Mems resonator and mems resonator array

Abstract

The application provides a MEMS resonator and a MEMS resonator array. The MEMS resonator comprises a vibration unit, a coupling energy storage unit, an anchor point and a first electrode. The vibration unit is used for generating resonance. The coupling energy storage unit is coupled with the vibration unit and is a high-Q vibration mode. The anchor point fixes the coupling energy storage unit on a substrate. The first electrode is arranged adjacent to the vibration unit and has a gap between the vibration unit. The application sets the coupling energy storage unit in the MEMS resonator. On the one hand, the coupling energy storage unit is equivalent to introducing other high-Q bulk mode vibration structures on the basis of the existing vibration unit, so as to improve the resonance Q value of the whole MEMS resonator. On the other hand, the coupling energy storage unit is coupled with the vibration unit, the coupling area is increased, the coupling efficiency is improved, and the resonance Q value is further improved. In addition, the coupling area of the coupling energy storage unit and the vibration unit can be increased, which is also beneficial to improve the coupling efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of MEMS (Microelectro Mechanical Systems), and in particular to a MEMS resonator and a MEMS resonator array. BACKGROUND

[0002] MEMS resonators are used to generate clock signals, and are widely used in circuit systems to provide time references and frequency references due to their small size, low failure rate, and good compatibility with integrated circuit manufacturing processes. In existing MEMS resonators, the vibration units of different resonators are coupled and connected by long strip-shaped structural members such as rods or beams. However, in this coupling and connection mode, the coupling area between the long strip-shaped structural members such as rods or beams and the vibration units is small, resulting in a small coupling area between the vibration units of different resonators, which leads to a low coupling efficiency and thus a low resonant Q value (quality factor). SUMMARY

[0003] In view of this, the embodiments of the present application provide a MEMS resonator and a MEMS resonator array, which can improve the problem of low resonant Q value caused by the coupling and connection mode between the vibration units of different resonators.

[0004] The MEMS resonator provided by the embodiments of the present application comprises:

[0005] a vibration unit, configured to generate resonance;

[0006] a coupling energy storage unit, coupled and connected with the vibration unit and being a high-Q vibration mode;

[0007] an anchor point, configured to fix the coupling energy storage unit on a substrate;

[0008] a first electrode, disposed adjacent to the vibration unit and having a gap between the vibration unit and the first electrode.

[0009] Optionally, the vibration unit is in a ring structure.

[0010] Optionally, the coupling energy storage unit is made of a flexible material.

[0011] Optionally, the coupling energy storage unit is in a phonon via structure.

[0012] Optionally, the coupling energy storage unit is in a rectangular shape along a line of sight direction perpendicular to the substrate.

[0013] Optionally, the vibration mode of the coupling energy storage unit in the rectangular shape is a lame mode.

[0014] Optionally, the coupling energy storage unit is circular in a direction perpendicular to a line of sight of the substrate.

[0015] Optionally, a vibration mode of the coupling energy storage unit is a WG mode.

[0016] Optionally, the MEMS resonator further comprises a second electrode, which is disposed adjacent to the coupling energy storage unit and has a gap between the coupling energy storage unit.

[0017] The MEMS resonator array provided by the embodiments of the present application comprises a plurality of the MEMS resonators as described in any of the above embodiments, and a coupling energy storage unit is arranged between adjacent vibration units.

[0018] Optionally, the plurality of MEMS resonators form a closed structure, that is, a coupling energy storage unit is arranged between and coupled to any two adjacent vibration units.

[0019] Optionally, the MEMS resonator array comprises 12 MEMS resonators and has a cross-shaped structure.

[0020] As described above, the coupling energy storage unit is arranged in the MEMS resonator, which on the one hand introduces other high-Q bulk mode vibration structures on the basis of the existing vibration unit, so as to improve the resonance Q value of the entire MEMS resonator; on the other hand, the coupling energy storage unit is coupled to the vibration unit, which increases the coupling area and is beneficial to improve the coupling efficiency, so as to further improve the resonance Q value of the entire MEMS resonator. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 a structure top view of a first MEMS resonator provided by the embodiments of the present application;

[0022] Figure 2 a structure top view of a second MEMS resonator provided by the embodiments of the present application;

[0023] Figure 3 a structure top view of a third MEMS resonator provided by the embodiments of the present application;

[0024] Figure 4 a structure top view of a first MEMS resonator array provided by the embodiments of the present application;

