CN218217327U

CN218217327U - Micro-electromechanical system resonator

Info

Publication number: CN218217327U
Application number: CN202222656334.7U
Authority: CN
Inventors: 雷永庆; 吴振云; 李轩
Original assignee: Mestar Microelectronics Shenzhen Co ltd
Current assignee: Mestar Microelectronics Shenzhen Co ltd
Priority date: 2022-10-08
Filing date: 2022-10-08
Publication date: 2023-01-03
Anticipated expiration: 2032-10-08

Abstract

The utility model discloses a micro-electromechanical system syntonizer relates to micro-electromechanical system technical field. The micro electro mechanical system resonator comprises a harmonic oscillator and a coupling beam; one end of the coupling beam is fixedly connected with the harmonic oscillator, and the other end of the coupling beam is used for being connected with the anchoring body; the harmonic oscillator is used for twisting around the extension direction of the coupling beam in a first driving mode and driving the coupling beam to twist; the harmonic oscillator is also used for at least partially radially extending and contracting in the second driving mode and driving the coupling beam to extend and contract. The MEMS resonator can output two frequencies, namely one frequency as an operating frequency and one frequency as a function of temperature. A structure achieves two functions, can be used as a working frequency output resonator, can also be used as a temperature sensitive sensor, thereby consuming less power and/or reducing the space occupancy rate, and can provide a more accurate temperature measurement result to be used as a reference for generating a temperature compensated frequency signal when being used as the temperature sensitive sensor.

Description

Micro-electromechanical system resonator

Technical Field

The utility model relates to a micro-electromechanical system technical field especially relates to a micro-electromechanical system syntonizer.

Background

Micro Electro Mechanical Systems (MEMS), also called Micro Electro Mechanical systems, microsystems, micromachines, etc., refer to high-tech devices with dimensions of a few millimeters or even smaller.

With the continuous development and progress of micromachining technology, micro-electromechanical system resonators (MEMS resonators) are being used in a large number of applications. The MEMS resonator has advantages of small size, low power consumption, low cost, compatibility with CMOS IC (Complementary Metal Oxide Semiconductor Integrated Circuit) process, etc., and the demand in the field of wireless communication, etc. is increasing day by day, and it will become a substitute for crystal resonator.

Mems resonators are subject to frequency deviations caused by several phenomena including temperature variations. Silicon mems resonators do not have a specific cut (cut) that reduces temperature sensitivity. Therefore, the roll over temperature is not easily controlled. In addition, the resonant frequency of silicon resonators is strongly temperature dependent (negative slope of about-30 ppm/deg.C) due to the highly negative Temperature Coefficient of Elasticity (TCE) of silicon. This slope is commonly referred to as the Temperature Coefficient of Frequency (TCF).

The temperature compensation method adopted by the existing mems resonator is to add an external circuit to the mems resonator to measure the temperature, which consumes more power and occupies more space, and it is not always possible to have an accurate temperature measurement result for compensating the frequency deviation caused by the temperature.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a micro-electromechanical system syntonizer, it can enough regard as operating frequency output syntonizer, can regard as the temperature sensitive sensor to use again, when reducing consumption and space occupancy, provides more accurate temperature measurement result as the reference of temperature compensation's frequency signal.

In order to achieve the above object, the present invention provides a mems resonator, which includes a harmonic oscillator; one end of the coupling beam is fixedly connected with the harmonic oscillator, and the other end of the coupling beam is used for being connected with the anchoring body; the harmonic oscillator is used for twisting around the extension direction of the coupling beam in a first driving mode and driving the coupling beam to twist; the harmonic oscillator is also used for at least partially radially extending and contracting in a second driving mode and driving the coupling beam to extend and contract.

Optionally, the harmonic oscillator is annular, and the coupling beam extends along a radial direction of the harmonic oscillator.

Optionally, the mems resonator includes two coupling beams, the two coupling beams are coaxially disposed, and the two coupling beams are disposed on two sides of the harmonic oscillator, respectively.

Optionally, the mems resonator further includes an out-of-plane driving electrode, an in-plane driving electrode, an out-of-plane sensing electrode, and an in-plane sensing electrode, where the out-of-plane sensing electrode, the resonator, and the out-of-plane driving electrode are sequentially stacked; the in-plane driving electrode is arranged on the outer side of the ring of the harmonic oscillator, the in-plane sensing electrode is arranged on the inner side of the ring of the harmonic oscillator, and the in-plane driving electrode extends along the circumferential direction of the harmonic oscillator.

