MEMS resonator

Abstract

The invention discloses an MEMS resonator, which comprises a plurality of resonance groups, a connecting beam, anchor points arranged on the connecting beam and a coupling beam connected between the resonance groups and the connecting beam, and is characterized in that each resonance group comprises two resonance units which are symmetrically arranged relative to the connecting beam; the plurality of resonance groups are arranged in an array manner and are distributed at equal intervals along the extension direction of the connecting beam; the coupling beam comprises a plurality of single-arm coupling beams which are respectively connected between each resonance unit and the connecting beam, and the two single-arm coupling beams which are respectively connected with the two resonance units of the same resonance group are symmetrically arranged relative to the connecting beam; the MEMS resonator comprises at least three resonance groups, a symmetry axis perpendicular to the connecting beam exists between every two adjacent resonance groups, and in an array combination correspondingly formed by the two adjacent resonance groups, the resonance units, the single-arm coupling beam and the connecting beam are symmetrically arranged relative to the symmetry axis.

Description

Technical Field

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

[0002] MEMS (Micro-Electro-Mechanical Systems) resonators primarily refer to miniature resonant structures manufactured using silicon-based semiconductor processes. They are capable of generating stable periodic motion and are often used in frequency reference or sensing applications. Compared to traditional quartz crystal resonators, MEMS resonators can use semiconductor processes to create smaller and more complex microstructures, thus enabling higher-integration, smaller, and lower-cost resonant components, and have great development potential.

[0003] High Q (Quality Factor) and low dynamic impedance are the key performance indicators of MEMS resonators. Q is determined by the resonator's inherent loss mechanisms, including thermoelastic losses, anchor point losses, Akhiezer damping losses, and air damping losses. Dynamic impedance is primarily determined by parameters such as the electromechanical transduction coefficient and the drive voltage.

[0004] In order to improve the overall performance, it is usually considered to increase the number of resonant units. However, the increase in the number of resonant units makes it easy for them to not work simultaneously in the optimal vibration mode with the same phase and amplitude, thereby affecting key performance indicators such as the Q value and dynamic impedance of the resonator, and thus limiting the application and development of resonators with multiple resonant units. Summary of the Invention

[0005] In view of this, the present invention provides a MEMS resonator, which can effectively improve the overall performance of the resonator including multiple resonance units.

[0006] The present application provides a MEMS resonator, comprising a plurality of resonance groups, connecting beams, anchor points provided on the connecting beams, and coupling beams connected between the resonance groups and the connecting beams, wherein each of the resonance groups comprises two resonance units symmetrically arranged relative to the connecting beams;

[0007] The plurality of resonant groups are arranged in an array and are distributed at equal intervals along the extension direction of the connecting beam;

[0008] The coupling beam comprises a plurality of single-arm coupling beams respectively connected between each of the resonant units and the connecting beam, and two single-arm coupling beams respectively connected to two resonant units of the same resonant group are symmetrically arranged relative to the connecting beam;

[0009] The MEMS resonator includes at least three resonance groups, and there is a symmetry axis perpendicular to the connecting beam between each two adjacent resonance groups. In the array combination formed by the corresponding two adjacent groups of resonance units, the resonance units, the single-arm coupling beam, and the connecting beam are all symmetrically arranged relative to the symmetry axis.

[0010] In some embodiments, the connecting beam includes multiple sections of inner connecting beams and outer connecting beams along its extension direction, each of the inner connecting beams is located between two adjacent resonance groups, the midpoint of each of the inner connecting beams is a virtual anchor point, and the outer connecting beams extend outward from the end of a corresponding inner connecting beam, and the anchor point is located at one end of the outer connecting beam away from the inner connecting beam.

[0011] In some embodiments, the length of the outer connecting beam is half of the length of the inner connecting beam, and the anchor point and the adjacent virtual anchor point are symmetrically arranged relative to the corresponding single-arm coupling beam.

[0012] In some embodiments, the outer connecting beams have the same length and the inner connecting beams have the same length.

[0013] In some embodiments, the number of the resonance groups is three, and the connecting beams include two inner connecting beams located between the three resonance groups, and two outer connecting beams located at two ends of the inner connecting beams;

[0014] In every two adjacent resonance groups, all the resonance units are symmetrically arranged relative to the inner connecting beam and symmetrically arranged relative to the symmetry axis that is perpendicular to the inner connecting beam and passes through the midpoint of the inner connecting beam.

[0015] In some embodiments, the number of the resonance groups is four, and the connecting beams include three inner connecting beams located between the four resonance groups, and two outer connecting beams located at two ends of the inner connecting beams;

[0016] In every two adjacent resonance groups, all the resonance units are symmetrically arranged relative to the inner connecting beam and symmetrically arranged relative to the symmetry axis that is perpendicular to the inner connecting beam and passes through the midpoint of the inner connecting beam.

