Low-temperature drift silicon resonance accelerometer structure

Abstract

The invention discloses a low-temperature drift silicon resonance accelerometer structure, which relates to the technical field of inertial navigation and comprises a middle layer, an upper glass cover plate and a lower glass cover plate, the upper-layer glass cover plate and the lower-layer glass cover plate respectively cover two sides of the outer frame of the middle layer and are bonded with the outer frame, so that the middle layer is packaged in vacuum; a supporting point of the resonator is designed at the geometric center of the middle layer of the accelerometer, a center anchor point, an amplification lever structure and the double-end fixed tuning fork type resonator are connected through a resonator center supporting beam, detection comb teeth are driven to measure resonant frequency influenced by inertia force, frequency signals are led out to the outside, and acceleration is represented; in the design of the invention, the measurement structure of the middle layer is fixed with the shell only through one supporting point, the influence of thermal stress on the performance of the accelerometer is obviously reduced, and the design enables the double-end fixed tuning fork type resonator to be close to a free thermal expansion state when the temperature of the accelerometer changes, so that the stable frequency response is kept.

Description

Technical Field

[0001] The invention relates to the technical field of inertial navigation, and in particular to a low-temperature drift silicon resonant accelerometer structure. Background Art

[0002] Silicon resonant accelerometer is a micromechanical inertial device that characterizes acceleration by measuring the change of resonant frequency based on the resonance principle. Compared with traditional capacitive accelerometers, resonant accelerometers modulate the acceleration sensitive signal on the frequency of the resonator before it enters the circuit, ensuring that the acceleration signal is not easily affected by amplitude errors, and it is easier to achieve high zero bias stability and scale factor stability. Silicon resonant accelerometers also have the advantages of small size, low price, easy integration, semi-digital output, etc., and have the potential to develop towards navigation-level accuracy, and have broad application prospects in the defense and military fields.

[0003] Silicon resonant accelerometers are generally composed of a sensitive mass block, a lever amplification structure, a resonator, a support mechanism, a driving mechanism, and a detection mechanism. The main principle of a resonant accelerometer is that the driving mechanism maintains the resonance of the resonator. When there is acceleration input from the outside, the sensitive mass block converts the acceleration into an inertial force, which is then amplified by the amplifying lever and applied to the resonator. The resonator undergoes tension or compression changes, causing its resonant frequency to change. Based on the force-frequency characteristics of the resonator, the acceleration information can be obtained by detecting the change in the resonant frequency of the resonator through the detection mechanism.

[0004] The silicon resonant accelerometer originated from the Draper experiment in the United States. The silicon resonant accelerometer currently developed by the Draper experiment is still in the world's leading position, with zero-bias monthly stability of up to 10000 Hz. In addition, the University of California, Berkeley, designed a silicon resonant accelerometer with a two-stage amplification lever mechanism, with a scale factor of up to 160Hz / g. Seoul National University in South Korea, Politecnico di Milano in Italy, and the French Space Agency have also conducted related research. Tsinghua University, Peking University, Beijing Aerospace Control Instrument Research Institute, Nanjing University of Science and Technology and other universities and research institutions in China have actively carried out research on silicon resonant accelerometers and proposed a variety of silicon resonant accelerometer structures. Although silicon resonant accelerometers with various structural forms such as multi-axis, high sensitivity, and large range have been developed at home and abroad, environmental adaptability has always been a key indicator restricting the development of silicon resonant accelerometers, and extreme temperature change conditions have further restricted the actual engineering application of silicon resonant accelerometers. Changes in ambient temperature have an important impact on the performance of silicon resonant accelerometers, mainly because thermal stress is generated by thermal expansion mismatch of support anchor points, resulting in unstable accelerometer performance, reduced measurement accuracy and deteriorated performance, limiting the engineering application of silicon resonant accelerometers to high-precision systems. Summary of the invention

[0005] The purpose of the present invention is to reduce the influence of thermal stress caused by temperature changes by optimizing the structural design of a silicon resonant accelerometer, thereby improving its stability and measurement accuracy in an extreme temperature change environment.

