MEMS resonator structure with high frequency stability and MEMS resonant instrument and apparatus thereof

Abstract

The invention provides a high-frequency-stability MEMS resonator structure which comprises a first MEMS resonator and a second MEMS resonator which are connected to the left end and the right end of an elastic connecting beam respectively, and the upper side and the lower side of the elastic connecting beam are connected with a first variable function structure and a second variable function structure respectively. The first and second variable function structures are respectively connected with the first and second anchoring structures; according to the MEMS resonator, the anchoring loss of a pair of MEMS resonators which vibrate at the same frequency is reduced by means of modal matching, vibration counteracting, flexible supporting and the like, so that the Q value of the MEMS resonator is increased; by utilizing the structure of the double MEMS resonators, the motion impedance of the resonators is reduced; the quick and consistent in-situ frequency adjustment of the MEMS resonator structure is realized by using the Joule heating effect of the variable function structure positioned in the center of the structure under the action of the heating control voltage; the invention further provides an MEMS resonant type instrument and meter device with the MEMS resonator structure with the high frequency stability.

Description

Technical Field

[0001] The invention belongs to the technical field of resonators, and in particular relates to a MEMS resonator structure with high frequency stability and a MEMS resonant instrument and meter device thereof. Background Art

[0002] With the maturity of semiconductor processing technology, MEMS resonators have gradually replaced quartz resonators and become the core components of widely used micromechanical systems due to their advantages of small size, low cost, strong impact resistance, and good process consistency. Researchers have developed high-performance MEMS silicon-based clocks, MEMS resonant accelerometers, MEMS gyroscopes and other resonant instrumentation equipment with MEMS resonators as core components.

[0003] Frequency stability is the most critical performance indicator of MEMS resonators, and its quality directly determines the performance upper limit of the device. Factors affecting the frequency stability of MEMS resonators mainly include quality factor and motion impedance; the quality factor, or Q value, is a dimensionless quantity that represents the rate of energy loss in the vibration mode of the MEMS resonator. It is specifically defined as the ratio between the total energy stored in the system and the energy dissipated in each vibration cycle of the vibration mode; the motion impedance represents the power attenuation of the MEMS resonator to the input signal.

[0004] Existing MEMS resonators usually anchor the MEMS resonator body to the substrate through a number of anchoring structures evenly distributed around the resonator body to achieve stable oscillation of the MEMS resonator. However, the stress generated in the MEMS resonator body and the anchoring structure by this anchoring method will significantly affect the modal vibration shape of the MEMS resonator, and the multi-anchor point method will aggravate the energy dissipation such as anchoring loss and thermoelastic loss during the vibration process, limiting the improvement of the MEMS resonator Q value; in addition, the existing MEMS resonator structure is usually a single resonator body, which is not conducive to the reduction of the resonator's motion impedance. Therefore, how to ensure that the frequency stability of the MEMS resonator is improved by improving the MEMS resonator Q value and reducing the dynamic impedance without significantly affecting the modal vibration shape and the stable oscillation of the MEMS resonator has become one of the problems that technicians in this field need to solve urgently.

[0005] In response to the above-mentioned problems of MEMS resonators, existing solutions mainly achieve the improvement of Q value by optimizing the structural design of the anchoring structure. For example, a patent application named "A MEMS Resonator" (CN 220553997 U) provides a multi-level soft connection solution, hoping to reduce the energy transmission loss between the MEMS resonator and the supporting anchor point by means of flexible connection; however, it is basic common sense in the field of MEMS resonators to reduce the anchoring loss by setting a flexible connection. This patent application does not consider the impact of the flexible connection on the thermoelastic loss of the resonator. The complex auxiliary structure will increase the irreversible heat flow during the vibration process, thereby increasing the thermoelastic dissipation, which seriously restricts the performance of the resonator. In terms of motion impedance, existing solutions usually use piezoelectric detection, piezoresistive detection and other detection methods to reduce motion impedance; however, the piezoelectric detection method in the existing literature (Xiao Y, Han J, Zhu K, et al. A piezoelectric mechanically coupled Lamé mode resonator with ultra-high Q [J]. Applied Physics Letters, 2023, 122 (11).) will increase the processing difficulty and cost and reduce the device processing yield; and the existing piezoresistive detection method, such as the patent application named "A MEMS resonator and its preparation method" (CN114172487A), provides a piezoresistive detection scheme based on a T-type anchor structure, which realizes efficient electromechanical transduction, but this scheme will increase the system power consumption and degrade the Q value of the MEMS resonator. Summary of the invention