[0017] In some embodiments, each of the single-arm coupling beams is perpendicular to the connecting beam.

[0018] In some embodiments, each of the resonance units includes a resonance part connected to the single-arm coupling beam, and a driving structure arranged corresponding to the resonance part, the driving structure is used to drive and detect the vibration of the resonance part, the resonance part is a hollow ring structure, and the driving structure and the resonance part are arranged along the axial or radial direction of the resonance part.

[0019] In some embodiments, the driving structure includes a driving electrode and a detecting electrode, wherein the driving electrode and the detecting electrode are respectively spaced apart from the resonating portion, the driving electrode is used to drive the resonating portion to vibrate, and the detecting electrode is used to detect the vibration of the resonating portion;

[0020] The driving electrode is arranged on the radial inner side of the resonating part, and the detection electrode is arranged on the radial outer side of the resonating part, or the driving electrode is arranged on the radial outer side of the resonating part, and the detection electrode is arranged on the radial inner side of the resonating part, or both the driving electrode and the detection electrode are arranged on the radial inner side of the resonating part, or both the driving electrode and the detection electrode are arranged on the radial outer side of the resonating part.

[0021] In some embodiments, the driving structure includes an upper electrode layer and a lower electrode layer spaced apart from each other, and a piezoelectric layer located between the upper electrode layer and the lower electrode layer, wherein one of the upper electrode layer and the lower electrode layer is connected to one axial side of the resonating portion;

[0022] The piezoelectric layers of the same driving structure drive and detect the vibration of the resonating part, or the piezoelectric layers of different driving structures respectively drive the vibration of the resonating part and detect the vibration of the resonating part.

[0023] The MEMS resonator provided by the present invention includes multiple resonance groups, wherein two resonance units in the same resonance group and single-arm coupling beams respectively connected to the two resonance units are symmetrically arranged relative to the connecting beam. An axis of symmetry perpendicular to the connecting beam exists between each two adjacent resonance groups. In an array combination formed by two adjacent resonance groups, the resonance units, the single-arm coupling beam, and the connecting beam are all symmetrically arranged relative to the symmetry axis. In this way, the forces generated by the vibration of the two resonance units in the same group can be offset at the position where the connecting beam and the single-arm coupling beam are connected. The forces generated by the vibration of two adjacent resonance groups can be offset at the intersection of the connecting beam and the symmetry axis, thereby reducing the energy loss of the MEMS resonator and improving the overall Q value of the MEMS resonator.

[0024] In addition, multiple resonance groups are arranged at intervals along the extension direction of the connecting beam. Two resonance units in the same resonance group are directly connected to the connecting beam through a corresponding single-arm coupling beam respectively. There is no direct connection relationship between the resonance units of different resonance groups. The increase in the number of resonance units has a smaller impact on the vibration mode of each resonance unit due to the connection structure. Moreover, the resonance units and corresponding single-arm coupling beams of the same resonance group and the resonance units and corresponding coupling beams of different resonance groups are all symmetrically arranged, which is more conducive to enabling all resonance units to simultaneously operate in the optimal vibration mode with the same phase and the same amplitude, thereby increasing the transduction coefficient of the MEMS resonator, reducing the dynamic impedance, and effectively improving the overall performance of the MEMS resonator.

[0025] In summary, the design of the MEMS resonator provided in the embodiment of the present invention can fully utilize the advantages brought by increasing the number of resonant units to form an array-designed resonator as a whole. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a structural diagram of the MEMS resonator provided in the first embodiment of the present invention when the driving structure is omitted;

[0027] Figure 2 for Figure 1 Schematic diagram of the MEMS resonator in breathing mode;

[0028] Figure 3 for Figure 1 A schematic diagram of two adjacent resonant groups of MEMS resonators shown in FIG forming an array combination;

[0029] Figure 4 for Figure 1 Schematic diagram of the MEMS resonator with the addition of a driving structure;

[0030] Figure 5 A cross-sectional view of a MEMS resonator provided in accordance with another embodiment of the present invention;

[0031] Figure 6 A schematic structural diagram of a MEMS resonator provided in the second embodiment of the present invention;

[0032] Figure 7 for Figure 6 Schematic diagram of the MEMS resonator in breathing mode.

[0033] In the figure: 10, MEMS resonator; 12, resonant unit; 13, connecting beam; 14, anchor point; 15, resonant group; 16, coupling beam; 18, single-arm coupling beam; 20, inner connecting beam; 22, outer connecting beam; 23, array combination; 24, resonant part; 26, driving structure; 28, driving electrode; 30, detection electrode. DETAILED DESCRIPTION

[0034] The present invention will be further described below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0035] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, inside, outside, top, bottom, etc.) are only used to explain the relative position relationship between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0036] It should also be noted that when an element is referred to as being “fixed on” or “disposed on” another element, the element may be directly on the other element or there may be an intermediate element. When an element is referred to as being “connected to” another element, it may be directly connected to the other element or there may be an intermediate element.

