A high-precision biaxial silicon capacitor accelerometer based on micro / nano technology

Abstract

This invention relates to the field of high-precision accelerometer technology, and in particular to a biaxial silicon capacitive high-precision accelerometer based on micro-nano technology. It includes two coaxially arranged micromechanical sensing units, vertically aligned. Each micromechanical sensing unit includes a silicon substrate, with a sensitive mass block positioned above the substrate. Fixed teeth are symmetrically arranged between the silicon substrate and the sensitive mass block, and movable teeth are positioned on opposite sides of the two fixed teeth. Support components for supporting the sensitive mass block are symmetrically arranged between the two movable teeth. A temperature compensation circuit for real-time monitoring and temperature compensation is provided on the silicon substrate, and a fixed electrode is located at one end of the silicon substrate. This invention enables consistent X-axis and Y-axis measurement performance and allows simultaneous measurement of acceleration along two axes in two-dimensional space. Furthermore, it effectively achieves high-precision and high-reliability acceleration measurement under high-impact and temperature-varying environments.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of high-precision accelerometers, in particular to a dual-axis silicon capacitance high-precision accelerometer based on micro-nano technology. BACKGROUND

[0002] In many key fields of modern science and technology, such as high-precision weapon equipment, aerospace inertial navigation and automobile safety systems, extremely strict requirements are put forward for the performance of accelerometers. Traditional accelerometers gradually fail to meet the growing demand in terms of sensitivity, accuracy and anti-interference ability. Although micro-mechanical accelerometers have the advantages of low cost and small size to some extent, they still have many limitations in high-performance application fields. At present, the working principles of accelerometers mainly include capacitive and piezoresistive types, and the piezoresistive accelerometer has the disadvantages of low precision and poor temperature characteristics, and its application field is limited. The capacitive accelerometer has become the mainstream product at present.

[0003] For the technical improvement of the accelerometer, the corresponding solution method is given in the existing patent literature, for example, the patent literature CN118962183A discloses a capacitive accelerometer and a manufacturing method thereof, a three-layer silicon structure design of a substrate, a structure layer and a cover plate is adopted to significantly improve the impact resistance of the accelerometer, so that the accelerometer can still maintain stable performance in a harsh environment. And the N-type silicon substrate and the cover plate polished on both sides, and the heavily doped P-type silicon structure layer effectively reduce the influence of packaging stress on the performance of the accelerometer, and improve the measurement accuracy and reliability. The manufacturing method is relatively simple, which reduces the production cost to some extent and improves the production efficiency. However, there are still some limitations. Although the three-layer silicon structure design improves the impact resistance and the influence of packaging stress, the capacitive change may still be limited, which affects the sensitivity and accuracy of the accelerometer. And the patent does not explicitly mention the temperature compensation mechanism, and the temperature change may have a great influence on the capacitive measurement, resulting in a decrease in measurement accuracy. Most of the existing accelerometers are mainly for single-axis accelerometers, and for two-dimensional or multi-dimensional acceleration measurement, multiple single-axis accelerometers need to be combined for use, which increases the system complexity and cost

[0004] Therefore, a high-performance dual-axis silicon capacitance accelerometer based on micro-nano technology is needed, which can not only effectively realize high-precision and high-reliability acceleration measurement, but also has temperature stability and multi-axis measurement function. SUMMARY

[0005] The application aims to provide a dual-axis silicon capacitance high-precision accelerometer based on micro-nano technology to solve the problems existing in the prior art.

[0006] In order to achieve the above object, the application provides the following scheme: a double-shaft silicon capacitor high-precision accelerometer based on micro-nano technology, comprising two coaxially arranged micro-mechanical sensing units, the two micro-mechanical sensing units are arranged vertically, the micro-mechanical sensing unit comprises a silicon substrate, a sensitive mass block is arranged above the silicon substrate, a fixed tooth is symmetrically arranged between the silicon substrate and the sensitive mass block, a movable tooth is arranged on the opposite side of the two fixed teeth, a support assembly for supporting the sensitive mass block is symmetrically arranged between the two movable teeth, the silicon substrate is provided with a temperature compensation circuit for real-time monitoring and compensation of temperature, and one end of the silicon substrate is provided with a fixed pole.