[0025] Figure 5 a structure top view of a second MEMS resonator array provided by the embodiments of the present application;

[0026] Figure 6 a structure top view of a third MEMS resonator array provided by the embodiments of the present application;

[0027] Figure 7 A top view of the structure of the fourth MEMS resonator array provided in the embodiments of this application;

[0028] Figure 8 A top view of the structure of the fourth MEMS resonator provided in the embodiments of this application;

[0029] Reference numerals: 1. MEMS resonator; 10. Substrate; 11. Vibration unit; 12. Coupled energy storage unit; 13. Anchor point; 14. First electrode; 141. Driving electrode; 142. Sensing electrode; 15. Second electrode. Detailed Implementation

[0030] To address the aforementioned problems in the prior art, this application provides a MEMS resonator and a MEMS resonator array. These two protection subjects are based on the same concept, and the principles for solving the problems are basically the same or similar. The implementation methods of each protection subject can be referred to mutually, and repeated details will not be elaborated.

[0031] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly described below in conjunction with specific embodiments and corresponding drawings. Obviously, the embodiments described below are only a part of the embodiments of this application, and not all of them. Unless otherwise specified, the following embodiments and their technical features can be combined with each other, and also belong to the technical solutions of this application.

[0032] In the description of the embodiments of this application, the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the technical solutions of the corresponding embodiments, and are not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. They should not be construed as limitations on this application.

[0033] Please see Figure 1 The image shown is a top view of a MEMS resonator 1 provided in an embodiment of this application. For better description, the top view direction can be referred to as the second direction y, that is, the direction perpendicular to the substrate 10 of the MEMS resonator 1. Figure 1 The first direction x and the third direction z shown can be regarded as the other two coordinate axes of the three-dimensional Cartesian coordinate system where the MEMS resonator 1 is located.

[0034] In addition to the substrate 10, the MEMS resonator 1 of the present application further comprises a vibrating unit 11, a coupling energy storage unit 12, an anchor point 13, and a first electrode 14 disposed on the substrate 10.

[0035] The substrate 10 includes, but is not limited to, a doped silicon substrate, and is a planar structure as a whole.

[0036] The vibrating unit 11 can also be referred to as a vibrator, and is used to generate vibrations of a desired frequency, i.e., to generate resonance at a preset resonant frequency. In an actual scenario, the vibrating unit 11 is a ring structure, and the shape (or rather, the orthographic projection shape) of the cross section (i.e., the x-z plane) thereof can be a circular ring shape as shown in the figure, and of course can also be a rectangular ring, a hexagonal ring, or other polygonal ring. Figures 1 to 8 The vibrating unit 11 can also be referred to as a vibrator, and is used to generate vibrations of a desired frequency, i.e., to generate resonance at a preset resonant frequency. In an actual scenario, the vibrating unit 11 is a ring structure, and the shape (or rather, the orthographic projection shape) of the cross section (i.e., the x-z plane) thereof can be a circular ring shape as shown in the figure, and of course can also be a rectangular ring, a hexagonal ring, or other polygonal ring.

[0037] The vibrating unit 11 can be made of a semiconductor material. For example, a material in column IV of the periodic table, including but not limited to silicon, germanium, carbon, and their suitable combinations or compounds, such as silicon germanium or silicon carbide; for another example, a combination or compound of a material in column III-V of the periodic table, including but not limited to gallium phosphide, aluminum gallium phosphide; for yet another example, a combination or compound of a material in column III, IV, V, or VI of the periodic table, including but not limited to at least one of silicon nitride, silicon oxide, aluminum carbide, aluminum nitride, and aluminum oxide; of course, it can also include at least one of a metal silicide, germanide, and carbide, including but not limited to at least one of nickel silicide, cobalt silicide, tungsten carbide, and platinum germanium silicide; a doped variant, including but not limited to silicon or germanium doped with phosphorus, arsenic, antimony, boron, or aluminum, a combination of silicon and germanium, such as silicon germanium; a material with various crystal structures and their suitable combinations (which can be doped or undoped), including but not limited to at least one of single crystal, polycrystal, nanocrystal, and amorphous crystal.