[0037] In designing a resonator including multiple resonant units, the inventors of this application conducted the following research:

[0038] At present, the known resonators containing multiple resonant units are mainly based on four resonant units. For example, in the patent document with publication number CN110661506A, a resonator containing four resonant units is provided, wherein the four resonant units are connected end to end in sequence to form a closed ring structure. However, in the resonator, any two adjacent resonant units are connected to the central anchor point through a connecting structure, and each resonant unit is connected to at least two connecting structures. As the number of resonant units increases, the vibration mode of each resonant unit is more susceptible to the influence of other resonant units and the added connecting structures. When there is an inconsistency in the setting of external connecting structures (such as connecting beams, anchoring structures, etc.), it is very easy to cause multiple resonant units to be unable to work simultaneously in the optimal vibration mode of the same phase and amplitude, thereby weakening the advantages brought by the combination of multiple resonant units. The design concept of forming a closed ring structure with multiple resonant units also greatly limits the application and development of the overall performance of the resonator in the relevant technical field that is expected to be improved by increasing the number of resonant units.

[0039] Based on this, the inventors creatively proposed a design concept for arranging multiple resonant units in parallel and in an array to form an arrayed resonant unit combination. This concept leverages the fact that the vibration forces between adjacent resonant units in a determinant arrangement can offset each other, fully leveraging the advantages of increasing the number of resonant units to form an arrayed resonator design. Various embodiments of resonators based on this design concept are described below.

[0040] See also Figure 1 and Figure 3 A MEMS resonator 10 provided in a first embodiment of the present invention includes a plurality of resonant units 12, a connecting beam 13, an anchor point 14, and a coupling beam 16. The plurality of resonant units 12 form a plurality of resonant groups 15, each of which includes two resonant units 12. The two resonant units 12 in the same resonant group 15 are located on opposite sides of the connecting beam 13, and the plurality of resonant groups 15 are arranged along the length of the connecting beam 13. The coupling beam 16 is connected between the resonant units 12 and the connecting beam 13, and includes a plurality of single-arm coupling beams 18, each of which connects a corresponding resonant unit 12 and the connecting beam 13. The anchor point 14 is provided on the connecting beam 13, and the MEMS resonator 10 is fixed to an external component via the anchor point 14.

[0041] The plurality of resonance groups 15 are arranged in an array and are distributed at equal intervals along the extension direction of the connecting beam 13. That is, the plurality of resonance groups 15 are arranged in sequence along the extension direction of the connecting beam 13, and the two resonance units 12 of the same resonance group 15 are arranged in a direction perpendicular to the extension direction of the connecting beam 13, forming an array arrangement effect. By providing a plurality of resonance groups 15 arranged in an array, the number of resonance units 12 is increased, thereby increasing the sensing area of the MEMS resonator 10 and improving the overall performance of the MEMS resonator 10. At the same time, the two resonance units 12 of the same resonance group 15 are respectively connected to the connecting beam 13 through a corresponding single-arm coupling beam 18. There is no direct connection between the resonance units 12 of different resonance groups 15. Therefore, the increase in the number of resonance units 12 has less influence on the vibration mode of the resonance unit 12 itself being affected by the connection structure, thereby ensuring the advantages brought by the array design of multiple resonance units 12.

[0042] In an optional example, the MEMS resonator includes at least three resonance groups 15 , so the number of resonance units 12 is an even number and is at least six, and the at least three resonance groups 15 are distributed at equal intervals along the length direction of the connecting beam 13 .

[0043] Each resonant group 15 includes two resonant units 12 located on opposite sides of a connecting beam 13. Each resonant unit 12 is connected to the connecting beam 13 via a single-arm coupling beam 18. That is, one end of each single-arm coupling beam 18 is connected to a corresponding resonant unit 12, and the other end is connected to the connecting beam 13. The two resonant units 12 in the same resonant group 15, as well as the single-arm coupling beams 18 connected to the two resonant units 12 in the same resonant group 15, are arranged symmetrically with respect to the connecting beam 13. This allows the forces generated by the two resonant units 12 in the same resonant group 15 to be offset at the connection between the connecting beam 13 and the single-arm coupling beam 18. This reduces energy loss between the two resonant units 12 in the same resonant group 15, which helps improve the overall Q value of the MEMS resonator 10.

[0044] It can be understood that the two single-arm coupling beams 18 connected to the two resonant units 12 of the same resonant group 15 can be two parts of the same beam, or can be two independent beams that are not integrally formed.

