MEMS resonator and MEMS integrated product

Abstract

The invention provides an MEMS resonator and an MEMS integrated product. The MEMS resonator comprises an anchoring part and a vibrating arm connected to the anchoring part. The vibration arm comprises a mass beam and an elastic beam, composite tooth parts are arranged on the two opposite sides of the mass beam respectively, each composite tooth part comprises a first tooth-shaped part and a second tooth-shaped part which are arranged in the first axis direction, the mass beam and the elastic beam are arranged along the first axis, and under the action of driving force, the first tooth-shaped part and the second tooth-shaped part are arranged in the first axis direction. The vibration arm swings relative to the anchoring part in the direction of a second axis perpendicular to the first axis; wherein the first tooth-shaped part is relatively located at the position closer to the anchoring part, the first tooth-shaped part comprises a plurality of first teeth, the second tooth-shaped part comprises a plurality of second teeth, and the first teeth and the second teeth protrude and extend outwards from the corresponding sides of the mass beam respectively. The tooth bottom is connected with the mass beam, the tooth top is opposite to the tooth bottom, the tooth side face is connected between the tooth top and the tooth bottom, the tooth side face of the first tooth is parallel to the second axis, and the tooth side face of the second tooth inclines relative to the second axis.

Description

Technical Field

[0001] The present application relates to the field of micro-electromechanical technology, and in particular to a MEMS resonator and a MEMS integrated product. Background Art

[0002] Microelectromechanical system (MEMS) resonators are micro-nanoscale resonators manufactured using semiconductor technology. MEMS resonators can generate mechanical vibrations at specific frequencies and are widely used in a variety of fields. Integrated products containing MEMS resonators include clock oscillators, radio frequency filters, and resonant sensors.

[0003] For example, MEMS resonators combined with drive circuits can be used to construct MEMS oscillators, which are used to provide periodic clock signals to other electronic chips and have a wide range of applications. Traditional oscillators are generally made of quartz because of its low temperature drift coefficient and excellent long-term stability. However, after recent developments, silicon-based MEMS oscillators have achieved basic performance close to that of quartz oscillators, demonstrating their advantages in small size, strong vibration resistance, and ease of integration.

[0004] MEMS resonators can be divided into electrostatically driven resonators and piezoelectrically driven resonators based on their driving principles. Electrostatically driven resonators generally use single-crystal silicon materials, which can achieve a higher resonator Q value, but the electromechanical transduction coefficient of electrostatic drive is low. The performance of piezoelectrically driven resonators is the opposite. The piezoelectric material reduces the resonator's Q value, but can significantly improve the electromechanical transduction coefficient.

[0005] To improve the electromechanical transduction coefficient of electrostatic resonators, the main methods used are to increase the capacitor area, reduce the capacitor gap, and increase the bias voltage. However, when using a small capacitor gap for driving or detection, the resonator vibration easily enters the nonlinear region, affecting the resonator's operating performance. Therefore, under existing technical conditions, further improving the linear operating range of electrostatically driven resonators at ultra-small capacitor gaps is a technical challenge that needs to be solved urgently. Summary of the Invention

[0006] In order to solve the existing technical problems, the present application provides a MEMS resonator and a MEMS integrated product that can effectively improve the linear working performance.

[0007] In a first aspect, the present application provides a MEMS resonator, comprising an anchor portion and a vibration arm connected to the anchor portion;

[0008] The vibration arm includes a mass beam and an elastic beam, wherein serrations are respectively provided on opposite sides of the mass beam, and the composite tooth portion includes a first tooth-shaped portion and a second tooth-shaped portion arranged along a first axis. The mass beam and the elastic beam are both arranged along the first axis. Under the action of a driving force, the vibration arm swings relative to the anchor portion in a second axis direction perpendicular to the first axis.

[0009] In which, the first tooth-shaped portion is relatively located closer to the anchoring portion, the first tooth-shaped portion includes a plurality of first teeth, the second tooth-shaped portion includes a plurality of second teeth, the first teeth and the second teeth respectively protrude outward from the corresponding sides of the mass beam, and include a tooth bottom connected to the mass beam, a tooth top opposite to the tooth bottom, and a tooth side surface connected between the tooth top and the tooth bottom, the tooth side surface of the first tooth is parallel to the second axis, and the tooth side surface of the second tooth is inclined relative to the second axis.