Optionally, a first gap is disposed between the out-of-plane driving electrode and the harmonic oscillator, and a second gap is disposed between the out-of-plane sensing electrode and the harmonic oscillator.

Optionally, the first gap and the second gap are equal in value.

Optionally, the out-of-plane driving electrode includes two sub-driving electrodes arranged side by side, and a third gap is provided between the two sub-driving electrodes.

Optionally, an extending direction of the third gap is parallel to an extending direction of the coupling beam, and a projection of the third gap in the thickness direction of the resonator is coaxially arranged with a projection of the coupling beam in the thickness direction of the resonator; and/or the out-of-plane sensing electrode comprises two sub sensing electrodes arranged side by side, and a fourth gap is arranged between the two sub sensing electrodes; the extending direction of the fourth gap is parallel to the extending direction of the coupling beam, and the projection of the fourth gap along the thickness direction of the harmonic oscillator is coaxial with the projection of the coupling beam along the thickness direction of the harmonic oscillator.

Optionally, a fifth gap is disposed between the in-plane sensing electrode and the inner side surface of the resonator, and a sixth gap is disposed between the in-plane driving electrode and the outer side surface of the resonator.

Optionally, the fifth gap and the sixth gap have the same value.

The micro-electro-mechanical system resonator provided by the application can realize two vibration modes by the same structure, and can output two frequencies, wherein one frequency is output as a working frequency and the other frequency is output as a temperature function. One structure performs two functions, both as an operating frequency output resonator and as a temperature sensitive sensor, thereby consuming less power and/or reducing space occupancy, thus resulting in power and/or space economy. Meanwhile, when the temperature sensor is used as a temperature sensitive sensor, a more accurate temperature measurement result can be provided to be used as a reference for generating a temperature compensated frequency signal.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the prior art descriptions will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

Fig. 1 is a schematic diagram of an embodiment of a mems resonator according to the present invention.

Fig. 2 is a schematic diagram of another embodiment of a mems resonator according to the present invention.

Fig. 3 is a perspective view of another embodiment of the mems resonator of the present invention.

Fig. 4 is an exploded view of another embodiment of the mems resonator of the present invention.

Fig. 5 is a schematic diagram illustrating a torsional mode simulation according to an embodiment of the resonator of the present invention.

Fig. 6 is a schematic diagram illustrating simulation of a stretching mode according to an embodiment of the present invention.

The reference numbers illustrate:

reference numerals	Name (R)	Reference numerals	Name (R)
				100	Harmonic oscillator	200	Coupling beam
300	Anchoring body	410	Out-of-plane drive electrode
				411	First gap	412	Third gap
420	In-plane drive electrode	421	Sixth gap
				510	Out-of-plane sensing electrode	511	Second gap
512	Fourth gap	520	In-plane sensing electrode
				521	Fifth gap

The realization, the functional characteristics and the advantages of the utility model are further explained by combining the embodiment and referring to the attached drawings.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by a person skilled in the art without making creative efforts belong to the protection scope of the present invention.

It should be noted that, if directional indications (such as up, down, left, right, front, and back … …) are involved in the embodiment of the present invention, the directional indications are only used to explain the relative position relationship between the components, the motion situation, and the like in a specific posture, and if the specific posture is changed, the directional indications are changed accordingly.

In addition, if there is a description relating to "first", "second", etc. in the embodiments of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, if the meaning of "and/or" and/or "appears throughout, the meaning includes three parallel schemes, for example," A and/or B "includes scheme A, or scheme B, or a scheme satisfying both schemes A and B. In addition, the technical solutions in the embodiments may be combined with each other, but it must be based on the realization of those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should not be considered to exist, and is not within the protection scope of the present invention.

Example one

Referring to fig. 1, a mems resonator includes a resonator element 100, a coupling beam 200, and an anchor 300. The harmonic oscillator 100 is annular, and may be a rectangular ring, a circular ring, an elliptical ring, or the like.

The coupling beam 200 should have a certain elasticity, and the number thereof is one. One end of the coupling beam 200 is fixedly connected with the outer side surface of the harmonic oscillator 100. The other end of the coupling beam 200 may be fixedly connected with an anchor 300. The anchor 300 is used to fixedly connect to a substrate (wafer).

In the first driving mode, the resonator 100 uses the coupling beam 200 as a rotation axis, and the resonator 100 twists around the extending direction of the coupling beam 200 and drives the coupling beam 200 to twist.