[0006] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a MEMS resonator structure with high frequency stability, which reduces the anchoring loss of a pair of MEMS resonators vibrating at the same frequency by means of mode matching, vibration cancellation and flexible support, thereby achieving an improvement in the Q value of the MEMS resonator; utilizing the structure of the dual MEMS resonators to reduce the motion impedance of the resonator; utilizing the Joule heating effect of the variable functional structure located at the center of the structure under the action of the heating control voltage to achieve fast and consistent in-situ frequency adjustment of the MEMS resonator structure; based on the MEMS resonator structure with high frequency stability, the purpose of the present invention is also to provide corresponding MEMS resonant instrumentation equipment, including but not limited to MEMS silicon-based clocks, MEMS resonant accelerometers or MEMS gyroscopes.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] A MEMS resonator structure with high frequency stability comprises a first MEMS resonator 1-1 and a second MEMS resonator 1-2 respectively connected to the left and right ends of an elastic connecting beam 2; the upper and lower sides of the elastic connecting beam 2 are respectively connected to a first variable function structure 3-1 and a second variable function structure 3-2; the first variable function structure 3-1 and the second variable function structure 3-2 are respectively connected to a first anchoring structure 4-1 and a second anchoring structure 4-2.

[0009] The first MEMS resonator 1 - 1 and the second MEMS resonator 1 - 2 have the same or different structural sizes.

[0010] The structures of the first MEMS resonator 1 - 1 and the second MEMS resonator 1 - 2 are vibration structures formed by MEMS technology.

[0011] A first transition structure 6-1 and a second transition structure 6-2 are provided between the first MEMS resonator 1-1, the second MEMS resonator 1-2 and the elastic connecting beam 2 to reduce the influence of the elastic connecting beam 2 on the modal vibration shape of the MEMS resonator and suppress the dissipation of vibration energy.

[0012] The equivalent mass centers of the vibration modes of the first MEMS resonator 1 - 1 and the second MEMS resonator 1 - 2 are located on the axis of the elastic connecting beam 2 in the length direction.

[0013] The first variable function structure 3-1 and the second variable function structure 3-2 are located at the center of the entire MEMS resonator structure, and are used to support the elastic connecting beam 2 and the first MEMS resonator 1-1 and the second MEMS resonator 1-2 respectively connected to the two ends of the elastic connecting beam 2, and fix the entire structure on the substrate through the first anchoring structure 4-1 and the second anchoring structure 4-2.

[0014] The first MEMS resonator 1-1, the second MEMS resonator 1-2, the elastic connecting beam 2, the first variable function structure 3-1, the second variable function structure 3-2 are all spaced apart from the substrate, and the spacings are equal or unequal, so that the first MEMS resonator 1-1, the second MEMS resonator 1-2, the elastic connecting beam 2, the first variable function structure 3-1, the second variable function structure 3-2 are suspended together above the substrate.

[0015] The structures of the first variable function structure 3 - 1 and the second variable function structure 3 - 2 may be acoustic impedance structures or Joule heating structures.

[0016] When the first variable function structure 3-1 and the second variable function structure 3-2 are acoustic impedance structures, they are used to realize the function of suppressing vibration energy dissipation; when the first variable function structure 3-1 and the second variable function structure 3-2 are Joule heat heating structures, they are used to realize the in-situ frequency control function of the MEMS resonator structure.

[0017] When the first variable function structure 3 - 1 and the second variable function structure 3 - 2 are Joule heat heating structures, an array of flexible straight beam structures can be used and symmetrically arranged at the center of the entire MEMS resonator structure.

[0018] When the first variable function structure 3-1 and the second variable function structure 3-2 are acoustic impedance structures, a series phononic crystal structure can be used, one end of the series phononic crystal structure is connected to the midpoint of the elastic connecting beam 2, and the other end of the series phononic crystal structure is connected to the first anchoring structure 4-1 and the second anchoring structure 4-2.

[0019] The vibrations of the first MEMS resonator 1-1 and the second MEMS resonator 1-2 are kept at the same frequency, so that the effects of the vibrations of the first MEMS resonator 1-1 and the second MEMS resonator 1-2 are offset at the first variable function structure 3-1 and the second variable function structure 3-2.