[0007] Preferably, the support assembly comprises a plurality of suspension beams, adjacent two suspension beams are connected through a spring beam, and the sensitive mass block is suspended above the silicon substrate through the spring beam.

[0008] Preferably, a polysilicon layer is grown on the silicon substrate, and the suspension beam and the spring beam are formed on the polysilicon layer through micro-nano processing etching.

[0009] Preferably, the spring beam is a high-elasticity modulus folded beam.

[0010] Preferably, the fixed tooth is fixedly connected with the silicon substrate, so that the fixed tooth forms an electrode on the silicon substrate.

[0011] Preferably, the movable tooth is fixedly connected with the sensitive mass block, so that the movable tooth forms an electrode on the sensitive mass block.

[0012] Preferably, the movable tooth and the fixed tooth are staggered to form a comb-tooth shape, and the movable tooth and the fixed tooth on the same side of the silicon substrate are symmetrically arranged.

[0013] Preferably, an epitaxial silicon layer is grown on the silicon substrate, and the sensitive mass block is formed on the epitaxial silicon layer through micro-nano processing etching.

[0014] Preferably, the spring beam and the sensitive mass block are made of polysilicon material.

[0015] Preferably, an oxide layer is arranged between the fixed pole and the silicon substrate.

[0016] The application discloses the following technical effects:

[0017] This invention utilizes two coaxially arranged micromechanical sensing units, with the two micromechanical sensing units positioned vertically to each other, to ensure consistent X-axis and Y-axis measurement performance and to simultaneously measure two axial accelerations in two-dimensional space. Furthermore, the support assembly effectively prevents damage to the moving and fixed teeth under high impact, enabling high-precision and high-reliability acceleration measurement even in environments with high impact and temperature variations. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the symmetrical arrangement structure along the X and Y axes of the present invention;

[0020] Figure 2 This is a front view structural diagram of the present invention;

[0021] Figure 3 This is a flowchart illustrating the working principle of the present invention;

[0022] Figure 4 This is a flowchart illustrating the dual-axis symmetry design of the present invention;

[0023] Figure 5 This is a flowchart illustrating the design process of the motion protection structure of this invention.

[0024] Among them, 1. fixed tooth; 2. moving tooth; 3. suspended beam; 4. spring beam; 5. fixed electrode; 6. epitaxial silicon layer; 7. polycrystalline silicon layer; 8. oxide layer; 9. silicon substrate. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] Example 1

[0028] Reference Figures 1-2The application provides a double-axis silicon capacitor high-precision accelerometer based on micro-nano technology, which comprises two coaxially arranged micro-mechanical sensing units, the two micro-mechanical sensing units are arranged vertically, the micro-mechanical sensing unit comprises a silicon substrate 9, a sensitive mass block is arranged above the silicon substrate 9, a fixed tooth 1 is symmetrically arranged between the silicon substrate 9 and the sensitive mass block, a movable tooth 2 is arranged on the opposite side of the two fixed teeth 1, a supporting assembly for supporting the sensitive mass block is symmetrically arranged between the two movable teeth 2, the silicon substrate 9 is provided with a temperature compensation circuit for real-time monitoring and compensation of temperature, and one end of the silicon substrate 9 is provided with a fixed pole 5.

[0029] The silicon substrate 9 is the basic structure of the accelerometer, which provides mechanical support and electrical isolation.

[0030] The two coaxially arranged micro-mechanical sensing units are arranged vertically, that is, the micro-mechanical sensing units on the X-axis and the micro-mechanical sensing units on the Y-axis have the same pattern, only the placement position is different, which can ensure that the measurement performance of the accelerometer in the two axial directions is balanced, and the acceleration in the two axial directions in the two-dimensional space can be measured at the same time.

