Annular coupling MEMS gyroscope and preparation process thereof

Abstract

The invention provides an annular coupling MEMS gyroscope and a preparation process thereof, and relates to the technical field of MEMS sensors. The gyroscope comprises a base layer, a device layer and a packaging layer, and the device layer comprises a resonance unit which is suspended above the base layer and comprises a coupling ring, at least two pairs of resonance frames distributed along the outer circle of the coupling ring and at least two pairs of mass blocks respectively fixed in each pair of resonance frames; the connecting lines of each pair of resonance frames are mutually crossed and the intersection point passes through the center of the coupling ring; the excitation unit and the resonance frames form an excitation capacitor, and the excitation unit is used for driving the two resonance frames of each pair of resonance frames to oppositely vibrate or reversely vibrate; and the detection unit forms a detection capacitor with the mass block and is used for detecting a vibration signal of the mass block. The four-mass-block full-symmetric vibration structure is adopted, vibration of the four frame-type resonance units is coupled through the coupling rings, the quality factor is improved, and it is ensured that the working modes are consistent under the machining error condition and the external interference resistance stability is high.

Description

Technical Field

[0001] The present invention relates to the technical field of MEMS sensors, and particularly to a ring-coupled MEMS gyroscope and a manufacturing process thereof. Background Art

[0002] A MEMS gyroscope (Micro-Electro-Mechanical Systems Gyroscope) is a miniaturized sensor that determines the direction and speed of rotation based on detecting the Coriolis force generated when an object rotates. MEMS gyroscopes are small in size and light in weight, and are suitable for integration into various portable devices that require attitude sensing and motion control, such as smartphones and tablets, drones and autonomous vehicles, and sports bracelets.

[0003] A MEMS frame gyroscope (beam gyroscope) is a MEMS gyroscope that measures the angular velocity of rotation by measuring the amplitude change of the resonant beam during the rotation of the gyroscope. The frame gyroscope has the advantages of high sensitivity, being able to accurately measure small changes in the angular velocity of rotation; low operating current, low power consumption, suitable for battery power supply; and no moving parts with friction and wear, having high reliability and long life.

[0004] However, the existing MEMS frame gyroscopes currently mainly have the following disadvantages:

[0005] 1. The currently widely used gyroscope forms with a single mass block or two mass blocks are prone to asymmetric vibration of the device due to the influence of structural design and processing errors, thereby reducing the structural quality factor and resulting in a decrease in sensitivity and measurement accuracy.

[0006] 2. Currently, some gyroscopes also adopt the form of multiple mass blocks (4), but most of the mass blocks are coupled pairwise, and it is difficult to achieve overall coupling to obtain higher vibration symmetry, and the structural quality factor is not high, so the sensitivity and measurement accuracy still cannot be guaranteed.

[0007] 3. For the currently existing gyroscopes with the above structural forms, when subjected to external vibration or shock, it will cause unexpected displacement of the mass block, resulting in measurement error.

[0008] In summary, the existing MEMS frame gyroscopes have problems of asymmetric vibration caused by structural design and processing errors and unexpected displacement caused by external vibration, and these problems will reduce the device performance and result in low measurement accuracy.

[0009] Based on this, the present invention is proposed. Summary of the Invention

[0010] The object of the present invention is to provide a ring-coupled MEMS gyroscope and its manufacturing process, ensuring the consistency of the working mode under processing errors, and having better stability of the working mode when subjected to external vibration and impact.

