Resonant silicon microaccelerometer

Abstract

The application discloses a resonant silicon micro accelerometer and relates to the technical field of micro electro mechanical systems, which comprises a lower substrate silicon and an upper mechanical structure, the substrate silicon is provided with a left anchor point and a right anchor point, and the upper mechanical structure is anchored on the left anchor point and the right anchor point; the mechanical structure comprises two left tuning fork beam resonators and right tuning fork beam resonators which are symmetrical along an X axis, the left tuning fork beam resonator is fixed on the substrate silicon through the left anchor point, and the right tuning fork beam resonator is fixed on the substrate silicon through the right anchor point; the left anchor point and the right anchor point are located between the left tuning fork beam resonator and the right tuning fork beam resonator and are symmetrically arranged along the X axis, and the left anchor point, the right anchor point, the left tuning fork beam resonator and the right tuning fork beam resonator are on the same straight line; the X axis is a sensitive axis direction. According to the scheme, the number of fixed anchor points is reduced to two, and the fixed anchor points are arranged as close to the center as possible, so that the influence of temperature stress on the sensitive structure is further reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of micro-electro-mechanical system, and particularly relates to a resonant silicon micro-accelerometer. BACKGROUND

[0002] According to the detection principle of the accelerometer, the MEMS accelerometer can be divided into capacitive type, piezoelectric type, resonant type and the like. The working principle of the resonant accelerometer is to detect the axial inertial force generated by the mass under the action of external acceleration on two resonators (mainly double-end fixed tuning fork structure-DETF), one resonator is subjected to tensile force and the resonant frequency increases, and the other resonator is subjected to thrust and the resonant frequency decreases. The frequency difference is proportional to the size of the external acceleration. By detecting the change of the frequency, the size of the external input acceleration can be obtained. Compared with other types of accelerometers, the resonant accelerometer has the advantages of stable scale factor, large linear range, low power consumption, quasi-digital frequency signal output, strong anti-interference ability, large dynamic range, strong impact resistance and great potential for precision improvement. In particular, it has the characteristics of large range and high precision.

[0003] The resonant accelerometer outputs a frequency signal and senses acceleration according to the change of the resonant frequency. In the actual use environment, the change of temperature will cause the change of the material properties and thermal stress of the resonant accelerometer structure layer, thereby changing the resonant frequency of the resonator, which is the drift caused by the change of temperature. The frequency drift caused by temperature and the frequency change caused by acceleration are mixed together and difficult to distinguish, thereby causing a large measurement error.

[0004] For example, Nanjing University of Technology proposed an invention patent in 2016 (application number 201610955241.0) for a structure design for stress isolation of a sensitive resonant structure. The main scheme is to optimize the hard connection of the fixed anchor point and the structure frame into a flexible beam connection. However, it only isolates the stress at the anchor point. Although the flexible stress isolation mechanism can isolate part of the environmental stress, the flexible beam structure at the anchor point cannot completely eliminate the environmental stress. Although part of the environmental stress is isolated, the stress can still be transmitted to the sensitive structure through the flexible beam structure.

[0005] For example, the scheme of a paper published by Peking University in 2020 and the patent of Peking University "Low-stress-sensitive silicon micro resonant accelerometer structure" CN111812355B, the anchor points of the guide beam (folded beam) structure are distributed on the four sides of the chip. Since the material of the sensitive structure is Si, the thermal expansion coefficients of the substrate glass material and the chip and the packaging tube shell, the packaging substrate and other materials do not match, and additional stress can still be caused. SUMMARY

[0006] The present application aims at providing a resonant silicon micro accelerometer to solve the problems of the prior art.

[0007] The present application is achieved by the following technical solutions:

[0008] A resonant silicon micro accelerometer comprises a lower substrate silicon and an upper mechanical structure, the substrate silicon is provided with a left anchor point and a right anchor point, and the upper mechanical structure is anchored on the left anchor point and the right anchor point.

[0009] The mechanical structure comprises two left tuning fork beam resonators and right tuning fork beam resonators which are symmetrical along the X axis, the left tuning fork beam resonator is fixed on the substrate silicon through the left anchor point, and the right tuning fork beam resonator is fixed on the substrate silicon through the right anchor point.