[0031] The symmetric design ensures that the measurement performance of the accelerometer in the X-axis and Y-axis directions is completely consistent, including sensitivity, resolution and dynamic range. The accelerometer can provide uniform measurement accuracy in two-dimensional space, avoiding measurement errors caused by axial differences. Since the structure and performance of the two axial directions are completely the same, the calibration process can be simplified, and the calibration parameters of the other axial direction can be directly applied, improving the production efficiency and consistency. At the same time, the symmetric design reduces the axial performance difference caused by manufacturing errors or environmental changes, improving the overall reliability and stability of the accelerometer.

[0032] The double-axis symmetric design enables the accelerometer to simultaneously measure the acceleration in the two axial directions in the two-dimensional space, and can simultaneously provide acceleration data of the X-axis and Y-axis, which is suitable for application scenarios requiring two-dimensional acceleration information, such as inertial navigation, automobile safety system, unmanned aerial vehicle control, etc. The measurement data of the two axial directions can be output in real time, which is convenient for data fusion and further processing, improving the response speed and real-time performance of the system. The symmetric design and reasonable placement position ensure high-precision measurement of each axial direction, improving the measurement accuracy and reliability of the overall system.

[0033] The specific steps of arranging the micro-mechanical sensing unit on the X-axis and the micro-mechanical sensing unit on the Y-axis are as follows: symmetric design, symmetrically arranging the micro-mechanical sensing units of the X-axis and the Y-axis on the silicon substrate 9, ensuring that the structure and performance of the two axial directions are completely consistent. Placement position, reasonably arrange the placement position of the X-axis and the Y-axis, reduce the cross-axis interference, ensure that the measurement result of each axial direction is independent and accurate.

[0034] The application can make the X-axis and Y-axis measurement performance consistent and can simultaneously measure two-axis acceleration in two-dimensional space through two coaxially arranged micromechanical sensing units arranged vertically on each other.

[0035] In a further optimization scheme, the support assembly comprises a plurality of suspension beams 3, and two adjacent suspension beams 3 are connected through a spring beam 4, and the sensitive mass is suspended above the silicon substrate 9 through the spring beam 4.

[0036] When acceleration acts on the sensitive mass, the sensitive mass is displaced, causing the capacitance between the movable tooth 2 and the fixed tooth 1 to change, and the acceleration can be measured by detecting the capacitance change.

[0037] In a further optimization scheme, a polysilicon layer 7 is grown on the silicon substrate 9, and the suspension beam 3 and the spring beam 4 are formed on the polysilicon layer 7 through micro-nano machining etching. The suspension beam 3 and the spring beam 4 have high-precision geometric dimensions and good mechanical properties.

[0038] The specific steps of etching the spring beam 4 are as follows: (1) material selection, selecting a high elastic modulus polysilicon material to ensure stability and reliability under high acceleration conditions. (2) Micro-nano machining, using photolithography technology and plasma enhanced chemical vapor deposition (PECVD) technology to form a polysilicon layer 7 on the silicon substrate 9, and then forming a folded beam structure through etching process. (3) Anchor point design, etching anchor points on the silicon substrate 9 to ensure the fixation and support of the spring beam 4, while reducing the restriction on the movement of the sensitive mass.

[0039] In a further optimization scheme, the spring beam 4 is a high elastic modulus folded beam. The length of the spring beam can be greatly increased in a limited space, so that the sensitive mass can produce greater displacement under the same external force, thereby increasing the capacitance change and enhancing the measurement precision. Greater displacement means greater capacitance change, thereby improving the sensitivity of the accelerometer, allowing it to more accurately measure smaller acceleration changes. The folded beam can achieve a longer equivalent length in a limited space, optimizing the overall size of the accelerometer and making it more compact, suitable for miniaturized applications.

[0040] The sensitive mass is suspended above the silicon substrate 9 by the spring beam 4, which provides the necessary mechanical support and elastic restoring force for the sensitive mass; it can allow the sensitive mass to move freely when subjected to acceleration, thereby generating displacement. The spring beam 4 not only provides the necessary mechanical support, but also ensures that the motion of the sensitive mass has sufficient degrees of freedom to produce significant displacement changes under acceleration.

