A MEMS resonator structure with high frequency stability and a MEMS resonator instrument device thereof

Abstract

The application provides a MEMS resonator structure with high frequency stability, comprising a first MEMS resonator and a second MEMS resonator connected to left and right ends of an elastic connecting beam respectively, upper and lower sides of the elastic connecting beam are connected to a first variable function structure and a second variable function structure respectively; the first variable function structure and the second variable function structure are connected to a first anchor structure and a second anchor structure respectively; the MEMS resonator reduces anchor loss of a pair of MEMS resonators with the same frequency vibration through mode matching, vibration cancellation and flexible support, so that the Q value of the MEMS resonator is improved; the structure of the double MEMS resonator is used to reduce the movement impedance of the resonator; the Joule heat effect of the variable function structure located at the center of the structure under the action of a heating control voltage is used to realize rapid and consistent in-situ frequency adjustment of the MEMS resonator structure; the application also provides a MEMS resonator type instrument and meter device with the MEMS resonator structure with high frequency stability.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of resonators, and particularly relates to a MEMS resonator structure with high frequency stability and a MEMS resonator instrument and metering device. BACKGROUND

[0002] With the maturity of semiconductor processing technology, MEMS resonators gradually replace quartz resonators to become widely used micro-mechanical system core elements due to their small size, low cost, strong impact resistance, and good process consistency. Researchers develop high-performance MEMS silicon-based clocks, MEMS resonator accelerometers, MEMS gyroscopes, and other resonator instrument and metering devices with MEMS resonators as core elements.

[0003] Frequency stability is the most critical performance indicator of a MEMS resonator, and directly determines the upper limit of the performance of the device. Factors affecting the frequency stability of a MEMS resonator mainly include the quality factor and the motion impedance; the quality factor, i.e., the Q value, is a dimensionless quantity representing the rate of energy loss in the vibration mode of the MEMS resonator, and is specifically defined as the ratio between the total energy stored in the system and the energy dissipation 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 plurality of anchor structures uniformly distributed around the resonator body to realize stable vibration of the MEMS resonator. However, the stress generated in the MEMS resonator body and the anchor structure by this anchoring method can significantly affect the modal shape of the MEMS resonator, and the multi-anchor method can exacerbate energy dissipation such as anchor loss and thermoelastic loss during vibration, limiting the improvement of the Q value of the MEMS resonator; in addition, the existing MEMS resonator structure is usually a single resonator body, which is not conducive to the reduction of the motion impedance of the resonator. Therefore, how to ensure that the Q value of the MEMS resonator is improved and the dynamic impedance is reduced without significantly affecting the modal shape and the stable vibration of the MEMS resonator has become one of the problems to be solved by those skilled in the art.

[0005] In view of the problems of the MEMS resonator, the existing solutions mainly realize the improvement of the Q value through the structural optimization design of the anchor structure. For example, the patent application entitled "MEMS resonator" (CN 220553997 U) provides a multi-stage soft connection scheme, hoping to reduce the energy transmission loss between the MEMS resonator and the supporting anchor point through flexible connection. However, it is a basic common sense in the field of MEMS resonators to reduce the anchor loss by setting flexible connection. The patent application does not consider the influence of flexible connection on the thermal elastic loss of the resonator. The complex auxiliary structure will increase the irreversible heat flow during vibration and increase the thermal elastic dissipation, which seriously restricts the performance of the resonator. In terms of motion impedance, the existing solutions usually use piezoelectric detection, piezoresistive detection and other detection methods to reduce the 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. The existing piezoresistive detection method, such as the patent application entitled "MEMS resonator and preparation method thereof" (CN 114172487 A), provides a piezoresistive detection scheme based on T-shaped anchor structure, which realizes efficient electromechanical energy conversion. However, this scheme will increase the system power consumption and deteriorate the Q value of the MEMS resonator. SUMMARY