[0010] In a second aspect, the present application provides a MEMS integrated product, including the MEMS resonator described in any embodiment of the present application;

[0011] The MEMS integrated product is one of the following: a clock oscillator, a radio frequency filter, and a resonant sensor.

[0012] In the MEMS resonator provided by the above embodiment, the composite tooth portion arranged on the mass beam of the vibration arm includes a first tooth-shaped portion and a second tooth-shaped portion, the first tooth-shaped portion and the second tooth-shaped portion are arranged along the first axis direction, the first tooth-shaped portion is located on the mass beam closer to the anchor portion, the tooth side surface of the first tooth in the first tooth-shaped portion is parallel to the second axis, and the tooth side surface of the second tooth in the second tooth-shaped portion is inclined relative to the second axis. In this way, during the operation of the MEMS resonator, in the vibration motion of the mass beam swinging in the second axis direction perpendicular to the first axis relative to the anchor portion, the second tooth-shaped portion of the composite tooth portion, which is relatively far away from the anchor portion, is easier to enter the nonlinear region due to its larger displacement, thereby increasing the size of the nonlinear working region of the MEMS resonator, and the first tooth-shaped portion relatively close to the anchor portion can maintain good linearity within a larger torsion angle, thereby increasing the change in gap capacitance in the MEMS resonator under unit torsion angle.

[0013] In the above embodiments, the MEMS integrated product and the corresponding MEMS resonator embodiments belong to the same concept, and thus have the same technical effects as the various MEMS resonator embodiments, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Schematic diagram of the structure of the first type of MEMS resonator.

[0015] Figure 2Schematic diagram of the structure of the second type of MEMS resonator.

[0016] Figure 3 Schematic diagram of the structure of the third type of MEMS resonator.

[0017] Figure 4 for Figures 1 to 3 A graph showing the relationship between vibration angle and capacitance change for three types of MEMS resonators.

[0018] Figure 5 A schematic structural diagram of a MEMS resonator provided in one embodiment of the present application.

[0019] Figure 6 for Figure 2 MEMS resonators of the type shown are Figure 5 The graph shows the relationship between the vibration angle and capacitance change of the MEMS resonator.

[0020] Figure 7 A schematic structural diagram of a MEMS resonator provided in another embodiment of the present application. DETAILED DESCRIPTION

[0021] The technical solution of the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] In order to make the purpose, technical solutions and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings. The described embodiments should not be regarded as limiting this application. All other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0023] In the following description, the expression "some embodiments" is involved, which describes a subset of all possible embodiments. It should be noted that "some embodiments" may be the same subset or different subsets of all possible embodiments, and may be combined with each other without conflict.

[0024] In the following description, the terms "first, second, and third" are merely used to distinguish similar objects and do not represent a specific ordering of the objects. It is understandable that "first, second, and third" can be interchanged with a specific order or sequence where permitted, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein.

[0025] In their research on improving the electromechanical transduction coefficient of electrostatically driven resonators using ultra-small capacitor gaps, the inventors of this application faced the problem of how to effectively improve the linear operating range of electrostatic resonators under ultra-small capacitor gaps. They conducted the following comparative analysis of the operating performance of different types of electrostatically driven resonators with different structural forms:

[0026] like Figure 1 As shown, the first type MEMS resonator includes an anchor point 11, a vibration beam 12, and a positive drive area 13 and a negative drive area 14 respectively arranged on opposite sides of the vibration beam 12. The vibration beam 12 includes a mass beam 121 and an elastic beam 122. The mass beam 121 is connected and fixed to the anchor point 11 through the elastic beam 122, and can perform a left-right swinging vibration motion around the anchor point 11. A linear plate gap 15 is formed between the mass beam 121 and the positive drive area 13, and between the mass beam 121 and the negative drive area 14, respectively. The two linear plate gaps 15 constitute two differential drive capacitors for driving the vibration beam 12 to vibrate. During the operation of the first type MEMS resonator to generate vibration through electrostatic drive, the positive drive area 13 and the negative drive area 14 can also be used as a positive detection area and a negative detection area. The two linear plate gaps 15 constitute two differential detection capacitors for detecting the movement of the resonator. In this first type MEMS resonator, the two linear plate gaps 15 can be equivalent to a parallel plate capacitor. Since the mass beam 121 is in a torsional motion around the anchor point 11 when vibrating, the capacitance gap in the capacitance region far from the anchor point 11 will be rapidly reduced, causing the resonator to enter the nonlinear working region more quickly.