[0045] There is a symmetry axis X between any two adjacent resonant groups 15, and the symmetry axis X is perpendicular to the connecting beam 13. The MEMS resonator 10 includes at least three resonant groups 15, and there is a symmetry axis X between any two adjacent resonant groups 15, so the number of symmetry axes X is at least two.

[0046] In the array combination 23 formed by two adjacent resonance groups 15, the resonance groups 15, the single-arm coupling beams 18, and the connecting beams 13 are all symmetrically arranged relative to the symmetry axis X. That is, the two adjacent resonance groups 15, the single-arm coupling beams 18 connected to the two adjacent resonance groups 15, and the connecting beams 13 corresponding to the two adjacent resonance groups 15 are all symmetrically arranged relative to the symmetry axis X. In this way, the two resonance units 12 of the same resonance group 15 are symmetrical about the connecting beam 13, and the resonance units 12 of the two adjacent resonance groups 15 are symmetrical about the symmetry axis X. Therefore, the forces generated by the two resonance units 12 of the same resonance group 15 when vibrating can be offset at the connection between the connecting beam 13 and the single-arm coupling beam 18, and the forces generated by the resonance units 12 of the two adjacent resonance groups 15 when vibrating can be offset at the intersection of the connecting beam 13 and the symmetry axis, thereby reducing the energy loss of the MEMS resonator 10 and improving the overall Q value of the MEMS resonator 10. In addition, the multiple resonance groups 15 are arranged in sequence along the extension direction of the connecting beam 13 to form a parallel array. In the arrayed design, each resonant unit 12 is connected to the connecting beam 13 through a corresponding single-arm coupling beam 18, and there is no direct connection between the resonant units 12 of different resonant groups 15. Therefore, the vibration mode of the resonant unit 12 itself is less affected by the increase in the number of resonant units 12, which is beneficial for all the resonant units 12 of the MEMS resonator 10 to operate simultaneously in the optimal vibration mode with the same phase and the same amplitude, increasing the transduction coefficient of the MEMS resonator 10, reducing the dynamic impedance, and being beneficial to improving the overall performance of the MEMS resonator, thereby giving full play to the advantages of the MEMS resonator with an array design formed by increasing the number of resonant units 12.

[0047] In the array combination 23 formed corresponding to two adjacent resonance groups 15, the combination corresponding to each resonance group 15 includes two resonance units 12, single-arm coupling beams 18 respectively connected to the two resonance units 12, and partial connecting beams 13 respectively located on opposite sides of the single-arm coupling beams 18. The two resonance units 12, the two single-arm coupling beams 18 and the corresponding partial connecting beams 13 form a cross-shaped structure, and the cross-shaped structure corresponding to one resonance group 15 is symmetrical with the cross-shaped structure corresponding to the other resonance group 15 about the symmetry axis X.

[0048] Two adjacent resonance groups 15 form an array combination 23. Therefore, the number of array combinations 23 is related to the number of resonance groups 15. For example, when the number of resonance groups 15 is three, two array combinations 23 can be formed. When the number of resonance groups 15 is four, three array combinations 23 can be formed. That is, the number of array combinations 23 formed by the MEMS resonator 10 is one less than the number of resonance groups 15.

[0049] Please refer to Figure 3 Optionally, each array assembly 23 includes a total of four resonant units 12, which are arranged in two rows and two columns along a direction perpendicular to the connecting beam 13. Two resonant units 12 are located on one side of the connecting beam 13, and the other two resonant units 12 are located on the opposite side of the connecting beam 13. The two resonant units 12 located on the same side of the connecting beam 13 belong to different resonant groups 15, and the two resonant units 12 located on opposite sides of the connecting beam 13 and corresponding to each other belong to the same resonant group 15. The two resonant units 12 located on different sides of the connecting beam 13 are symmetrically arranged about the connecting beam 13, and the two resonant units 12 located on the same side of the connecting beam 13 are symmetrically arranged about the symmetry axis X. The two single-arm coupling beams 18 connecting the two resonant units 12 of the same resonant group 15 are referred to as a group of single-arm coupling beams 18. The array assembly 23 includes two groups of single-arm coupling beams 18. The two single-arm coupling beams 18 belonging to the same group are symmetrically arranged about the connecting beam 13, and the two adjacent groups of single-arm coupling beams 18 are symmetrically arranged about the symmetry axis X. The portion of the connecting beam 13 located between two adjacent groups of single-arm coupling beams 18 and the portion of the connecting beam 13 located outside the two groups of single-arm coupling beams 18 are part of the array combination 23, and the portion of the connecting beam 13 belonging to the array combination 23 is symmetrically arranged about the symmetry axis X.