[0006] In order to overcome the shortcomings of the existing technology, the purpose of the present application is to provide a MEMS resonator structure with high frequency stability. Through modal matching, vibration cancellation and flexible support, the anchor loss of a pair of MEMS resonators with the same frequency vibration is reduced, thereby realizing the improvement of the Q value of the MEMS resonator. The structure of the double MEMS resonator is used to reduce the motion impedance of the resonator. The Joule heating effect of the variable function structure located at the center of the structure under the action of the heating control voltage is used to realize the rapid 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 application is also to provide corresponding MEMS resonator instrument and meter equipment, including but not limited to MEMS silicon-based clock, MEMS resonator accelerometer or MEMS gyroscope.

[0007] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:

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

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

[0010] The first MEMS resonator 1-1 and the second MEMS resonator 1-2 are vibrating structures formed by using a MEMS process.

[0011] The first MEMS resonator 1-1, the second MEMS resonator 1-2 and the elastic connecting beam 2 are provided with a first transition structure 6-1 and a second transition structure 6-2, which are used for reducing the influence of the elastic connecting beam 2 on the modal vibration mode of the MEMS resonator and inhibiting the dissipation of vibration energy.

[0012] 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.

[0013] The first variable function structure 3-1 and the second variable function structure 3-2 are located at the center of the whole MEMS resonator structure, and are used for supporting the elastic connecting beam 2 and the first MEMS resonator 1-1 and the second MEMS resonator 1-2 connected to the two ends of the elastic connecting beam 2 respectively, and fixing the whole structure on a 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 and the second variable function structure 3-2 are all kept at a distance from the substrate, and the distance is equal or unequal, so that the first MEMS resonator 1-1, the second MEMS resonator 1-2, the elastic connecting beam 2 and the first variable function structure 3-1 and the second variable function structure 3-2 are collectively suspended above the substrate.

[0015] The first variable function structure 3-1 and the second variable function structure 3-2 can be an acoustic impedance structure or a Joule heating structure.

[0016] The first variable function structure 3-1 and the second variable function structure 3-2 are acoustic impedance structures, and are used to realize the function of vibration energy dissipation suppression; the first variable function structure 3-1 and the second variable function structure 3-2 are Joule heat heating structures, and are used to realize the function of in-situ frequency regulation 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 flexible straight beam structure can be used, and the array flexible straight beam structure is 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 anchor structure 4-1 and the second anchor 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 actions of the vibrations of the first MEMS resonator 1-1 and the second MEMS resonator 1-2 on the first variable function structure 3-1 and the second variable function structure 3-2 are cancelled out.

[0020] The resonance frequency of the length direction tensile mode of the elastic connecting beam 2 is consistent with the resonance 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 keeps the same frequency and phase vibration with the MEMS resonator when the MEMS resonator vibrates.

[0021] The first MEMS resonator 1-1 and the second MEMS resonator 1-2 are connected to an 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 is in a capacitive, piezoelectric, optical or electromagnetic mode.

[0024] When the excitation and detection structure is capacitive, 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 located around the first MEMS resonator 1-1 and forming a capacitor with the first MEMS resonator 1-1, which excites and detects 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 located around the second MEMS resonator 1-2 and forming a capacitor with the second MEMS resonator 1-2, which excites and detects the resonant motion of the second MEMS resonator 1-2.

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

[0026] The Joule heat heating structure is based on the resistance loss characteristics of the material itself, and heat is generated through the energy conduction caused by the collision between the conduction electrons and the atoms, so as to convert the electrical energy into heat energy (Joule heat).

[0027] The Joule heat changes the stiffness of the MEMS resonator, so as to realize the regulation of the output frequency of the MEMS resonator.

[0028] The heating control voltage is applied across the first variable functional structure 3-1 and the second variable functional structure 3-2 through the first anchor structure 4-1 and the second anchor structure 4-2.

[0029] 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 structure is located on the symmetry axis of the entire MEMS resonator structure, so as to realize the rapid and consistent temperature control of the first MEMS resonator 1-1 and the second MEMS resonator 1-2, and further realize the rapid and consistent frequency regulation.

