CN115347878A

CN115347878A - Micromechanical resonator

Info

Publication number: CN115347878A
Application number: CN202210981335.0A
Authority: CN
Inventors: 雷永庆; 李明
Original assignee: Mestar Microelectronics Shenzhen Co ltd
Current assignee: Mestar Microelectronics Shenzhen Co ltd
Priority date: 2022-08-16
Filing date: 2022-08-16
Publication date: 2022-11-15

Abstract

The application discloses a micromechanical resonator. The micromechanical resonator comprises a first resonance unit and a second resonance unit, one end of the second resonance unit is a connecting end connected with the first resonance unit, the other end of the second resonance unit is an anchoring end connected with the substrate, and the rigidity near the anchoring end is larger than that near the connecting end. Through the mode, in the vibrating process of the second resonance unit, the rigidity of the anchoring end of the second resonance unit is larger than that of the connecting end, and the displacement of the anchoring end is restrained, so that the anchor point loss is reduced, and the quality factor of the micromechanical resonator is improved.

Description

Micromechanical resonator

Technical Field

The present application relates to the field of microelectronics, and in particular to micromechanical resonators.

Background

Micro Electro Mechanical Systems (MEMS) is a miniaturized mechanical device or system manufactured based on semiconductor micro-nano processing technology, and has the advantages of small volume, light weight, low power consumption, low price, compatibility with integrated circuit manufacturing process and the like. The micromechanical resonator is a device mainly composed of a micromechanical structure, and the operation mode is that when the resonator is excited by an external physical signal, and the frequency of a driving signal is equal to the natural frequency of a system, the mechanical structure of the system resonates near the natural frequency, the amplitude of the system reaches the maximum, and the generated resonant signal is converted into other physical signals to be output. Since the amplitude of the micromechanical resonator is the largest at the natural frequency, the energy conversion efficiency is the highest, and the mechanical frequency selection of the micromechanical resonator is realized through mechanical vibration. In recent years, oscillators, filters, and duplexers based on micromechanical resonators have been widely used in the field of wireless communication. In addition, in the field of precision detection, the micromechanical resonator also has a wide application market.

The main performance parameters of the micro-mechanical resonator include a resonance frequency, a quality factor (Q value), a dynamic impedance, a frequency temperature coefficient, and the like, wherein a high quality factor is a key parameter for improving the performance of the resonator.

The energy loss mechanism influencing the quality factor of the micromechanical resonator mainly comprises four parts, including air damping loss, thermoelastic loss, material loss and anchor point loss. Wherein the anchor point loss is an energy loss generated by conduction of an elastic wave/acoustic wave from the resonator body to the substrate through the support beam. Dissipation of the acoustic waves through the support beam reduces the energy stored in the resonator, resulting in a reduction in the quality factor of the micromechanical resonator. Therefore, how to reduce the anchor point loss is an important issue in designing the micromechanical resonator.

Disclosure of Invention

The technical problem that this application mainly solved provides a micromechanical resonator, can reduce anchor point loss thereby improves the figure of merit.

In order to solve the technical problem, the application adopts a technical scheme that: provided is a micromechanical resonator including a first resonance unit;

and one end of the second resonance unit is a connecting end connected with the first resonance unit, the other end of the second resonance unit is an anchoring end connected with the substrate, and the rigidity near the connecting end is smaller than that near the anchoring end.

The beneficial effect of this application is: different from the situation of the prior art, the micromechanical resonator comprises a first resonance unit and a second resonance unit, one end of the second resonance unit is a connecting end connected with the first resonance unit, the other end of the second resonance unit is an anchoring end connected with a substrate, and the rigidity near the anchoring end is larger than that near the connecting end. In the process of vibration of the second resonance unit, because the rigidity of the anchoring end of the second resonance unit is higher than that of the connecting end, the displacement of the anchoring end is inhibited, so that the anchor point loss is reduced, and the quality factor of the micromechanical resonator is improved.

