MEMS sensor chip structure and MEMS resonant sensor chip

Abstract

The invention discloses an MEMS sensor chip structure and an MEMS resonant sensor chip, and relates to the technical field of precision detection, and the MEMS sensor chip structure comprises a substrate which is provided with a cavity of a groove structure; the movable polar plate assembly comprises a movable polar plate, a driving part and a fixing part, and the movable polar plate is located above the cavity and installed on the base through the fixing part; the vibrating reed assembly comprises a vibrating reed located above the cavity and arranged on the face, away from the substrate, of the movable polar plate, a gap is formed between the vibrating reed and the movable polar plate, and the vibrating reed and the movable polar plate can conduct reciprocating torsional vibration; the position of the movable pole plate relative to the vibrating reed at least comprises a non-working position and a working position, when the movable pole plate is in the non-working position, the distance between the movable pole plate and the vibrating reed is a first preset distance, and when the movable pole plate is in the working position, the distance between the movable pole plate and the vibrating reed is a second preset distance; the first preset distance is larger than the second preset distance, and the driving part is used for driving the movable polar plate to move and switch between the working position and the non-working position.

Description

Technical Field

[0001] This invention relates to the field of precision detection technology, and in particular to a MEMS sensor chip structure and a MEMS resonant sensor chip. Background Technology

[0002] MEMS (Micro-Electro-Mechanical Systems) resonant sensor chip structures can be used in high-precision vibration detection, temperature monitoring, inertial detection, vacuum detection, pressure detection and other fields, and have good application prospects. It is a new type of high-end sensing technology.

[0003] Currently, a promising new principle measurement chip technology for high-precision detection in high-end applications is the MEMS resonant sensor chip structure. The core sensing structure of this chip is a vibrating diaphragm supported by a torsion beam. The diaphragm actively vibrates and interacts with the field of the measured physical quantity (vacuum, pressure, inertia, vibration, etc.), causing a shift in the diaphragm's resonant frequency. This shift has a linear relationship with the measured physical quantity, thus achieving high-precision measurement. This technology achieves high-precision measurement of physical quantities by detecting the shift in resonant frequency, making it a high-end sensing and testing technology. However, due to the presence of a movable structure (the vibrating diaphragm), it is prone to adhesion to the substrate under atmospheric or low-vacuum conditions due to moisture or contaminant particles, leading to chip structure failure and affecting its long-term reliability.

[0004] Therefore, how to improve the reliability of chip structure is a technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a MEMS sensor chip structure and a MEMS resonant sensor chip. The MEMS sensor chip structure provided by this invention is used to improve the reliability of the chip structure.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A MEMS sensor chip structure, comprising:

[0008] A substrate, one side of which has a cavity with a groove structure;

[0009] A movable electrode assembly includes a movable electrode, a driving part, and a fixing part. The movable electrode is located above the cavity, and the movable electrode is mounted on the substrate through the fixing part.

[0010] A vibrating plate assembly includes a vibrating plate located above the cavity. The vibrating plate assembly is disposed on the side of the movable electrode plate facing away from the substrate, and there is a gap between the vibrating plate and the movable electrode plate. The vibrating plate is capable of reciprocating torsional vibration. The position of the movable electrode plate relative to the vibrating plate includes at least a non-working position and a working position. When the movable electrode plate is in the non-working position, the distance between the movable electrode plate and the vibrating plate is a first preset distance. When the movable electrode plate is in the working position, the distance between the movable electrode plate and the vibrating plate is a second preset distance. The first preset distance is greater than the second preset distance. The driving unit is used to drive the movable electrode plate to move and switch between the working position and the non-working position.

[0011] Optionally, in the above-mentioned MEMS sensor chip structure, a stop block is also provided on the side of the vibrating plate assembly near the movable electrode plate. When the movable electrode plate moves to a distance of the second preset distance from the vibrating plate, the movable electrode plate abuts against the stop block.

[0012] Optionally, in the above-mentioned MEMS sensor chip structure, the vibrating plate assembly further includes a fixed frame and a torsion beam. One end of the torsion beam is connected to the fixed frame, and the other end of the torsion beam is connected to the vibrating plate. A clearance gap is provided between the fixed frame and the side of the vibrating plate. The vibrating plate assembly is mounted on the movable electrode plate assembly through the fixed frame.

[0013] Optionally, in the above-described MEMS sensor chip structure, the stop block is disposed on the side of the fixed frame facing the movable electrode plate.

