-type resonance beam.

5. The design and production method according to claim 1, characterized in that: The step S7 comprises: Sub-step S7a: cutting a gas guide hole on the glass BF33 by laser processing; Sub-step S7b: Place the glass BF33 and the sensor chip manufactured in step S6 into a bonding machine and apply pressure, temperature and voltage to perform anodic bonding.

6. The design and production method according to claim 1, characterized in that: The manufacturing method further comprises step S8: assembling the sensor chip; The assembling of the sensor chip comprises: fixing the glass assembly layer of the sensor chip on the Kovar alloy base through silicone rubber, processing a through hole on the Kovar alloy base for connecting one of the pressure sources, and interconnecting the electrodes on the substrate layer of the sensor chip with the pins on the Kovar alloy base through gold wires; A through hole is processed on the top of the metal pipe cap for connecting another pressure source. The processed metal pipe cap is welded and sealed to the Kovar alloy base, so that the two pressure sources can be isolated from each other.

7. The design and production method according to claim 1, characterized in that: The resonant differential pressure sensor based on the eutectic bonding process comprises: a sensor sensitive unit (100), wherein the sensor sensitive unit SOI is composed of a device layer (110), a buried oxide layer (120), and a substrate layer (130); a first pressure sensitive film (132) and a lead hole (131) are provided on the substrate layer (130); a first resonator (140) and a second resonator (150) are provided on the device layer (110), wherein the first resonator (140) and the second resonator (150) are respectively located in the middle and edge regions of the pressure sensitive film domain; a first resonator (140) and a second resonator (150) are respectively coupled to a substrate layer (130) via anchor points located on a buried oxide layer (120); a sensor packaging cover plate (200), the sensor packaging cover plate being composed of a silicon layer (220) and a glass layer (210), and a second pressure sensitive film (221) being disposed on the silicon layer (220); the sensor sensitive unit (100) and the packaging cover plate (200) are vacuum packaged via eutectic bonding, and the glass layer (210) and the silicon layer (220) are connected via anodic bonding.

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