Drawings

Figure 1 is a schematic structural view of a first embodiment of a micromechanical resonator according to the present application;

figure 2 is a schematic structural view of a second embodiment of a micromechanical resonator according to the present application;

figure 3 is a schematic structural view of a third embodiment of a micromechanical resonator according to the present application;

fig. 4 is a schematic structural view of a fourth embodiment of a micromechanical resonator according to the present application;

figure 5 is a schematic diagram of the integrated quality factor of the micromechanical resonator of the embodiment of figure 4 as a function of the length and width of the second resonator element;

fig. 6 is a schematic structural diagram of a fifth embodiment of a micromechanical resonator according to the present application;

figure 7 is a schematic structural view of a sixth embodiment of a micromechanical resonator according to the present application;

fig. 8 is a schematic structural diagram of a seventh embodiment of a micromechanical resonator according to the present application;

fig. 9 is a schematic structural diagram of an eighth embodiment of a micromechanical resonator according to the present application;

FIG. 10 is a schematic diagram of the thermoelastic loss quality factor of the micromechanical resonator and the relationship between the length and width of the second resonant cell and the micromechanical resonator in the embodiment of FIG. 9;

FIG. 11 is a schematic diagram of the integrated quality factor of the micromechanical resonator and the relationship between the length and width of the second resonant unit and the micromechanical resonator in the embodiment of FIG. 9;

figure 12 is a schematic structural view of a ninth embodiment of a micromechanical resonator according to the present application;

fig. 13 is a schematic structural diagram of a tenth embodiment of a micromechanical resonator according to the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It should be noted that the terms "first", "second" and "third" in the present application are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of indicated technical features. Thus, a feature defined as "first," "second," or "third" may explicitly or implicitly include at least one of the feature. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless explicitly specifically limited otherwise.

As shown in fig. 1, fig. 1 is a schematic structural diagram of a first embodiment of a micromechanical resonator according to the present application. In the present embodiment, the micromechanical resonator includes a first resonance unit 10 and a second resonance unit 20.

In this embodiment, the first resonant unit 10 may be a rectangle with rounded corners, but in other embodiments, the first resonant unit 10 may also be a circle, an ellipse, a polygon, or other shapes.

During operation of the micromechanical resonator, the first resonator element 10 may oscillate in an extension/compression or breathing mode when induced. In this case, the micromechanical resonator exhibits an elongation/compression-like or respiration-like motion.

The second resonance unit 20 is provided with a structure for suppressing anchor loss, and the second resonance unit 20 includes an anchor end 20a and a connection end 20b. Wherein the anchored end 20a and the connection end 20b are opposite ends of the second resonance unit 20, the connection end 20b is for connection with the outer surface of the first resonance unit 10, and the anchored end 20a is for connection with a substrate (not shown).

Optionally, the micromechanical resonator may further comprise an anchor 30, the anchor 30 being anchored at said anchoring end 20a, the anchoring end 20a being connected to the substrate by the anchor 30.

In the present embodiment, the anchor end 20a of the second resonance unit 20 has a structure that suppresses anchor loss, and specifically, the rigidity of the anchor end 20a is greater than the rigidity of the connection end 20b. In the process of vibrating the first resonance unit 10 and the second resonance unit 20, since the stiffness of the anchored end 20a is greater than that of the connection end 20b, and the deformation amount of the anchored end 20a is smaller than that of the connection end 20b, the displacement near the anchored end 20a is smaller than that of the connection end 20b, and the anchor loss near the anchored end 20a is effectively suppressed, thereby improving the quality factor of the micromechanical resonator.

Specifically, in the present embodiment, the second resonance unit 20 may include a main beam portion 21 and an auxiliary beam portion 22 connected to the main beam portion 21.

Wherein one end of the auxiliary beam portion 22 is connected to the outer surface of the first resonance unit 10, the other end is connected to the auxiliary beam portion 22, and the connection end 20b is provided on the auxiliary beam portion 22. The main beam portion 21 is for connection to a substrate, the anchor end 20a is provided on the main beam portion 21, and the anchor 30 is anchored to the main beam portion 21.

In this embodiment, the cross-sectional area of the main beam portion 21 is larger than the cross-sectional area of the auxiliary beam portion 22, so the material area of the cross-section of the main beam portion 21 is larger than the material area of the cross-section of the auxiliary beam portion 22, the stiffness of the main beam portion 21 is larger than the stiffness of the auxiliary beam portion 22, the stiffness of the main beam portion 21 near the anchor end 20a is larger than the stiffness near the connection end 20b, the anchor point loss near the anchor end 20a is effectively suppressed, and the quality factor of the micromechanical resonator is improved. Here, the cross section of the main beam portion 21 and the cross section of the auxiliary beam portion 22 refer to planes perpendicular to the direction from the main beam portion 21 to the auxiliary beam portion 22.