[0006] The technical solution of the present invention is: to provide a low temperature drift silicon resonant accelerometer structure, the structure comprising: an intermediate layer, an upper glass cover plate and a lower glass cover plate;

[0007] The middle layer includes: mass block, amplifying lever structure, resonator center support beam, drive detection comb teeth, center anchor point and outer frame;

[0008] The upper glass cover plate and the lower glass cover plate are respectively covered on both sides of the outer frame of the middle layer and bonded thereto, so that the middle layer is vacuum-sealed. In addition, a metal wire is arranged inside the upper glass cover plate to connect with the driving detection comb teeth of the middle layer;

[0009] The central anchor point is set at the exact center of the middle layer and bonded to the upper glass cover plate. The mechanical structure of the middle layer is symmetrically distributed on both sides with the central anchor point as the center. One end of the drive detection comb tooth is fixed to the central anchor point through the central support beam of the resonator, and the other end is bonded to the upper glass cover plate. The amplifying lever structure is connected to the other end of the central support beam of the resonator. When the accelerometer structure has acceleration, the mass block applies an inertial force to the amplifying lever structure under the action of inertia. The inertial force is amplified by the amplifying lever structure, and then the resonant frequency of the drive detection comb tooth is changed based on the force-frequency characteristic. The drive detection comb tooth measures the resonant frequency affected by the inertial force, and leads the frequency signal to the outside through the metal wire to characterize the acceleration.

[0010] In any of the above technical solutions, further, the middle layer also includes: a double-ended fixed tuning fork resonator;

[0011] The double-ended fixed tuning fork resonator is connected to the central support beam of the resonator, and the thin end of the central support beam of the resonator is fixed to one side of the central anchor point;

[0012] Two groups of amplifying lever structures are respectively installed on both sides of the thick end of the central supporting beam of the resonator through the third beam, the second beam of the amplifying lever structure is connected to the double-end fixed tuning fork resonator, and the first beam of the amplifying lever structure is connected to the mass block.

[0013] In any of the above technical solutions, further, the double-ended fixed tuning fork resonator comprises: a first resonator beam, a second resonator beam and two resonator side beams;

[0014] The first resonator crossbeam and the second resonator crossbeam are both fixed on the central support beam of the resonator, and the first resonator crossbeam is closer to the central anchor point; the two resonator side beams are connected to the end points of the first resonator crossbeam and the second resonator crossbeam to form a closed frame structure, and the drive detection comb teeth are installed at the center of the outer side of the resonator side beam.

[0015] In any of the above technical solutions, further, the rigidity of a portion of the resonator side beam close to the first resonator cross beam is greater, and the rigidity of a side close to the second resonator cross beam is smaller.

[0016] In any of the above technical solutions, further, the driving detection comb teeth include: movable comb teeth, first fixed comb teeth, second fixed comb teeth, and electrodes;

[0017] The movable comb teeth are fixed on the side beam of the resonator, and the electrodes are respectively connected to one end of the first fixed comb teeth and the second fixed comb teeth, and the first fixed comb teeth and the second fixed comb teeth are bonded to the upper glass cover plate through the electrodes connected to them respectively; the comb teeth of the movable comb teeth and the first fixed comb teeth are interlaced to form a driving capacitor, and the first fixed comb teeth exert an electrostatic force on the movable comb teeth to drive it to move, thereby causing the side beam of the resonator to resonate; at the same time, the second fixed comb teeth and the movable comb teeth form a detection capacitor, and the capacitance change is detected by the second fixed comb teeth, so as to measure the resonant frequency of the side beam of the resonator and characterize the magnitude of acceleration.

[0018] In any of the above technical solutions, further, the middle layer also includes: a mass block support anchor point and a mass block support beam;

[0019] The mass block is connected to four mass block support anchor points through four mass block support beams. The four mass block support anchor points are arranged in four frame corners of the outer frame and bonded to the upper glass cover plate.

[0020] In any of the above technical solutions, further, the mass block support beam is a U-shaped beam structure.

[0021] In any of the above technical solutions, further, the resonant frequency of the resonator side beam changes after being subjected to pressure or tension, and the resonant frequency of a single resonator side beam can be expressed as:

[0022]

[0023] In the formula, f F is the resonant frequency of the resonator side beam after being stressed, E is the Young's modulus of single crystal silicon, w is the width of the resonator side beam, L f is the length of the resonator side beam, h is the thickness of the intermediate layer, F is the pressure on a single resonator side beam, which is a negative value if it is a tensile force, ρ is the density of single crystal silicon, and m is the mass of the active comb teeth connected to the resonator side beam;

[0024] The above formula can be expanded by Taylor, eliminating the higher-order terms to obtain:

[0025]

[0026] In the formula, f nIt is the resonant frequency of the side beam of the resonator when it is not subjected to tensile or compressive stress; therefore, the resonant frequency of the side beam of the resonator is linearly related to the force applied, and can be used to characterize the magnitude of acceleration.