In the second driving mode, the resonator 100 at least partially radially expands and contracts and drives the coupling beam 200 to expand and contract, that is, the resonator 100 oscillates in the expansion/compression or breathing mode (or in the primary or substantially expansion/compression or breathing mode), and at the same time, the coupling beam 200 oscillates along with the expansion/compression or breathing mode (or in the primary or substantially expansion/compression or breathing mode) of the resonator 100.

In the first driving mode, the resonator 100 is twisted with the coupling beam 200 as the rotation axis, so that the torsional mode of the resonator 100 has small thermoelastic damping, thereby improving the quality factor value (Q value) of the mems resonator. The torsional mode of the resonator of the micro-electro-mechanical system is insensitive to temperature and is used as a normal mode output frequency. The mems resonator is then present as a resonator that outputs the operating frequency.

In the second driving mode, the resonator 100 oscillates in an elongation/compression or breathing mode (or in a primary or substantially elongation/compression or breathing mode), and at the same time, the coupling beam 200 oscillates in an elongation/compression or breathing mode (or in a primary or substantially elongation/compression or breathing mode) with the resonator 100. In such a mode, the resonant frequency of the resonator of the micro electro mechanical system is a function of temperature and is sensitive to temperature, and when the external temperature changes slowly, the resonant frequency and the frequency change of the resonator of the micro electro mechanical system can accurately reflect the temperature and the temperature change condition in real time and monitor the temperature in real time, so that the resonator of the micro electro mechanical system can be used as a temperature sensitive sensor. Of course, the mems resonator as a temperature sensitive sensor can be combined with a circuit in the control chip to output a digital signal, which is convenient for signal processing.

The micro-electro-mechanical system resonator can realize two vibration modes by the same structure, and can output two frequencies, wherein one frequency is used as working frequency output and the other frequency is used as temperature function frequency. One structure performs two functions, both as an operating frequency output resonator and as a temperature sensitive sensor, thereby consuming less power and/or reducing space occupancy, thus resulting in power and/or space economy. Meanwhile, when the temperature sensor is used as a temperature sensitive sensor, a more accurate temperature measurement result can be provided to be used as a reference for generating a temperature compensated frequency signal.

Example two

On the basis of the structure of the above embodiment, the structure of the mems resonator is further improved, wherein the number of the coupling beams 200 is two, the two coupling beams 200 are symmetrically arranged with respect to the resonator 100, and the two coupling beams 200 are coaxial. One end of each of the coupling beams 200 is fixedly connected to the outer side surface of the resonator 100, and the other ends of the two coupling beams 200 may be collectively and fixedly connected to an anchor 300, or the other ends of the two coupling beams 200 are also fixedly connected to an anchor 300, respectively, and the anchor 300 is used for being fixedly connected to a substrate (wafer), as shown in fig. 2.

In the first driving mode, the resonator 100 is twisted with the two coupling beams 200 serving as a rotation axis together, so as to ensure stability of the twist.

The two coupling beams 200 improve the connection stability of the resonator 100, and the two coupling beams 200 are coaxially arranged, so that the resonator 100 can smoothly twist around the extension direction of the coupling beams 200, that is, when being induced, the resonator 100 twists with the two coupling beams 200 as a common rotation axis.

EXAMPLE III

Based on the structure of the second embodiment, the structure of the mems resonator is further improved, as shown in fig. 3 and 4, the mems resonator further includes an out-of-plane driving electrode 410, an in-plane driving electrode 420, an out-of-plane sensing electrode 510, and an in-plane sensing electrode 520.

The out-of-plane sensing electrode 510, the harmonic oscillator 100 and the out-of-plane driving electrode 410 are sequentially stacked. The out-of-plane driving electrode 410 is located above the resonator 100, the out-of-plane sensing electrode 510 is located below the resonator 100, and the out-of-plane driving electrode 410 and the out-of-plane sensing electrode 510 are vertically opposite to each other.

A first gap 411 is left between the out-of-plane driving electrode 410 and the top surface of the resonator 100, and a second gap 511 is left between the out-of-plane sensing electrode 510 and the bottom surface of the resonator 100. Preferably, the first gap 411 and the second gap 511 are equal in value. The first gap 411 and the second gap 511 have the same value, which is beneficial to unifying the processing parameters so as to improve the manufacturing efficiency.

In addition, referring to fig. 3, the out-of-plane driving electrode 410 includes two sub-driving electrodes arranged side by side, and a third gap 412 is formed between the two sub-driving electrodes, which is beneficial to further increase the driving efficiency.