[0011] To achieve the above object, the present invention provides the following technical solutions:

[0012] In a first aspect, the present invention provides a ring-coupled MEMS gyroscope, including a base layer, a device layer, and a packaging layer. The device layer includes: a resonant unit suspended above the base layer, including a coupling ring, at least two pairs of resonant frames distributed along the outer circle of the coupling ring, and at least two pairs of mass blocks respectively fixed inside each pair of resonant frames; the connecting lines of each pair of resonant frames intersect with each other and the intersection point passes through the center of the coupling ring; an excitation unit fixed on the base layer and located outside the resonant frames, forming an excitation capacitance with the resonant frames, for driving the two resonant frames of each pair of resonant frames to vibrate towards each other or away from each other; a detection unit fixed on the base layer and located inside the resonant frames, forming a detection capacitance with the mass blocks, for detecting the vibration signal of the mass blocks; a signal lead-out unit, partially disposed between the base layer and the device layer, and partially disposed inside the base layer, for leading out the signals generated by the device layer.

[0013] In a first aspect, the present invention provides a preferred solution. To further ensure that the resonant unit is suspended and vibrates stably, the device layer further includes: a fixing unit fixed on the base layer and connected to the resonant frames of the resonant unit, for supporting the resonant unit to suspend the resonant unit above the base layer.

[0014] Further, to better achieve symmetric vibration, the fixing unit includes at least four anchor points respectively distributed between two adjacent resonant frames.

[0015] In a first aspect, the present invention provides a preferred solution. To ensure the low-order characteristics of the working mode and eliminate the influence of interference modes, the fixing unit is connected to the resonant frame through a first cantilever beam. Two such first cantilever beams are connected to both outer sides of each resonant frame, and the lower surface of the first cantilever beam is higher than the upper surface of the fixing unit. The first cantilever beam bends and drives the resonant frame to vibrate.

[0016] In a first aspect, the present invention provides a preferred solution. To further ensure the low-order characteristics of the working mode and eliminate the influence of interference modes, the mass block is connected to the resonant frame through a second cantilever beam; two such second cantilever beams are connected to both inner sides of each resonant frame, and the lower surface of the second cantilever beam is higher than the upper surface of the mass block. The second cantilever beam bends and drives the mass block to vibrate.

[0017] More preferably, in order to further improve the quality factor and detection accuracy, there are four resonance frames arranged in two pairs and four mass blocks arranged in two pairs; the connections of each pair of resonance frames are perpendicular to each other, realizing more stable fully symmetric vibration, reducing the energy dissipation of the structure, and having better stability in the working mode when subjected to external vibration and impact.

[0018] Preferably, there are six resonance frames arranged in three pairs and six mass blocks arranged in three pairs; the six resonance frames are evenly distributed along the outer ring of the coupling ring. It can realize symmetric vibration of the six-wave belly vibration mode, reduce the energy dissipation of the structure, and have better stability in the working mode when subjected to external vibration and impact.

[0019] In the first aspect of the present invention, a preferred solution is provided. In order to further improve the vibration coupling effect, the coupling ring is a circular ring.

[0020] In the first aspect of the present invention, a preferred solution is provided. In order to improve the reliability of the signal extraction structure, the signal extraction unit includes a conductive connection point connected in the device layer and a conductive connection column in contact conduction with the conductive connection point, and the conductive connection column longitudinally penetrates the base layer to extract the signal to the outside.

[0021] In the first aspect of the present invention, a preferred solution is provided. The base layer is made of silicon dioxide, the device layer is made of silicon, and the encapsulation layer is made of silicon.

[0022] In the second aspect of the present invention, a preparation process of a ring-coupled MEMS gyroscope is provided, including:

[0023] S1. Fabricating the encapsulation layer: Take a base silicon wafer, clean it, spin-coat photoresist, pattern it and etch to form a cavity structure, and remove the photoresist to obtain the encapsulation layer;

[0024] S2. Fabricating the base layer: Take another base glass wafer, clean it, form TGV vias, fill with the first conductive material Cu, spin-coat photoresist, pattern it and etch the photoresist to expose the first conductive material, sputter the second conductive material Au on the overall surface, and then strip the photoresist and the second conductive material to obtain the connection of the second conductive material at the top of the first conductive material, and obtain the signal extraction unit and the base layer;

[0025] S3. Fabricating the device layer: Take another base silicon wafer, clean it, spin-coat photoresist, pattern it and etch to form a boss structure. After bonding one side of the boss structure to the base layer, the other side is thinned, and then photoresist is spin-coated on the surface, patterned and etched for each device unit in the device layer, and after removing the photoresist, the device layer grown on the base layer is obtained;

[0026] S4. Overall encapsulation: Bond the encapsulation layer and the base layer with the grown device layer to complete the fabrication of the overall structure of the MEMS gyroscope.