[0014] Optionally, in the above-described MEMS sensor chip structure, the driving part is a driving beam, one end of the driving beam is connected to the fixed part, and the other end of the driving beam is connected to the movable electrode plate;

[0015] The drive beam includes a first material layer and a second material layer stacked along the thickness direction. The first material layer is located on the side of the drive beam facing the substrate, and the coefficient of thermal expansion of the first material layer is greater than that of the second material layer. The drive beam is used to drive the movable electrode plate to move closer to the vibrating plate after being energized.

[0016] Optionally, in the above-mentioned MEMS sensor chip structure, the driving beams are arranged in multiple ways, each driving beam surrounds the movable electrode plate, and each driving beam is arranged symmetrically with the movable electrode plate as the center of symmetry.

[0017] Optionally, in the above-described MEMS sensor chip structure, the driving beams are arranged on both sides of the movable electrode plate, and the driving beams include a first connecting segment and a second connecting segment connected to each other. The first connecting segment is connected to the fixed part, and the second connecting segment is connected to the movable electrode plate. The connection point between the first connecting segment and the fixed part and the connection point between the second connecting segment and the movable electrode plate are located on the same side.

[0018] Optionally, in the above-described MEMS sensor chip structure, the movable electrode assembly further includes an elastic beam, and the movable electrode is connected to the fixed part through the elastic beam;

[0019] The driving part includes a comb-shaped structure formed by alternating grooves and comb teeth disposed on the movable electrode plate and the fixed part. The comb teeth of one of the movable electrode plate and the fixed part correspond to the grooves of the other, and the comb teeth of the movable electrode plate are closer to the vibrating plate assembly relative to the comb teeth of the fixed part. The comb-shaped structure is used to drive the movable electrode plate to move closer to the vibrating plate after being energized.

[0020] Optionally, in the above-described MEMS sensor chip structure, the driving unit includes:

[0021] A magnet, the magnet being disposed on the side of the substrate facing away from the cavity;

[0022] A coil is disposed on one side of the movable pole plate. By passing current through the coil, the magnetic repulsion between the coil and the magnet causes the movable pole plate to move closer to the vibrating plate.

[0023] Compared with the prior art, in the MEMS sensor chip structure provided by the present invention, the substrate, the movable electrode assembly, and the vibrating plate assembly are stacked sequentially. The movable electrode in the movable electrode assembly is located above the cavity of the substrate, and the vibrating plate in the vibrating plate assembly is located on the side opposite to the movable electrode and the substrate. There is a gap between the vibrating plate and the movable electrode. The driving part of the movable electrode assembly can drive the movable electrode to move, adjusting the distance between the movable electrode and the vibrating plate, so that the position of the movable electrode relative to the vibrating plate includes at least a non-working position and a working position. When the movable electrode is in the non-working position, the distance between the movable electrode and the vibrating plate is... The distance between the movable electrode and the vibrating plate is a first preset distance. When the movable electrode is in the working position, the distance between the movable electrode and the vibrating plate is a second preset distance. The first preset distance is greater than the second preset distance. Therefore, when the MEMS sensor chip structure needs to work, the driving unit drives the movable electrode to move to the working position. At this time, the distance between the movable electrode and the vibrating plate is the second preset distance. The physical quantity to be measured is tested by the vibration of the vibrating plate. After the test is completed, the movable electrode returns to the non-working position. At this time, the distance between the movable electrode and the vibrating plate is the first preset distance, and there is a large gap between the movable electrode and the vibrating plate. Therefore, the movable electrode in the MEMS sensor chip structure provided by the present invention has two position states. When the driving unit drives the movable electrode to move to the working position, there is a smaller second preset distance between the movable electrode and the vibrating plate, ensuring normal operation of the chip. When the chip is not working, there is a larger first preset distance between the movable electrode and the vibrating plate. This effectively solves the problem of structural adhesion failure of the vibrating plate caused by water molecules or particles in the air under low vacuum, and improves the reliability of the chip structure.

[0024] The present invention also provides a MEMS resonant sensor chip, comprising a package cap structure and a MEMS sensor chip structure, wherein the package cap structure encapsulates the MEMS sensor chip structure, and the MEMS sensor chip structure is the MEMS sensor chip structure as described in any of the preceding claims.