[0050] Optionally, the number of single-arm coupling beams 18 is the same as the number of resonant units 12 and corresponds one to one. The length and shape of all single-arm coupling beams 18 are the same, so that the single-arm coupling beams 18 can form a symmetrical effect relative to the connecting beam 13 and the symmetry axis X.

[0051] Optionally, both the single-arm coupling beam 18 and the connecting beam 13 are straight beams, and each single-arm coupling beam 18 is perpendicular to the connecting beam 13 .

[0052] In one embodiment, there are two anchor points 14, one at each end of the connecting beam 13. Along the length of the connecting beam 13, each anchor point 14 is equidistant from the midpoint of the connecting beam 13, such that the two anchor points 14 are symmetrically disposed relative to the midpoint of the connecting beam 13.

[0053] The connecting beam 13 includes multiple inner connecting beams 20 and outer connecting beams 22 along its extension direction. Each inner connecting beam 20 is located between two adjacent groups of resonant units 12, and its ends are respectively connected to two adjacent groups of single-arm coupling beams 18. The number of inner connecting beams 20 is one less than the number of resonant groups 15. For example, when the MEMS resonator 10 includes three resonant groups 15, the number of inner connecting beams 20 is two, and when the MEMS resonator 10 includes four resonant groups 15, the number of inner connecting beams 20 is three. There are two outer connecting beams 22, each connected to the two ends of the inner connecting beam 20. The multiple inner connecting beams 20 are arranged in sequence along the length of the connecting beam 13. The two ends of the multiple inner connecting beams 20 are also the two ends farthest apart in the length direction. The outer connecting beams 22 extend outward from the ends of the inner connecting beams 20 and extend outward from the outer ends of the single-arm coupling beams 18.

[0054] The inner connecting beam 20 is located between two adjacent sets of single-arm coupling beams 18, while the outer connecting beam 22 extends to the outside of the single-arm coupling beams 18. Both the inner connecting beam 20 and the outer connecting beam 22 are perpendicular to the single-arm coupling beams 18. The anchor point 14 is located at the end of the outer connecting beam 22 away from the inner connecting beam 20. The midpoint of the inner connecting beam 20 serves as a virtual anchor point, and the symmetry axis X passes through this virtual anchor point. That is, along the extension direction of the connecting beam 13, the virtual anchor point is equidistant from the two adjacent sets of single-arm coupling beams 18.

[0055] It can be understood that the multiple sections of inner connecting beams 20 and outer connecting beams 22 can be different parts of the same beam, and multiple groups of single-arm coupling beams 18 are respectively connected to different parts of the same beam, or the multiple sections of inner connecting beams 20 and outer connecting beams 22 can also be multiple independent beams, each beam is connected to the corresponding single-arm coupling beam 18.

[0056] The length L1 of the inner connecting beam 20 is twice the length L2 of the outer connecting beam 22, i.e., L1 = 2*L2. The anchor point 14 and the adjacent virtual anchor point are symmetrically arranged relative to the corresponding single-arm coupling beam 18, and the two adjacent virtual anchor points are symmetrically arranged relative to the corresponding single-arm coupling beam 18. Optionally, the two outer connecting beams 22 have the same length, and the multiple inner connecting beams 20 have the same length, that is, the length of any inner connecting beam 20 is twice the length of the outer connecting beam 22. Along the extension direction of the connecting beam 13, the distance from each resonance group 15 to the anchor point 14 and / or the virtual anchor point is L2, that is, the resonance unit 12 of each resonance group 15 is connected to the anchor point 14 and / or the virtual anchor point through a connecting beam 13 with a length of L2, so that all the resonance units 12 of the MEMS resonator 10 can operate simultaneously in the diaphragm mode with the same phase and the same amplitude, and the force generated when two adjacent resonance groups 15 vibrate can be better offset at the virtual anchor point, thereby reducing energy loss and improving the Q value of the MEMS resonator 10.

[0057] like Figure 3 As shown, the MEMS resonator 10 includes three resonance groups 15, and an array combination 23 formed by two adjacent resonance groups 15 includes four resonance units 12 arranged in two rows and two columns, four single-arm coupling beams 18 respectively connected to the four resonance units 12, an inner connecting beam 20 located between the two resonance groups 15, half of the inner connecting beam 20 located outside one resonance group 15, an outer connecting beam 22 located outside the other resonance group 15, two virtual anchor points located on the corresponding inner connecting beams 20, and an anchor point 14 located on the outer connecting beam 22. That is, the partial connecting beam 13 included in the array combination 23 has a total length of 2*L1, and is composed of a complete inner connecting beam 20, the other half of the inner connecting beam 20 located at one end of the inner connecting beam 20, and an outer connecting beam 22 located at the other end of the inner connecting beam 20.