[0027] Compared with the prior art, the present invention has the following beneficial technical effects:

[0028] The gyroscope structure of the present invention achieves a higher quality factor through symmetrical vibration (e.g., four or six masses). Furthermore, the present invention uses a coupling ring to couple the vibration of the frame-shaped resonant unit (frame-type sensitive structure), enabling the structure to maintain consistent operating modes within certain manufacturing tolerances and achieving greater stability in the operating modes when subjected to external vibrations and impacts.

[0029] In a preferred gyroscope structure of the present invention, a fully symmetrical vibration structure of four masses is adopted, the coupling ring vibration mode is a four-antinode vibration mode, and the frame structure vibration mode of the resonant unit is opposite vibration and opposite vibration. The consistency of the two vibration modes can effectively reduce the amplitude drop problem caused by coupling. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0031] Figure 1 A structural plan view of a device layer of a ring-coupled MEMS gyroscope provided in a specific embodiment of the present invention;

[0032] Figure 2 A schematic diagram of the internal three-dimensional structure of a ring-coupled MEMS gyroscope provided in a specific embodiment of the present invention;

[0033] Figure 3 A schematic cross-sectional view of a ring-coupled MEMS gyroscope provided in accordance with one embodiment of the present invention;

[0034] Figure 4 A schematic structural diagram of a frame-type sensitive structure (resonant unit) of a ring-coupled MEMS gyroscope provided in a specific embodiment of the present invention;

[0035] Figure 5 A schematic plan view of a base layer and a signal lead-out unit of a ring-coupled MEMS gyroscope provided in a specific embodiment of the present invention;

[0036] Figure 6 A schematic diagram of the excitation mode of a ring-coupled MEMS gyroscope provided in a specific embodiment of the present invention;

[0037] Figure 7Schematic diagram of the detection mode of the ring-coupled MEMS gyroscope provided by a specific embodiment of the present invention;

[0038] Figure 8 Process flow for preparing the encapsulation layer of the ring-coupled MEMS gyroscope provided by a specific embodiment of the present invention;

[0039] Figure 9 Process flow for preparing the base layer of the ring-coupled MEMS gyroscope provided by a specific embodiment of the present invention;

[0040] Figure 10 Process flow for preparing the boss during the preparation of the device layer of the ring-coupled MEMS gyroscope provided by a specific embodiment of the present invention;

[0041] Figure 11 Process flow for preparing the device layer of the ring-coupled MEMS gyroscope provided by a specific embodiment of the present invention.

[0042] The reference numerals are as follows: base layer 100, base 110, device layer 200, resonant unit 210, coupling ring 211, mass block 212, resonant frame 213, first cantilever beam 214, second cantilever beam 215, excitation unit 220, excitation electrode 221, detection unit 230, detection electrode 231, fixing unit 240, anchor point 241, encapsulation layer 300, cap 310, signal extraction unit 400, conductive connection point 410, conductive connection post 420. Specific Embodiment

[0043] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0044] Please refer to Figure 1 、 Figure 2 and Figure 3 As shown, in a specific embodiment, a provided ring-coupled MEMS gyroscope is a planar Z-axis gyroscope, which is composed of a base layer 100, a device layer 200, and an encapsulation layer 300. The device layer 200 mainly consists of a resonant unit 210, a coupling ring 211, a mass block 212, a resonant frame 213, a first cantilever beam 214, a second cantilever beam 215, an excitation unit 220, an excitation electrode 221, a detection unit 230, a detection electrode 231, a fixing unit 240, and an anchor point 241.