[0025] The MEMS resonant sensor chip provided by this invention has all the technical effects of the above-mentioned MEMS sensor chip structure, which will not be repeated here. Attached Figure Description

[0026] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0027] Figure 1 This is a schematic diagram of the MEMS sensor chip structure disclosed in an embodiment of the present invention;

[0028] Figure 2 This is a schematic diagram of the movable electrode plate in the working position in the MEMS sensor chip structure disclosed in the embodiment of the present invention;

[0029] Figure 3 This is a schematic diagram of the structure of the vibrating plate assembly disclosed in an embodiment of the present invention;

[0030] Figure 4 This is a schematic diagram of the structure of the movable electrode assembly with a drive beam disclosed in an embodiment of the present invention;

[0031] Figure 5 This is a schematic diagram of a movable electrode assembly with a drive beam disclosed in another embodiment of the present invention;

[0032] Figure 6 for Figure 5 Schematic diagram of the cross section of AA;

[0033] Figure 7 This is a schematic diagram of a comb-like structure provided in a movable electrode assembly disclosed in an embodiment of the present invention;

[0034] Figure 8 for Figure 7 Cross-sectional view of BB;

[0035] Figure 9 This is a cross-sectional schematic diagram of the movable pole plate assembly with magnets and coils disclosed in an embodiment of the present invention;

[0036] Figure 10 This is a top view of the movable pole plate assembly disclosed in an embodiment of the present invention, which includes a magnet and a coil.

[0037] Figure label:

[0038] 100 is the base, 110 is the cavity;

[0039] 200 is a movable electrode assembly, 210 is a movable electrode, 220 is a fixing part, 230 is a drive beam, 231 is a first material layer, 232 is a second material layer, 240 is an elastic beam, 250 is a comb tooth, 260 is a magnet, and 270 is a coil.

[0040] 300 is the vibrating plate assembly, 310 is the vibrating plate, 320 is the fixed frame, 330 is the torsion beam, and 340 is the clearance.

[0041] Stop at 400. Detailed Implementation

[0042] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0043] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0044] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. "Several" means one or more, unless otherwise explicitly specified.

[0045] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0046] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0047] The core of this invention lies in providing a MEMS sensor chip structure to improve the reliability of the chip structure;

[0048] Another core aspect of this invention is to provide a MEMS resonant sensor chip having the aforementioned MEMS sensor chip structure.

[0049] like Figure 1 and Figure 2As shown, this embodiment of the invention discloses a MEMS resonant sensor chip structure, including a substrate 100, a movable electrode assembly 200, and a vibrating plate assembly 300. The substrate 100, the movable electrode assembly 200, and the vibrating plate assembly 300 are sequentially stacked along the direction from the vibrating plate assembly 300. A cavity 110 with a groove structure is formed on the substrate 100, with the groove opening facing the movable electrode assembly 200. The movable electrode assembly 200 is provided with a movable electrode 210, a driving part, and a fixing part 220. The movable electrode 210 is mounted and fixed to the substrate 100 through the fixing part 220, at which time the movable electrode 210 is located above the cavity 110. The vibrating plate assembly 300 includes a vibrating plate 310 also located above the cavity 110. The vibrating plate 310 can reciprocate along the thickness direction of the substrate 100. The vibrating plate 310 is disposed on the side of the movable electrode plate 210 facing away from the substrate 100, and there is a gap between the vibrating plate 310 and the movable electrode plate 210. The movable electrode plate 210 has at least two position states relative to the vibrating plate 310: a non-working position and a working position. When the movable electrode plate 210 is in the non-working position, the distance between the movable electrode plate 210 and the vibrating plate 310 is a first preset distance. When the driving unit drives the movable electrode plate 210 to move towards the vibrating plate 310 to the working position, the distance between the movable electrode plate 210 and the vibrating plate 310 is a second preset distance. The second preset distance is smaller than... Therefore, in the working state, the distance between the movable electrode 210 and the vibrating plate 310 of the MEMS resonant sensor chip structure provided in this embodiment is the first preset distance, ensuring that the vibration of the vibrating plate 310 can normally test the physical quantity to be measured. In the non-working state, the distance between the movable electrode 210 and the vibrating plate 310 is a larger second preset distance. The movable electrode 210 is driven by the driving unit to move and switch between the working and non-working positions in a timely manner. The larger second preset distance effectively solves the problem of structural adhesion failure caused by water molecules or particles in the air under low vacuum due to the consistently small distance between the vibrating plate 310 and the movable electrode 210, thus improving the reliability of chip operation. Furthermore, the MEMS sensor chip structure provided in this embodiment, fabricated using MEMS technology, has advantages such as small size, high yield, good product consistency, and low cost.