[0058] It can be understood that when the MEMS resonator 10 includes four or more resonance groups 15, the array combination 23 formed by two adjacent groups located in the middle of the plurality of resonance groups 15, such as Figure 6 As shown, it consists of four resonant units 12 arranged in two rows and two columns, four single-arm coupling beams 18 respectively connected to the four resonant units 12, an inner connecting beam 20 located between two adjacent resonant groups 15, half of the inner connecting beam 20 located outside one resonant group 15, an outer connecting beam 22 located outside the other resonant group 15, two virtual anchor points located on the corresponding inner connecting beams 20, and an anchor point 14 located on the outer connecting beam 22.

[0059] like Figure 1As shown, in one embodiment, the MEMS resonator 10 includes six resonant units 12, which are divided into three resonant groups 15. The three resonant groups 15 are arranged at equal intervals along the length of the connecting beam 13. The connecting beam 13 includes two inner connecting beams 20 and two outer connecting beams 22. The two inner connecting beams 20 are respectively located between the three resonant groups 15, that is, there is an inner connecting beam 20 between each two adjacent resonant groups 15, and the two outer connecting beams 22 are connected to the two ends of the two inner connecting beams 20. In each two adjacent resonant groups 15, all the resonant units 12 are arranged symmetrically with respect to the inner connecting beams 20. All the resonant units 12 are arranged symmetrically with respect to the symmetry axis X, which is perpendicular to the inner connecting beams 20 and passes through the midpoint of the inner connecting beam 20. In other words, the symmetry axis X is the midline passing through the midpoint of the inner connecting beam 20. The number of the symmetry axes X is the same as the number of the inner connecting beams 20 , and each symmetry axis X is perpendicular to a corresponding inner connecting beam 20 and passes through the midpoint of the connecting beam 13 .

[0060] In a direction perpendicular to the connecting beam 13, the three resonant units 12 located on one side of the connecting beam 13 and the three resonant units 12 located on the other side of the connecting beam 13 are symmetrically arranged about the inner connecting beam 20, and every two adjacent resonant units 12 located on the same side of the connecting beam 13 are symmetrically arranged about a corresponding symmetry axis X, so that the six resonant units 12 can simultaneously operate in the optimal vibration mode with the same phase and the same amplitude.

[0061] Figure 2 This figure shows a MEMS resonator 10 comprising six resonant units 12 in breathing mode. The six resonant units 12 in the figure operate simultaneously in their optimal vibration mode with the same phase and amplitude, resulting in a relatively high Q value. The color bar on the right represents the magnitude of displacement during vibration, which increases from bottom to top. Blue areas indicate smaller displacements, while red areas indicate larger displacements.

[0062] In one embodiment, each resonant unit 12 includes a resonant portion 24 and a driving structure 26 corresponding to the resonant portion 24. The resonant portion 24 is connected to the single-arm coupling beam 18. The driving structure 26 is used to drive the resonant portion 24 to vibrate and detect the vibration of the resonant portion 24. The resonant portion 24 is a hollow annular structure, and the driving structure 26 and the resonant portion 24 are arranged along the axial or radial direction of the resonant portion 24. The annular structure can be a circular ring, an elliptical ring, a rectangular ring, or a ring of varying width. In this embodiment, the resonant portion 24 is a hollow circular ring structure.

[0063] It is understandable that the driving structure 26 can drive the resonance portion 24 to vibrate by electrostatic driving or piezoelectric driving.

[0064] See also Figure 4In an optional example, the driving structure 26 drives the resonating portion 24 to vibrate by electrostatic drive. The driving structure 26 includes a driving electrode 28 and a detecting electrode 30, wherein the driving electrode 28 is used to drive the resonating portion 24 to vibrate, and the detecting electrode 30 is used to detect the vibration of the resonating portion 24. The driving electrode 28 is located radially inward of the resonating portion 24, and the detecting electrode 30 is located radially outward of the resonating portion 24. Both the driving electrode 28 and the detecting electrode 30 are spaced apart from the resonating portion 24 to leave space required for the vibration of the resonating portion 24. After current is passed through the driving electrode 28, the driving electrode 28 generates an electrostatic force on the resonating portion 24. The resonating portion 24 vibrates under the action of the electrostatic force, and the detecting electrode 30 detects the vibration signal of the resonating portion 24.

[0065] Optionally, the distance between the driving electrode 28 and the resonating portion 24 and the distance between the detecting electrode 30 and the resonating portion 24 are close to each other, and the range of the distance is 0.01-5 μm.

[0066] In other embodiments, the driving electrode 28 may also be arranged on the radial outside of the resonating portion 24, and the detection electrode 30 may be arranged on the radial inside of the resonating portion 24, or the driving electrode 28 and the detection electrode 30 may also be located on the same side of the resonating portion 24, that is, the driving electrode 28 and the detection electrode 30 are both located on the radial inside or radial outside of the resonating portion 24.