[0045] Please refer to Figure 1 、Figure 2 , Figure 4 , the resonant unit 210, adopting a frame-type sensitive structure, is suspended above the base layer 100. It mainly consists of a coupling ring 211 in the middle, at least two pairs of resonant frames 213 distributed along the outer ring of the coupling ring 211, and at least two pairs of mass blocks 212 respectively fixed inside each pair of resonant frames 213. The main body of the base layer 100 is the base 110. The excitation unit 220 is fixed on the base layer 100 and located outside the resonant frames 213, forming an excitation capacitance with the resonant frames 213, and is used to drive the two resonant frames 213 of each pair of resonant frames 213 to vibrate towards each other or away from each other. The specific implementation form of the excitation unit 220 can be an excitation electrode 221. The detection unit 230 is fixed on the base layer 100 and located inside the resonant frames 213, forming a detection capacitance with the mass block 212, and is used to detect the vibration signal of the mass block 212. The specific implementation form of the detection unit 230 can be a detection electrode 231.

[0046] Please refer to Figure 3 and Figure 5 , the signal extraction unit 400, part of which is arranged between the base layer 100 and the device layer 200, and part of which is arranged inside the base layer 100, is used to extract the signal generated by the device layer 200. In a preferred implementation manner, the specific composition form of the signal extraction unit 400 is as follows: It mainly consists of a conductive connection point 410 connected to the device layer 200 and a conductive connection column 420 in contact conduction with the conductive connection point 410. The conductive connection column 420 longitudinally penetrates the base layer 100 to extract the signal to the outside.

[0047] Please refer to Figure 1 and Figure 2 , in a preferred implementation manner, two pairs of resonant frames 213, a total of four, are provided. Correspondingly, four mass blocks 212 are also provided, that is, one is arranged inside each resonant frame 213. The connection lines of each pair of resonant frames 213 intersect with each other and the intersection point passes through the center of the coupling ring 211. The adjacent two resonant frames 213 and the other two resonant frames 213 form a symmetric structure. Under the drive of the excitation unit 220, the two resonant frames 213 of each pair of resonant frames 213 vibrate towards each other or away from each other, forming a symmetric vibration. Please refer to Figure 6When the four frame-type sensitive structures vibrate symmetrically, if the gyroscope rotates about the Z-axis at this time, the mass block 212 will be subjected to the Coriolis force, generating vibrations perpendicular to the vibration direction and the rotation direction of the frame-type sensitive structure. Through the detection unit 230, that is, the detection capacitor formed by the mass block 212 and the detection electrode 231, the vibration signal of the mass block 212 is detected. An annular-coupled MEMS gyroscope provided in this embodiment uses a coupling ring to couple the vibrations of the four frame-type sensitive structures, enabling the gyroscope structure to maintain the consistency of the working mode under certain processing errors, and at the same time having better stability of the working mode when subjected to external vibrations and impacts.

[0048] Please refer to Figure 1 and Figure 2 , in a preferred embodiment, the device layer 200 of the annular-coupled MEMS gyroscope further has a fixing unit 240, which is fixed to the base layer 100 and connected to the resonant frame 213 of the resonant unit 210, and is used to support the resonant unit 210 so that the resonant unit 210 is suspended above the base layer 100. Further, the specific structure of the fixing unit 240 can be realized by a corresponding number of anchor points 241, that is, at least four anchor points 241 are corresponding, and are respectively distributed between two adjacent resonant frames 213. For the embodiment in which two pairs of a total of 4 are provided for the resonant frame 213, 4 anchor points 241 are also correspondingly provided. The setting of the corresponding number of anchor points can ensure that each frame-type sensitive structure has a corresponding support structure, further ensuring the symmetry of the overall structure, so that the frame-type sensitive structure can better achieve symmetric vibration.