In this embodiment, the cross-section of the main beam portion 21 and the cross-sectional shape of the auxiliary beam portion 22 are rectangular, the length of the rectangular cross-section of the main beam portion 21 is greater than the length of the rectangular cross-section of the auxiliary beam portion 22, and the width of the rectangular cross-section of the main beam portion 21 is greater than the width of the rectangular cross-section of the auxiliary beam portion 22, so that the area of the rectangular cross-section of the main beam portion 21 is greater than the area of the rectangular cross-section of the auxiliary beam portion 22. In other words, the main beam portion 21 and the auxiliary beam portion 22 in the present embodiment are both rectangular solids, and the main beam portion 21 is thicker than the auxiliary beam portion 22.

In other embodiments, the cross-sectional shape of the main beam portion 21 and the cross-sectional shape of the auxiliary beam portion 22 may also be circular, oval, polygonal, and are not limited herein, as long as the cross-sectional area of the main beam portion 21 is larger than that of the auxiliary beam portion 22 to achieve a greater stiffness of the main beam portion 21 than that of the auxiliary beam portion 22.

Referring to fig. 2, fig. 2 is a schematic structural diagram of a micromechanical resonator according to a second embodiment of the present application. In the present embodiment, the micromechanical resonator includes two first resonance units 10 and two second resonance units 20.

Each second resonator unit 20 comprises an anchored end 20a and a connected end 20b. Wherein the anchored end 20a and the connecting end 20b are opposite ends of the second resonance unit 20, the connecting end 20b is for connecting with an outer surface of one of the first resonance units 10, and the anchored end 20a is for connecting with a substrate. The two anchoring ends 20a are fixedly connected to connect the two second resonance units 20.

In this embodiment, the first resonance unit 10, the second resonance unit 20, and the first resonance unit 10 are sequentially connected and arranged in a straight line. Of course, in other embodiments, the anchoring ends 20a of the two second resonator elements 20 may be connected in other ways.

Optionally, the micromechanical resonator may further comprise two anchors 30, each anchor 30 being anchored at one of the anchoring ends 20a, the anchoring end 20a being connected to the substrate by the anchor 30.

The cross-sectional area of the main beam portion 21 of each second resonance unit 20 is larger than that of the auxiliary beam portion 22, so that the rigidity of the anchored end 20a is larger than that of the connecting end 20b. In the process of vibrating the first resonant unit 10 and the second resonant unit 20, because the rigidity of the anchoring end 20a is greater than that of the connecting end 20b, and the deformation amount of the anchoring end 20a is smaller than that of the connecting end 20b, the displacement near the anchoring end 20a is smaller than that of the connecting end 20b, the anchor point loss near the anchoring end 20a is effectively suppressed, and the quality factor of the micromechanical resonator is further improved.

Referring to fig. 3, fig. 3 is a schematic structural diagram of a micromechanical resonator according to a third embodiment of the present application. In the present embodiment, the micromechanical resonator includes four first resonance units 10 and four second resonance units 20.

In the present embodiment, each second resonator unit 20 includes an anchored end 20a and a connected end 20b. The anchored end 20a and the connection end 20b are opposite ends of the second resonance unit 20, the connection end 20b is for connection with an outer surface of one of the first resonance units 10, and the anchored end 20a is for connection with a substrate. The four anchoring ends 20a are fixedly connected to connect the four second resonance units 20, and to connect the four first resonance units 10 and the four second resonance units 20 together.

In the present embodiment, the anchored end 20a of each second resonance unit 20 has a structure suppressing anchor loss, and the stiffness of the anchored end 20a of each second resonance unit 20 is greater than that of the connection end 20b thereof. In the process of vibrating each first resonant unit 10 and each second resonant unit 20, since the rigidity of the anchoring end 20a is greater than that of the connecting end 20b, and the deformation amount of the anchoring end 20a is smaller than that of the connecting end 20b, the displacement near the anchoring end 20a is smaller than that of the connecting end 20b, the anchor point loss near the anchoring end 20a is effectively suppressed, and the quality factor of the micromechanical resonator is further improved.