[0010] The left anchor point and the right anchor point are located between the left tuning fork beam resonator and the right tuning fork beam resonator and are symmetrically arranged along the X axis, and the left anchor point, the right anchor point, the left tuning fork beam resonator and the right tuning fork beam resonator are arranged on the same straight line, and the X axis is the sensitive axis direction.

[0011] Compared with the prior art, the frequency drift caused by temperature and the frequency change caused by acceleration are mixed together, it is difficult to distinguish, thereby causing a large measurement error, the present application provides a resonant silicon micro accelerometer, the chip is mainly packaged on the substrate or in the tube shell, since the MEMS chip is mainly made of single crystal silicon, the thermal expansion coefficients of silicon and the packaging ceramic substrate are different, different expansion or shrinkage will occur when the environment temperature changes, stress will be generated on the anchor point after the thermal expansion or shrinkage, the stress is transmitted through the anchor point, the resonator axial stress is changed due to the temperature change, thereby changing the resonant frequency of the resonator, in the specific scheme of the present application, based on the bulk silicon SOI MEMS process, the sensitive structure is fixed on the substrate silicon through two anchor points, the typical thickness of the sensitive structure is 60 or 80 microns, the present application is only provided with a left anchor point and a right anchor point, and the upper mechanical structure is anchored on the substrate silicon through the left anchor point and the right anchor point, that is, the guide beam or the micro lever in the mechanical structure is only fixed on the substrate silicon through two anchor points, thereby reducing the number of anchor points as much as possible and reducing the transmission of stress by the anchor points; in addition, since the generated stress is related to the temperature and the distance between the two anchor points, compared with the patent of Beijing University, the present application reduces the number of anchor points to two, the two anchor points are closely close in the two directions of the XY axis, and are placed in the middle of the chip, and are located in the middle of the two resonators and are distributed in a straight line, thereby further reducing the transmission of stress by the setting positions of the two anchor points and the shortening of the distance between the two anchor points, so as to further reduce the influence of temperature stress on the sensitive structure.

[0012] Further optimization, the mechanical structure further comprises a left beam structure and a right beam structure, one end of the left beam structure is fixed on the left anchor point, the other end of the left beam structure is provided with a first mounting slot, and the left tuning fork beam resonator is arranged in the first mounting slot; one end of the right beam structure is fixed on the right anchor point, the other end of the right beam structure is provided with a second mounting slot, and the right tuning fork beam resonator is arranged in the second mounting slot; for installing resonators and integrating positioning other structures.

[0013] Further optimization, the mechanical structure further comprises a mass block, the mass block comprises a left mass block and a right mass block, the left beam structure is outwardly extended with a first guide beam and a second guide beam on the upper side and the lower side respectively, the left mass block is arranged around the left beam structure and connected to the left beam structure through the first guide beam and the second guide beam; the right beam structure is outwardly extended with a third guide beam and a fourth guide beam on the upper side and the lower side respectively, the right mass block is arranged around the right beam structure and connected to the right beam structure through the third guide beam and the fourth guide beam; the first guide beam, the second guide beam, the third guide beam and the fourth guide beam are perpendicular to the X-axis direction; for reducing the influence of stress on sensitive structure.

[0014] Further optimization, the mass block is provided with a connecting structure in the middle part, the connecting structure is located between the left anchor point and the right anchor point, and the left mass block is connected to the right mass block through the connecting structure; for improving the overall stiffness of the mass block, strengthening the structural dynamics characteristics, and making the working mode far away from the nearby interference mode.

[0015] Further optimization, the mechanical structure further comprises a first micro lever and a second micro lever on the left side, and a third micro lever and a fourth micro lever on the right side; the first micro lever and the second micro lever, and the third micro lever and the fourth micro lever are symmetrically distributed along the X-axis up and down; the first micro lever and the second micro lever, the third micro lever and the fourth micro lever are connected with the mass block through the input support point at one end and connected with the left tuning fork beam resonator and the right tuning fork beam resonator through the output support point at the other end; wherein the micro lever passes through the input support point and the output support point, so as to amplify the inertial force of the mass block and act on the resonator, so that the natural frequency of the resonator changes.