[0027] The beneficial effects of the present invention are:

[0028] In the present invention, by designing a central support beam and a central anchor point, the support point of the double-ended fixed tuning fork resonator is concentrated at the geometric center of the accelerometer, effectively reducing the influence of thermal expansion mismatch and thermal stress caused by temperature changes. This structural design allows the sensitive part (such as the resonator) to be close to a free thermal expansion state when the temperature changes, reducing the measurement error caused by temperature changes and significantly reducing temperature drift (low temperature drift).

[0029] Due to the suppression of thermal stress by temperature change, the invention significantly improves the zero bias stability and scale factor stability of the accelerometer. The accelerometer can still maintain highly stable performance in an extreme temperature change environment and is suitable for high-precision navigation and inertial measurement systems.

[0030] By optimizing the layout of the support beams and support anchor points, the accelerometer designed in the present invention reduces unnecessary support points, making the overall structure more concise. After the structure is simplified, the processing requirements are reduced, thereby reducing the common mode error introduced by inaccurate processing, and further improving the stability and performance of the accelerometer. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The advantages of the above and additional aspects of the present invention will become apparent and easily understood in the description of the embodiments in conjunction with the following drawings, in which:

[0032] Figure 1 is a schematic diagram of an intermediate layer structure of a low temperature drift silicon resonant accelerometer structure according to an embodiment of the present invention;

[0033] Figure 2 2 is a schematic diagram of a lever amplification structure of a low-temperature drift silicon resonant accelerometer structure according to an embodiment of the present invention;

[0034] Figure 3 1 is a schematic diagram of a double-terminal fixed tuning fork resonator structure of a low-temperature drift silicon resonant accelerometer structure according to an embodiment of the present invention;

[0035] Figure 4 2. It is a schematic diagram of a resonator center beam support structure of a low temperature drift silicon resonant accelerometer structure according to an embodiment of the present invention;

[0036] Figure 5 2 is a schematic diagram of a drive detection comb structure of a low temperature drift silicon resonant accelerometer structure according to an embodiment of the present invention;

[0037] Figure 6 2 is a schematic diagram of a mass support beam structure of a low-temperature drift silicon resonant accelerometer structure according to an embodiment of the present invention;

[0038] Figure 7 1 is a diagram of frequency and acceleration simulation results of a silicon resonant accelerometer having a low-temperature drift silicon resonant accelerometer structure according to an embodiment of the present invention.

[0039] Among them, 1-mass block, 2-amplifying lever structure, 3-double-ended fixed tuning fork resonator, 4-resonator center support beam, 5-drive detection comb teeth, 6-center anchor point, 7-mass block support anchor point, 8-mass block support beam, 9-outer frame, 10-first beam, 11-second beam, 12-third beam, 13-first resonator cross beam, 14-second resonator cross beam, 15-resonator side beam, 16-thin end, 17-thick end, 18-movable comb teeth, 19-first fixed comb teeth, 20-second fixed comb teeth, 21-electrode. DETAILED DESCRIPTION

[0040] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0041] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0042] like Figure 1 As shown, this embodiment provides a low-temperature drift silicon resonant accelerometer structure, including: an intermediate layer, an upper glass cover plate and a lower glass cover plate.

[0043] The upper glass cover plate and the lower glass cover plate are respectively covered on both sides of the outer frame of the middle layer and bonded thereto to make the middle layer vacuum-encapsulated. In addition, a metal wire is arranged inside the upper glass cover plate to connect with the electrodes of the drive detection comb teeth 5 of the middle layer to lead out the frequency signal to the outside.

[0044] The middle layer specifically includes: a mass block 1, an amplifying lever structure 2, a double-ended fixed tuning fork resonator 3, a resonator center support beam 4, a drive detection comb 5, a center anchor point 6, a mass block support anchor point 7, a mass block support beam 8, and an outer frame 9.

[0045] The mass block 1 is made of single crystal silicon using bulk silicon processing technology. The mass block 1 is connected to four mass block support anchor points 7 through four mass block support beams 8. The four mass block support anchor points 7 are arranged in four frame corners of the outer frame 9 and bonded to the upper glass cover plate.