[0049] Furthermore, considering the problem that there are interference modes before / during the operation of existing gyroscopes, which affect the vibration mode and quality factor, that is, the structural form and spatial layout of existing gyroscopes are prone to higher-order working mode problems and the problem that parasitic modes are close to the working mode, both of which will increase the difficulty of excitation detection. For this reason, the present invention provides an optimized structure. Please refer to Figure 1 、 Figure 2 and Figure 7 , in a preferred embodiment, the fixing unit 240 and the resonant frame 213 are connected by a "bilateral four-beam" cantilever beam. Specifically, the fixing unit 240 and the resonant frame 213 are connected by a first cantilever beam 214. Two first cantilever beams 214 are connected to both the outer sides of each resonant frame 213, and the lower surface of the first cantilever beam 214 is higher than the upper surface of the fixing unit 240. The first cantilever beam 214 is bent by the driving of the excitation unit 220 and drives the resonant frame 213 to vibrate. Please refer to Figure 1 、 Figure 2 、 Figure 3 and Figure 7, in a preferred embodiment, the mass block 212 and the resonant frame 213 are also connected by a "bilateral four-beam" cantilever beam. Specifically, the mass block 212 and the resonant frame 213 are connected by a second cantilever beam 215; two second cantilever beams 215 are connected to both sides inside each resonant frame 213, and the lower surface of the second cantilever beam 215 is higher than the upper surface of the mass block 212. The second cantilever beam 215 is driven by the detection unit 230 to bend and drive the mass block 212 to vibrate. The first cantilever beam 214 and the second cantilever beam 215 are of a bilateral four-beam structure, and there is a large distance between the two first cantilever beams 214 on the same side, and there is a large distance between the two second cantilever beams 215 on the same side. Through the arrangement of the cantilever beams, the mode of the frame-type sensitive structure is constrained, and the vibration trajectory of the mass block is constrained to ensure the low-order characteristics of the working mode and eliminate the influence of the interference mode. Through the above structural layout, the stable symmetric vibration of the resonant unit of the frame-type sensitive structure is further realized, the energy dissipation of the structure is reduced, which is beneficial to obtaining a higher quality factor and improving the detection accuracy. In addition, the flat and compact axisymmetric mechanical structure of the structure of the present invention makes the structure convenient for mass production.

[0050] Please refer to Figure 1 , in a more preferred embodiment, a provided ring-coupled MEMS gyroscope is a planar Z-axis gyroscope with a fully symmetric four-mass distribution. There are two pairs of a total of four resonant frames 213 provided, and two pairs of a total of four mass blocks 212 are provided; the connecting lines of each pair of resonant frames 213 are perpendicular to each other, and the coupling ring 211 is a circular ring. Simply put, the four resonant frames 213 are distributed in a "+" shape. This ring-coupled MEMS gyroscope with a fully symmetric four-mass distribution conforms to the four-wave belly vibration, has a better quality factor, and further improves the detection accuracy. More specifically, in the gyroscope structure of this embodiment, the coupling ring vibration mode is a four-wave belly vibration mode, and the frame structure vibration mode is an in-phase vibration and an out-of-phase vibration. The consistency of the two vibration modes can effectively reduce the problem of amplitude decrease caused by coupling. Of course, this is a relatively preferred embodiment of the present invention, but it is not limited to this distribution form. For example, in another preferred embodiment, there can be three pairs of a total of six resonant frames 213 provided, and three pairs of a total of six mass blocks 212 are correspondingly provided; the six resonant frames 213 are evenly distributed along the outer ring of the coupling ring 211 to realize that the coupling ring vibration mode is a six-wave belly vibration mode, and the frame structure vibration mode is also an in-phase vibration and an out-of-phase vibration. The consistency of the vibration modes can also effectively reduce the problem of amplitude decrease caused by coupling. In addition, when the coupling ring is an elliptical ring or a polygonal ring, the object of the present invention can also be achieved, and the effect that the gyroscope structure can maintain the consistency of the working mode under a certain processing error and has better stability of the working mode when subjected to external vibration and impact can be achieved.