[0041] Further optimization scheme, the fixed tooth 1 is fixedly connected with the silicon substrate 9, so that the fixed tooth 1 forms an electrode on the silicon substrate 9.

[0042] Further optimization scheme, the movable tooth 2 is fixedly connected with the sensitive mass, so that the movable tooth 2 forms an electrode on the sensitive mass.

[0043] The surfaces of the movable tooth 2 and the fixed tooth 1 are specially treated to reduce surface roughness and reduce capacitance measurement error.

[0044] The specific treatment method is chemical mechanical polishing, plasma cleaning and improving the flatness of the surface and atomic layer deposition.

[0045] Chemical mechanical polishing, through the combination of chemical reaction and mechanical grinding, polishes the surface to a very smooth state, significantly reducing the surface roughness.

[0046] Plasma cleaning, using active particles in plasma to bombard the surface to remove impurities and contaminants on the surface.

[0047] Improving the flatness of the surface and atomic layer deposition, depositing a uniform thin film on the surface to improve the flatness and electrical properties of the surface.

[0048] When acceleration acts on the sensitive mass, the sensitive mass displaces, causing the capacitance between the movable tooth 2 and the fixed tooth 1 to change, and the acceleration can be measured by detecting the capacitance change.

[0049] Further optimization scheme, the movable tooth 2 and the fixed tooth 1 are interlaced to form a comb-tooth shape, and the movable tooth 2 and the fixed tooth 1 on the same side of the silicon substrate 9 are symmetrically arranged.

[0050] The movable tooth 2 and the fixed tooth 1 are made of high-precision micro-nano machining technology, have fine comb-tooth structure and highly consistent size, and this high-precision machining technology ensures the geometric size and position accuracy of the movable tooth 2 and the fixed tooth 1, thereby improving the precision and consistency of the capacitance measurement; the surfaces of the movable tooth 2 and the fixed tooth 1 are specially treated to reduce surface roughness and reduce capacitance measurement error. The distance between adjacent capacitive movable tooth 2 and fixed tooth 1 is greater than the distance between the motion-protected fixed tooth 1 and movable tooth 2.

[0051] The adjacent movable teeth 2 and fixed teeth 1 are serrated, increasing the electrode surface area and improving the capacitance change amount, enhancing the resolution and measurement accuracy of the accelerometer.

[0052] By serrating the adjacent movable teeth 2 and fixed teeth 1, the contact area of the movable teeth 2 and fixed teeth 1 is increased, thereby increasing the capacitance change amount. The increase in capacitance change amount makes the accelerometer more responsive to acceleration, improving measurement accuracy. A larger electrode surface area means that smaller changes in acceleration can also cause significant changes in capacitance, thereby improving the resolution of the accelerometer, allowing it to detect more subtle changes in acceleration.

[0053] By optimizing the shape and size of the serrations, the electrode surface area is increased while ensuring that the gap between the electrodes is large enough to avoid interference between the electric fields of the electrodes.

[0054] The movable teeth 2 and fixed teeth 1 are symmetrically arranged in the pattern, ensuring uniformity and consistency of capacitance change, improving the stability of the measurement.

[0055] Further optimization scheme, the silicon substrate 9 grows an epitaxial silicon layer 6, the sensitive mass is etched on the epitaxial silicon layer 6 by micro-nano processing.

[0056] The thickness of the sensitive mass is 20-30um, which makes the sensitive mass have high mechanical strength and impact resistance; and the sensitive mass has high-precision geometric dimensions and good mechanical properties; the shape and size of the sensitive mass are optimized to improve its response sensitivity to acceleration and measurement accuracy.

[0057] By designing the thickness of the sensitive mass to be 20-30um, the thin mass can reduce the mass and improve the response speed to acceleration, enhancing the sensitivity of the accelerometer. Despite the thin thickness, the high mechanical strength of the polysilicon material ensures the stability of the mass under high acceleration conditions and prevents damage from external forces. The thin mass helps to reduce the overall size of the accelerometer, making it suitable for small-scale applications.