[0016] Further optimization, the left beam structure includes first beam structure and second beam structure distributed on the upper and lower sides of the first mounting slot, the end of the first beam structure away from the left anchor point is connected with the first micro lever middle part through a first fulcrum, and the end of the second beam structure away from the left anchor point is connected with the second micro lever middle part through a second fulcrum; the right beam structure includes third beam structure and fourth beam structure distributed on the upper and lower sides of the second mounting slot, the end of the third beam structure away from the right anchor point is connected with the third micro lever middle part through a third fulcrum, and the end of the fourth beam structure away from the right anchor point is connected with the fourth micro lever middle part through a fourth fulcrum; for reducing the influence of stress on sensitive structure.

[0017] Further optimization, the input fulcrum, output fulcrum, first fulcrum, second fulcrum, third fulcrum and fourth fulcrum are all perpendicular to the lever; the fulcrum and the lever are perpendicular to each other, so that the magnification of the lever is close to the ideal value level.

[0018] Further optimization, the left tuning fork beam resonator is sequentially provided with a first driving electrode and a first differential detection capacitor plate, and the right tuning fork beam resonator is sequentially provided with a second driving electrode and a second differential detection capacitor plate; the first driving electrode and the second driving electrode are away from the center of the mechanical structure, and the first differential detection capacitor plate and the second differential detection capacitor plate are close to the center of the mechanical structure; for detecting the natural frequency of the tuning fork beam resonator.

[0019] Further optimization, the length of the first differential detection capacitor plate and the second differential detection capacitor plate is greater than the length of the first driving electrode and the second driving electrode respectively; by designing the length of the detection electrode to be greater than the length of the driving electrode, the detection sensitivity is improved.

[0020] Compared with the prior art, the application has the following advantages and beneficial effects:

[0021] The application provides a resonant silicon micro accelerometer, and the number of fixed anchors is reduced to two by adopting the scheme, the two fixed anchors are arranged in the middle of the chip, and the tuning fork beam resonator, the guide beam and the micro lever share the two fixed anchors, so that the influence of temperature stress on the sensitive structure is further reduced. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be regarded as a limitation on the scope, and for those of ordinary skill in the art, other related drawings can also be obtained without paying creative labor. In the drawings:

[0023] Figure 1 A top view of a resonant silicon micro-accelerometer provided by the present application;

[0024] Figure 2 An A-A sectional view of a resonant silicon micro-accelerometer provided by the present application.

[0025] The marks in the drawings and the corresponding names of the parts:

[0026] 1A - left tuning fork beam resonator, 1B - right tuning fork beam resonator, 12B - mass block, 12C - connecting structure, 14A - left anchor point, 14B - right anchor point, 29 - substrate silicon, 52A - first guide beam, 52B - second guide beam, 52C - third guide beam, 52D - fourth guide beam, 22A - first micro lever, 22B - second micro lever, 22C - third micro lever, 22D - fourth micro lever, 16A - first beam structure, 16B - second beam structure, 16C - third beam structure, 16D - fourth beam structure, 24A - first fulcrum, 24B - second fulcrum, 24C - third fulcrum, 24D - fourth fulcrum, 20A - first upper driving electrode, 20B - first middle driving electrode, 20C - first lower driving electrode, 21A - first upper differential detection capacitor plate, 21B - first middle differential detection capacitor plate, 21C - first lower differential detection capacitor plate, 27C - second lower differential detection capacitor plate, 28C - second lower driving electrode. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the present application more clear, the following will further describe the present application in combination with the embodiments and drawings, the exemplary embodiments of the present application and the description thereof are only used to explain the present application, and should not be regarded as a limitation on the present application.

[0028] Embodiment: The present embodiment provides a resonant silicon micro-accelerometer, as shown in Figure 1 and Figure 2 shown, including a lower substrate silicon 29 and an upper mechanical structure, the substrate silicon 29 has a left anchor point 14A and a right anchor point 14B, and the upper mechanical structure is anchored on the left anchor point 14A and the right anchor point 14B;

[0029] The mechanical structure comprises two left tuning fork beam resonators 1A and right tuning fork beam resonators 1B symmetrical along the X axis, the left tuning fork beam resonator 1A is fixed on the substrate silicon 29 through a left anchor point 14A, and the right tuning fork beam resonator 1B is fixed on the substrate silicon 29 through a right anchor point 14B.