[0051] In a preferred embodiment, the base layer 100 is made of silicon dioxide, i.e., glass material, the device layer 200 is made of silicon material, the encapsulation layer 300 is made of silicon material and adopts the structure form of a cap 310, and the components in the device layer 200 are accommodated inside the cap 310. The conductive connection point 410 is made of Au material, i.e., a gold pad point, and the conductive connection column 420 is made of a copper column.

[0052] In a preferred embodiment, a manufacturing process for a ring-coupled MEMS gyroscope is provided, which is used to manufacture the above-mentioned gyroscope and is mainly realized through the following steps: including:

[0053] Please refer to Figure 8 , S1. Fabricate the encapsulation layer: Take a six-inch or four-inch substrate (silicon wafer), clean it, spin-coat photoresist, pattern it, etch to form a cavity structure, and remove the photoresist to obtain the encapsulation layer;

[0054] Please refer to Figure 9 , S2. Fabricate the base layer: Take another six-inch or four-inch substrate (glass wafer), clean it, form TGV vias, fill the first conductive material (Cu) as a signal lead-out, spin-coat photoresist, pattern it, etch the photoresist to expose the first conductive material, sputter the second conductive material (Au) on the overall surface, and then strip the photoresist and the second conductive material to obtain the connection of the second conductive material at the top of the first conductive material, and obtain the signal lead-out unit and the base layer;

[0055] Please refer to Figure 10 and Figure 11 , S3. Fabricate the device layer: Take another substrate (silicon wafer), clean it, spin-coat photoresist, pattern it, etch to form a boss structure, bond one side of the boss structure to the base layer (silicon-glass bonding), perform a thinning process (CMP thinning technology) on the other side, then spin-coat photoresist on the surface, pattern it, etch each device unit in the device layer, and remove the photoresist to obtain the device layer grown on the base layer;

[0056] Please refer to Figure 3 , S4. Integral encapsulation: Bond the encapsulation layer and the base layer with the device layer grown thereon to complete the fabrication of the overall structure of the MEMS gyroscope.

[0057] In summary, based on the above embodiments, the annularly coupled MEMS gyroscope provided by the preferred embodiment of the present invention uses four mass blocks for symmetric vibration, and the structure has a higher quality factor. The first cantilever beam 214 of the resonant frame connecting the outer layer of the support mass block and the second cantilever beam connecting the support mass block are both bilateral four-beam structures, and there is a large distance between the two cantilever beams on the same side. Through the arrangement of the beams, the modes of the frame-type sensitive structure are constrained to ensure the low-order characteristics of the working mode and eliminate the influence of the interference mode. A coupling ring is used to couple the vibrations of the 4 frame-type sensitive structures, so that the structure can maintain the consistency of the working mode under certain processing errors, and at the same time has better stability of the working mode when subjected to external vibrations and impacts. In addition, the flat and compact axisymmetric mechanical structure of the structure of the present invention makes the structure convenient for mass production.

[0058] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification. Moreover, the above embodiments only express several implementation manners of the present invention, and the description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the present invention. For those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention.

Claims

1. A ring-coupled MEMS gyroscope, comprising a base layer (100), a device layer (200) and a packaging layer (300), characterized in that, The device layer (200) includes: A resonant unit (210), suspended above the base layer (100), including a coupling ring (211), at least two pairs of resonant frames (213) distributed along the outer circle of the coupling ring (211), and at least two pairs of mass blocks (212) respectively fixed inside each pair of resonant frames (213); the connection lines of each pair of resonant frames (213) intersect each other and the intersection point passes through the center of the coupling ring (211); An excitation unit (220), fixed on the base layer (100) and located outside the resonant frame (213), forming an excitation capacitance with the resonant frame (213) for driving the two resonant frames (213) of each pair of resonant frames (213) to vibrate towards or away from each other; A detection unit (230), fixed on the base layer (100) and located inside the resonant frame (213), forming a detection capacitance with the mass block (212) for detecting the vibration signal of the mass block (212); A signal extraction unit (400), partially disposed between the base layer (100) and the device layer (200), and partially disposed inside the base layer (100), for extracting the signal generated by the device layer (200).

