Low support loss dual proof mass resonator
The mechanical resonator design with two vibrating proof masses and centered anchors effectively reduces support losses by canceling elastic energy, enhancing the Q factor and stability.
Patent Information
- Application Number
- JP2025529960
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-12-02
- Filing Date
- 2023-08-04
- Publication Date
- 2025-11-14
AI Technical Summary
Existing resonators suffer from high support losses, which reduce their Q value and make them susceptible to repeatability and hysteresis issues due to elastic energy leakage into the substrate.
A mechanical resonator design featuring two identical proof masses vibrating in phase perpendicular to the connecting beam, with anchors positioned opposite each other at the center of the beam to cancel out elastic energy leakage, and utilizing electrostatic or piezoelectric transduction for vibration.
Minimizes support losses by canceling out elastic energy at the center of the connecting beam, thereby improving the Q factor and reducing repeatability and hysteresis issues.
Smart Images
Figure 2025537352000001_ABST
Abstract
Description
[Technical Field]
[0001] The present disclosure relates to a low support loss dual proof mass resonator. Specifically, the dual proof mass resonator comprises two identical proof masses adapted to vibrate in phase perpendicular to the direction of the connecting beam. The resonator may be of various shapes, such as rectangular. [Background technology]
[0002] Although resonators are popular and widely used in a variety of applications, they have relatively high support losses, which reduces the resonator's Q value. When a resonator vibrates, some of its elastic energy leaks into the substrate and is dissipated.
[0003] Extensive efforts have been made to reduce support losses by modifying either one or more of the anchors or the resonator body, and / or even the substrate, but there are still some popular resonators whose support losses may not be low enough.
[0004] Therefore, there is a need for techniques to reduce support losses (or anchor losses) in mechanical resonators. Summary of the Invention
[0005] In one aspect, a mechanical resonator comprises two identical proof masses adapted to vibrate in phase in a direction perpendicular to the direction of the connecting beams, at least one connecting beam connecting the two identical proof masses, and at least one anchor attached to the center of the at least one connecting beam.
[0006] In one embodiment, the two identical proof masses are resonant plates and are fixed with at least anchors to the substrate.
[0007] The at least one anchor may include two anchors attached to the center of the at least one connecting beam so as to be positioned opposite each other.
[0008] Furthermore, at least one connection beam has an outer peripheral ring at its center, and at least the anchor is disposed at the center of the outer peripheral ring and is connected to the outer peripheral ring via two sub-connection beams.
[0009] The outer ring may be a rectangular ring.
[0010] Alternatively, the outer ring may be in the form of a circular ring.
[0011] In embodiments using electrostatic transduction, a direct current (DC) bias voltage is applied across the mechanical resonator.
[0012] In embodiments using piezoelectric transduction, an alternating current (AC) voltage signal is applied to one port of the mechanical resonator, and the resulting AC voltage or current signal is measured using the other port of the mechanical resonator.
[0013] In piezoelectric transduction, the two resonator plates each consist of a piezoelectric material or contain a semiconductor layer coated with a thin layer of piezoelectric material.
[0014] Additionally, each of the two resonator plates further includes a patterned metal layer formed as an electrode on top of the thin layer of piezoelectric material.
[0015] The mechanical resonator may further include a first anchor and a second anchor, wherein one end of the first anchor is electrically connected to a patterned metal layer formed on one of the two resonator plates and the other end of the first anchor is fixed to ground, and one end of the second anchor is electrically connected to a patterned metal layer formed on the other of the two resonator plates and the other end of the second anchor is fixed to ground.
[0016] In yet another embodiment, the two resonator plates are each divided into an upper and a lower portion, where a first patterned metal layer is formed on the upper portions of the two resonator plates and a second patterned metal layer is formed on the lower portions of the two resonator plates.
[0017] The connecting beam may also be divided into an upper portion covered with a first patterned metal layer and a lower portion covered with a second patterned metal layer.
[0018] Additionally, an AC voltage signal may be applied to the first and second patterned metal layers.
[0019] In yet another embodiment, the two resonator plates are each divided into an outer and an inner portion, where a first patterned metal layer is formed on the outer portions of the two resonator plates and a second patterned metal layer is formed on the inner portions of the two resonator plates.