[0058] The specific steps of etching the sensitive mass are as follows: (1) material selection, high-purity single crystal silicon material is selected to ensure good mechanical and electrical properties. (2) Micro-nano processing, using deep reactive ion etching (DRIE) technology to etch the pattern of the sensitive mass on the silicon substrate 9, ensuring high-precision geometric dimensions. (3) Surface treatment, chemical mechanical polishing (CMP) treatment is performed on the surface of the sensitive mass to reduce surface roughness and reduce capacitance measurement error.

[0059] Further optimization scheme, the spring beam 4 and the sensitive mass use polysilicon material. It has high elastic modulus and good fatigue life.

[0060] The polycrystalline silicon material has high mechanical strength, good elastic modulus, and high electrical conductivity; the polycrystalline silicon material has high mechanical strength and can withstand large external forces, ensuring the stability of the mass under high acceleration conditions; the polycrystalline silicon material has good elastic modulus and can produce appropriate displacement when subjected to external forces, and quickly returns to its original position after the force disappears, improving the sensitivity and accuracy of the measurement, and the high electrical conductivity of the polycrystalline silicon material is conducive to the accuracy and stability of the capacitance measurement.

[0061] The polycrystalline silicon material is not prone to fatigue fracture under repeated acceleration, and can maintain stable performance for a long time, ensuring the reliability and durability of the accelerometer.

[0062] In order to avoid the spring beam 4 of the accelerometer from producing excessive displacement under high impact conditions, causing physical contact and damage between the moving teeth 2 and the fixed teeth 1; such damage not only affects the measurement accuracy, but also can cause the failure of the accelerometer.

[0063] When the spring beam 4 is overloaded, the physical contact and damage between the moving teeth 2 and the fixed teeth 1 can be effectively prevented, ensuring the reliability and stability of the accelerometer under high impact conditions.

[0064] A limiting structure is provided on the movement path of the moving teeth 2 and the fixed teeth 1, which will prevent the further contact between the moving teeth 2 and the fixed teeth 1 when the displacement of the spring beam 4 exceeds a certain range, protecting the capacitance structure from damage. Under high impact conditions, the reliability of the accelerometer is significantly improved, reducing measurement errors and equipment failures caused by physical damage; and a buffer material is provided between the moving teeth 2 and the fixed teeth 1 to absorb part of the impact energy and reduce the collision force between the moving teeth and the fixed teeth.

[0065] Further optimization scheme, between the fixed pole 5 and the silicon substrate 9 is provided with an oxide layer 8. The oxide layer 8 is an oxide layer for insulation and protection, preventing short circuit and physical damage between the fixed poles 5.

[0066] Temperature changes have a significant impact on capacitance measurements, as the electrical and mechanical properties of materials change with temperature. In order to ensure the measurement accuracy and stability of the accelerometer under different temperature conditions, a temperature compensation circuit is essential.

[0067] The temperature compensation circuit obtains temperature information through a temperature sensor integrated on the silicon substrate 9, and the integrated temperature sensor can accurately measure the temperature of the environment where the accelerometer is located, providing real-time temperature data and correcting the capacitance measurement results according to the preset temperature compensation algorithm.

[0068] By integrating the temperature sensor with other components of the accelerometer on the same silicon substrate 9, the overall size is reduced, making it suitable for miniaturization applications. The integrated temperature sensor can quickly respond to temperature changes and provide timely temperature information, ensuring the timeliness and accuracy of temperature compensation.

[0069] The present application achieves high-precision and high-sensitivity acceleration measurement by using micro-nano processing technology to manufacture the sensitive mass, spring beam 4, moving tooth 2 and fixed tooth 1. In addition, by integrating the temperature compensation circuit, this design is more convenient in terms of temperature stability and easy to achieve high-precision measurement while maintaining the stability and reliability of the system.