[0030] The left anchor point 14A and the right anchor point 14B are located between the left tuning fork beam resonator 1A and the right tuning fork beam resonator 1B and are symmetrically arranged along the X axis, and the left anchor point 14A, the right anchor point 14B, the left tuning fork beam resonator 1A and the right tuning fork beam resonator 1B are on the same straight line; the X axis is the sensitive axis direction.

[0031] Compared with the prior art, the frequency drift caused by temperature and the frequency change caused by acceleration are mixed together, it is difficult to distinguish, thereby causing a large measurement error, the chip of the resonant silicon micro-accelerometer is mainly packaged on the substrate or in the tube shell, since the chip is mainly made of monocrystalline silicon, the thermal expansion coefficients of silicon and the packaging substrate are different, different expansion or shrinkage occurs when the environment temperature changes, stress is generated on the anchor point after thermal expansion or shrinkage, the stress is transmitted through the anchor point, the resonator axial stress change caused by temperature change is generated, thereby the resonant frequency of the resonator is changed, in the specific scheme of the application, based on the bulk silicon SOI MEMS process, the sensitive structure is fixed on the substrate silicon 29 through two anchor points, the typical thickness of the sensitive structure is 60 or 80 microns, the application is only provided with the left anchor point 14A and the right anchor point 14B, and the upper mechanical structure is anchored on the substrate silicon 29 through the left anchor point 14A and the right anchor point 14B, that is, whether the guide beam or the micro-lever in the mechanical structure is fixed on the substrate silicon 29 only through two anchor points, so as to reduce the number of anchor points as much as possible and reduce the transmission of stress by the anchor points; in addition, since the generated stress is related to the distance between the two anchor points and the temperature, compared with the patent of Peking University, the number of anchor points is reduced to two in the application, the two anchor points are closely close in the two directions of the XY axis, and are centrally arranged in the middle of the chip, and are arranged in a line between the two resonators, so that the position of the two anchor points is set and the distance between the two anchor points is shortened, thereby further reducing the transmission of stress, so as to further reduce the influence of temperature stress on the sensitive structure.

[0032] Please refer to Figure 1, as a specific embodiment for installing resonators and integrating other structures, the mechanical structure further comprises a left beam structure and a right beam structure, one end of the left beam structure is fixed to the left anchor point 14A, the other end of the left beam structure is provided with a first mounting slot, and the left tuning fork beam resonator 1A is arranged in the first mounting slot; one end of the right beam structure is fixed to the right anchor point 14B, the other end of the right beam structure is provided with a second mounting slot, and the right tuning fork beam resonator 1B is arranged in the second mounting slot; it can be understood that in this embodiment, the left beam structure and the right beam structure are symmetrically arranged and are respectively fixed to the left anchor point 14A and the right anchor point 14B, wherein the left beam structure comprises a first beam structure 16A and a second beam structure 16B arranged on the upper side and the lower side, respectively, and a first mounting slot is reserved between the first beam structure 16A and the second beam structure 16B for mounting the left tuning fork beam resonator 1A; the right beam structure comprises a third beam structure 16C and a fourth beam structure 16D arranged on the upper side and the lower side, respectively, and a second mounting slot is reserved between the third beam structure 16C and the fourth beam structure 16D for mounting the right tuning fork beam resonator 1B; at this time, the outer side and the end of the left beam structure and the right beam structure can be reserved for positioning the positions of the remaining components.