[0020] In this embodiment, the at least one connection beam may include a first and a second connection beam, where the first connection beam is at least partially covered by a first patterned metal layer and the second connection beam is at least partially covered by a second patterned metal layer.
[0021] The first connection beam also includes a first anchor, where one end of the first anchor is electrically connected to the first patterned metal layer and the other end of the first anchor is fixed to ground.
[0022] Furthermore, the second connection beam includes a second anchor, wherein one end of the second anchor is electrically connected to the second patterned metal layer and the other end of the second anchor is fixed to ground.
[0023] Other aspects, advantages and distinguishing features of the present disclosure will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses illustrative embodiments of the present disclosure.
[0024] Before embarking on the detailed description below, it may be helpful to clarify definitions of certain terms used throughout this patent document. The terms "include" and "comprise," and their derivatives, mean inclusion without limitation. The term "or" is inclusive and / or. The phrases "associated with" and "associated therewith," and their derivatives, can mean include, be included within, interconnect with, contain, be contained within, connect to or with, coupled to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, or have a property of, etc. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether local or remote. Definitions of certain terms are provided throughout this patent document, and those skilled in the art should understand that in many, if not most, cases, definitions apply to prior and subsequent uses of such defined terms. [Brief explanation of the drawings]
[0025] For a more complete understanding of the present disclosure, and the advantages thereof, reference is now made to the following description taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts, and in which: [Figure 1A]FIG. 1A shows an exemplary schematic diagram of a mechanical resonator having two plates adapted to vibrate perpendicular to the direction of a connecting beam, according to one embodiment of the present disclosure. [Figure 1B] FIG. 1B shows an illustrative diagram of a vibrating mechanical resonator with two plates adapted to vibrate perpendicular to the direction of the connecting beams, according to one embodiment of the present disclosure. [Figure 2] FIG. 2 shows an exemplary schematic diagram of a mechanical resonator having two plates and an anchor adapted to vibrate perpendicular to the direction of the connecting beam, according to one embodiment of the present disclosure. [Figure 3] FIG. 3 shows another exemplary schematic diagram of a mechanical resonator having two plates and an anchor adapted to vibrate perpendicular to the direction of the connecting beam, according to an embodiment of the present disclosure. [Figure 4] FIG. 4 shows an exemplary schematic diagram of a mechanical resonator having two plates and two anchors adapted to vibrate perpendicular to the direction of the connecting beam, according to one embodiment of the present disclosure. [Figure 5] FIG. 5 shows another exemplary schematic diagram of a mechanical resonator having two plates and two anchors adapted to vibrate perpendicular to the direction of the connecting beam, according to an embodiment of the present disclosure. [Figure 6] FIG. 6 shows another exemplary schematic diagram of a mechanical resonator having two plates and four anchors adapted to vibrate perpendicular to the direction of the connecting beams, according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION
[0026] It should be noted that like reference numbers are used throughout the drawings to denote the same or similar elements, features, and structures.
[0027] 1A-6 described below and various embodiments used in this patent document to explain the principles of the present disclosure are merely illustrative and should not be construed in any way as limiting the scope of the present disclosure. Those skilled in the art will understand that the principles of the present disclosure can be implemented in any appropriately configured system and method. The following description, taken in conjunction with the accompanying drawings, is provided to aid in a comprehensive understanding of various embodiments of the present disclosure, as defined by the claims and their equivalents. While it includes numerous specific details to aid understanding, these should be considered merely as examples. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the various embodiments described herein without departing from the scope and spirit of the present disclosure. Furthermore, descriptions of well-known functions and structures may be omitted for clarity and conciseness.
[0028] It will be apparent to those skilled in the art that the following description of various embodiments of the present disclosure is provided for illustrative purposes only and is not intended to limit the present disclosure as defined by the appended claims and equivalents thereof.
[0029] Although ordinal terms such as "first" and "second" are used to describe various components, these components are not limited herein. These terms are used merely to distinguish one component from another. For example, a first component can be referred to as a second component, and similarly, a second component can be referred to as a first component, without departing from the teachings of the inventive concept.
[0030] The terminology used herein is merely for the purpose of describing various embodiments and is not intended to be limiting. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. It will be further understood that as used herein, the terms "comprises" and / or "has" specify the presence of stated features, numbers, steps, operations, components, elements, or combinations thereof, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, components, elements, or combinations thereof.