[0046] The central anchor point 6 is set in the center of the middle layer and bonded to the upper glass cover plate. The mechanical structure of the middle layer is symmetrically distributed on both sides with the central anchor point 6 as the center. Only one side is described below, and the symmetry of the other side is not repeated.

[0047] like Figures 2 to 4 As shown, the double-ended fixed tuning fork resonator 3 is connected to the resonator central support beam 4 , and the thin end 16 of the resonator central support beam 4 is fixed to one side of the central anchor point 6 .

[0048] The two groups of amplifying lever structures 2 are respectively installed on both sides of the thick end 17 of the central support beam 4 of the resonator through the third beam 12, the second beam 11 of the amplifying lever structure 2 is connected to the double-ended fixed tuning fork resonator 3, and the first beam 10 of the amplifying lever structure 2 is connected to the mass block 1.

[0049] Specifically, the double-ended fixed tuning fork resonator 3 includes a first resonator beam 13, a second resonator beam 14 and two resonator side beams 15; the first resonator beam 13 and the second resonator beam 14 are both fixed on the resonator center support beam 4, and the first resonator beam 13 is closer to the center anchor point 6; the two resonator side beams 15 are connected to the end points of the first resonator beam 13 and the second resonator beam 14 to form a closed frame structure, and the drive detection comb 5 is installed at the center of the outer side of the resonator side beam 15.

[0050] In particular, the resonator side beam 15 has a larger rigidity near the first resonator cross beam 13 to ensure the stability of the connection, and the side near the second resonator cross beam 14 has a smaller rigidity to increase the amplification factor of the amplifying lever structure 2 when transmitting pressure.

[0051] like Figure 5 As shown, the drive detection comb teeth 5 include: movable comb teeth 18 , first fixed comb teeth 19 , second fixed comb teeth 20 , and electrodes 21 .

[0052] The movable comb teeth 18 are fixed on the resonator side beam 15, and the electrodes 21 are respectively connected to one end of the first fixed comb teeth 19 and the second fixed comb teeth 20. The first fixed comb teeth 19 and the second fixed comb teeth 20 are bonded to the upper glass cover plate through their respective connected electrodes 20; the comb teeth of the movable comb teeth 18 and the first fixed comb teeth 19 are interlaced to form a driving capacitor, and the first fixed comb teeth 19 exert an electrostatic force on the movable comb teeth 18 to drive it to move, thereby causing the resonator side beam 15 to resonate; at the same time, the second fixed comb teeth 19 and the movable comb teeth 18 form a detection capacitor, and the capacitance change is detected by the second fixed comb teeth 20, so as to measure the resonant frequency of the resonator side beam 15, and the electrode 21 leads a frequency signal to the outside through the metal wire of the upper glass cover plate connected to it, thereby representing the magnitude of acceleration.

[0053] like Figure 6 As shown, in order to eliminate the thermal stress of the mass block support anchor point 7 along the X-sensitive axis direction, the mass block support beam 8 is designed as a U-shaped beam structure to reduce its stiffness along the X direction while ensuring its stiffness in the Y direction to avoid orthogonal coupling errors.

[0054] When the accelerometer senses the external acceleration in the X direction, the mass block support beam 8 supports and buffers the mass block. Under the action of inertia, the mass block 1 applies an inertial force to the first beam 10 of the amplifying lever structure 2. The inertial force is transmitted to the resonator side beam 15 through the amplifying lever structure 2 and the double-ended fixed tuning fork resonator 3 in turn. The driving detection comb 5 installed on the resonator side beam 15 detects the vibration change of the resonator side beam 15 to calculate the acceleration received by the low-temperature drift silicon resonant accelerometer structure.

[0055] Specifically, the resonant frequency of the resonator side beam 15 changes after being subjected to pressure or tension. The resonant frequency of a single resonator side beam 15 can be expressed as:

[0056]

[0057] In the formula, f F is the resonant frequency of the resonator side beam 15 after being subjected to force, E is the Young's modulus of single crystal silicon, w is the width of the resonator side beam 15, L f is the length of the resonator side beam 15, h is the thickness of the middle layer, F is the pressure on a single resonator side beam 15, which is a negative value if it is a tensile force, ρ is the density of single crystal silicon, and m is the mass of the movable comb teeth 18 connected to the resonator side beam 15.