[0027] like Figure 2 The figure shows the structure of the second type of MEMS resonator. Figure 1 The main difference of the first type of MEMS resonator shown is that the mass beam 221 has a sawtooth structure on opposite sides. A sawtooth gap 25 is formed between one side of the mass beam 221 and the positive drive region 23, and between the other side of the mass beam 221 and the negative drive region 24. The two sawtooth gaps 25 form two differential drive capacitors for driving the vibration beam 22. Similarly, the positive drive region 23 and the negative drive region 24 can also serve as the positive and negative detection regions, and the two sawtooth gaps 25 can also form two differential detection capacitors for detecting the movement of the resonator.

[0028] like Figure 3 The figure shows the structure of the third type of MEMS resonator. Figure 1 The main difference of the first type of MEMS resonator shown is that a comb-tooth structure is provided on opposite sides of the mass beam 321. Comb-tooth gaps 35 are formed between one side of the mass beam 321 and the positive drive region 33, and between the other side of the mass beam 321 and the negative drive region 34. The two comb-tooth gaps 35 constitute two differential drive capacitors for driving the vibration beam 32 to vibrate. Similarly, the positive drive region 33 and the negative drive region 34 can also serve as the positive and negative detection regions, and the two comb-tooth gaps 35 can also constitute two differential detection capacitors for detecting the movement of the resonator.

[0029] According to the principles of electrostatic drive (Formula 1 below) and capacitance detection (Formula 2 below):

[0030]

[0031] Among them, F e is the vibration force, U is the applied bias voltage, C is the capacitance value, and θ is the vibration angle;

[0032] V out ∝(C1-C2); (Formula 2)

[0033] Among them, V out Refers to the output voltage detected by the differential detection circuit. C1 and C2 are the capacitance values of the two differential detection capacitors. The output voltage V out It is proportional to the difference in capacitance of the differential sense capacitors.

[0034] Combining Formula 1 and Formula 2, Figures 1 to 3 The three types of MEMS resonators are analyzed, calculated and compared, as shown in the figure. Figure 4 As shown in FIG, the relationship between the angle θ and the capacitance change ΔC of the three types of MEMS resonators during vibration, among which the first type of MEMS resonator enters the nonlinear region after a smaller torsion angle. Figure 3 The overall curve relationship shown for the third type of MEMS resonator differs less from the overall curve relationship for the first type of MEMS resonator. Figure 2 The second-type MEMS resonator shown can maintain good linearity over a wide torsion angle, but the capacitance change ΔC produced by the second-type resonator for the same change in angle θ is relatively smaller. Based on this, the inventors of this application proposed a design concept of providing a composite tooth portion on the mass beam. This composite tooth design addresses the compatibility issue of using an ultra-small capacitor gap to improve the electromechanical transduction coefficient of the electrostatically driven resonator and improving the linear operating range under the ultra-small capacitor gap.

[0035] See also Figure 5, a MEMS resonator provided in one embodiment of the present application, includes an anchor portion 51 and a vibration arm 53 connected to the anchor portion 51. The vibration arm 53 includes a mass beam 531 and an elastic beam 532. Composite teeth 57 are provided on opposite sides of the mass beam 531. The composite teeth 57 include a first tooth-shaped portion and a second tooth-shaped portion arranged along a first axis X. The mass beam 531 and the elastic beam 532 are both arranged along the first axis. Under the action of a driving force, the vibration arm 53 swings relative to the anchor portion 51 in the direction of a second axis Y perpendicular to the first axis X. In which, the first tooth-shaped portion is relatively located closer to the anchoring portion 51, the first tooth-shaped portion includes a plurality of first teeth 571, and the second tooth-shaped portion includes a plurality of second teeth 572. The first teeth 571 and the second teeth 572 respectively protrude outward from the corresponding sides of the mass beam 531, and include a tooth bottom 575 connected to the mass beam 531, a tooth top 573 opposite to the tooth bottom 575, and a tooth side surface 574 connected between the tooth top 573 and the tooth bottom 575. The tooth side surface 574 of the first tooth 571 is parallel to the second axis Y, and the tooth side surface 574 of the second tooth 572 is inclined relative to the second axis Y.