2. The annularly coupled MEMS gyroscope according to claim 1, wherein The device layer (200) further includes: a fixing unit (240), fixed on the base layer (100) and connected to the resonant frame (213) of the resonant unit (210), for supporting the resonant unit (210) to suspend the resonant unit (210) above the base layer (100).

3. The annularly-coupled MEMS gyroscope according to claim 2, wherein The fixing unit (240) includes at least four anchor points (241), respectively distributed between two adjacent resonant frames (213).

4. The annularly coupled MEMS gyroscope according to claim 2 or 3, characterized in that, The fixing unit (240) is connected to the resonant frame (213) through a first cantilever beam (214), and two of the first cantilever beams (214) are connected to both outer sides of each resonant frame (213), and the lower surface of the first cantilever beam (214) is higher than the upper surface of the fixing unit (240), and the first cantilever beam (214) bends to drive the resonant frame (213) to vibrate.

5. The annularly coupled MEMS gyroscope according to claim 1, characterized in that, The mass block (212) is connected to the resonant frame (213) through a second cantilever beam (215); two of the second cantilever beams (215) are connected to both inner sides of each resonant frame (213), and the lower surface of the second cantilever beam (215) is higher than the upper surface of the mass block (212), and the second cantilever beam (215) bends to drive the mass block (212) to vibrate.

6. The annularly coupled MEMS gyroscope according to claim 2, wherein, There are two pairs (a total of four) of the resonant frames (213), and two pairs (a total of four) of the mass blocks (212); the connection lines of each pair of resonant frames (213) are perpendicular to each other.

7. The annularly coupled MEMS gyroscope according to claim 2, characterized in that, There are three pairs (a total of six) of the resonant frames (213), and three pairs (a total of six) of the mass blocks (212); the six resonant frames (213) are evenly distributed along the outer circle of the coupling ring (211).

8. The annularly coupled MEMS gyroscope according to claim 1, wherein, The coupling ring (211) is a circular ring.

9. The annularly-coupled MEMS gyroscope according to claim 1, wherein, The base layer (100) is made of silicon dioxide, the device layer (200) is made of silicon, and the encapsulation layer (300) is made of silicon.

10. A preparation process for preparing the annularly coupled MEMS gyroscope according to any one of claims 1 to 9 above, characterized in that, It includes: S1. Fabricate the encapsulation layer: Take a substrate, spin-coat photoresist after cleaning, form a cavity structure by patterning and etching, and remove the photoresist to obtain the encapsulation layer; S2. Fabricate the base layer: Take another substrate, form TGV vias after cleaning, fill with the first conductive material, spin-coat photoresist, etch the photoresist after patterning to expose the first conductive material, sputter the second conductive material on the overall surface, and then strip the photoresist and the second conductive material to obtain the connection of the second conductive material at the top of the first conductive material, and obtain the signal lead-out unit and the base layer; S3. Fabricate the device layer: Take yet another substrate, spin-coat photoresist after cleaning, form a boss structure by patterning and etching. After bonding one side of the boss structure to the base layer, perform thinning treatment on the other side, then spin-coat photoresist on the surface, pattern and etch each device unit in the device layer, and remove the photoresist to obtain the device layer grown on the base layer; S4. Integral encapsulation: Bond the encapsulation layer and the base layer with the device layer grown thereon to complete the fabrication of the overall structure of the MEMS gyroscope.

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