[0030] Further, the application also provides a MEMS resonant type instrument and meter device, which is configured with a resonator having the MEMS resonator structure with high frequency stability as described above.

[0031] Further, the MEMS resonant type instrument and meter device includes but is not limited to a MEMS silicon-based clock, a MEMS resonant type accelerometer, a MEMS gyroscope, a MEMS resonant type force sensor, and a MEMS temperature sensor.

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

[0033] The working mode of the elastic connecting beam 2 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, mode matching is realized; when the MEMS resonator vibrates, the elastic connecting beam 2 vibrates with the first MEMS resonator 1-1 and the second MEMS resonator 1-2 at the same frequency, which can reduce the influence of the elastic connecting beam 2 on the mode shape of the MEMS resonator and increase the Q value of the MEMS resonator under the premise of ensuring effective support.

[0034] 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 of the length direction of the elastic connecting beam 2; the geometric structure makes the first MEMS resonator 1-1 and the second MEMS resonator 1-2 which vibrate at the same frequency produce an effect on the first variable function structure 3-1 and the second variable function structure 3-2 (vibration cancellation), which reduces 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, and realizes the reduction of the anchoring loss and the further improvement of the Q value.

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

[0036] The first variable function structure 3-1 and the second variable function structure 3-2 can be an acoustic impedance structure or a joule heating structure; when the first variable function structure 3-1 and the second variable function structure 3-2 are joule heating structures, the first MEMS resonator 1-1 and the second MEMS resonator 1-2 can be rapidly and uniformly temperature-controlled under the action of the joule heat control voltage, and then rapid and uniform in-situ frequency adjustment is realized; when the first variable function structure 3-1 and the second variable function structure 3-2 are acoustic impedance structures, the vibration energy of the first MEMS resonator 1-1 and the second MEMS resonator 1-2 dissipated to the substrate through the anchoring structure can be suppressed, and then the Q value of the MEMS resonator is further improved.

[0037] In summary, the application provides a MEMS resonator structure with high frequency stability, which realizes the reduction of the anchoring loss and the improvement of the Q value under the premise of ensuring effective support and not introducing additional thermoelastic loss through mode matching, vibration cancellation and variable function structure. The application provides a new idea for the design of high-performance MEMS resonators and high-precision MEMS resonator devices, and has very high theoretical and engineering application value. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 A high-frequency stability MEMS resonator structure schematic diagram for embodiment 1 of the present application.

[0039] Figure 2 A high-frequency stability MEMS resonator structure schematic diagram for embodiment 2 of the present application.

[0040] Figure 3 A high-frequency stability MEMS resonator structure schematic diagram for embodiment 3 of the present application.

[0041] Figure 4 A mode shape schematic diagram calculated by finite element simulation software for an embodiment of the present application, wherein the first MEMS resonator 1-1 and the second MEMS resonator 1-2 vibrate in phase in a bulk mode, and the elastic connecting beam 2 vibrates in phase with the bulk mode of the MEMS resonator in a length extension mode.

[0042] Figure 5 Another mode shape schematic diagram calculated by finite element simulation software for an embodiment of the present application, 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 extension mode.

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

[0044] The present application will be described in detail below with reference to embodiments and the accompanying drawings.

[0045] Embodiment 1

[0046] Reference Figure 1The application discloses a MEMS resonator structure with high frequency stability, which comprises a first MEMS resonator 1-1 and a second MEMS resonator 1-2 connected to left and right ends of an elastic connecting beam 2 respectively, the first MEMS resonator 1-1 and the second MEMS resonator 1-2 are used for simultaneously generating resonant motion under the action of an exciting force so as to realize the output of a reference frequency signal, and the elastic connecting beam 2 is used for supporting the MEMS resonator; the upper and lower sides of the elastic connecting beam 2 are connected with a first variable function structure 3-1 and a second variable function structure 3-2 respectively; the first variable function structure 3-1 and the second variable function structure 3-2 are connected with a first anchoring structure 4-1 and a second anchoring structure 4-2 respectively, the variable function structure is used for supporting the whole MEMS resonator structure on a substrate through the anchoring structure, and realizes the stable vibration of the MEMS resonator.