The four first resonator elements 10 and the four second resonator elements 20 may be arranged in the manner shown in fig. 3, i.e. each second resonator element 20 is connected together, and each first resonator element 10 is arranged around, or may be arranged in other manners.

As for the structures of the first resonant unit 10 and the second resonant unit 20, reference may be made to the description of the first resonant unit 10 and the second resonant unit 20 in the above embodiments, which is not described herein again.

In further embodiments, the micromechanical resonator may further include three first resonant units 10 and three second resonant units 20, and may also include more first resonant units 10 and second resonant units 20, and the anchoring end 20a of each second resonant unit 20 is fixedly connected, which is not exhaustive here.

Referring to fig. 4, fig. 4 is a schematic structural diagram of a fourth embodiment of a micromechanical resonator according to the present invention. The micromechanical resonator comprises a first resonance unit 10 and a second resonance unit 20.

In the present embodiment, the first resonance unit 10 is a ring-shaped body, and the outer surface of the first resonance unit 10 includes a circular or substantially circular shape having an outer radius of curvature, and the inner surface thereof includes a circular or substantially circular shape having an inner radius of curvature.

Alternatively, the first resonant unit 10 may have a rounded rectangular shape, but in other embodiments, the first resonant unit 10 may have other shapes such as a circle, an ellipse, a polygon, and so on.

The second resonance unit 20 is provided with a structure for suppressing anchor loss, and the second resonance unit 20 includes an anchor end 20a and a connection end 20b. Wherein the anchored end 20a and the connection end 20b are opposite ends of the second resonance unit 20, the connection end 20b is for connection with the outer surface of the first resonance unit 10, and the anchored end 20a is for connection with the substrate.

Optionally, the micromechanical resonator may further comprise an anchor 30, the anchor 30 being anchored at said anchoring end 20a, the anchoring end 20a being connected to the substrate by the anchor 30. The anchor 30 fastens, fixes and/or connects the second resonance unit 20 to the substrate. The second resonator element 20 operates in a bulk-elongated mode or in a flexural mode to manage, control, reduce, eliminate and/or minimize the loading of the micromechanical resonator as a whole. In this manner, in operation, anchor 30 "matches" (or substantially "matches") the extension/compression motion and/or frequency of the toroid, allowing the micromechanical resonator to oscillate or vibrate in its "natural" mode shape and frequency, whereby all portions of the structure may expand/contract with uniform/uniform or substantially uniform/uniform extension or breathing motion.

In the present embodiment, the cross-sectional area of the connecting end 20b to the anchoring end 20a gradually increases, that is, the material area of the cross-section of the second resonant unit 20 from the connecting end 20b gradually increases, so that the rigidity of the connecting end 20b to the anchoring end 20a gradually increases. Therefore, the rigidity of the connecting end 20b is greater than that of the anchoring end 20a. In the process of vibrating the first resonant unit 10 and the second resonant unit 20, because the rigidity of the anchoring end 20a is greater than that of the connecting end 20b, and the deformation amount of the anchoring end 20a is smaller than that of the connecting end 20b, the displacement near the anchoring end 20a is smaller than that of the connecting end 20b, the anchor point loss near the anchoring end 20a is effectively suppressed, and the quality factor of the micromechanical resonator is further improved.

Alternatively, the shape of the second resonator element 20 may be a cone or a half-cone as shown in fig. 4, the connecting end 20b is a head with a smaller cross section of the cone or the half-cone, and the anchoring end 20a is a bottom with a smaller cross section of the cone or the half-cone. The cone or the half cone may be a cone, a pyramid, a half cone, or a half pyramid, and is not limited herein.

Referring to fig. 5, fig. 5 is a schematic diagram illustrating a relationship between a comprehensive quality factor of the micromechanical resonator and a length and a width of the second resonant unit in the embodiment of fig. 4. Where Q is the overall quality factor of the micromechanical resonator, W1 is the width of the anchored end 20a of the second resonator element 20, and L is the length of the second resonator element 20, i.e. the distance from the anchored end 20a to the connection end 20b.

When the second resonance unit 20 has different length values, the comprehensive quality factor Q of the micromechanical resonator increases with the increase of the width W1 of the anchoring end 20a of the second resonance unit 20, the micromechanical resonator has a high comprehensive quality factor Q, and the anchor point loss is significantly reduced.