[0020] The resonant frequency of the tension mode in the length direction of the elastic connecting beam 2 is consistent with the resonant frequency of the vibration mode of the first MEMS resonator 1-1 and the second MEMS resonator 1-2, so that the MEMS resonators vibrate at the same frequency and phase when vibrating.

[0021] The first MEMS resonator 1 - 1 and the second MEMS resonator 1 - 2 are connected to the excitation detection structure.

[0022] The first MEMS resonator 1 - 1 and the second MEMS resonator 1 - 2 simultaneously generate vibration signals under the action of the excitation detection structure.

[0023] The excitation detection structure adopts capacitance, piezoelectric, optical or electromagnetic.

[0024] When the excitation detection structure adopts a capacitive type, it includes: a first electrode plate 5-1, a second electrode plate 5-2, a third electrode plate 5-3, a fourth electrode plate 5-4, a fifth electrode plate 5-5, a sixth electrode plate 5-6, and a seventh electrode plate 5-7, which are located around the first MEMS resonator 1-1 and form a capacitor therewith, to excite and detect the resonant motion of the first MEMS resonator 1-1; an eighth electrode plate 5-8, a ninth electrode plate 5-9, a tenth electrode plate 5-10, an eleventh electrode plate 5-11, a twelfth electrode plate 5-12, a thirteenth electrode plate 5-13, and a fourteenth electrode plate 5-14, which are located around the second MEMS resonator 1-2 and form a capacitor therewith, to excite and detect the resonant motion of the second MEMS resonator 1-2.

[0025] When the first variable function structure 3 - 1 and the second variable function structure 3 - 2 are Joule heat heating structures, in-situ frequency regulation of the output frequency of the MEMS resonator is achieved through the Joule heat effect.

[0026] The Joule heat heating structure generates heat by utilizing energy conduction caused by collisions between conduction electrons and atoms based on the resistance loss characteristics of the material itself, thereby converting electrical energy into thermal energy (Joule heat).

[0027] The Joule heat changes the stiffness of the MEMS resonator, thereby achieving regulation of the output frequency of the MEMS resonator.

[0028] The heating control voltage is applied to both ends of the first variable function structure 3 - 1 and the second variable function structure 3 - 2 through the first anchoring structure 4 - 1 and the second anchoring structure 4 - 2 .

[0029] When the first variable function structure 3-1 and the second variable function structure 3-2 are Joule heat heating structures, the Joule heat heating structures are located on the symmetry axis of the entire MEMS resonator structure, thereby achieving fast and consistent temperature control of the first MEMS resonator 1-1 and the second MEMS resonator 1-2, and further achieving fast and consistent frequency regulation.

[0030] Furthermore, the present invention also provides a MEMS resonant instrument device, which is equipped with a resonator, and the resonator has any one of the above-mentioned MEMS resonator structures with high frequency stability.

[0031] Furthermore, the MEMS resonant instrument equipment includes but is not limited to MEMS silicon-based clocks, MEMS resonant accelerometers, MEMS gyroscopes, MEMS resonant force sensors and MEMS temperature sensors.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] The working mode of the elastic connecting beam 2 of the present invention is a length-direction tensile mode with the same resonant frequency as the first MEMS resonator 1-1 and the second MEMS resonator 1-2, thereby achieving modal matching; when the MEMS resonator vibrates, the elastic connecting beam 2 vibrates at the same frequency as the first MEMS resonator 1-1 and the second MEMS resonator 1-2, thereby reducing the influence of the elastic connecting beam 2 on the modal vibration type of the MEMS resonator while ensuring effective support, thereby increasing the Q value of the MEMS resonator.

[0034] In the present invention, the first MEMS resonator 1-1 and the second MEMS resonator 1-2 are symmetrically arranged on both sides of the first variable function structure 3-1, the second variable function structure 3-2 and the anchoring structure, and the center of the vibration mode effective mass of the first MEMS resonator 1-1 and the second MEMS resonator 1-2 is on the axis in the length direction of the elastic connecting beam 2; this geometric structure makes the effects generated by the first MEMS resonator 1-1 and the second MEMS resonator 1-2 vibrating at the same frequency cancel each other out (vibration cancellation) at the first variable function structure 3-1 and the second variable function structure 3-2, reducing the vibration energy transmitted to the substrate through the first variable function structure 3-1, the second variable function structure 3-2 and the anchoring structure, thereby achieving a reduction in anchoring loss and a further improvement in Q value.