[0047] The first MEMS resonator 1-1 and the second MEMS resonator 1-2 have the same structure size, and the structure of the MEMS resonator is a vibration structure formed by using a MEMS process; the MEMS process forming specifically includes all or part of processing steps such as photolithography, epitaxy, thin film deposition, oxidation, diffusion, implantation, sputtering, evaporation, etching and wafer slicing.

[0048] First and second transition structures 6-1 and 6-2 are arranged between the first MEMS resonator 1-1, the second MEMS resonator 1-2 and the elastic connecting beam 2, and are used for reducing the influence of the elastic connecting beam 2 on the modal vibration mode of the MEMS resonator and inhibiting the dissipation of vibration energy.

[0049] The first and second variable function structures 3-1 and 3-2 are located at the center of the whole MEMS resonator structure, and are used for supporting the elastic connecting beam 2 and the first and second MEMS resonators 1-1 and 1-2 connected to the two ends of the elastic connecting beam 2 respectively, and fixing the whole structure on the substrate through the anchoring structure.

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

[0051] The vibration of the first MEMS resonator 1-1 and the second MEMS resonator 1-2 remains the same frequency, so that the first MEMS resonator 1-1 and the second MEMS resonator 1-2 are counteracted at the first variable functional structure 3-1 and the second variable functional structure 3-2 due to the vibration, further reducing the anchor loss and further improving the Q value.

[0052] The resonant frequency of the length direction 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 as to keep the same frequency and phase vibration with the MEMS resonator when the MEMS resonator vibrates, further reducing the influence of the elastic connecting beam 2 on the mode vibration 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 functional structure 3-1, the second variable functional structure 3-2 and the substrate are all kept at a distance, and the distance is equal or unequal, so that the first MEMS resonator 1-1, the second MEMS resonator 1-2, the elastic connecting beam 2 and the first variable functional structure 3-1, the second variable functional structure 3-2 are collectively suspended above the substrate, reducing the energy dissipated to the substrate through the anchor structure.

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

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

[0056] The excitation detection structure adopts a capacitive, piezoelectric, optical or electromagnetic type.

[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 structure utilizes the energy conduction caused by the collision between the conduction electrons and the atoms based on the resistance loss characteristics of the material itself, so as to convert the electric energy into heat energy (Joule heat).

[0058] The Joule heat changes the stiffness of the MEMS resonator, so as to realize the regulation of the output frequency of the MEMS resonator.

[0059] The heating control voltage is applied across the first variable functional structure 3-1 and the second variable functional structure 3-2 through the first anchor structure 4-1 and the second anchor structure 4-2.

[0060] When the first variable function structure 3-1 and the second variable function structure 3-2 are the joule heat heating structure, the joule heat heating structure is located on the symmetry axis of the whole MEMS resonator structure, so that the first MEMS resonator 1-1 and the second MEMS resonator 1-2 are quickly and uniformly controlled in temperature, and then the frequency is quickly and uniformly adjusted.

[0061] By using the MEMS resonator structure with high frequency stability, corresponding MEMS resonator type instrument and meter equipment, such as MEMS silicon-based clock, MEMS resonator type accelerometer, MEMS gyroscope, MEMS resonator type force sensor and MEMS temperature sensor, are prepared.

[0062] Embodiment 2

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

[0064] The capacitive excitation and detection structure 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 located around the first MEMS resonator 1-1 and forming a capacitor with the first MEMS resonator 1-1, exciting and detecting 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 located around the second MEMS resonator 1-2 and forming a capacitor with the second MEMS resonator 1-2, exciting and detecting 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 disc type MEMS resonators with the same structure size, and a first transition structure 6-1 and a second transition structure 6-2 are arranged between the disc type MEMS resonators and the elastic connecting beam 2, for reducing the influence of the elastic connecting beam 2 on the modal vibration mode of the MEMS resonator.