[0070] The present application not only maintains stable performance in high-impact and temperature change environments, but also simultaneously measures the acceleration of two axes in two-dimensional space, with high precision, high sensitivity and high reliability. This makes the accelerometer have a significant advantage in high-precision and high-reliability measurement, and is suitable for acceleration measurement in various complex environments, such as aerospace, automotive safety, inertial navigation, etc.

[0071] The present application ensures the high precision and consistency of each component by using high-precision micro-nano processing technology to manufacture the sensitive mass, spring beam 4, moving tooth 2 and fixed tooth 1, significantly improving the overall performance and reliability of the accelerometer. Not only does it improve measurement accuracy, but it also enhances the stability and durability of the accelerometer in complex environments.

[0072] The present application uses a high-elasticity modulus of polysilicon material to make the spring beam 4, and designs it as a folded beam, significantly increasing the equivalent length of the spring beam 4. Not only does it increase the displacement of the sensitive mass when subjected to acceleration, thereby increasing the capacitance change and measurement accuracy, but it also ensures the mechanical strength and reliability of the accelerometer under high-impact conditions. In addition, by precisely controlling the size and anchor point design of the spring beam 4, the performance of the accelerometer is further optimized, enabling it to maintain high precision and high stability in complex environments.

[0073] The present application increases the electrode surface area by designing the sawtooth-shaped moving tooth 2 and fixed tooth 1, thereby increasing the capacitance change, enhancing the resolution and measurement accuracy of the accelerometer. Not only does it improve the sensitivity of the measurement, but it also reduces nonlinear errors, further improving the accuracy and reliability of the measurement.

[0074] The present application obtains temperature information through the temperature sensor integrated on the silicon substrate 9, and corrects the capacitance measurement results according to the preset temperature compensation algorithm. This ensures the measurement accuracy and stability of the accelerometer under different temperature conditions, improving the reliability and applicability of the accelerometer.

[0075] The dual-axis design of the application enables the accelerometer to measure the acceleration of two axes simultaneously in a two-dimensional space, and the X-axis and Y-axis are graphically symmetrical and placed differently, ensuring balanced measurement performance of the two axes. This design not only improves the comprehensiveness and accuracy of measurement, but also simplifies the calibration process, improves production efficiency and consistency.

[0076] Referring to Figure 3 , is the working principle flow chart of the accelerometer, when external acceleration acts on the accelerometer, the acceleration causes the displacement of the sensitive mass. In turn, the displacement of the sensitive mass causes the capacitance change between the moving tooth 2 and the fixed tooth 1, and the detection circuit measures the capacitance change. Then the temperature compensation circuit corrects the capacitance measurement result according to the data of the temperature sensor, and outputs the final acceleration measurement result. And data processing and application are carried out on the measurement result, and feedback and adjustment are carried out according to real-time data.

[0077] Referring to Figure 4 , the dual-axis symmetrical design flow is to arrange the X-axis and Y-axis symmetrically, and arrange the micromechanical sensing unit of the X-axis and Y-axis symmetrically on the silicon substrate 9. Through symmetrical design, the structure and performance of the two axes are ensured to be consistent. Reasonably arrange the placement position of the X-axis and Y-axis to reduce the cross-axis interference. Ensure that the measurement result of each axis is independent and accurate, and the acceleration of the X-axis and Y-axis can be measured simultaneously. Through the dual-axis design, the comprehensiveness and accuracy of measurement are improved. Since the structure and performance of the two axes are exactly the same, the calibration process can be simplified.

[0078] Referring to Figure 5 , is the motion protection structure design flow chart, first, the motion protection structure is designed, and the motion protection structure of the moving tooth 2 and the fixed tooth 1 is designed. Then set the limit structure, set the limit structure on the motion path of the moving tooth 2 and the fixed tooth 1. The limit structure will prevent the moving tooth 2 and the fixed tooth 1 from further contacting. Then set the buffer material between the moving tooth 2 and the fixed tooth 1. The buffer material absorbs part of the impact energy, reducing the collision force between the moving tooth 2 and the fixed tooth 1. Through the limit and buffer design, the reliability of the accelerometer under high impact conditions is improved. By reducing physical damage, the service life of the accelerometer is prolonged.