[0035] The first MEMS resonator 1-1 and the second MEMS resonator 1-2 of the present invention are supported on a substrate through a first variable function structure 3-1 and a second variable function structure 3-2.

[0036] The first variable function structure 3-1 and the second variable function structure 3-2 of the present invention can be acoustic impedance structures or Joule heating structures; when the first variable function structure 3-1 and the second variable function structure 3-2 are Joule heat heating structures, the first MEMS resonator 1-1 and the second MEMS resonator 1-2 can be quickly and consistently temperature controlled under the action of the Joule heat control voltage, thereby achieving fast and consistent in-situ frequency adjustment; when the first variable function structure 3-1 and the second variable function structure 3-2 are acoustic impedance structures, the vibration energy dissipated by the first MEMS resonator 1-1 and the second MEMS resonator 1-2 to the substrate through the anchoring structure can be suppressed, thereby achieving further improvement of the Q value of the MEMS resonator.

[0037] In summary, the present invention provides a MEMS resonator structure with high frequency stability, which reduces anchoring loss and improves Q value by means of modal matching, vibration cancellation and variable functional structure, while ensuring effective support and not introducing additional thermoelastic loss. The present invention provides a new idea for the design of high-performance MEMS resonators and high-precision MEMS resonant devices, and has extremely high theoretical and engineering application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a schematic diagram of the structure of a MEMS resonator with high frequency stability according to Example 1 of the present invention.

[0039] Figure 2 This is a schematic diagram of the structure of a MEMS resonator with high frequency stability according to Example 2 of the present invention.

[0040] Figure 3 This is a schematic diagram of the structure of a MEMS resonator with high frequency stability according to Example 3 of the present invention.

[0041] Figure 4 It is a schematic diagram of a modal vibration shape calculated by finite element simulation software according to an embodiment of the present invention, wherein the first MEMS resonator 1-1 and the second MEMS resonator 1-2 vibrate in phase in a body mode, and the elastic connecting beam 2 vibrates in phase with the body mode of the MEMS resonator in a length stretching mode.

[0042] Figure 5 This is a schematic diagram of another modal vibration shape calculated by finite element simulation software according to an embodiment of the present invention, wherein the first MEMS resonator 1-1 and the second MEMS resonator 1-2 vibrate in phase in a shear (Lame) mode, and the elastic connecting beam 2 vibrates in phase with the shear (Lame) mode of the MEMS resonator in a length tension mode.

[0043] In the figure: 1-1 is the first MEMS resonator; 1-2 is the second MEMS resonator; 2 is the elastic support beam; 3-1 is the first variable function structure; 3-2 is the second variable function structure; 4-1 is the first anchoring structure; 4-2 is the second anchoring structure; 5-1 is the first electrode plate; 5-2 is the second electrode plate; 5-3 is the third electrode plate; 5-4 is the fourth electrode plate; 5-5 is the fifth electrode plate; 5-6 is the sixth electrode plate; 5-7 is the seventh electrode plate; 5-8 is the eighth electrode plate; 5-9 is the ninth electrode plate; 5-10 is the tenth electrode plate; 5-11 is the eleventh electrode plate; 5-12 is the twelfth electrode plate; 5-13 is the thirteenth electrode plate; 5-14 is the fourteenth electrode plate; 6-1 is the first transition structure; 6-2 is the second transition structure. DETAILED DESCRIPTION

[0044] The present invention is described in detail below in conjunction with embodiments and drawings.

[0045] Example 1

[0046] Reference Figure 1A high-frequency stability MEMS resonator structure comprises a first MEMS resonator 1-1 and a second MEMS resonator 1-2 respectively connected to the left and right ends of an elastic connecting beam 2, wherein the first MEMS resonator 1-1 and the second MEMS resonator 1-2 are used to simultaneously generate resonant motion under the action of an exciting force so as to output a reference frequency signal, and the elastic connecting beam 2 is used to support the MEMS resonator; the upper and lower sides of the elastic connecting beam 2 are respectively connected to a first variable function structure 3-1 and a second variable function structure 3-2; the first variable function structure 3-1 and the second variable function structure 3-2 are respectively connected to a first anchoring structure 4-1 and a second anchoring structure 4-2, and the variable function structure is used to support the entire MEMS resonant structure on a substrate through the anchoring structure to achieve stable vibration of the MEMS resonator.