[0067] The specific method of connecting the driving structure 26 of multiple resonant units 12 to external elements is not limited. All driving electrodes 28 of all resonant units 12 can be connected together, all detection electrodes 30 can be connected together, and then connected to external elements respectively. Alternatively, all driving electrodes 28 located on the same side of the connecting beam 13 can be connected together, all detection electrodes 30 can be connected together, and then connected to external elements respectively.

[0068] In this embodiment, the resonating portion 24 , the driving electrode 28 , and the detecting electrode 30 are all made of silicon material, and the material of the resonating portion 24 , the driving electrode 28 , and the detecting electrode 30 can be low-resistance silicon.

[0069] See also Figure 5 In another embodiment, the driving structure 26 drives the resonating portion 24 to vibrate using piezoelectric drive, and the driving structure 26 is located on one axial side of the resonating portion 24. The driving structure 26 includes an upper electrode layer, a lower electrode layer, and a piezoelectric layer. The upper electrode layer and the lower electrode layer are spaced apart and arranged relative to each other. The piezoelectric layer is located between the upper electrode layer and the lower electrode layer, and one of the upper electrode layer and the lower electrode layer is connected to one axial side of the resonating portion 24. When a voltage is applied between the upper electrode layer and the lower electrode layer, the piezoelectric layer deforms, thereby driving the resonating portion 24 to vibrate. The vibration signal is then detected through the inverse piezoelectric effect of the piezoelectric layer.

[0070] It can be understood that the piezoelectric layer of the same driving structure 26 can drive and detect the vibration of the resonant part 24, that is, the resonant unit 12 includes a driving structure 26, the piezoelectric layer of which can both drive the resonant part 24 to vibrate and detect the vibration of the resonant part 24, or the piezoelectric layers of different driving structures 26 can respectively drive and detect the vibration of the resonant part 24, that is, the resonant unit 12 includes at least two driving structures 26, the piezoelectric layer of one driving structure 26 is used to drive the resonant part 24 to vibrate, and the piezoelectric layer of the other driving structure 26 is used to detect the vibration of the resonant part 24.

[0071] In this embodiment, the upper electrode layer and the lower electrode layer are both metal layers. During the manufacturing process, a piezoelectric driving structure 26 can be formed on the axial side of the resonant part 24 by stacking a metal layer-piezoelectric layer-metal layer in sequence on the axial side of the resonant part 24.

[0072] The main structure of the MEMS resonator 10, such as the resonating part 24, the coupling beam 16, and the connecting beam 13, can be made of common semiconductor materials, such as single crystal silicon, polycrystalline silicon, silicon oxide, silicon nitride, silicon carbide, and a combination of various materials, and can be prepared on a semiconductor material substrate through processes such as photolithography, etching, corrosion, deposition, bonding, and thinning. The above materials and processes are the existing technologies for preparing MEMS resonators 10 in the field and will not be described in detail here.

[0073] The main differences between the MEMS resonator 10 provided in the second embodiment of the present invention and the MEMS resonator 10 in the first embodiment are:

[0074] See also Figure 6 and Figure 7 In this embodiment, the MEMS resonator 10 includes eight resonant units 12, which are divided into four resonant groups 15. The four resonant groups 15 are evenly spaced along the length of the connecting beam 13. The connecting beam 13 includes three inner connecting beams 20 and two outer connecting beams 22. The three inner connecting beams 20 are located between the four resonant groups 15, that is, there is an inner connecting beam 20 between each two adjacent resonant groups 15, and the two outer connecting beams 22 are respectively connected to the two farthest ends of the three inner connecting beams 20. In each two adjacent resonant groups 15, all the resonant units 12 are symmetrically arranged relative to the inner connecting beams 20. All the resonant units 12 are symmetrically arranged relative to the symmetry axis X, which is perpendicular to the inner connecting beams 20 and passes through the midpoint of the inner connecting beams 20. In other words, the symmetry axis X is the midline passing through the midpoint of the inner connecting beam 20. The number of the symmetry axes X is the same as the number of the inner connecting beams 20 , and each symmetry axis X is perpendicular to a corresponding inner connecting beam 20 and passes through the midpoint of the connecting beam 13 .

[0075] In a direction perpendicular to the connecting beam 13, the four resonant units 12 located on one side of the connecting beam 13 and the four resonant units 12 located on the other side of the connecting beam 13 are symmetrically arranged about the inner connecting beam 20, and the two adjacent resonant units 12 located on the same side of the connecting beam 13 are symmetrically arranged about a corresponding symmetry axis X, so that the eight resonant units 12 can simultaneously operate in the optimal vibration mode with the same phase and the same amplitude.