[0050] In some embodiments, the MEMS sensor chip structure is further provided with a stop block 400. The stop block 400 is arranged on the side of the vibrating plate assembly 300 near the movable electrode plate 210. The driving part in the movable electrode plate assembly 200 drives the movable electrode plate 210 to move towards the vibrating plate 310 until the distance between the movable electrode plate 210 and the vibrating plate 310 reaches a second preset distance. At this point, the side of the movable electrode plate 210 facing the vibrating plate 310 abuts against the stop block 400. The stop block 400 restricts the continued movement of the movable electrode plate 210. The stop block 400 plays a limiting role for the movable electrode plate 210, preventing the movable electrode plate 210 from getting too close to the vibrating plate 310 and causing a short circuit or structural damage. At the same time, it ensures the stability of the working position distance between the movable electrode plate 210 and the vibrating plate 310, improves measurement consistency, and further improves the reliability of the MEMS sensor chip structure provided in this embodiment.

[0051] like Figure 3 As shown, in some embodiments, the vibrating plate assembly 300 further includes a fixed frame 320 and a torsion beam 330. One end of the torsion beam 330 is connected to the fixed frame 320, and the other end of the torsion beam 330 is connected to the vibrating plate 310. The vibrating plate 310 is connected to the torsion beam 330, and one end of the two suspended ends of the vibrating plate 310 is twisted downward and the other end is twisted upward. In this way, the vibrating plate 310 can stably reciprocate torsional vibration. Furthermore, a clearance gap 340 is provided between the fixed frame 320 and the side of the vibrating plate 310 to avoid interference from the fixed frame 320 to the vibrating plate 310 during the reciprocating vibration of the vibrating plate 310, ensuring that the vibrating plate 310 vibrates smoothly and stably. The fixed frame 320 in the vibrating plate assembly 300 is connected to the fixing part 220 in the movable electrode assembly 200, so that the vibrating plate assembly 300 is installed and fixed on the movable electrode assembly 200 through the fixed frame 320, thereby realizing the fixation of the vibrating plate assembly 300.

[0052] like Figure 1As shown, the stop block 400 in the MEMS sensor chip structure provided in this example is disposed on the side of the fixed frame 320 of the vibrating plate assembly 300 facing the movable electrode plate 210. Since the fixed frame 320 stably fixes the fixed part 220 in the movable electrode plate assembly 200, the stop block 400 disposed on the fixed frame 320 has good stability, thus playing a good limiting role for the movable electrode plate 210 during its movement. When the movable electrode plate 210 switches to the working position, it ensures the stability and accuracy of the distance between the movable electrode plate 210 and the vibrating plate 310 being the second preset distance. In addition, in a specific embodiment, the vibrating plate 310 is preferably made of low-resistivity monocrystalline silicon or low-resistivity polycrystalline silicon, using an all-silicon structure and microfabrication technology, resulting in low structural stress, small initial deformation, and good consistency. Mature silicon microfabrication technology is more conducive to miniaturization and mass production, or a combination of silicon and metal structures, which will not be elaborated here.

[0053] like Figure 4 and Figure 6 As shown, this embodiment provides a specific driving part of the movable electrode assembly 200, which is a driving beam 230. One end of the driving beam 230 is connected to the fixing part 220 of the movable electrode assembly 200, and the other end of the driving beam 230 is connected to the movable electrode 210. The driving beam 230 has two different materials: a first material layer 231 and a second material layer 232. The first material layer 231 and the second material layer 232 are stacked along the thickness direction of the driving beam 230. The first material layer 231 is located on the side of the driving beam 230 facing the substrate 100, and the coefficient of thermal expansion of the first material layer 231 is greater than that of the second material layer 232. Therefore, when it is necessary to switch the movable electrode 210 from the non-working position to the working position, the driving beam 230 is activated. When the beam 230 is energized and a voltage is applied, the electrical power generates heat. Since the coefficient of thermal expansion of the first material layer 231 is greater than that of the second material layer 232, the driving beam 230 bends towards the vibrating plate assembly 300. The bent driving beam 230 then pushes the movable plate 210 connected to it upward until the movable plate 210 comes into contact with the stop block 400. At this point, the distance between the movable plate 210 and the vibrating plate 310 reaches the second preset distance. After the current is cut off from the driving beam 230, the first material layer 231 and the second material layer 232 in the driving beam 230 dissipate heat and return to their initial state. At this point, the driving beam 230 drives the movable plate 210 back to the non-working position, and the distance between the movable plate 210 and the vibrating plate 310 is the larger first preset distance.