[0047] The first MEMS resonator 1-1 and the second MEMS resonator 1-2 have the same structural size, and the structure of the MEMS resonator is a vibration structure processed and formed by MEMS technology; the MEMS process processing and forming specifically includes all or part of the steps of lithography, epitaxy, thin film deposition, oxidation, diffusion, injection, sputtering, evaporation, etching, and scribing.

[0048] A first transition structure 6-1 and a second transition structure 6-2 are provided between the first MEMS resonator 1-1, the second MEMS resonator 1-2 and the elastic connecting beam 2 to reduce the influence of the elastic connecting beam 2 on the modal vibration shape of the MEMS resonator and suppress the dissipation of vibration energy.

[0049] The first variable function structure 3-1 and the second variable function structure 3-2 are located at the center of the entire MEMS resonator structure, and are used to support the elastic connecting beam 2 and the first MEMS resonator 1-1 and the second MEMS resonator 1-2 respectively connected at both ends of the elastic connecting beam 2, and fix the entire structure on the substrate through an anchoring structure.

[0050] The equivalent mass center of the vibration mode of the first MEMS resonator 1-1 and the second MEMS resonator 1-2 is located on the axis in the length direction of the elastic connecting beam 2; the first variable function structure 3-1 and the second variable function structure 3-2 can be acoustic impedance structures or Joule heating structures; when the first variable function structure 3-1 and the second variable function structure 3-2 are acoustic impedance structures, they are used to reduce the vibration energy transmitted to the substrate through the anchoring structure, thereby improving the Q value of the MEMS resonator; when the first variable function structure 3-1 and the second variable function structure 3-2 are Joule heating structures, the in-situ frequency regulation of the output frequency of the MEMS resonator can be achieved through the Joule heating effect.

[0051] The vibrations of the first MEMS resonator 1-1 and the second MEMS resonator 1-2 are kept at the same frequency, so that the effects of the vibrations of the first MEMS resonator 1-1 and the second MEMS resonator 1-2 are offset at the first variable function structure 3-1 and the second variable function structure 3-2, thereby further reducing the anchoring loss and further improving the Q value.

[0052] The resonant frequency of the lengthwise tensile mode of the elastic connecting beam 2 is consistent with the resonant frequency of the vibration mode of the first MEMS resonator 1-1 and the second MEMS resonator 1-2, so that when the MEMS resonator vibrates, it maintains the same frequency and phase as the MEMS resonator, further reducing the influence of the elastic connecting beam 2 on the modal vibration type of the MEMS resonator.

[0053] The first MEMS resonator 1-1, the second MEMS resonator 1-2, the elastic connecting beam 2, the first variable function structure 3-1, the second variable function structure 3-2 are all spaced apart from the substrate, and the spacings are equal or unequal, so that the first MEMS resonator 1-1, the second MEMS resonator 1-2, the elastic connecting beam 2, the first variable function structure 3-1, the second variable function structure 3-2 are suspended together above the substrate, reducing the energy dissipated to the substrate through the anchoring structure.

[0054] The first MEMS resonator 1 - 1 and the second MEMS resonator 1 - 2 are connected to an excitation detection structure for exciting the first MEMS resonator 1 - 1 and the second MEMS resonator 1 - 2 to generate vibration and detecting vibration signals.

[0055] The first MEMS resonator 1 - 1 and the second MEMS resonator 1 - 2 simultaneously generate vibration signals under the action of the excitation detection structure, thereby increasing the electromechanical coupling system of the MEMS resonator structure and reducing the difficulty of subsequent circuit design.

[0056] The excitation detection structure adopts capacitance, piezoelectric, optical or electromagnetic.

[0057] When the first variable functional structure 3-1 and the second variable functional structure 3-2 are Joule heat heating structures, the Joule heat heating structures generate heat based on the resistance loss characteristics of the material itself, using the energy conduction caused by the collision between conduction electrons and atoms, thereby converting electrical energy into thermal energy (Joule heat).

[0058] The Joule heat changes the stiffness of the MEMS resonator, thereby achieving regulation of the output frequency of the MEMS resonator.

[0059] The heating control voltage is applied to both ends of the first variable function structure 3 - 1 and the second variable function structure 3 - 2 through the first anchoring structure 4 - 1 and the second anchoring structure 4 - 2 .

[0060] When the first variable function structure 3-1 and the second variable function structure 3-2 are Joule heat heating structures, the Joule heat heating structures are located on the symmetry axis of the entire MEMS resonator structure, thereby achieving fast and consistent temperature control of the first MEMS resonator 1-1 and the second MEMS resonator 1-2, and further achieving fast and consistent frequency regulation.