[0058] The above formula can be expanded by Taylor, eliminating the higher-order terms to obtain:

[0059]

[0060] In the formula, f nThe resonant frequency of the resonator side beam 15 when it is not subjected to tensile or compressive stress. Therefore, the resonant frequency of the resonator side beam 15 is linearly related to the force applied, and can be used to characterize the magnitude of acceleration. The results of structural simulation using COMSOL software are shown in Figure 1. Figure 7 As shown, the input acceleration is linearly related to the resonant frequency of a single resonant beam. A high temperature 70°C thermal stress simulation is also performed. The simulation results show that the thermal stress of the resonator side beam 15 is very small, with a maximum of only 0.02 MPa, and the impact on the resonant frequency of the resonator side beam 15 is basically negligible.

[0061] In summary, the present invention proposes a low-temperature drift silicon resonant accelerometer structure, comprising: an intermediate layer, an upper glass cover plate and a lower glass cover plate.

[0062] The middle layer includes: a mass block 1, an amplifying lever structure 2, a resonator central support beam 4, drive detection comb teeth 5, a central anchor point 6 and an outer frame 9.

[0063] The upper glass cover plate and the lower glass cover plate are respectively covered on both sides of the outer frame of the middle layer and bonded thereto, so that the middle layer is vacuum-sealed. In addition, a metal wire is arranged inside the upper glass cover plate to connect with the driving detection comb teeth 5 of the middle layer.

[0064] The central anchor point 6 is set in the center of the middle layer and bonded to the upper glass cover plate. The mechanical structure of the middle layer is symmetrically distributed on both sides with the central anchor point 6 as the center. One end of the drive detection comb tooth 5 is fixed to the central anchor point 6 through the central support beam 4 of the resonator, and the other end is bonded to the upper glass cover plate. The amplifying lever structure 2 is connected to the other end of the central support beam 4 of the resonator. When the accelerometer structure has acceleration, the mass block 1 applies an inertial force to the amplifying lever structure 2 under the action of inertia. The inertial force is amplified by the amplifying lever structure 2, and then the resonant frequency of the drive detection comb tooth 5 is changed based on the force-frequency characteristic. The drive detection comb tooth 5 measures the resonant frequency affected by the inertial force, and leads the frequency signal to the outside through the metal wire to characterize the acceleration.

[0065] In the present invention, the terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense. For example, "connect" can be a fixed connection, a detachable connection, or an integral connection; "connect" can be a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0066] The shapes of various components in the drawings are schematic, and certain differences from their actual shapes are not excluded. The drawings are only used to illustrate the principles of the present invention and are not intended to limit the present invention.

[0067] Although the present invention is disclosed in detail with reference to the accompanying drawings, it should be understood that these descriptions are merely exemplary and are not intended to limit the application of the present invention. The scope of protection of the present invention is defined by the appended claims and may include various modifications, alterations and equivalents made to the invention without departing from the scope and spirit of the present invention.

Claims

1. A low temperature drift silicon resonant accelerometer structure, characterized in that: The structure comprises: an intermediate layer, an upper glass cover plate and a lower glass cover plate; The middle layer includes: a mass block (1), an amplifying lever structure (2), a resonator central support beam (4), drive detection comb teeth (5), a central anchor point (6) and an outer frame (9); The upper glass cover plate and the lower glass cover plate are respectively covered on both sides of the outer frame of the middle layer and bonded thereto, so that the middle layer is vacuum-sealed. In addition, a metal wire is arranged inside the upper glass cover plate to connect with the drive detection comb teeth (5) of the middle layer. The central anchor point (6) is arranged at the exact center of the middle layer and bonded to the upper glass cover plate. The mechanical structure of the middle layer is symmetrically distributed on both sides with the central anchor point (6) as the center. One end of the drive detection comb (5) is fixed to the central anchor point (6) through the central support beam (4) of the resonator, and the other end is bonded to the upper glass cover plate. The amplifying lever structure (2) is connected to the other end of the central support beam (4) of the resonator. When the accelerometer structure has acceleration, the mass block (1) applies an inertial force to the amplifying lever structure (2) under the action of inertia. The inertial force is amplified by the amplifying lever structure (2), and then the resonant frequency of the drive detection comb (5) is changed based on the force-frequency characteristic. The drive detection comb (5) measures the resonant frequency after being affected by the inertial force, and leads the frequency signal to the outside through the metal wire to represent the magnitude of the acceleration.