[0054] like Figure 4As shown, in some embodiments, multiple drive beams 230 are provided. The specific number of drive beams 230 can be set to 2, 3, 4, or more. Each drive beam 230 surrounds the movable pole plate 210 and is symmetrically arranged with the movable pole plate 210 as the center of symmetry. For example, the movable pole plate 210 is rectangular, and each drive beam 230 is located around the movable pole plate 210. The length direction of each drive beam 230 is parallel to the side length of the movable pole plate 210, and one end of each drive beam 230 is connected to the corresponding corner of the movable pole plate 210. The multiple and symmetrically arranged drive beams 230 not only provide a balanced driving force, enabling the movable electrode plate 210 to move smoothly and evenly at all positions, preventing the movable electrode plate 210 from shifting or tilting during movement, thus improving the balance of the distance between the movable electrode plate 210 and the vibrating plate 310 and improving the accuracy of chip measurement, but also enhance the reliability of the connection structure between the movable electrode plate 210 and the fixed part 220.

[0055] like Figure 5 As shown, in some embodiments, drive beams 230 are arranged on both sides of the movable electrode plate 210. Each drive beam 230 includes a first connecting section and a second connecting section connected together. One end of the first connecting section is connected to the fixed part 220, and one end of the second connecting section is connected to the movable electrode plate 210. The connection point between the first connecting section and the fixed part and the connection point between the second connecting section and the movable electrode plate 210 are located on the same side, forming a U-shaped drive beam 230. The drive beams 230 symmetrically arranged on both sides of the movable electrode plate 210 promote its smooth movement. At this time, clearance gaps are also provided between the other two sides of the movable electrode plate 210 and the fixed part 220 to prevent interference from the fixed part 220 during the movement of the movable electrode plate 210. Alternatively, those skilled in the art can design other arrangements of the drive beams 230 according to actual needs; these will not be listed here.

[0056] like Figure 7 and Figure 8As shown, this embodiment provides another specific driving part in the movable electrode assembly 200. The movable electrode assembly 200 includes an elastic beam 240, and the movable electrode 210 is connected to the fixed part 220 via the elastic beam. The driving part includes a comb-like structure. Both the side of the movable electrode 210 and the fixed part 220 are provided with a comb-like structure formed by alternating grooves and comb teeth 250. Furthermore, the comb teeth 250 of one of the movable electrode 210 and the fixed part 220 extend into the groove of the other. Simultaneously, the comb teeth 250 of the movable electrode 210 are positioned relative to the comb teeth of the fixed part 220. The tooth 250 moves upward toward the vibrating plate assembly 300. After voltage is applied and current is introduced, the movable electrode 210 is driven upward by the electrostatic driving force of the comb-shaped structure, so that the movable electrode 210 moves closer to the vibrating plate 310 until the movable electrode 210 abuts against the stop block 400. The distance between the movable electrode 210 and the vibrating plate 310 is the second preset position, and the movable electrode 210 enters the working position. When the chip is not working, the voltage is removed, and the movable electrode 210 returns to the non-working position. At this time, the distance between the movable electrode 210 and the vibrating plate 310 is the first preset distance, which is larger.

[0057] In another specific embodiment, such as Figure 9 and Figure 10 Another type of drive unit shown includes a magnet 260 and a coil 270. The magnet 260 is disposed on the side of the substrate 100 away from the cavity 110, while the coil 270 is disposed on one side of the movable pole plate 210. Specifically, the coil 270 can be disposed on the side of the movable pole plate 210 away from the substrate 100, or it can be disposed on the side of the movable pole plate 210 facing the substrate 100. When the chip is working, current is supplied to the coil 270, causing the coil 270 to generate a magnetic field that repels the magnet 260. This magnetic force then pushes the movable plate 210 toward the vibrating plate 310 until the movable plate 210 comes into contact with the stop block 400. The distance between the movable plate 210 and the vibrating plate 310 is a second preset position, and the movable plate 210 enters the working position. When the chip is not working, the current to the coil 270 is cut off, and the movable plate 210 returns to the non-working position. The distance between the movable plate 210 and the vibrating plate 310 is a first preset distance, which effectively solves the problem of structural adhesion failure of the vibrating plate 310 caused by water molecules or particles in the air under low vacuum.