The extending direction of the third gap 412 is parallel to the extending direction of the coupling beam 200, and the projection of the third gap 412 in the thickness direction of the resonator 100 is coaxial with the projection of the coupling beam 200 in the thickness direction of the resonator 100, which is favorable for further improving the driving efficiency; and/or the out-of-plane sensing electrode 510 includes two sub-sensing electrodes arranged side by side, and a fourth gap 512 is arranged between the two sub-sensing electrodes, which is beneficial to improving the sensing efficiency; the extending direction of the fourth gap 512 is parallel to the extending direction of the coupling beam 200, and the projection of the fourth gap 512 in the thickness direction of the resonator 100 is coaxial with the projection of the coupling beam 200 in the thickness direction of the resonator 100, so as to further improve the sensing efficiency.

The in-plane sensing electrode 520 is located inside the resonator 100, and a fifth gap 521 is left between the in-plane sensing electrode and the inner surface of the resonator 100; the in-plane driving electrode 420 is located outside the resonator 100 with a sixth gap 421 from the outer surface of the resonator 100. Preferably, the fifth gap 521 and the sixth gap 421 are equal in value. The fifth gap 521 and the sixth gap 421 have the same value, which is beneficial for processing by uniform processing parameters, and improves the overall manufacturing efficiency of the mems resonator.

The out-of-plane drive electrodes 410 are connected to an out-of-plane drive circuit (not shown) to induce oscillation or vibration of the harmonic oscillator 100, wherein the oscillation or vibration has one or more resonant frequencies.

The out-of-plane sense electrodes 510 are connected to out-of-plane sense circuitry (not shown) to sense, sample, and/or detect signals having the one or more resonant frequencies.

The in-plane drive electrode 420 is coupled to an in-plane drive circuit (not shown) to induce oscillation or vibration of the resonator 100, wherein the oscillation or vibration has one or more resonant frequencies.

In-plane sense electrodes 520 are connected to in-plane sense circuitry (not shown) to sense, sample and/or detect signals having the one or more resonant frequencies.

The drive and sense electrodes, drive circuitry, and sense circuitry described above may be of conventional well-known types, or may be of any type and/or shape now known or later developed. Further, physical electrode mechanisms may include, for example, capacitance, piezoresistive, piezoelectric, inductive, magnetoresistive, and the like.

Referring to fig. 5, in the first driving mode, after the out-of-plane driving electrode 410 is powered, a DC and/or AC voltage is applied between the resonator 100 and the out-of-plane driving electrode 410, so that the resonator 100 twists around the coupling beam 200 as a rotation axis and drives the coupling beam 200 to twist, for example, along the direction M in fig. 5, where the dark part is a twisted entity. In this case, the coupling beam 200 may be configured to have a certain elasticity around the extending direction, i.e. the coupling beam 200 has a better torsion resistance.

As the resonator 100 is twisted, the value of the gap between the out-of-plane sensing electrode 510 and the resonator 100 is changed, and thus the average capacitance between the out-of-plane sensing electrode 510 and the resonator 100 is changed at a substantially constant frequency, improving the linearity of the capacitance, so that the out-of-plane sensing electrode 510 can measure the capacitance and then the resulting signal can be used to generate a timing signal.

The torsional mode of the resonator 100 has small thermoelastic damping, so that the Q value of the mems resonator can be increased. The torsional mode of the resonator of the micro-electro-mechanical system is insensitive to temperature and is used as a normal mode output frequency. The mems resonator is then present as a resonator that outputs the operating frequency.

The out-of-plane driving electrode 410 and the out-of-plane sensing electrode 510 realize that the harmonic oscillator 100 twists around the extension direction of the coupling beam 200 and drives the coupling beam 200 to twist; the out-of-plane driving electrode 410, the harmonic oscillator 100 and the out-of-plane sensing electrode 510 are sequentially stacked, so that the compactness of the resonator of the micro electro mechanical system is improved.

As shown in fig. 6, in the second driving mode, after the in-plane driving electrode 420 is powered, a DC and/or AC voltage is applied between the resonator 100 and the in-plane driving electrode 420, so that the resonator 100 at least partially radially expands and contracts and drives the coupling beam 200 to expand and contract, see the expansion and contraction along the R direction shown in fig. 6. That is, the harmonic oscillator 100 oscillates in an elongation/compression or breathing mode (or in a primary or substantially elongation/compression or breathing mode), while the coupling beam 200 oscillates in an elongation/compression or breathing mode (or in a primary or substantially elongation/compression or breathing mode) of the harmonic oscillator 100. As the resonator 100 oscillates, the value of the gap between the in-plane sensing electrode 520 and the resonator 100 is changed, and thus the average capacitance between the sensing electrode 5 and the resonator 100 is changed at a substantially constant frequency, which improves the linearity of the capacitance, so that the in-plane sensing electrode 520 can measure the capacitance, and then the resulting signal can be used to generate a timing signal.