Referring to fig. 6, fig. 6 is a schematic structural diagram of a fifth embodiment of a micromechanical resonator according to the present application.

The present embodiment is relative to the fourth embodiment, and on the basis of the fourth embodiment, the micromechanical resonator further includes a driving electrode 31 and a sensing electrode 32.

The driving electrode 31 is spaced apart from the outer surface of the first resonant cell 10, and the sensing electrode 32 is spaced apart from the outer surface of the first resonant cell 10.

The driving electrode 31 is provided on an outer surface of the first resonator element 10 to surround the first resonator element 10, and a first gap is provided between the driving electrode 31 and the outer surface of the first resonator element 10. The sensing electrode 32 is disposed inside the first resonant cell 10 and surrounded by the first resonant cell 10 with a second gap between the sensing electrode 32 and the inner surface of the first resonant cell 10. Optionally, the first gap and the second gap are equal in value.

The driving electrode 31 is used to connect with a driving circuit (not shown) to induce the first resonant unit 10 to oscillate or vibrate, wherein the oscillation or vibration has one or more resonant frequencies.

The sensing electrode 32 is adapted to be connected to a sensing circuit (not shown) for sensing, sampling and/or detecting signals having the one or more resonant frequencies.

The drive electrodes 31, sense electrodes 32, drive circuitry, and sense circuitry may be any type and/or shape of electrodes known to those skilled in the art. Physical electrode mechanisms may include, for example, capacitance, piezoresistive, piezoelectric, inductive, magnetoresistive, and thermal.

Referring to fig. 7, fig. 7 is a schematic structural diagram of a sixth embodiment of a micromechanical resonator according to the present application, where the micromechanical resonator includes four first resonant units 10 and four second resonant units 20, as compared to the fourth embodiment.

In the present embodiment, the anchored end 20a of each second resonance unit 20 has a structure suppressing anchor loss, and the stiffness of the anchored end 20a of each second resonance unit 20 is greater than that of the connection end 20b thereof. In the process of vibrating each first resonance unit 10 and each second resonance unit 20, since the stiffness of the anchored end 20a is greater than that of the connection end 20b, and the deformation amount of the anchored end 20a is smaller than that of the connection end 20b, the displacement near the anchored end 20a is smaller than that of the connection end 20b, and the anchor loss near the anchored end 20a is effectively suppressed, thereby improving the quality factor of the micromechanical resonator.

The four first resonator elements 10 and the four second resonator elements 20 may be arranged in the manner shown in fig. 7, i.e. each second resonator element 20 is connected together, and each first resonator element 10 is arranged around, or may be arranged in other manners.

As for the structures of the first resonant unit 10 and the second resonant unit 20, reference may be made to the description of the first resonant unit 10 and the second resonant unit 20 in the fourth embodiment, which is not described herein again.

In further embodiments, the micromechanical resonator may further include two or three first resonant units 10 and two or three second resonant units 20, and may also include more first resonant units 10 and second resonant units 20, and the anchoring end 20a of each second resonant unit 20 is fixedly connected, which is not exhaustive here.

Referring to fig. 8, fig. 8 is a schematic structural diagram of a seventh embodiment of a micromechanical resonator according to the present application. The present embodiment is related to the fifth embodiment in that the micromechanical resonator includes four first resonant cells 10, four second resonant cells 20, four driving electrodes 31, and four sensing electrodes 32.

In the present embodiment, each second resonator unit 20 includes an anchored end 20a and a connected end 20b. The anchored end 20a and the connection end 20b are opposite ends of the second resonance unit 20, the connection end 20b is for connection with an outer surface of one of the first resonance units 10, and the anchored end 20a is for connection with a substrate. The four anchor ends 20a are fixedly connected to connect the four second resonance units 20, and to connect the four first resonance units 10 and the four second resonance units 20 together.

In further embodiments, the micromechanical resonator may further include two or three first resonant units 10, two or three second resonant units 20, a driving electrode 31 and four sensing electrodes 32, or may include more first resonant units 10, two or more second resonant units 20, a driving electrode 31 and four sensing electrodes 32, and the anchoring end 20a of each second resonant unit 20 is fixedly connected, which is not exhaustive here.