2. The low temperature drift silicon resonant accelerometer structure according to claim 1, characterized in that: The middle layer also includes: a double-ended fixed tuning fork resonator (3); The double-ended fixed tuning fork resonator (3) is connected to the resonator central support beam (4), and the thin end (16) of the resonator central support beam (4) is fixed to one side of the central anchor point (6); Two groups of amplifying lever structures (2) are respectively installed on both sides of the thick end (17) of the central support beam (4) of the resonator through a third beam (12); the second beam (11) of the amplifying lever structure (2) is connected to the double-end fixed tuning fork resonator (3); and the first beam (10) of the amplifying lever structure (2) is connected to the mass block (1).

3. The low temperature drift silicon resonant accelerometer structure according to claim 2, characterized in that: The double-ended fixed tuning fork resonator (3) comprises: a first resonator crossbeam (13), a second resonator crossbeam (14) and two resonator side beams (15); The first resonator crossbeam (13) and the second resonator crossbeam (14) are both fixed on the resonator central support beam (4), and the first resonator crossbeam (13) is closer to the central anchor point (6); two resonator side beams (15) are connected to the end points of the first resonator crossbeam (13) and the second resonator crossbeam (14) to form a closed frame structure, and the drive detection comb teeth (5) are installed at the center of the outer side of the resonator side beam (15).

4. The low temperature drift silicon resonant accelerometer structure according to claim 3, characterized in that: The part of the resonator side beam (15) close to the first resonator cross beam (13) has a greater rigidity, and the part close to the second resonator cross beam (14) has a smaller rigidity.

5. The low temperature drift silicon resonant accelerometer structure according to claim 4, characterized in that: The drive detection comb teeth (5) include: movable comb teeth (18), first fixed comb teeth (19), second fixed comb teeth (20), and electrodes (21); The movable comb teeth (18) are fixed on the resonator side beam (15); the electrodes (21) are respectively connected to one end of the first fixed comb teeth (19) and the second fixed comb teeth (20); the first fixed comb teeth (19) and the second fixed comb teeth (20) are bonded to the upper glass cover plate through the electrodes (20) connected to them; the comb teeth of the movable comb teeth (18) and the first fixed comb teeth (19) are interlaced to form a driving capacitor; the first fixed comb teeth (19) exert an electrostatic force on the movable comb teeth (18) to drive the movable comb teeth to move, thereby causing the resonator side beam (15) to resonate; at the same time, the second fixed comb teeth (19) and the movable comb teeth (18) form a detection capacitor; the capacitance change is detected by the second fixed comb teeth (20), thereby measuring the resonant frequency of the resonator side beam (15) and indicating the magnitude of acceleration.

6. The low temperature drift silicon resonant accelerometer structure according to claim 1, characterized in that: The middle layer further comprises: a mass block support anchor point (7) and a mass block support beam (8); The mass block (1) is connected to four mass block support anchor points (7) via four mass block support beams (8); the four mass block support anchor points (7) are arranged in four frame corners of the outer frame (9) and are bonded to the upper glass cover plate.

7. The low temperature drift silicon resonant accelerometer structure according to claim 6, characterized in that: The mass block support beam (8) is a U-shaped beam structure.

8. The low temperature drift silicon resonant accelerometer structure according to claim 5, characterized in that: The resonant frequency of the resonator side beam (15) changes after being subjected to pressure or tension. The resonant frequency of a single resonator side beam (15) can be expressed as: In the formula, f F is the resonant frequency of the resonator side beam (15) after being subjected to force, E is the Young's modulus of single crystal silicon, w is the width of the resonator side beam (15), L f is the length of the resonator side beam (15), h is the thickness of the intermediate layer, F is the pressure on a single resonator side beam (15), which is a negative value if it is a tensile force, ρ is the density of single crystal silicon, and m is the mass of the movable comb teeth (18) connected to the resonator side beam (15); The above formula can be expanded by Taylor, eliminating the higher-order terms to obtain: In the formula, f n The resonant frequency of the resonator side beam (15) is when it is not subjected to tensile or compressive stress; therefore, the resonant frequency of the resonator side beam (15) is linearly related to the force applied, and can be used to characterize the magnitude of acceleration.

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