[0038] The vibrating unit 11 can also be referred to as a vibrator, and is used to generate vibrations of a desired frequency, i.e., to generate resonance at a preset resonant frequency. In an actual scenario, the vibrating unit 11 is a ring structure, and the shape (or rather, the orthographic projection shape) of the cross section (i.e., the x-z plane) thereof can be a circular ring shape as shown in the figure, and of course can also be a rectangular ring, a hexagonal ring, or other polygonal ring. In the etching process, the area of the semiconductor substrate base material corresponding to the orthographic projection of the vibrating unit 11 is not etched and hollowed out, so that a substrate 10 which is a planar structure as a whole or a plate-like structure can be obtained, and a ring-shaped vibrating unit 11 on the substrate 10 can also be obtained. In this scenario, the main materials of the vibrating unit 11 and the substrate 10 can be the same.

[0039] The coupling energy storage unit 12 can be disposed on the substrate 10. The coupling energy storage unit 12 is coupled to the vibration unit 11 and has a high Q vibration mode. The high Q vibration mode can mean that the Q value of the vibration mode of the coupling energy storage unit 12 is higher than the Q value of the vibration mode of the vibration unit 11.

[0040] The anchor points 13 fix the coupling energy storage unit 12 on the substrate 10. For example, a single coupling energy storage unit 12 can be fixed on the substrate 10 by four anchor points 13, which can be disposed in a rectangular shape, for example, connected to the four corners of the rectangular coupling energy storage unit 12. The number of anchor points 13 is not limited for fixing the coupling energy storage unit 12 on the substrate 10; preferably, an even number of anchor points 13 are disposed on opposite sides of the coupling energy storage unit 12.

[0041] The first electrode 14 is disposed adjacent to the vibration unit 11 with a certain gap, which can also be referred to as an air gap, and the distance can be adapted according to actual needs, for example, can be between 100 nm and 1.2 μm. The first electrode 14 is used to electrically connect the IC circuit (not shown in the figure) to induce mechanical oscillation of the vibration unit 11. By controlling the electrical parameters (such as the frequency of the driving voltage) of the first electrode 14, the vibration frequency of the vibration unit 11 can be controlled.

[0042] In the scenario as shown in FIG. 1, Figure 1 The first electrode 14 can include a driving electrode 141 and a sensing electrode 142, which are disposed on opposite sides of the vibration unit 11. For example, for a vibration unit 11 in the shape of a circular ring in cross section, the driving electrode 141 can be disposed on the outside of the vibration unit 11 with a first gap from the outer side of the vibration unit 11, and the sensing electrode 142 can be disposed on the inside of the vibration unit 11 with a second gap from the inner side of the vibration unit 11, which can be equal to the first gap. The driving electrode 141 is electrically connected to the driving circuit in the IC circuit, and the sensing electrode 142 is electrically connected to the sensing circuit in the IC circuit; in operation, the vibration unit 11 of the MEMS resonator 1 is induced to oscillate or vibrate by the driving electrode 141. The sensing electrode 142 is used to sense, sample and / or detect signals with one or more resonance frequencies, so as to detect the vibration frequency of the vibration unit 11. For those skilled in the art, the above-mentioned driving electrode 141, sensing electrode 142, driving circuit and sensing circuit can be of a conventional and well-known type, or can be of any type known at present or developed later, which will not be described here.

[0043] As mentioned above, the coupling energy storage unit 12 is added in the MEMS resonator 1 of the present application, on one hand, it is equivalent to introducing other high quality factor bulk mode vibration structure on the basis of the existing vibration unit 11, so as to improve the resonance Q value of the whole MEMS resonator 1, on the other hand, the coupling energy storage unit 12 is coupled with the vibration unit 11, the area of the coupling is increased, which is beneficial to improve the coupling efficiency, and the resonance Q value of the whole MEMS resonator 1 can be further improved.

[0044] It should be understood that the number of the coupling energy storage units 12 arranged in the single MEMS resonator 1 is not limited to Figure 1 the one shown in the figure, but can also be other numbers, for example Figure 2 two as shown in the figure. Moreover, the positions of the coupling energy storage units 12 relative to the vibration unit 11 can be adaptive according to actual needs, for example Figure 2 two coupling energy storage units 12 are arranged on the left and right sides of the vibration unit 11, and the included angle α between the two coupling energy storage units 12 coupled with the vibration unit 11 is 60°-180°, by setting the included angle α in the threshold range, a closed structure can be formed when multiple vibration units 11 are coupled.