Referring to fig. 9, fig. 9 is a schematic structural diagram of an eighth embodiment of a micromechanical resonator according to the present application. In the present embodiment, the micromechanical resonator includes a first resonance unit 10 and a second resonance unit 20.

In the present embodiment, the first resonance unit 10 is a ring-shaped body, and the outer surface of the first resonance unit 10 includes a circular or substantially circular shape having a certain outer radius of curvature, and the inner surface thereof includes a circular or substantially circular shape having an inner radius of curvature.

During operation of the micromechanical resonator, the first resonance unit 10 may oscillate in an extension/compression or breathing mode when induced. In this case, the micromechanical resonator exhibits an elongation/compression-like or respiration-like motion.

The second resonance unit 20 is provided with a structure for suppressing anchor loss, and the second resonance unit 20 includes an anchor end 20a and a connection end 20b. Wherein the anchored end 20a and the connection end 20b are opposite ends of the second resonance unit 20, the connection end 20b is for connection with the outer surface of the first resonance unit 10, and the anchored end 20a is for connection with the substrate. The second resonator element 20 may be shaped as a cylinder of equal width.

Optionally, the micromechanical resonator may further comprise an anchor 30, the anchor 30 being anchored at said anchoring end 20a, the anchoring end 20a being connected to the substrate by the anchor 30. The anchor 30 fastens, fixes and/or connects the second resonance unit 20 to the substrate. The second resonator element 20 operates in a bulk-elongated mode or in a flexural mode to manage, control, reduce, eliminate and/or minimize the loading of the micromechanical resonator as a whole. In this manner, in operation, anchors 30 "match" (or substantially "match") the elongation/compression motion and/or frequency of the toroid, allowing the micromechanical resonator to oscillate or vibrate in its "natural" mode shape and frequency, whereby all portions of the structure may expand/contract in a uniform/uniform or substantially uniform/uniform elongation or breathing motion.

In this embodiment, the second resonant unit 20 is provided with a first slot 201 and a second slot 202. Wherein the first recess 201 is closer to the first resonator element 10 than the second recess 202, and the second recess 202 is closer to the second resonator element 20 than the first recess 201. That is, the first cutout 201 is closer to the connecting end 20b than the second cutout 202, and the second cutout 202 is closer to the anchoring end 20a than the first cutout 201.

Wherein the volume of the second recess 202 is larger than the volume of the first recess 201, so that the density of the second recess 202 in the second resonator element 20 is higher than the density of the first recess 201 in the second resonator element 20. The second cutout 202 is closer to the second resonance unit 20 than the first cutout 201, and therefore the rigidity of the anchor end 20a is greater than the rigidity of the connection end 20b, and during vibration of the second resonance unit 20, the deformation amount of the anchor end 20a is smaller, which is equivalent to the deformation amount of the connection end 20b, and the displacement near the anchor end 20a is smaller than the displacement of the connection end 20b, and the anchor loss near the anchor end 20a is effectively suppressed, thereby improving the quality factor of the micromechanical resonator.

Alternatively, the first cutout 201 and/or the second cutout 202 may have a hollow groove shape, a through hole shape communicating both sides of the second resonance unit 20, a non-communicating blind hole shape, a stepped hole shape having a certain gradient, a screw thread shape having a screw thread, or the like, as long as the first cutout 201 and the second cutout 202 are provided such that the rigidity of the anchoring end 20a is greater than that of the connection end 20b.

Therefore, in the present embodiment, the second resonant unit 20 is provided with the grooves, so as to change the rigidity of the second resonant unit 20 at different positions, thereby improving the quality factor of the micromechanical resonator.

Referring to fig. 10, fig. 10 is a schematic diagram illustrating the relationship between the thermoelastic loss quality factor of the micromechanical resonator and the length and width of the second resonant unit and the micromechanical resonator in the embodiment of fig. 9. Where QTED is the thermoelastic loss quality factor of the micromechanical resonator, W is the width of the second resonant cell 20, and L is the length of the second resonant cell 20, i.e. the distance from the anchored end 20a to the connected end 20b.