In the second drive mode, the resonant frequency of the mems resonator is a function of temperature and is sensitive to temperature. When the external temperature changes slowly, the resonance frequency and the frequency change of the resonator of the micro electro mechanical system can accurately reflect the temperature and the temperature change condition in real time and monitor the temperature in real time, so that the resonator of the micro electro mechanical system can be used as a temperature sensitive sensor. Of course, the mems resonator as a temperature sensitive sensor can be combined with a circuit in the control chip to output a digital signal, which is convenient for signal processing.

The mems resonators of the present application may be fabricated from known materials using known techniques. For example, the mems resonator may be made of a well-known semiconductor such as silicon, germanium, silicon germanium, or gallium arsenide. Indeed, the mems resonator may be composed 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 mems resonator may be formed in or on a semiconductor-on-insulator (SOI) substrate using well-known photolithography, etching, deposition and/or doping techniques, such that the resonator 100, the coupling beam 200, and the anchor 300 are integrally formed. For the sake of brevity, such fabrication techniques are not discussed herein. However, all techniques, whether now known or later developed, for forming or fabricating the mems resonator structures of the present application 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, with a lower/bottom wafer including a sacrificial layer (e.g., silicon oxide) disposed thereon, and an upper/top wafer thereafter thinned (down or back ground) and polished to receive mechanical structures therein or thereon).

Claims

1. A mems resonator, comprising:

a harmonic oscillator;

one end of the coupling beam is fixedly connected with the harmonic oscillator, and the other end of the coupling beam is used for being connected with the anchoring body;

the harmonic oscillator is used for twisting around the extension direction of the coupling beam in a first driving mode and driving the coupling beam to twist; the harmonic oscillator is also used for at least partially radially extending and contracting in a second driving mode and driving the coupling beam to extend and contract.

2. The mems resonator of claim 1 wherein the resonator is ring-shaped, and the coupling beam extends in a radial direction of the resonator.

3. The mems resonator of claim 1, wherein the mems resonator comprises two coupling beams, the two coupling beams being coaxially disposed, the two coupling beams being disposed on opposite sides of the resonator, respectively.

4. The mems resonator of any one of claims 1 to 3, further comprising an out-of-plane drive electrode, an in-plane drive electrode, an out-of-plane sense electrode, and an in-plane sense electrode, wherein the out-of-plane sense electrode, the resonator, and the out-of-plane drive electrode are sequentially stacked; the in-plane driving electrode is arranged on the outer side of the ring of the harmonic oscillator, the in-plane sensing electrode is arranged on the inner side of the ring of the harmonic oscillator, and the in-plane driving electrode extends along the circumferential direction of the harmonic oscillator.

5. The mems resonator of claim 4 wherein a first gap is provided between the out-of-plane drive electrode and the resonator and a second gap is provided between the out-of-plane sense electrode and the resonator.

6. The mems resonator of claim 5 wherein the first gap and the second gap are equal in value.

7. The mems resonator of claim 5 wherein the out-of-plane drive electrode comprises two sub-drive electrodes disposed side-by-side with a third gap disposed therebetween.

8. The mems resonator of claim 7, wherein the third gap extends in parallel with the coupling beam, and a projection of the third gap in the thickness direction of the resonator is coaxial with a projection of the coupling beam in the thickness direction of the resonator; and/or the out-of-plane sensing electrode comprises two sub sensing electrodes arranged side by side, and a fourth gap is arranged between the two sub sensing electrodes; the extending direction of the fourth gap is parallel to the extending direction of the coupling beam, and the projection of the fourth gap along the thickness direction of the harmonic oscillator is coaxial with the projection of the coupling beam along the thickness direction of the harmonic oscillator.

9. The mems resonator of claim 8 wherein a fifth gap is provided between the in-plane sensing electrode and the inner side of the resonator and a sixth gap is provided between the in-plane driving electrode and the outer side of the resonator.

10. The mems resonator of claim 9 wherein the fifth gap and the sixth gap are equal in value.