[0061] By using the high frequency stability MEMS resonator structure of this embodiment, corresponding MEMS resonant instrumentation equipment is prepared, such as a MEMS silicon-based clock, a MEMS resonant accelerometer, a MEMS gyroscope, a MEMS resonant force sensor, and a MEMS temperature sensor.

[0062] Example 2

[0063] Reference Figure 2 A high-frequency stability MEMS resonator structure comprises a first MEMS resonator 1-1 and a second MEMS resonator 1-2 respectively connected to the left and right ends of an elastic connecting beam 2; the upper and lower sides of the elastic connecting beam 2 are respectively connected to a first variable function structure 3-1 and a second variable function structure 3-2; the first variable function structure 3-1 and the second variable function structure 3-2 are respectively connected to a first anchoring structure 4-1 and a second anchoring structure 4-2; the first MEMS resonator 1-1 and the second MEMS resonator 1-2 are respectively connected to a capacitive excitation detection structure.

[0064] The capacitive excitation detection structure includes: a first electrode plate 5-1, a second electrode plate 5-2, a third electrode plate 5-3, a fourth electrode plate 5-4, a fifth electrode plate 5-5, a sixth electrode plate 5-6, and a seventh electrode plate 5-7, which are located around the first MEMS resonator 1-1 and form a capacitor therewith, and excite and detect the resonant motion of the first MEMS resonator 1-1; an eighth electrode plate 5-8, a ninth electrode plate 5-9, a tenth electrode plate 5-10, an eleventh electrode plate 5-11, a twelfth electrode plate 5-12, a thirteenth electrode plate 5-13, and a fourteenth electrode plate 5-14, which are located around the second MEMS resonator 1-2 and form a capacitor therewith, and excite and detect the resonant motion of the second MEMS resonator 1-2.

[0065] The first MEMS resonator 1-1 and the second MEMS resonator 1-2 are disk-type MEMS resonators with the same structural dimensions. A first transition structure 6-1 and a second transition structure 6-2 are arranged between the disk-type MEMS resonator and the elastic connecting beam 2 to reduce the influence of the elastic connecting beam 2 on the modal vibration type of the MEMS resonator.

[0066] The first variable functional structure 3-1 and the second variable functional structure 3-2 are Joule heat heating structures in the form of array flexible straight beam structures, which are symmetrically arranged at the center of the entire MEMS resonator structure. They are used to quickly suppress the in-situ frequency control of the first MEMS resonator 1-1 and the second MEMS resonator 1-2 through the Joule heat effect while ensuring stable support.

[0067] By using the high frequency stability MEMS resonator structure of this embodiment, corresponding MEMS resonant instrumentation equipment is prepared, such as a MEMS silicon-based clock, a MEMS resonant accelerometer, a MEMS gyroscope, a MEMS resonant force sensor, and a MEMS temperature sensor.

[0068] Example 3

[0069] Reference Figure 3 , a MEMS resonator structure with high frequency stability, which differs from Example 2 in that: the electrode shape in the capacitive excitation detection structure is different, but the function and usage are the same; the first variable function structure 3-1 and the second variable function structure 3-2 are acoustic impedance structures in the form of series phononic crystal structures, one end of the series phononic crystal structure is connected to the midpoint of the elastic connecting beam 2, and the other end of the series phononic crystal structure is connected to the first anchoring structure 4-1 and the second anchoring structure 4-2, which is used to support the entire MEMS resonator structure while utilizing the attenuation effect of the phononic crystal on the vibration energy within a specific frequency bandwidth, thereby reducing the vibration energy transmitted to the substrate through the first variable function structure 3-1 and the second variable function structure 3-2, reducing the anchoring loss and improving the Q value of the MEMS resonator structure.

[0070] Reference Figure 4 , the first MEMS resonator 1-1 and the second MEMS resonator 1-2 work in phase in the body mode, and the elastic connecting beam 2 works in the length extension mode; refer to Figure 5 , the first MEMS resonator 1-1 and the second MEMS resonator 1-2 work in phase in the fourth-order shear mode, and the elastic connecting beam 2 works in the length tension mode. The vibrations of the first MEMS resonator 1-1 and the second MEMS resonator 1-2 are kept at the same frequency, so that the effects of the vibrations of the first MEMS resonator 1-1 and the second MEMS resonator 1-2 are offset at the variable functional structure, thereby achieving a further reduction in anchoring loss and a further improvement in Q value.