[0033] Please refer to Figure 1 and Figure 2 , as a specific embodiment for reducing the influence of stress on sensitive structures, the mechanical structure further comprises a mass block 12B, the mass block 12B comprises a left mass block 12B and a right mass block 12B, the upper side and the lower side of the left beam structure respectively extend outwardly a first guide beam 52A and a second guide beam 52B, the left mass block 12B is arranged around the left beam structure and is connected to the left beam structure through the first guide beam 52A and the second guide beam 52B; the upper side and the lower side of the right beam structure respectively extend outwardly a third guide beam 52C and a fourth guide beam 52D, the right mass block 12B is arranged around the right beam structure and is connected to the right beam structure through the third guide beam 52C and the fourth guide beam 52D; the first guide beam 52A, the second guide beam 52B, the third guide beam 52C and the fourth guide beam 52D are perpendicular to the X-axis direction; it can be understood that in this embodiment, the guide beams are fixed to the support beam structure which is led out from the one end anchor point of the resonator, and in the specific structure, the support beam structure is the left beam structure and the right beam structure, and the guide beams are respectively arranged on the upper side and the lower side of the left beam structure and the right beam structure, and the guide beams are perpendicular to the sensitive axis, at this time, the mass block 12B is connected to the support beam structure through the guide beams, so that the fixed anchor points of the guide beams and the fixed anchor points of the resonators are shared, further reducing the anchor points, thereby reducing the influence of temperature stress on the sensitive structure; wherein through reasonable size design of the first guide beam 52A, the second guide beam 52B, the third guide beam 52C and the fourth guide beam 52D, the cross-coupling coefficient of the resonant accelerometer (SOA) can be effectively reduced.

[0034] Please refer to Figure 1 andFigure 2 As a specific embodiment for improving the overall stiffness of the mass 12B and strengthening the structural dynamics characteristics, the middle part of the mass 12B is provided with a connecting structure 12C, which is located between the left anchor point 14A and the right anchor point 14B, and the left mass 12B is connected to the right mass 12B through the connecting structure 12C. It can be understood that in this embodiment, the upper and lower halves of the mass 12B are connected together through the connecting structure 12C, and the mass 12B structure passes through the middle of the two anchor points, so as to improve the overall stiffness of the mass 12B, strengthen the structural dynamics characteristics, make the working mode far away from the nearby interference mode, and improve the anti-vibration impact ability of the resonant accelerometer in the plane.

[0035] Please refer to Figure 1 As a specific embodiment for changing the natural frequency of the resonator, the mechanical structure further includes a first micro-lever 22A and a second micro-lever 22B on the left side, and a third micro-lever 22C and a fourth micro-lever 22D on the right side; the first micro-lever 22A and the second micro-lever 22B, and the third micro-lever 22C and the fourth micro-lever 22D are symmetrically distributed along the X axis; the first micro-lever 22A and the second micro-lever 22B, the third micro-lever 22C and the fourth micro-lever 22D are connected with the mass 12B through the input support point at one end and the output support point at the other end, and are connected with the left tuning fork beam resonator 1A and the right tuning fork beam resonator 1B through the output support point respectively; wherein the micro-lever passes through the input support point and the output support point, so as to amplify the inertial force of the mass 12B and act on the resonator, so that the natural frequency of the resonator is changed.

[0036] Please refer to Figure 1As a specific embodiment for reducing the influence of stress on sensitive structure, it is provided that: the left beam structure includes a first beam structure 16A and a second beam structure 16B distributed on the upper and lower sides of the first mounting groove, the end of the first beam structure 16A away from the left anchor point 14A is connected through the first fulcrum 24A and the middle part of the first micro-lever 22A, and the end of the second beam structure 16B away from the left anchor point 14A is connected through the second fulcrum 24B and the middle part of the second micro-lever 22B; the right beam structure includes a third beam structure 16C and a fourth beam structure 16D distributed on the upper and lower sides of the second mounting groove, the end of the third beam structure 16C away from the right anchor point 14B is connected through the third fulcrum 24C and the middle part of the third micro-lever 22C, and the end of the fourth beam structure 16D away from the right anchor point 14B is connected through the fourth fulcrum 24D and the middle part of the fourth micro-lever 22D; it can be understood that in the embodiment, the micro-lever is fixed on the support beam structure leading to the anchor point at one end of the resonator, and in the specific structure, the middle part of the first micro-lever 22A is the first fulcrum 24A, the first fulcrum 24A is connected to the first anchor point through the first beam structure 16A, the middle part of the second micro-lever 22B is the second fulcrum 24B, the second fulcrum 24B is connected to the first anchor point through the second beam structure 16B, and by analogy, the third fulcrum 24C is connected to the second anchor point through the third beam structure 16C, and the fourth fulcrum 24D is connected to the second anchor point through the fourth beam structure 16D; through the above setting, the micro-lever is fixed on the same support beam structure leading to the resonator and the guide beam, so as to further reduce the anchor point and reduce the influence of temperature stress on the sensitive structure.