[0031] Anchor loss can affect a resonator in several ways. First, anchor loss can reduce the overall Q factor of the resonator and can make the Q factor of the resonator dependent on the boundary conditions and stresses of the substrate. Second, anchor loss makes the resonator susceptible to repeatability and hysteresis issues. The present disclosure provides a mechanical resonator designed to reduce anchor loss during operation.
[0032] 1A shows an exemplary schematic diagram of a mechanical resonator 10A according to one embodiment of the present disclosure. FIG. 1B shows an exemplary diagram 10B of a vibrating mechanical resonator with two anchors according to one embodiment of the present disclosure.
[0033] The mechanical resonator 10 includes two resonator plates 11 and 12, two anchors 14 and 15, and a connecting beam 13 that connects the anchors 14 and 15 to the two resonator plates 11 and 12. The connecting beam 13 may be connected to a node of the resonator plates 11 and 12. The two resonator plates 11 and 12 vibrate in the direction of an arrow 12a, which is perpendicular to the direction of the connecting beam 13.
[0034] The resonator plates 11, 12, anchors 14, 15, and connecting beam 13 may be etched into a substrate, such as a substrate including silicon, doped silicon, N-type silicon, P-type silicon, silicon oxide, silicon carbide, and germanium.
[0035] The two resonator plates 11, 12 are two identical proof masses connected via a connecting beam 13. The two resonator plates 11, 12 may have various dimensions and / or shapes. In one embodiment, the two resonator plates 11, 12 may be rectangular. For example, the two resonator plates 11 and 12 may be any size from a 10 μm x 10 μm square to a 1 m x 1 m square.
[0036] The anchors 14, 15 can be etched into substrates 14A and 15A made of a variety of materials, such as N-type or P-type silicon, silicon oxide, silicon carbide, and germanium.
[0037] The mechanical resonator 10 can use electrostatic or piezoelectric transduction to drive the two resonant plates. Alternatively, the mechanical resonator 10 can use piezoresistive, electromagnetic, or thermal transduction. In the case of electrostatic transduction, a DC voltage is applied to the entire resonator, including the resonant plates and connecting beams. In the case of piezoelectric transduction, an AC voltage signal is applied to one port of the mechanical resonator 10 (e.g., an electrode on the resonant plates), and the resulting AC voltage or current signal is measured using the other port of the mechanical resonator 10 (e.g., an anchor or beam).
[0038] As a result of electrostatic or piezoelectric conversion, the two resonator plates 11 and 12 vibrate in the same phase in the directions of the arrows 11 a and 12 a , which are perpendicular to the direction of the connecting beam 13 .
[0039] With the above structure, the elastic energies leaking from the two resonator plates 11 and 12 to the connecting beam 13 are equal in magnitude but travel in opposite directions, and therefore cancel each other out at the center of the connecting beam.
[0040] The two anchors 14, 15 may be attached to the center of the connecting beam 13 so as to be located opposite each other. The center of the connecting beam is a suitable location for fixing the resonator 10, because the elastic energy leaking from the two resonator plates 11, 12 can be canceled out, thereby minimizing support loss.
[0041] FIG. 2 shows an exemplary schematic diagram of a mechanical resonator 20 having one anchor, according to one embodiment of the present disclosure.
[0042] 2, the mechanical resonator 20 comprises two resonator plates 21, 22, a connecting structure 23, and an anchor 28. The two resonator plates 21, 22 may be two identical proof masses connected via a beam. Repetitive descriptions of identical components are omitted for the sake of brevity.
[0043] The connecting structure 23 has a peripheral ring 23c in the center, and an anchor 25 is disposed at the center of the peripheral ring 23c via two inner connecting beams 23d and 23e. In this embodiment, the peripheral ring 23c has a circular ring shape.
[0044] The anchor 25 is located at the center of the connecting beam 23, where the elastic energies leaking from the two resonator plates 21 and 22 cancel each other out, minimizing support loss. The anchor 25 can be etched from substrates made of various materials, such as N-type or P-type silicon, silicon oxide, silicon carbide, and germanium.
[0045] By electrostatic or piezoelectric conversion, the two resonator plates 21 and 22 vibrate in the same phase in the directions of the arrows 21 a and 22 a , which are perpendicular to the direction of the connecting beam 23 .