[0045] In addition, as shown in Figures 1 to 3 , and Figure 8 , the single MEMS resonator 1 can be provided with at least one vibration unit 11; the single MEMS resonator 1 in other scenarios can be provided with two or more vibration units 11, and one coupling energy storage unit 12 is arranged between the adjacent two vibration units 11, and the one coupling energy storage unit 12 is coupled with the adjacent two vibration units 11 respectively.

[0046] Optionally, the coupling energy storage unit 12 can be a high quality factor bulk mode vibration structure, for example, it can be made of flexible material and has good elasticity; for another example, the coupling energy storage unit 12 can be a phonon via structure. Of course, it is not limited to this, as long as the coupling energy storage unit 12 has the effect of coupling and returning the vibration transmitted by the vibration unit 11 to the vibration unit 11.

[0047] The materials of the coupling energy storage unit 12 and the anchor point 13 can be the same, and of course, they can also be the same as the material of the vibration unit 11. The coupling energy storage unit 12 and the anchor point 13 can be made by the same or similar process as the vibration unit 11, for example, by at least one of lithography, etching, deposition, and doping. For the scenario that the single MEMS resonator 1 only contains one vibration unit 11, the coupling energy storage unit 12 and the vibration unit 11 can be formed by the same process or form the main part, so as to simplify the preparation process, and of course, the anchor point 13 can also be formed by the same process.

[0048] In an implementation scenario, the coupling energy storage unit 12 is observed along a line of sight direction perpendicular to the substrate 10, i.e., along the second direction y, as shown in FIG. 1B. Figure 1 、 Figure 2 、 Figures 4 to 8 As shown in FIG. 1C, the coupling energy storage unit 12 can be rectangular, and the vibration mode of the rectangular coupling energy storage unit 12 is optionally a lame mode, i.e., the opposite sides of the coupling energy storage unit 12 (one side coupled to the vibration unit 11 and the other side opposite to the one side) continuously expand and contract to achieve vibration. Figure 3 As shown in FIG. 1D, the coupling energy storage unit 12 can also be circular, and the vibration mode of the circular coupling energy storage unit 12 is optionally a wine glass mode.

[0049] Compared with the conventional coupling connection through a long strip-shaped structural member such as a rod or a beam, in the embodiment of the present application, the coupling energy storage unit 12 and the vibration unit 11 can be considered as a surface contact, the contact area is large, the coupling area between adjacent vibration units 11 can be increased, so that the coupling efficiency between the vibration units 11 of different MEMS resonators 1 is high, which is beneficial to improve the resonance Q value.

[0050] Please continue to refer to Figure 8 The MEMS resonator 1 of an embodiment of the present application can further include a second electrode 15, which is arranged adjacent to the coupling energy storage unit 12 and has a gap therebetween, which can also be referred to as an air gap, the distance of which can be adaptive according to actual requirements, for example, can be between 100 nm and 1.2 μm.

[0051] Specifically, the second electrode 15 includes a first electrode sheet and a second electrode sheet, which are arranged adjacent to the opposite sides of the coupling energy storage unit 12 and have a gap therebetween, respectively. The first electrode sheet and the second electrode sheet are used to electrically connect an IC circuit (not shown in the figure) to induce mechanical oscillation of the coupling energy storage unit 12. By controlling the electrical parameters (such as the frequency of the driving voltage) of the second electrode 15, the vibration frequency of the coupling energy storage unit 12 can be controlled. The second electrode 15 can be considered as a detection and driving structure, through the cooperation of the coupling energy storage unit 12 and the second electrode 15, the driving strength is improved, the modal displacement is reduced, and the overall impedance of the MEMS resonator 1 is further reduced; and the resonance Q value and the coupling efficiency of the entire MEMS resonator 1 can be further improved.

[0052] The embodiment of the present application further provides a MEMS resonator array comprising a plurality of the MEMS resonator 1 of any of the above embodiments, wherein a coupling energy storage unit 12 is arranged between adjacent vibration units 11 in different MEMS resonators 1 and the adjacent vibration units 11 are coupled through the coupling energy storage unit 12. In this way, the MEMS resonator array can have the beneficial effects of the corresponding embodiment of the MEMS resonator 1.

[0053] In an implementation scenario, the coupling connection between the plurality of MEMS resonators 1 can be implemented as a closed structure.

[0054] For example, referring to the scenario shown in Figure 4 , the MEMS resonator array comprises three MEMS resonators 1, each of which comprises a vibration unit 11 and a coupling energy storage unit 12, and the MEMS resonators 1 are coupled in sequence to form a triangular structure.