[0036] The composite tooth portion 57 refers to a tooth-shaped portion including at least two teeth of different shapes. For ease of description and distinction, in the embodiment of the present application, the teeth of different shapes in the composite tooth portion 57 are respectively referred to as the first tooth 571 and the second tooth 572. The tooth bottom 575 refers to the end of each tooth corresponding to the side connected to the mass beam 531. The tooth top 573 refers to the end of each tooth protruding and extending in the direction away from the mass beam 531. The tooth side surface 574 is connected between the tooth top 573 and the tooth bottom 575, and the gap capacitance is formed between the tooth side surfaces 574 of the two teeth that are meshed with each other, such as, the two meshing teeth are respectively located on the mass beam 531 and the driving part that drives the mass beam 531 to vibrate. Among them, the tooth side surface 574 of the first tooth 571 is parallel to the second axis Y. In the same compound tooth-shaped portion, a tooth groove is formed between two adjacent first teeth 571, which is parallel to the second axis Y and has a constant width from the tooth top 573 to the tooth bottom 575; the tooth side surface 574 of the second tooth 572 is inclined relative to the second axis Y. In this way, a tooth groove is formed between the tooth side surfaces 574 of two adjacent second teeth 572, which is inclined relative to the second axis Y and has a gradually changing width from the tooth top 573 to the tooth bottom 575, wherein the gradual change can refer to an increase in width from the tooth top 573 to the tooth bottom 575, or a decrease in width from the tooth top 573 to the tooth bottom 575.

[0037] In the above embodiment, a composite tooth portion 57 including a first tooth-shaped portion and a second tooth-shaped portion is provided on the mass beam 531 of the vibrating arm 53. The first tooth-shaped portion is located on the mass beam 531 relatively closer to the anchor portion 51. The tooth flanks of the first teeth 571 in the first tooth-shaped portion are parallel to the second axis, while the tooth flanks of the second teeth 572 in the second tooth-shaped portion are inclined relative to the second axis. Thus, during operation of the MEMS resonator, during the vibration motion of the mass beam 531 swinging relative to the anchor portion 51 in the direction of the second axis Y perpendicular to the first axis X, the second tooth-shaped portion relatively farther away from the anchor portion 51 experiences a greater displacement due to vibration and is more likely to enter the nonlinear region, thereby increasing the size of the nonlinear operating region of the MEMS resonator. The first tooth-shaped portion relatively closer to the anchor portion 51 can maintain good linearity within a larger torsion angle, thereby increasing the change in gap capacitance per unit torsion angle in the MEMS resonator. The design of the composite tooth portion 57 effectively solves the compatibility problem of using an ultra-small capacitor gap to improve the electromechanical transduction coefficient of the electrostatically driven resonator and improving the linear operating region under the ultra-small capacitor gap.

[0038] Optionally, in the vibration arm 53, the width of the elastic beam 532 in the direction perpendicular to the first axis X is smaller than the width of the mass beam 532. The elastic beam 532 and the mass beam 531 extend along the first axis direction X, and the center lines of the elastic beam 532 and the mass beam 531 are located on the same straight line, so that the vibration arm 53 has a symmetrical shape. The vibration arm 53 is divided into two sections: the mass beam 531 with a relatively large width and the elastic beam 532 with a relatively small width. The vibration arm 53 is connected to the anchor portion 51 through the elastic beam 532 with a relatively small width. The provision of the elastic beam 532 is more conducive to the vibration arm 53 forming a vibration motion of the desired direction and amplitude relative to the anchor portion 51 under the action of the same driving force.

[0039] Optionally, one end of the elastic beam 532 is connected to the mass beam 531, and the other end is connected to the anchoring portion 51. In the design of a MEMS resonator including a single vibration arm, the vibration arm 53 can be directly connected to the anchoring portion 51 through the elastic beam 532. In this case, the vibration arm 53 as a whole vibrates with the end where the elastic beam 532 is connected to the anchoring portion 51 as the fulcrum. This makes it easier to design the vibration arm 53 to obtain a desired direction and amplitude of vibration under a certain driving force.