[0046] FIG. 3 shows another exemplary schematic diagram of a mechanical resonator 30 having one anchor, according to one embodiment of the present disclosure.
[0047] 2, the mechanical resonator 30 comprises two resonator plates 31 and 32, a connecting structure 33, and an anchor 38. Repetitive descriptions of identical components will be omitted for the sake of brevity.
[0048] The connecting structure 33 includes a central peripheral ring 33c, and an anchor 35 is disposed at the center of the peripheral ring 33c via two inner connecting beams 33d and 33e. In this embodiment, the peripheral ring 33c is rectangular. The resonator plates 31 and 32 may also have various shapes, such as rectangular, circular, and polygonal. The inner connecting beams 33d and 33e may connect the resonator plates 31 and 32 to their respective nodes.
[0049] By electrostatic or piezoelectric conversion, the two resonator plates 31 and 32 vibrate in the same phase in the directions of the arrows 31 a and 32 a , which are perpendicular to the direction of the connecting beam 33 .
[0050] FIG. 4 shows an exemplary schematic diagram of a mechanical resonator 40 having two anchors and patterned electrodes, according to one embodiment of the present disclosure.
[0051] 2, the mechanical resonator 40 comprises two resonator plates 41, 42 connecting a beam 43 which connects two anchors 45, 46 to the resonator plates 41, 42. Repetitive descriptions of identical components are omitted for the sake of brevity.
[0052] Each of the two resonator plates 41, 42 includes a semiconductor layer covered with a thin layer of piezoelectric material. Patterned metal layers 41b, 42b are formed as electrodes on top of the thin layers of piezoelectric material 41a, 42a.
[0053] One end of anchor 45 is electrically connected to patterned metal layer 41b, and the other end of anchor 45 is fixed to ground, and one end of anchor 46 is electrically connected to patterned metal layer 42b, and the other end of anchor 46 is fixed to ground.
[0054] Similarly, when an AC voltage signal is applied to the electrodes to cause piezoelectric conversion, the two resonator plates 41 and 42 vibrate in the same phase in a direction perpendicular to the direction of the connecting beam 43 .
[0055] FIG. 5 shows another exemplary schematic diagram of a mechanical resonator 50 having two anchors and patterned electrodes, according to an embodiment of the present disclosure.
[0056] 4, the mechanical resonator 50 comprises two resonator plates 51, 52 and a connecting beam 55 connecting two anchors 56, 57 to the resonator plates 51, 52. Repetitive descriptions of identical components will be omitted for the sake of brevity.
[0057] In this embodiment, two resonator plates 51 and 52 are each divided into an upper part and a lower part. A patterned metal layer 53 is formed on the upper part of the resonator plates 51 and 52, and a patterned metal layer 54 is formed on the lower part of the resonator plates 51 and 52. The connecting beam 55 may also be divided into an upper part and a lower part, which are covered with the patterned metal layers 53 and 54, respectively.
[0058] When an AC voltage signal can be applied to the patterned metal layers 53, 54, the two resonator plates 51, 52 vibrate in phase in a direction perpendicular to the direction of the connecting beam 55.
[0059] FIG. 6 shows yet another exemplary schematic diagram of a mechanical resonator 60 having two anchors and patterned electrodes, according to an embodiment of the present disclosure.
[0060] 2, the mechanical resonator 60 includes two resonator plates 61 and 62 and connecting beams 65 and 68. Two anchors 66 and 67 are disposed at the center of the connecting beam 65 so as to be located opposite each other, and two anchors 69 and 70 are disposed at the center of the connecting beam 68 so as to be located opposite each other. Repetitive descriptions of identical components will be omitted for the sake of brevity.
[0061] In this embodiment, two resonator plates 61, 62 are each divided into an inner and outer portion. Patterned metal layer 63 is formed on the outer portions of resonator plates 61, 62 and connected to anchors 66 fixed to ground. Patterned metal layer 64 is formed on the inner portions of resonator plates 61, 62 and connected to anchors 70 fixed to ground.
[0062] When an AC voltage signal is applied to the patterned metal layers 63,64 to allow piezoelectric transduction, the two resonator plates 61,62 vibrate in phase in a direction perpendicular to the direction of the connecting beams 65,68.