[0055] For another example, referring to the scenario shown in Figure 5 , the MEMS resonator array comprises four MEMS resonators 1, each of which comprises a vibration unit 11 and a coupling energy storage unit 12, and the MEMS resonators 1 are coupled in sequence to form a rectangular structure.

[0056] For another example, referring to the scenario shown in Figure 6 , the MEMS resonator array comprises six MEMS resonators 1, each of which comprises a vibration unit 11 and a coupling energy storage unit 12, and the MEMS resonators 1 are coupled in sequence to form a hexagonal structure.

[0057] For another example, referring to the scenario shown in Figure 7 , the MEMS resonator array comprises twelve MEMS resonators 1, each of which comprises a vibration unit 11 and a coupling energy storage unit 12, and the MEMS resonators 1 are coupled in sequence to form a cross-shaped structure.

[0058] The closed structure can be such that each vibration unit 11 is coupled to two coupling energy storage units 12, and each coupling energy storage unit 12 is coupled to two vibration units 11, so that a larger coupling area can be achieved and a higher coupling efficiency can be achieved. In addition, in the MEMS resonator array of the closed structure, the MEMS resonators 1 are connected in parallel, so that the overall impedance can be reduced.

[0059] It should be noted that Figures 3 to 7In the shown scenario, the corresponding electrodes, such as the aforementioned first electrode 14 and second electrode 15, are not shown. In an actual scenario, each vibration unit 11 is provided with at least a driving electrode and a sensing electrode, the positions of which are not limited to Figure 1 and Figure 2 as shown.

[0060] It should be understood that the MEMS resonator and the MEMS resonator array provided by the embodiments of the present application are corresponding complete devices, and each has the structure of a known device. Here, only the components related to the vibration unit and the electrode in the device are described, and other components are not described in detail.

[0061] The above only describes some embodiments of the present application, and does not limit the patent scope of the present application. For those of ordinary skill in the art, equivalent structural transformations made using the content of the present application and the accompanying drawings are also included in the patent protection scope of the present application.

[0062] Although the terms "first", "second", and the like are used herein to describe various information, the information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. In addition, the singular forms "one", "a", and "the" are intended to include the plural forms. The terms "or" and "and / or" are interpreted as inclusive, or mean any one or any combination. Only when the combination of elements, functions, steps or operations is inherently mutually exclusive in some way, will there be an exception to this definition.

Claims

1. A MEMS resonator, characterized in that, include: A vibration unit, used to generate resonance, wherein the vibration unit is a ring structure; The coupled energy storage unit is directly coupled to the vibration unit and is in a high-Q vibration mode. Along the line of sight perpendicular to the substrate, the coupled energy storage unit is rectangular or circular. A single coupled energy storage unit is used to directly couple to adjacent vibration units. Anchor points are used to fix the coupled energy storage unit onto the substrate; A first electrode is disposed adjacent to the vibration unit and has a gap between it and the vibration unit. The first electrode includes a driving electrode and a sensing electrode. The driving electrode is disposed on the outside of the vibration unit and has a first gap with the outer surface of the vibration unit. The sensing electrode is disposed on the inside of the vibration unit and has a second gap with the inner surface of the vibration unit.

2. The MEMS resonator according to claim 1, characterized in that, The coupled energy storage unit is made of flexible material.

3. The MEMS resonator according to claim 1 or 2, characterized in that, The coupled energy storage unit is a phonon through-hole structure.

4. The MEMS resonator according to claim 1, characterized in that, The vibration mode of the rectangular coupled energy storage unit is the Lame mode; The vibration mode of the circular coupled energy storage unit is the WG mode.

5. The MEMS resonator according to claim 1, characterized in that, The MEMS resonator further includes a second electrode, which is disposed adjacent to the coupled energy storage unit and has a gap between it and the coupled energy storage unit.

6. A MEMS resonator array, characterized in that, It includes a plurality of MEMS resonators as described in any one of claims 1 to 5, wherein a coupling energy storage unit is provided between adjacent vibration units.

7. The MEMS resonator array according to claim 6, characterized in that, Multiple MEMS resonators form a closed structure.

8. The MEMS resonator array according to claim 7, characterized in that, The MEMS resonator array includes 12 MEMS resonators in a cross-shaped structure.

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