[0040] Optionally, the MEMS resonator further includes a first driver 54 and a second driver 55 disposed on opposite sides of the mass beam 531. The first driver 54 and the second driver 55 are each provided with a tooth-shaped structure on a side proximal to the mass beam 531 that matches the composite tooth portion 57. Gap capacitance is formed between the first driver 54 and the mass beam 531, and between the second driver 55 and the mass beam 531. One of the first driver 54 and the second driver 55 is a positive driver, and the other is a negative driver. The opposite ends of the first and second drive units 54 and 55 along the first axis X are aligned with the mass beam 531, and the tooth structures are complementary to the composite tooth portions 57 on one side of the mass beam 531. The gap capacitors comprise a first positive gap region 521 formed between the tooth structure of the positive drive unit and the first tooth-shaped portion of the mass beam, and a second positive gap region 522 formed between the tooth structure of the positive drive unit and the second tooth-shaped portion of the mass beam; a first negative gap region 561 formed between the tooth structure of the negative drive unit and the first tooth-shaped portion of the mass beam 531, and a second negative gap region 562 formed between the tooth structure of the negative drive unit and the second tooth-shaped portion of the mass beam. The first positive gap region 521 and the second positive gap region 522 constitute the positive drive capacitor 52, while the first negative gap region 561 and the second negative gap region 562 constitute the negative drive capacitor 56. The positive drive capacitor 52 and the negative drive capacitor 56 form two differential drive capacitors, which are used to drive the vibration beam 53 to swing left and right, with the location where the elastic beam 532 is connected to the anchor portion 51 as the fulcrum.

[0041] During the working process of the MEMS resonator generating vibration through electrostatic drive, the first driving part 54 and the second driving part 55 can also be used as the positive detection area and the negative detection area. The first positive gap area 521 and the second positive gap area 522 constitute a positive detection capacitor, and the first negative gap area 561 and the second negative gap area 562 constitute a negative detection capacitor. The positive detection capacitor and the negative detection capacitor constitute a differential detection capacitor, which is used to detect the vibration movement of the MEMS resonator.

[0042] It should be noted that, in the embodiment of the present application, the gap region can be an air gap or a vacuum gap, and the spacing of the gap region is 0.01-3um. In the MEMS resonator, the mass beam 531, the elastic beam 532, the anchoring region 51, the first drive portion 54, and the second drive portion 55 are all made of common semiconductor materials, such as single crystal silicon, polycrystalline silicon, silicon oxide, silicon nitride, silicon carbide, etc., or a combination of the foregoing materials. In the MEMS resonator using the composite tooth portion 57, in the second tooth-shaped portion relatively far away from the anchoring portion 51, the second tooth 572 uses an inclined tooth side surface 574, which makes it less likely for a very small gap to appear and enter the nonlinear region when the vibrating arm 53 undergoes torsional motion, so the size of the nonlinear working area of the MEMS resonator can be increased. In the first tooth-shaped portion relatively close to the anchoring portion 51, the first tooth 571 uses parallel tooth side surfaces 574, which can increase the area of the capacitor surface within a unit volume. Since the parallel tooth side surfaces and tooth bottom surfaces of the first tooth 571 can be used as capacitor detection surfaces, the capacitor detection surface is larger than that of the second tooth 572, so the change in gap capacitance under unit torsion angle can be increased.

[0043] In the MEMS resonator, the composite tooth portion 57 on the mass beam 53 meshes with the tooth-shaped structure in the corresponding driving portion, and a first gap capacitor parallel to the second axis Y is formed between the tooth side surfaces 574 of the two meshing first teeth 571, and a second gap capacitor inclined relative to the second axis Y is formed between the tooth side surfaces 574 of the two meshing second teeth 572. The first gap capacitor formed between the two meshing first teeth 571 can further include a gap formed between the tooth tops 573 and tooth bottoms 575 of the two meshing first teeth 571, thereby increasing the area of the capacitor surface between the two meshing teeth.

[0044] In an alternative specific example, such as Figure 5 As shown, the first tooth 571 is a rectangular tooth. Accordingly, the tooth top 573 and tooth bottom 575 of the first tooth 571 are both linear. The tooth top 573 of the second tooth 572 is pointed, while the tooth bottom 575 is linear. Accordingly, the second tooth 572 is a triangular tooth. Through the design of the shapes of the first teeth 571 and the second teeth 572, the tooth groove between two adjacent first teeth 571 is formed into a rectangular shape, and the width of the tooth groove is evenly formed between the two first teeth. The tooth groove between two adjacent second teeth 572 is formed into a triangle or an inverted trapezoid. The width of the tooth groove gradually decreases from the tooth top 573 of the second tooth 572 away from the edge of the mass beam to the tooth bottom 575 connected to the mass beam 531.