[0037] As a redundancy scheme, the input fulcrum, the output fulcrum, the first fulcrum 24A, the second fulcrum 24B, the third fulcrum 24C and the fourth fulcrum 24D are all perpendicular to the lever; by making the fulcrum and the lever perpendicular to each other, the magnification multiple of the lever is close to the ideal value level.

[0038] Please refer to Figure 1As a specific embodiment for detecting the natural frequency of the tuning fork beam resonator, the first driving electrode and the first differential detection capacitor plate are sequentially arranged on the left tuning fork beam resonator 1A, and the second driving electrode and the second differential detection capacitor plate are sequentially arranged on the right tuning fork beam resonator 1B; the first driving electrode and the second driving electrode are both away from the mechanical structure center, and the first differential detection capacitor plate and the second differential detection capacitor plate are both close to the mechanical structure center; it can be understood that in the embodiment, the first upper driving electrode 20A, the first middle driving electrode 20B and the first lower driving electrode 20C form two pairs of driving electrodes of the left tuning fork beam resonator 1A, and the first upper differential detection capacitor plate 21A, the first middle differential detection capacitor plate 21B and the first lower differential detection capacitor plate 21C form two pairs of differential detection capacitor plates of the left tuning fork beam resonator 1A, and the right tuning fork beam resonator 1B has a symmetrical structure, such as the second lower driving electrode 28C and the second lower differential detection capacitor plate 27C; due to the high Q value of the vacuum packaged tuning fork beam, a smaller driving force can drive the resonant beam.

[0039] As a redundancy scheme, the length of the first differential detection capacitor plate and the length of the second differential detection capacitor plate are both greater than the length of the first driving electrode and the length of the second driving electrode; by designing the length of the detection electrode to be greater than the length of the driving electrode, the detection sensitivity is improved.

[0040] Working principle: when an external force is input to the accelerometer, the mass block 12B converts the measured acceleration into an inertial force, which acts on the first micro lever 22A, the second micro lever 22B, the third micro lever 22C and the fourth micro lever 22D, and the inertial force is amplified through the micro lever to be applied to the tuning fork beam resonator in the axial direction, one tuning fork beam resonator bears the axial tension, the natural frequency increases, and the other tuning fork beam resonator bears the axial pressure, the natural frequency decreases, so the two tuning fork beam resonators form a set of differential sensitive structure, and the difference between the natural frequencies of the two tuning fork beam resonators is measured as the output of the accelerometer, that is, the value of the acceleration component along the X-axis direction can be calculated. In the above scheme, the number of fixed anchor points is reduced to 2, and the fixed anchor points are centrally arranged in the middle of the chip, and the tuning fork beam resonator, the guide beam and the micro lever all share two fixed anchor points, thereby further reducing the influence of temperature stress on the sensitive structure; the structure of the application is simple, the response of the sensitive structure to the environmental stress is optimized through the anchor point layout, and the purpose of reducing the temperature coefficient of the resonant frequency is achieved.