[0066] The first variable function structure 3-1 and the second variable function structure 3-2 are Joule heat heating structures in the form of an array flexible straight beam structure, symmetrically arranged at the center of the entire MEMS resonator structure, for in-situ frequency regulation of the first MEMS resonator 1-1 and the second MEMS resonator 1-2 through Joule heat effect under the premise of ensuring stable support.

[0067] The high-frequency-stability MEMS resonator structure is used to prepare corresponding MEMS resonator type instrument and meter equipment, such as a MEMS silicon-based clock, a MEMS resonator type accelerometer, a MEMS gyroscope, a MEMS resonator type force sensor, and a MEMS temperature sensor.

[0068] Embodiment 3

[0069] Referring to Figure 3 The high-frequency-stability MEMS resonator structure differs from that of Embodiment 2 in that the electrode shape in the capacitive excitation detection structure is different, but the function and use 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 a series phononic crystal structure, 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 anchor structure 4-1 and the second anchor structure 4-2, for supporting the entire MEMS resonator structure while reducing the vibration energy transmitted to the substrate through the first variable function structure 3-1 and the second variable function structure 3-2 by using the vibration energy attenuation effect of the phononic crystal within a specific frequency bandwidth, reducing the anchor loss, and improving the Q value of the MEMS resonator structure.

[0070] Referring to Figure 4 The first MEMS resonator 1-1 and the second MEMS resonator 1-2 work in the body mode, and the elastic connecting beam 2 works in the length tensile mode; referring to Figure 5 The first MEMS resonator 1-1 and the second MEMS resonator 1-2 work in the four-order shear mode, and the elastic connecting beam 2 works in the length tensile mode. The vibrations of the first MEMS resonator 1-1 and the second MEMS resonator 1-2 remain the same frequency, so that the effects of the vibrations of the first MEMS resonator 1-1 and the second MEMS resonator 1-2 on the variable function structure are offset, achieving further reduction of the anchor loss and further improvement of the Q value.

[0071] The resonant frequency of the length direction 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 mode shape of the MEMS resonator.

[0072] With the MEMS resonator structure of high frequency stability of the embodiment, corresponding MEMS resonator type instrument and meter equipment such as MEMS silicon-based clock, MEMS resonator type accelerometer, MEMS gyroscope, MEMS resonator type force sensor and MEMS temperature sensor are prepared.

[0073] The above is only to illustrate the technical idea of the present application, and cannot limit the protection scope of the present application. Any modification made according to the technical idea of the present application on the basis of the technical scheme falls within the protection scope of the claims of the present application.

Claims

1. A MEMS resonator structure with high frequency stability, characterized by: The first MEMS resonator (1-1) and the second MEMS resonator (1-2) are respectively connected to the left and right ends of the elastic connecting beam (2), and the upper and lower sides of the elastic connecting beam (2) are respectively connected to the first variable function structure (3-1) and the 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 the first anchor structure (4-1) and the second anchor structure (4-2); The first transition structure (6-1) and the second transition structure (6-2) are arranged between the first MEMS resonator (1-1) and the elastic connecting beam (2) and between the second MEMS resonator (1-2) and the elastic connecting beam (2), for reducing the influence of the elastic connecting beam (2) on the modal vibration mode of the MEMS resonator and inhibiting the dissipation of vibration energy; 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) are 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 heating structures, an array flexible straight beam structure is adopted and symmetrically arranged at the center of the entire MEMS resonator structure; 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 adopted, 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 anchor structure (4-1) and the second anchor structure (4-2).

2. The MEMS resonator structure of claim 1, wherein: The first MEMS resonator (1-1) and the second MEMS resonator (1-2) have the same or different structure sizes.