[0045] See also Figure 6, which is a comparison chart of the relationship between the angle θ and the capacitance change ΔC during vibration of a MEMS resonator using a composite tooth portion and a MEMS resonator with a single tooth shape. Among them, the MEMS resonator using a composite tooth portion can increase the capacitance change ΔC per unit angle θ change while increasing the linear working area, thereby helping to increase the electromechanical coupling coefficient of the MEMS resonator.

[0046] In other embodiments, the MEMS resonator may be a combination of vibration beams formed by connecting multiple vibration arms. Figure 7 , a MEMS resonator provided in another embodiment of the present application, includes four vibration arms 53, and also includes a coupling beam 58 connected between the elastic beam 532 and the anchoring portion 51. Each of the vibration arms 53 includes a mass beam 531 and an elastic beam 532. The four vibration arms 53 are arranged in an H-shape, and the anchoring portion 51 includes two anchoring points 511 located on opposite sides of the coupling beam 58. The MEMS resonator adopts a combination of multiple vibration arm structures to improve the overall performance of the resonator.

[0047] Each of the anchoring points 511 is located between a group of the vibration arms 53, and includes a first straight edge parallel to the coupling beam 58, two second straight edges located at both ends of the first straight edge and parallel to the vibration arms 53, and a third arc-shaped edge connected between the second straight edges. The two anchoring points 511 are symmetrically located on opposite sides of the coupling beam 58, and each coupling beam 58 can provide an equivalent anchoring effect to the two vibration arms 53 on the same side as it, providing more stable support for the vibration of the vibration arms 53. By designing the anchoring point 511 so that the edge connected to the coupling beam 58 is a straight edge, and the outer edge away from the coupling beam 58 is designed to be an arc-shaped edge, it is beneficial to reduce the area of the anchoring point region, reduce parasitic parameters, and improve the Q value.

[0048] Optionally, a through-groove 510 is provided on the anchor point 511 near the first straight edge, and the through-groove 510 is parallel to the first straight edge; the coupling beam 58 is provided with a plurality of first grooves 581 and second grooves 582 extending in different directions, and the first grooves 581 and the second grooves 582 are arranged at intervals along the coupling beam 58 and are symmetrically distributed. In this embodiment, based on the optimized design of the geometric shape and overall dimensions of the anchor point 511, a transversely extending through-groove 510 is provided at the end where the anchor point 511 connects to the coupling beam 58, and grooves extending in different directions are provided at intervals on the coupling beam 58. This can optimize the stress distribution on the vibration arm 53, reduce anchor point losses, and improve the resonant frequency stability of the MEMS resonator.

[0049] Optionally, the mass beam 531 is provided with a plurality of strip grooves 533, and the strip grooves 533 are arranged vertically along the mass beam 531 to form a plurality of strip groove columns. In each two adjacent strip groove columns, the interval between the two strip grooves 533 in one strip groove column is staggered with the interval between the two strip grooves 533 in the other strip groove column. In this embodiment, the strip groove columns include 5 columns, and are arranged at equal intervals along the width of the mass beam 531, and are symmetrically distributed relative to the center line of the mass beam 531. The arrangement of the strip groove columns can optimize the mass distribution and stiffness of the vibration arm 53, regulate the vibration characteristics of the MEMS resonator, and reduce the thermoelastic loss of the MEMS resonator. Optionally, in the vibration arm 53, the elastic beam 532 is provided with an annular groove 534 with an opening at one end. The annular groove 534 extends along the length direction of the elastic beam 532, and the opening is provided at one end close to the coupling beam 58. Specifically, by providing an annular groove 534 having a shape substantially consistent with the overall contour of the elastic beam 532 , the thermoelastic loss generated by the vibration arm 53 during the vibration process can be reduced, thereby improving the quality factor of the MEMS resonator.

[0050] Overall, the MEMS resonator provided in the embodiment of the present application designs composite tooth portions 57 on opposite sides of the mass beam 531 in the vibration arm 53. In the composite tooth portion 57, the teeth close to the anchor point have tooth side surfaces 574 parallel to the torsion direction of the vibration arm 53, and the teeth relatively far from the anchor point have tooth side surfaces 574 inclined to the torsion direction of the vibration arm 53. This can improve the linear operating range of the electrostatically driven MEMS resonator under ultra-small capacitance gaps and increase the capacitance change ΔC per unit angle θ change, thereby helping to increase the electromechanical coupling coefficient of the resonator.