When the lengths L of the second resonant units 20 are different values, assuming that the first slot 201 is infinitely close to the connection end 20b of the second resonant unit 20, and the second slot 202 is infinitely close to the connection end 20b of the second resonant unit 20, at this time, the energy loss caused by thermoelastic damping (TED) is minimum, and the thermoelastic loss quality factor QTED value of the micromechanical resonator is maximum. For example, when the length L of the second resonant unit 20 is 47um and the width thereof is 25um, the first slot 201 is infinitely close to the connection end 20b of the second resonant unit 20, and the second slot 202 is infinitely close to the connection end 20b of the second resonant unit 20, the thermoelastic damping quality factor QTED of the micromechanical resonator is 2.34E06. The micromechanical resonator has a high quality factor and the anchor point loss is significantly reduced.

Referring to fig. 11, fig. 11 is a schematic diagram illustrating a relationship between an overall quality factor of the micro-mechanical resonator and a length and a width of the second resonant unit and the micro-mechanical resonator in the embodiment of fig. 9. Where Q is the overall quality factor of the micromechanical resonator, W is the width of the second resonant cell 20, and L is the length of the second resonant cell 20, i.e. the distance from the anchored end 20a to the connected end 20b.

When the lengths L of the second resonance units 20 are different values, it is assumed that the first slot 201 is infinitely close to the connection end 20b of the second resonance unit 20, and the second slot 202 is infinitely close to the connection end 20b of the second resonance unit 20, at this time, the overall quality factor Q of the micromechanical resonator is maximum. For example, when the length L of the second resonant unit 20 is 45um and the width thereof is 25um, the first groove 201 is infinitely close to the connection end 20b of the second resonant unit 20, and the second groove 202 is infinitely close to the connection end 20b of the second resonant unit 20, the overall quality factor Q of the micromechanical resonator is 7.47E06. The micromechanical resonator has a high quality factor and the anchor point loss is significantly reduced.

Referring to fig. 12, fig. 12 is a schematic structural diagram of a ninth embodiment of a micromechanical resonator according to the present application.

This embodiment is relative to the eighth embodiment, and on the basis of the eighth embodiment, the micromechanical resonator further includes a driving electrode 31 and a sensing electrode 32.

The driving electrode 31 is provided on an outer surface of the first resonator element 10 to surround the first resonator element 10, and a first gap is provided between the driving electrode 31 and the outer surface of the first resonator element 10. The sensing electrode 32 is disposed inside the first resonant cell 10 and surrounded by the first resonant cell 10, and a second gap is formed between the sensing electrode 32 and the inner surface of the first resonant cell 10. Optionally, the first gap and the second gap are equal in value.

Referring to fig. 13, fig. 13 is a schematic structural diagram of a tenth embodiment of a micromechanical resonator according to the present application.

The present embodiment is related to the eighth embodiment in that the micromechanical resonator includes three first resonance units 10 and three second resonance units 20.

In the present embodiment, each second resonator unit 20 includes an anchored end 20a and a connected end 20b. The anchored end 20a and the connection end 20b are opposite ends of the second resonance unit 20, the connection end 20b is for connection with an outer surface of one of the first resonance units 10, and the anchored end 20a is for connection with a substrate. The three anchoring ends 20a are fixedly connected to connect the three second resonance units 20, and to connect the three first resonance units 10 and the four second resonance units 20 together.

In the present embodiment, the anchoring end 20a of each second resonant unit 20 has a structure for suppressing the anchor loss, and the second resonant unit 20 is provided with a first cutout 201 and a second cutout 202. Wherein the first cutout 201 is closer to the first resonator element 10 than the second cutout 202, so that the stiffness of the anchored end 20a of each second resonator element 20 is greater than the stiffness of the connected end 20b thereof. In the process of vibrating each first resonant unit 10 and each second resonant unit 20, since the rigidity of the anchoring end 20a is greater than that of the connecting end 20b, and the deformation amount of the anchoring end 20a is smaller than that of the connecting end 20b, the displacement near the anchoring end 20a is smaller than that of the connecting end 20b, the anchor point loss near the anchoring end 20a is effectively suppressed, and the quality factor of the micromechanical resonator is further improved.

In other embodiments, the micromechanical resonator may further include two or more first resonance units 10 and two or more second resonance units 20, and the anchoring end 20a of each second resonance unit 20 is fixedly connected, which is not exhaustive here.

In summary, the anchoring end of the second resonant unit in the embodiment of the micromechanical resonator provided by the present application has a relatively high stiffness, the anchor point loss near the anchoring end is effectively suppressed, and the micromechanical resonator has a relatively high quality factor.