[0063] The mechanical resonators can be rectangular proof mass resonators made of a single semiconductor material (e.g., single-crystal silicon) that vibrates in bulk elastic width / length stretching modes. These resonators can function in the first stretching mode or any higher-order modes. Such resonators made of silicon are called silicon bulk acoustic wave resonators (SiBARs).
[0064] Another example of such a resonator may consist of a semiconductor layer covered with a thin layer of piezoelectric material, with a patterned metal layer on top to form electrodes. These resonators can have vibration mode shapes similar to those of SiBARs. Such silicon resonators can be called thin-film piezoelectric-on-silicon (TPoS) resonators.
[0065] Yet another example of the resonator may be a contour vibration mode resonator, which is made of a piezoelectric material. Additionally, there is a patterned metal layer on the top surface (and even the bottom surface) that acts as an electrode. The vibration mode shape may be similar to the other resonators mentioned above.
[0066] Although the present disclosure has been described with exemplary embodiments, various changes and modifications may be suggested by those skilled in the art, and the present disclosure is intended to cover such changes and modifications as fall within the scope of the appended claims.
Claims
1. two identical proof masses adapted to vibrate in phase in a direction perpendicular to the direction of the at least one connecting beam; the at least one connecting beam connecting the two identical proof masses; at least one anchor attached to the center of the at least one connecting beam; A mechanical resonator comprising:
2. Two identical proof masses are resonator plates, the at least one anchor is fixed to a substrate; The mechanical resonator of claim 1 .
3. the at least one anchor comprises two opposite anchors attached to a center of the at least one connecting beam; The mechanical resonator of claim 1 .
4. the at least one connecting beam having a peripheral ring at its center; The at least one anchor is disposed at the center of the peripheral ring and is connected to the peripheral ring via two sub-connection beams. The mechanical resonator of claim 1 .
5. The outer ring is a rectangular ring. The mechanical resonator according to claim 4 .
6. The outer ring is a circular ring. The mechanical resonator according to claim 4 .
7. When using electrostatic transduction, a DC bias voltage is applied across the mechanical resonator; The mechanical resonator of claim 1 .
8. When using piezoelectric transduction, each of the two resonator plates comprises a semiconductor layer covered with a thin layer of piezoelectric material. The mechanical resonator of claim 1 .
9. each of the two resonator plates further includes a patterned metal layer formed as an electrode on top of the thin layer of piezoelectric material; The mechanical resonator of claim 8 .
10. an AC voltage signal is applied to each of the patterned metal layers of the two resonator plates; The mechanical resonator of claim 9.
11. a first anchor; a second anchor; and Equipped with one end of the first anchor is electrically connected to a patterned metal layer formed on one of the two resonator plates, and the other end of the first anchor is fixed to ground; one end of the second anchor is electrically connected to a patterned metal layer formed on the other of the two resonator plates, and the other end of the second anchor is fixed to ground; The mechanical resonator of claim 9.
12. Each of the two resonator plates is divided into an upper part and a lower part, a first patterned metal layer formed on the top of the two resonator plates; a second patterned metal layer is formed on the bottom of the two resonator plates; The mechanical resonator of claim 10.
13. the connecting beam is divided into an upper portion covered with the first patterned metal layer and a lower portion covered with the second patterned metal layer; The mechanical resonator of claim 12.
14. an AC voltage signal is applied to the first and second patterned metal layers; The mechanical resonator of claim 12.
15. Each of the two resonator plates is divided into an outer and an inner part, a first patterned metal layer is formed on the exterior of the two resonator plates; a second patterned metal layer is formed on the interior of the two resonator plates; The mechanical resonator of claim 1 .
16. the at least one connection beam includes a first and a second connection beam; the first connection beam is at least partially covered with the first patterned metal layer; the second connection beam is at least partially covered with the second patterned metal layer; 16. The mechanical resonator of claim 15.
17. the first connection beam comprises a first anchor, one end of the first anchor being electrically connected to the first patterned metal layer and the other end of the first anchor being fixed to ground; the second connection beam comprises a second anchor, one end of the second anchor being electrically connected to the second patterned metal layer and the other end of the second anchor being fixed to ground; 17. The mechanical resonator of claim 16.