[0058] This invention also discloses a MEMS resonant sensor chip, including a packaging cap structure and a MEMS sensor chip structure. The packaging cap structure is used to encapsulate the MEMS sensor chip structure in a vacuum to ensure the normal testing and operation of the MEMS resonant sensor chip. Since this MEMS resonant sensor chip has the aforementioned MEMS sensor chip structure, it also possesses all the technical effects of the aforementioned MEMS sensor chip structure, which will not be elaborated further here.

[0059] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0060] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A MEMS sensor chip structure, characterized in that, include: A substrate, one side of which has a cavity with a groove structure; A movable electrode assembly includes a movable electrode, a driving part, and a fixing part. The movable electrode is located above the cavity, and the movable electrode is mounted on the substrate through the fixing part. A vibrating plate assembly includes a vibrating plate located above the cavity. The vibrating plate assembly is disposed on the side of the movable electrode plate facing away from the substrate, and there is a gap between the vibrating plate and the movable electrode plate. The vibrating plate is capable of reciprocating torsional vibration. The position of the movable electrode plate relative to the vibrating plate includes at least a non-working position and a working position. When the movable electrode plate is in the non-working position, the distance between the movable electrode plate and the vibrating plate is a first preset distance. When the movable electrode plate is in the working position, the distance between the movable electrode plate and the vibrating plate is a second preset distance. The first preset distance is greater than the second preset distance. The driving unit is used to drive the movable electrode plate to move and switch between the working position and the non-working position.

2. The MEMS sensor chip structure according to claim 1, characterized in that, A stop block is also provided on the side of the vibrating plate assembly near the movable electrode plate. When the movable electrode plate moves to a distance of the second preset distance from the vibrating plate, the movable electrode plate abuts against the stop block.

3. The MEMS sensor chip structure according to claim 2, characterized in that, The vibrating plate assembly also includes a fixed frame and a torsion beam. One end of the torsion beam is connected to the fixed frame, and the other end of the torsion beam is connected to the vibrating plate. A clearance gap is provided between the fixed frame and the side of the vibrating plate. The vibrating plate assembly is mounted on the movable electrode plate assembly through the fixed frame.

4. The MEMS sensor chip structure according to claim 3, characterized in that, The stop block is disposed on the side of the fixed frame facing the movable electrode plate.

5. The MEMS sensor chip structure according to claim 1, characterized in that, The driving part is a driving beam, one end of which is connected to the fixed part, and the other end of which is connected to the movable pole plate. The drive beam includes a first material layer and a second material layer stacked along the thickness direction. The first material layer is located on the side of the drive beam facing the substrate, and the coefficient of thermal expansion of the first material layer is greater than that of the second material layer. The drive beam is used to drive the movable electrode plate to move closer to the vibrating plate after being energized.

6. The MEMS sensor chip structure according to claim 5, characterized in that, The drive beams are arranged in multiple ways, each drive beam surrounds the movable pole plate, and each drive beam is arranged symmetrically with the movable pole plate as the center of symmetry.

7. The MEMS sensor chip structure according to claim 5, wherein the driving beams are arranged on both sides of the movable electrode plate, and the driving beams include a first connecting segment and a second connecting segment connected to each other, the first connecting segment being connected to the fixed part, the second connecting segment being connected to the movable electrode plate, and the connection point between the first connecting segment and the fixed part and the connection point between the second connecting segment and the movable electrode plate being located on the same side.

8. The MEMS sensor chip structure according to claim 1, characterized in that, The movable electrode assembly further includes an elastic beam, and the movable electrode is connected to the fixed part through the elastic beam; The driving part includes a comb-shaped structure formed by alternating grooves and comb teeth disposed on the movable electrode plate and the fixed part. The comb teeth of one of the movable electrode plate and the fixed part correspond to the grooves of the other, and the comb teeth of the movable electrode plate are closer to the vibrating plate assembly relative to the comb teeth of the fixed part. The comb-shaped structure is used to drive the movable electrode plate to move closer to the vibrating plate after being energized.

9. The MEMS sensor chip structure according to claim 1, characterized in that, The drive unit includes: A magnet, the magnet being disposed on the side of the substrate facing away from the cavity; A coil is disposed on one side of the movable pole plate. By passing current through the coil, the magnetic repulsion between the coil and the magnet causes the movable pole plate to move closer to the vibrating plate.

10. A MEMS resonant sensor chip, characterized in that, It includes a packaging cap structure and a MEMS sensor chip structure, wherein the packaging cap structure encapsulates the MEMS sensor chip structure, and the MEMS sensor chip structure is the MEMS sensor chip structure as described in any one of claims 1-9.

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