The resonant cells of the present application can be fabricated from known materials using known techniques. For example, the resonant cell may be made of a well-known semiconductor, such as silicon, germanium, silicon germanium, or gallium arsenide. In practice, the resonant cells may be made of materials such as those in column IV of the periodic table, e.g. silicon, germanium, carbon; also combinations of these, such as silicon germanium or silicon carbide; also III-V compounds, such as gallium phosphide, aluminum gallium phosphide or other III-V combinations; combinations of III, IV, V, or VI materials, such as silicon nitride, silicon oxide, aluminum carbide, aluminum nitride, and/or aluminum oxide; also metal silicides, germanides and carbides, such as nickel silicide, cobalt silicide, tungsten carbide or platinum germanium silicide; also doped variants including phosphorus, arsenic, antimony, boron or aluminum doped silicon or germanium, carbon or combinations such as silicon germanium; there are also such materials having various crystalline structures, including single crystal, polycrystalline, nanocrystalline or amorphous; but also a combination of crystal structures, such as regions having single crystal and polycrystalline structures (whether doped or undoped).

Furthermore, the resonant cells according to the present application may be formed in or on a semiconductor-on-insulator (SOI) substrate using well-known photolithography, etching, deposition and/or doping techniques. For the sake of brevity, such fabrication techniques are not discussed herein. However, all techniques for forming or fabricating the resonant cell structures of the present application, whether now known or later developed, are intended to fall within the scope of the present application (e.g., well-known forming, photolithography, etching, and/or deposition techniques and/or bonding techniques using standard or oversized ("thick") wafers (not shown) (i.e., two standard wafers are bonded together, where the lower/bottom wafer includes a sacrificial layer (e.g., silicon oxide) disposed thereon, and the upper/top wafer is thereafter thinned (down or back ground) and polished to receive mechanical structures therein or thereon).

The above description is only an example of the present application and is not intended to limit the scope of the present application, and all modifications of equivalent structures and equivalent processes, which are made by the contents of the specification and the drawings, or which are directly or indirectly applied to other related technical fields, are intended to be included within the scope of the present application.

Claims

1. A micromechanical resonator, comprising:

a first resonance unit;

and one end of the second resonance unit is a connecting end connected with the first resonance unit, the other end of the second resonance unit is an anchoring end connected with the substrate, and the rigidity near the anchoring end is greater than that near the connecting end.

2. The micromechanical resonator according to claim 1,

the second resonance unit include main roof beam portion and with the auxiliary beam portion that main roof beam portion is connected, the anchor end is located main roof beam portion, the link is located auxiliary beam portion, the cross sectional area of main roof beam portion is greater than auxiliary beam portion's cross sectional area.

3. The micromechanical resonator according to claim 2,

the main beam part cross section with the cross section of assisting the roof beam part is the rectangle, the cross section length width of main beam part is greater than the length width of assisting roof beam part cross section.

4. The micromechanical resonator of claim 1,

the cross-sectional area from the connecting end to the anchoring end is gradually increased.

5. The micromechanical resonator of claim 4,

the second resonance unit is in the shape of a cone or a half cone.

6. The micromechanical resonator of claim 1,

the second resonance unit is provided with a first digging groove and a second digging groove, the first digging groove is closer to the first resonance unit relative to the second digging groove, and the volume of the second digging groove is larger than that of the first digging groove.

7. The micromechanical resonator according to claim 6,

the first digging groove and/or the second digging groove are/is in the shape of a hollow groove, a through hole, a blind hole, a step hole or a thread.

8. The micromechanical resonator of claim 1,

the micromechanical resonator further comprises an anchor anchored at the anchoring end, the anchor for connection with the substrate.

9. The micromechanical resonator of claim 1,

the resonance type resonance circuit further comprises a driving electrode and a sensing electrode, wherein the driving electrode and the outer surface of the first resonance unit are arranged at intervals, and the sensing electrode and the inner surface of the first resonance unit are arranged at intervals.

10. The micromechanical resonator according to any of claims 1-9,

the number of the first resonance units and the second resonance units is multiple, the connecting end of each second resonance unit is respectively connected with the corresponding first resonance unit, and the anchoring ends of the second resonance units are fixedly connected with each other and connected with the substrate together.