[0071] The resonant frequency of the lengthwise tensile mode of the elastic connecting beam 2 is consistent with the resonant frequency of the vibration mode of the first MEMS resonator 1-1 and the second MEMS resonator 1-2, so that the elastic connecting beam 2 vibrates in phase with the MEMS resonator when the MEMS resonator vibrates, further reducing the influence of the elastic connecting beam 2 on the modal vibration type of the MEMS resonator.

[0072] By using the high frequency stability MEMS resonator structure of this embodiment, corresponding MEMS resonant instrumentation equipment is prepared, such as a MEMS silicon-based clock, a MEMS resonant accelerometer, a MEMS gyroscope, a MEMS resonant force sensor, and a MEMS temperature sensor.

[0073] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A MEMS resonator structure with high frequency stability, characterized in that: The invention comprises a first MEMS resonator (1-1) and a second MEMS resonator (1-2) respectively connected to the left and right ends of an elastic connection beam (2); the upper and lower sides of the elastic connection beam (2) are respectively connected to a first variable function structure (3-1) and a second variable function structure (3-2); the first variable function structure (3-1) and the second variable function structure (3-2) are respectively connected to a first anchoring structure (4-1) and a second anchoring structure (4-2).

2. A MEMS resonator structure with high frequency stability according to claim 1, characterized in that: The first MEMS resonator (1-1) and the second MEMS resonator (1-2) have the same or different structural sizes.

3. A MEMS resonator structure with high frequency stability according to claim 1, characterized in that: The structures of the first MEMS resonator (1-1) and the second MEMS resonator (1-2) are vibration structures processed and formed using MEMS technology.

4. The MEMS resonator structure with high frequency stability according to claim 1, characterized in that: A first transition structure (6-1) and a second transition structure (6-2) are provided between the first MEMS resonator (1-1), the second MEMS resonator (1-2) and the elastic connecting beam (2), and are used to reduce the influence of the elastic connecting beam (2) on the modal vibration shape of the MEMS resonator and suppress the dissipation of vibration energy.

5. The MEMS resonator structure with high frequency stability according to claim 1, characterized in that: The equivalent mass centers of the vibration modes of the first MEMS resonator (1-1) and the second MEMS resonator (1-2) are located on the axis of the elastic connecting beam (2) in the length direction.

6. The MEMS resonator structure with high frequency stability according to claim 1, characterized in that: The first variable function structure (3-1) and the second variable function structure (3-2) are located at the center of the entire MEMS resonator structure, and are used to support the elastic connection beam (2) and the first MEMS resonator (1-1) and the second MEMS resonator (1-2) respectively connected to the two ends of the elastic connection beam (2), and fix the entire structure on the substrate through the first anchoring structure (4-1) and the second anchoring structure (4-2).

7. A MEMS resonator structure with high frequency stability according to claim 6, characterized in that: The first MEMS resonator (1-1), the second MEMS resonator (1-2), the elastic connecting beam (2), the first variable function structure (3-1), the second variable function structure (3-2) and the substrate all maintain a spacing, and the spacing is equal or unequal, so that the first MEMS resonator (1-1), the second MEMS resonator (1-2), the elastic connecting beam (2), the first variable function structure (3-1), and the second variable function structure (3-2) are suspended together on the substrate.

8. The MEMS resonator structure with high frequency stability according to claim 1, characterized in that: The first variable function structure (3-1) and the second variable function structure (3-2) may be acoustic impedance structures or Joule heating structures.

9. A MEMS resonator structure with high frequency stability according to claim 8, characterized in that: When the first variable function structure (3-1) and the second variable function structure (3-2) are acoustic impedance structures, they are used to realize the function of suppressing vibration energy dissipation; when the first variable function structure (3-1) and the second variable function structure (3-2) are Joule heat heating structures, they are used to realize the frequency in-situ control function of the MEMS resonator structure.

10. The MEMS resonator structure with high frequency stability according to claim 8, characterized in that: When the first variable function structure (3-1) and the second variable function structure (3-2) are Joule heat heating structures, an array of flexible straight beam structures is adopted and symmetrically arranged at the center of the entire MEMS resonator structure.