3. The MEMS resonator structure of claim 1, wherein: The first MEMS resonator (1-1) and the second MEMS resonator (1-2) are vibration structures processed and formed by using a MEMS process.

4. The MEMS resonator structure of claim 1, wherein: 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, for supporting the elastic connecting beam (2) and the first MEMS resonator (1-1) and the second MEMS resonator (1-2) connected to the two ends of the elastic connecting beam (2) respectively, and fixing the entire structure on the substrate through the first anchor structure (4-1) and the second anchor structure (4-2).

5. The MEMS resonator structure of claim 4, wherein: 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 all spaced 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) and the first variable function structure (3-1) and the second variable function structure (3-2) are collectively suspended above the substrate.

6. The MEMS resonator structure of claim 1, wherein: The first variable function structure (3-1) and the second variable function structure (3-2) are acoustic impedance structures, and are used to realize the function of vibration energy dissipation suppression; the first variable function structure (3-1) and the second variable function structure (3-2) are Joule heat heating structures, and are used to realize the function of in-situ frequency control of the MEMS resonator structure.

7. The MEMS resonator structure of claim 1, wherein: The vibration of the first MEMS resonator (1-1) and the second MEMS resonator (1-2) is kept at the same frequency, so that the vibration generated by the first MEMS resonator (1-1) and the second MEMS resonator (1-2) acts on the first variable function structure (3-1) and the second variable function structure (3-2) and is cancelled out.

8. The MEMS resonator structure of claim 1, wherein: The resonant frequency of the length direction tensile mode of the elastic connecting beam (2) is kept 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) keeps the same frequency and phase vibration with the MEMS resonator when the MEMS resonator vibrates.

9. The MEMS resonator structure of claim 1, wherein: The first MEMS resonator (1-1) and the second MEMS resonator (1-2) are connected to the excitation detection structure.

10. The MEMS resonator structure of claim 9, wherein: 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.

11. The MEMS resonator structure of claim 9, wherein: The principle of the excitation detection structure adopts a capacitive type, a piezoelectric type, an optical type or an electromagnetic type.

12. The MEMS resonator structure of claim 11, wherein: When the excitation detection structure adopts the capacitive type, the excitation detection structure 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) located around the first MEMS resonator (1-1) and forming capacitors with the first MEMS resonator (1-1), and exciting and detecting the resonant movement 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) located around the second MEMS resonator (1-2) and forming capacitors with the second MEMS resonator (1-2), and exciting and detecting the resonant movement of the second MEMS resonator (1-2).

13. The MEMS resonator structure of claim 1, wherein: When the first variable function structure (3-1) and the second variable function structure (3-2) are Joule heat heating structures, the in-situ frequency control of the output frequency of the MEMS resonator is realized through the Joule heat effect.

14. The MEMS resonator structure of claim 13, wherein: The Joule heat heating structure is based on the resistance loss characteristics of the material itself, and heat is generated by the collision between the conduction electrons and the atoms, so that the electrical energy is converted into heat energy.

15. The MEMS resonator structure of claim 14, wherein: The Joule heat changes the stiffness of the MEMS resonator, thereby realizing the control of the output frequency of the MEMS resonator.

16. The MEMS resonator structure of claim 14, wherein: 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 anchor structure (4-1) and the second anchor structure (4-2).

17. The MEMS resonator structure of claim 13, wherein: 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, realizing fast and consistent temperature control of the first MEMS resonator (1-1) and the second MEMS resonator (1-2), and further realizing fast and consistent frequency adjustment.

18. A MEMS resonant instrument metering device configured with a resonator, characterized by: The resonator has the high-frequency stability of the MEMS resonator structure in any one of claims 1 to 17.

19. A MEMS resonant instrument device according to claim 18, wherein: The MEMS resonator includes a MEMS silicon-based clock, a MEMS resonant accelerometer, a MEMS gyroscope, a MEMS resonant force sensor, and a MEMS temperature sensor.

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