[0076] Figure 7 Figure 1 is a schematic diagram of a MEMS resonator 10 comprising eight resonant units 12 in breathing mode. The eight resonant units 12 in the figure operate simultaneously in their optimal vibration mode with the same phase and amplitude, resulting in a relatively high Q value. The color bar on the right represents the magnitude of displacement during vibration, which increases from bottom to top. Blue areas indicate smaller displacements, while red areas indicate larger displacements.

[0077] The above embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and replacements made by technicians in this field on the basis of the present invention fall within the scope of protection required by the present invention.

Claims

1. A MEMS resonator, characterized in that: The invention comprises a plurality of resonance groups, a connecting beam, an anchor point provided on the connecting beam, and a coupling beam connected between the resonance groups and the connecting beam, wherein each resonance group comprises two resonance units symmetrically arranged relative to the connecting beam; The plurality of resonant groups are arranged in an array and are distributed at equal intervals along the extension direction of the connecting beam; The coupling beam comprises a plurality of single-arm coupling beams respectively connected between each of the resonant units and the connecting beam, and two single-arm coupling beams respectively connected to two resonant units of the same resonant group are symmetrically arranged relative to the connecting beam; The MEMS resonator includes at least three resonance groups, and there is a symmetry axis perpendicular to the connecting beam between each two adjacent resonance groups. In the array combination formed by the corresponding two adjacent resonance groups, the resonance unit, the single-arm coupling beam, and the connecting beam are all symmetrically arranged relative to the symmetry axis.

2. The MEMS resonator according to claim 1, wherein The connecting beam includes multiple sections of inner connecting beams and outer connecting beams along its extension direction, each of the inner connecting beams is located between two adjacent resonant groups, the midpoint of each of the inner connecting beams is a virtual anchor point, the outer connecting beams extend outward from the end of a corresponding inner connecting beam, and the anchor point is located at one end of the outer connecting beam away from the inner connecting beam.

3. The MEMS resonator according to claim 2, wherein: The length of the outer connecting beam is half of the length of the inner connecting beam, and the anchor point and the adjacent virtual anchor point are symmetrically arranged relative to the corresponding single-arm coupling beam.

4. The MEMS resonator according to claim 3, wherein: The outer connecting beams have the same length, and the inner connecting beams have the same length.

5. The MEMS resonator according to claim 4, characterized in that The number of the resonance groups is three, and the connecting beams include two inner connecting beams located between the three resonance groups, and two outer connecting beams located at two ends of the inner connecting beams; In every two adjacent resonance groups, all the resonance units are symmetrically arranged relative to the inner connecting beam and symmetrically arranged relative to the symmetry axis that is perpendicular to the inner connecting beam and passes through the midpoint of the inner connecting beam.

6. The MEMS resonator according to claim 4, wherein: The number of the resonance groups is four, and the connecting beams include three inner connecting beams located between the four resonance groups, and two outer connecting beams located at two ends of the inner connecting beams; In every two adjacent resonance groups, all the resonance units are symmetrically arranged relative to the inner connecting beam and symmetrically arranged relative to the symmetry axis that is perpendicular to the inner connecting beam and passes through the midpoint of the inner connecting beam.

7. The MEMS resonator according to any one of claims 1 to 6, wherein: Each of the single-arm coupling beams is perpendicular to the connecting beam.

8. The MEMS resonator according to any one of claims 1 to 6, characterized in that: Each of the resonant units includes a resonant part connected to the single-arm coupling beam, and a driving structure arranged corresponding to the resonant part, wherein the driving structure is used to drive and detect the vibration of the resonant part. The resonant part is a hollow annular structure, and the driving structure and the resonant part are arranged along the axial or radial direction of the resonant part.

9. The MEMS resonator according to claim 8, wherein: The driving structure includes a driving electrode and a detecting electrode, wherein the driving electrode and the detecting electrode are respectively spaced apart from the resonating part, the driving electrode is used to drive the resonating part to vibrate, and the detecting electrode is used to detect the vibration of the resonating part; The driving electrode is arranged on the radial inner side of the resonating part, and the detection electrode is arranged on the radial outer side of the resonating part, or the driving electrode is arranged on the radial outer side of the resonating part, and the detection electrode is arranged on the radial inner side of the resonating part, or both the driving electrode and the detection electrode are arranged on the radial inner side of the resonating part, or both the driving electrode and the detection electrode are arranged on the radial outer side of the resonating part.

10. The MEMS resonator according to claim 8, wherein: The driving structure includes an upper electrode layer and a lower electrode layer that are spaced apart, and a piezoelectric layer located between the upper electrode layer and the lower electrode layer, wherein one of the upper electrode layer and the lower electrode layer is connected to one axial side of the resonator; The piezoelectric layers of the same driving structure drive and detect the vibration of the resonating part, or the piezoelectric layers of different driving structures respectively drive the vibration of the resonating part and detect the vibration of the resonating part.

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