[0051] On the other hand, an embodiment of the present application provides a MEMS integrated product, comprising a MEMS resonator according to any of the aforementioned embodiments, wherein the MEMS integrated product is a product comprising a MEMS resonator and is widely used in the fields of clock oscillators, radio frequency, sensors, vehicles, and artificial intelligence data centers, and may be one of the following: a clock oscillator, a radio frequency filter, and a resonant sensor.

[0052] The above are only specific embodiments of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A MEMS resonator, characterized in that: comprising an anchoring portion and a vibrating arm connected to the anchoring portion; The vibration arm includes a mass beam and an elastic beam, and composite teeth are respectively provided on opposite sides of the mass beam. The composite teeth include a first tooth-shaped portion and a second tooth-shaped portion arranged along a first axis. The mass beam and the elastic beam are both arranged along the first axis. Under the action of a driving force, the vibration arm swings relative to the anchor portion in a second axis direction perpendicular to the first axis. In which, the first tooth-shaped portion is relatively located closer to the anchoring portion, the first tooth-shaped portion includes a plurality of first teeth, the second tooth-shaped portion includes a plurality of second teeth, the first teeth and the second teeth respectively protrude outward from the corresponding sides of the mass beam, and include a tooth bottom connected to the mass beam, a tooth top opposite to the tooth bottom, and a tooth side surface connected between the tooth top and the tooth bottom, the tooth side surface of the first tooth is parallel to the second axis, and the tooth side surface of the second tooth is inclined relative to the second axis.

2. The MEMS resonator according to claim 1, wherein The width of the elastic beam in a direction perpendicular to the first axis is smaller than the width of the mass beam.

3. The MEMS resonator according to claim 2, wherein: One end of the elastic beam is connected to the mass beam, and the other end is connected to the anchoring portion.

4. The MEMS resonator according to claim 1, wherein: The mass beam further comprises a first driving portion and a second driving portion provided on opposite sides of the mass beam, wherein the first driving portion and the second driving portion are respectively provided with a tooth structure matching the composite tooth portion on a side close to the mass beam; Gap capacitance is formed between the first driving portion and the mass beam, and between the second driving portion and the mass beam.

5. The MEMS resonator according to claim 1, wherein: The vibration arms include a plurality of vibration arms, and each vibration arm further includes a coupling beam connected between the elastic beam and the anchoring portion.

6. The MEMS resonator according to claim 5, characterized in that The vibrating arms include four and are arranged in an H shape, and the anchoring portion includes two anchoring points respectively arranged on two opposite sides of the coupling beam.

7. The MEMS resonator according to claim 6, wherein: Each of the anchoring points is located between a group of the vibration arms, and includes a first straight edge parallel to the coupling beam, two second straight edges located at both ends of the first straight edge and parallel to the vibration arms, and a third arc-shaped edge connected between the second straight edges.

8. The MEMS resonator according to claim 7, wherein: A through groove is provided on the anchor point at a position close to the first straight edge, and the through groove is parallel to the first straight edge; The coupling beam is provided with a plurality of first grooves and second grooves extending in different directions. The first grooves and the second grooves are arranged at intervals along the coupling beam and are symmetrically distributed.

9. The MEMS resonator according to claim 5, wherein: The mass beam is provided with a plurality of strip grooves, and the strip grooves are arranged vertically along the mass beam to form a plurality of strip groove columns, and in every two adjacent strip groove columns, the interval between the two strip grooves in one strip groove column is staggered with the interval between the two strip grooves in the other strip groove column; and / or, An annular groove with an opening at one end is provided on the elastic beam. The annular groove extends along the length direction of the elastic beam, and the opening is provided at one end close to the coupling beam.

10. The MEMS resonator according to any one of claims 1 to 9, characterized in that A first gap capacitor parallel to the second axis is formed between the tooth flanks of the two meshing first teeth, and a second gap capacitor inclined relative to the second axis is formed between the tooth flanks of the two meshing second teeth.

11. The MEMS resonator according to claim 10, wherein: The first teeth are rectangular teeth, and the second teeth are triangular teeth.

12. A MEMS integrated product, characterized in that: comprising a MEMS resonator as claimed in any one of claims 1 to 11; The MEMS integrated product is one of the following: a clock oscillator, a radio frequency filter and a resonant sensor.

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