[0041] The above detailed description of the specific embodiments of the present application has been given to understand the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A resonant silicon micro-accelerometer, comprising a lower substrate silicon layer (29) and an upper mechanical structure, characterized in that, The substrate silicon (29) has a left anchor point (14A) and a right anchor point (14B), and the upper mechanical structure is anchored to the left anchor point (14A) and the right anchor point (14B); the resonant silicon micro accelerometer has only a left anchor point (14A) and a right anchor point (14B). The mechanical structure includes two left tuning fork beam resonators (1A) and right tuning fork beam resonators (1B) symmetrical along the X-axis. The left tuning fork beam resonator (1A) is fixed to the substrate silicon (29) by a left anchor point (14A), and the right tuning fork beam resonator (1B) is fixed to the substrate silicon (29) by a right anchor point (14B). The left anchor point (14A) and the right anchor point (14B) are both located between the left tuning fork beam resonator (1A) and the right tuning fork beam resonator (1B), and are symmetrically arranged along the X-axis. The left anchor point, the right anchor point, the left tuning fork beam resonator, and the right tuning fork beam resonator are all on the same straight line. The X-axis is the direction of the sensitive axis. The mechanical structure also includes a left beam structure and a right beam structure. One end of the left beam structure is fixed to the left anchor point (14A), and the other end of the left beam structure has a first mounting groove. The left tuning fork beam resonator (1A) is disposed in the first mounting groove. One end of the right beam structure is fixed to the right anchor point (14B), and the other end of the right beam structure has a second mounting groove. The right tuning fork beam resonator (1B) is disposed in the second mounting groove. The mechanical structure also includes a mass block (12B), which comprises a left mass block and a right mass block. A first guide beam (52A) and a second guide beam (52B) extend outward from the upper and lower sides of the left beam structure, respectively. The left mass block is arranged around the left beam structure and is connected to the left beam structure through the first guide beam (52A) and the second guide beam (52B). A third guide beam (52C) ​​and a fourth guide beam (52D) extend outward from the upper and lower sides of the right beam structure, respectively. The right mass block is arranged around the right beam structure and is connected to the right beam structure through the third guide beam (52C) ​​and the fourth guide beam (52D). The mass block (12B) has a connecting structure (12C) in the middle, which is located between the left anchor point (14A) and the right anchor point (14B). The left mass block is connected to the right mass block through the connecting structure (12C).

2. The resonant silicon micro-accelerometer according to claim 1, characterized in that, The first guide beam (52A), the second guide beam (52B), the third guide beam (52C), and the fourth guide beam (52D) are all perpendicular to the X-axis direction.

3. The resonant silicon micro-accelerometer according to claim 1, characterized in that, The mechanical structure also includes a first micro lever (22A) and a second micro lever (22B) located on the left side, and a third micro lever (22C) and a fourth micro lever (22D) located on the right side; the first micro lever (22A) and the second micro lever (22B), as well as the third micro lever (22C) and the fourth micro lever (22D), are all symmetrically distributed along the X-axis; the first micro lever (22A) and the second micro lever (22B), the third micro lever (22C) and the fourth micro lever (22D) are all connected to the mass block (12B) at one end through the input fulcrum, and connected to the left tuning fork beam resonator (1A) and the right tuning fork beam resonator (1B) respectively through the output fulcrum at the other end.

4. A resonant silicon micro-accelerometer according to claim 3, characterized in that, The left beam structure includes a first beam structure (16A) and a second beam structure (16B) distributed on the upper and lower sides of the first mounting groove. The end of the first beam structure (16A) away from the left anchor point (14A) is connected to the middle of the first micro lever (22A) through a first fulcrum (24A). The end of the second beam structure (16B) away from the left anchor point (14A) is connected to the middle of the second micro lever (22B) through a second fulcrum (24B). The right beam structure includes a third beam structure (16C) and a fourth beam structure (16D) distributed on the upper and lower sides of the second mounting groove. The end of the third beam structure (16C) away from the right anchor point (14B) is connected to the middle of the third micro lever (22C) through a third fulcrum (24C). The end of the fourth beam structure (16D) away from the right anchor point (14B) is connected to the middle of the fourth micro lever (22D) through a fourth fulcrum (24D).

5. A resonant silicon micro-accelerometer according to claim 4, characterized in that, The input fulcrum, output fulcrum, first fulcrum (24A), second fulcrum (24B), third fulcrum (24C) and fourth fulcrum (24D) are all perpendicular to the lever.

6. A resonant silicon micro-accelerometer according to claim 1, characterized in that, The left tuning fork resonator (1A) is provided with a first driving electrode and a first differential detection capacitor plate in sequence, and the right tuning fork resonator (1B) is provided with a second driving electrode and a second differential detection capacitor plate in sequence; the first driving electrode and the second driving electrode are both far away from the center of the mechanical structure, and the first differential detection capacitor plate and the second differential detection capacitor plate are both close to the center of the mechanical structure.

7. A resonant silicon micro-accelerometer according to claim 6, characterized in that, The lengths of the first differential detection capacitor plate and the second differential detection capacitor plate are both greater than the lengths of the first driving electrode and the second driving electrode, respectively.

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