[0079] Example two

[0080] This embodiment is the application of a dual-axis silicon capacitive high-precision accelerometer.

[0081] It is applied to aerospace inertial navigation. In the field of aerospace, the accelerometer is used to measure the acceleration of the aircraft, and provides accurate navigation data. Specifically, the installation position is used, the accelerometer is installed at the key position of the aircraft, such as the wing, the fuselage, etc., to ensure that the acceleration of the aircraft can be accurately measured. Through data fusion technology, the acceleration data of the X-axis and Y-axis are processed to provide real-time navigation information, ensuring the stable flight of the aircraft.

[0082] Accelerometers are used in automotive safety systems to detect collision acceleration and trigger safety devices such as airbags. They are installed at the front and sides of the vehicle to ensure timely detection of collision acceleration. When acceleration exceeding a preset threshold is detected, the airbags are immediately activated to protect passenger safety.

[0083] In the field of drones, accelerometers are used to measure the drone's acceleration, providing precise flight control data. Mounting the accelerometer at the center of the drone ensures accurate acceleration measurement. Real-time feedback of acceleration data allows for adjustments to the drone's flight attitude and speed, ensuring stable flight.

[0084] The biaxial silicon capacitor high-precision accelerometer based on micro-nano technology of the present invention has demonstrated its high precision, high sensitivity and high reliability in several key fields and has broad application prospects.

[0085] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0086] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A high-precision biaxial silicon capacitor accelerometer based on micro / nano technology, characterized in that: The application relates to a micro-mechanical sensor unit, which comprises two coaxially arranged micro-mechanical sensor units, the two micro-mechanical sensor units are arranged vertically to each other, the micro-mechanical sensor unit comprises a silicon substrate (9), a sensitive mass block is arranged above the silicon substrate (9), and a fixed tooth (1) is symmetrically arranged between the silicon substrate (9) and the sensitive mass block; one side of the two fixed teeth (1) is provided with a movable tooth (2); a supporting assembly for supporting the sensitive mass block is symmetrically arranged between the two movable teeth (2); the silicon substrate (9) is provided with a temperature compensation circuit for monitoring and compensating temperature in real time; and one end of the silicon substrate (9) is provided with a fixed pole (5). The supporting assembly comprises a plurality of suspension beams (3), adjacent two suspension beams (3) are connected through a spring beam (4), and the sensitive mass block is suspended above the silicon substrate (9) through the spring beam (4). A polysilicon layer (7) is grown on the silicon substrate (9), and the suspension beam (3) and the spring beam (4) are formed on the polysilicon layer (7) through micro-nano processing etching. The spring beam (4) is a high-elasticity modulus folded beam. The movable tooth (2) and the fixed tooth (1) are staggered to form a comb-tooth shape, and the movable tooth (2) and the fixed tooth (1) on the same side of the silicon substrate (9) are symmetrically arranged. An epitaxial silicon layer (6) is grown on the silicon substrate (9), and the sensitive mass block is formed on the epitaxial silicon layer (6) through micro-nano processing etching.

2. The dual-axis silicon capacitive high-precision accelerometer based on micro-nano technology according to claim 1, characterized in that: The fixed tooth (1) is fixedly connected with the silicon substrate (9), so that the fixed tooth (1) forms an electrode on the silicon substrate (9). 3.The micro-nano technology-based dual-axis silicon capacitor high-precision accelerometer of claim 1, wherein: The movable tooth (2) is fixedly connected with the sensitive mass block, so that the movable tooth (2) forms an electrode on the sensitive mass block.

4. The dual-axis silicon capacitive high-precision accelerometer based on micro-nano technology according to claim 1, characterized in that: The spring beam (4) and the sensitive mass block are made of polysilicon material.

5. The micro-nano technology based dual-axis silicon capacitive high-precision accelerometer according to claim 1, characterized in that: An oxide layer (8) is arranged between the fixed pole (5) and the silicon substrate (9).

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