11. The MEMS resonator structure with high frequency stability according to claim 8, characterized in that: When the first variable function structure (3-1) and the second variable function structure (3-2) are acoustic impedance structures, a series phononic crystal structure is used, one end of the series phononic crystal structure is connected to the midpoint of the elastic connecting beam (2), and the other end of the series phononic crystal structure is connected to the first anchoring structure (4-1) and the second anchoring structure (4-2).

12. A MEMS resonator structure with high frequency stability according to claim 1, characterized in that: The vibrations of the first MEMS resonator (1-1) and the second MEMS resonator (1-2) are kept at the same frequency, so that the effects of the vibrations of the first MEMS resonator (1-1) and the second MEMS resonator (1-2) are offset at the first variable function structure (3-1) and the second variable function structure (3-2).

13. The MEMS resonator structure with high frequency stability according to claim 1, characterized in that: The resonant frequency of the tension mode in the length direction of the elastic connection beam (2) is consistent with the resonant frequency of the vibration mode of the first MEMS resonator (1-1) and the second MEMS resonator (1-2), so that when the MEMS resonator vibrates, it maintains the same frequency and phase vibration.

14. A MEMS resonator structure with high frequency stability according to claim 1, characterized in that: The first MEMS resonator (1-1) and the second MEMS resonator (1-2) are connected to the excitation detection structure.

15. A MEMS resonator structure with high frequency stability according to claim 14, characterized in that: The first MEMS resonator (1-1) and the second MEMS resonator (1-2) simultaneously generate vibration signals under the action of the excitation detection structure.

16. A MEMS resonator structure with high frequency stability according to claim 14, characterized in that: The principle of the excitation detection structure adopts capacitance, piezoelectricity, optics or electromagnetic.

17. A MEMS resonator structure with high frequency stability according to claim 16, characterized in that: When the excitation detection structure adopts a capacitive type, it comprises: a first electrode plate (5-1), a second electrode plate (5-2), a third electrode plate (5-3), a fourth electrode plate (5-4), a fifth electrode plate (5-5), a sixth electrode plate (5-6), and a seventh electrode plate (5-7) which are located around the first MEMS resonator (1-1) and form a capacitor therewith, and are used to excite and detect the resonant motion of the first MEMS resonator (1-1); and an eighth electrode plate (5-8), a ninth electrode plate (5-9), a tenth electrode plate (5-10), an eleventh electrode plate (5-11), a twelfth electrode plate (5-12), a thirteenth electrode plate (5-13), and a fourteenth electrode plate (5-14) which are located around the second MEMS resonator (1-2) and form a capacitor therewith, and are used to excite and detect the resonant motion of the second MEMS resonator (1-2).

18. The MEMS resonator structure with high frequency stability according to claim 1, characterized in that: When the first variable function structure (3-1) and the second variable function structure (3-2) are Joule heat heating structures, in-situ frequency regulation of the output frequency of the MEMS resonator is achieved through the Joule heat effect.

19. A MEMS resonator structure with high frequency stability according to claim 18, characterized in that: The Joule heat heating structure generates heat by utilizing energy conduction caused by collisions between conduction electrons and atoms based on the resistance loss characteristics of the material itself, thereby converting electrical energy into thermal energy.

20. A MEMS resonator structure with high frequency stability according to claim 19, characterized in that: The Joule heat changes the stiffness of the MEMS resonator, thereby achieving regulation of the output frequency of the MEMS resonator.

21. The MEMS resonator structure with high frequency stability according to claim 19, characterized in that: The heating control voltage is applied to both ends of the first variable function structure (3-1) and the second variable function structure (3-2) through the first anchoring structure (4-1) and the second anchoring structure (4-2).

22. The MEMS resonator structure with high frequency stability according to claim 18, characterized in that: When the first variable function structure (3-1) and the second variable function structure (3-2) are Joule heat heating structures, the Joule heat heating structures are located on the symmetry axis of the entire MEMS resonator structure, thereby achieving rapid and consistent temperature control of the first MEMS resonator (1-1) and the second MEMS resonator (1-2), thereby achieving rapid and consistent frequency regulation.

23. A MEMS resonant instrument device, equipped with a resonator, characterized in that: The resonator of the configuration has a MEMS resonator structure with high frequency stability as claimed in any one of claims 1 to 22.

24. A MEMS resonant instrumentation device according to claim 23, characterized in that: Including MEMS silicon-based clocks, MEMS resonant accelerometers, MEMS gyroscopes, MEMS resonant force sensors and MEMS temperature sensors.

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