Piezoelectric resonator

Abstract

The piezoelectric resonator comprises a harmonic oscillator, the harmonic oscillator comprises a vibration part, an anchoring part and a connecting beam, and the vibration part comprises a base and at least three vibration arms; the vibrating arms extend in the Y-axis direction and are arranged side by side in the X-axis direction according to preset intervals. Each vibrating arm can be bent out of plane relative to the XY plane, and at least two vibrating arms can be bent out of plane in opposite directions; the width of the two vibration arms located on the outermost side in the X-axis direction is smaller than the width of the vibration arm located on the inner side in the X-axis direction. The base is provided with a front end part connected with the fixed end of each vibrating arm and a rear end part opposite to the front end part; the anchoring part is arranged around the vibration part and used for fixing the vibration part; the connecting beam is arranged between the anchoring part and the vibration part, one end of the connecting beam is connected with the base, and the other end of the connecting beam is connected with the anchoring part. According to the scheme, by optimizing the structures of the vibration part and the connecting beam, the Q value of the piezoelectric resonator is improved, and the motion impedance is reduced.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of micro-electromechanical technology, and in particular to a piezoelectric resonator. Background Art

[0002] The working principle of a piezoelectric resonator is that an electrical signal passes through electrodes to stimulate acoustic oscillations in a piezoelectric material, thereby achieving resonance of a specific frequency and wavelength. Piezoelectric resonators are widely used, for example, in timing reference, signal filtering, mass sensing, biosensing, motion sensing, etc. Compared to electrostatic resonators, piezoelectric resonators have more advantages, the most obvious of which is the motion impedance.

[0003] However, current piezoelectric resonators have high motion impedance and low quality factor (Q value). Summary of the invention

[0004] The embodiment of the present application provides a piezoelectric resonator, which can improve the Q value of the piezoelectric resonator and reduce the motion impedance.

[0005] The embodiment of the present application provides a piezoelectric resonator, including a resonator. The resonator includes a vibration part, and the vibration part includes a base and at least three vibration arms. Each vibration arm extends along the Y-axis direction and is arranged side by side in the X-axis direction at a preset interval, and the X-axis and the Y-axis constitute a plane rectangular coordinate system. Each vibration arm can be bent out of the plane relative to the XY plane, and at least two of the vibration arms can be bent out of the plane in opposite directions. The width of the two vibration arms located on the outermost side in the X-axis direction is smaller than the width of the vibration arms located on the inner side in the X-axis direction. Each vibration arm has a fixed end and a free end, and the base has a front end connected to the fixed end of each vibration arm and a rear end opposite to the front end. An anchor is arranged around the vibration part and is used to fix the vibration part. A connecting beam is arranged between the anchor and the vibration part, one end of the connecting beam is connected to the base, and the other end is connected to the anchor.

[0006] In the piezoelectric resonator provided in the embodiment of the present application, the two outermost vibration arms have the same width in the X-axis direction.

[0007] In the piezoelectric resonator provided in the embodiment of the present application, the resonator includes a resonator body and a driving function layer arranged on the resonator body, the driving function layer has a piezoelectric film and a first metal film and a second metal film arranged opposite to each other with the piezoelectric film sandwiched therebetween; one of the first metal film and the second metal film on each vibration arm is configured as a driving electrode, and the other is configured as a detection electrode.

[0008] In the piezoelectric resonator provided in the embodiment of the present application, the configuration of the driving electrodes and the detecting electrodes on the two outermost vibration arms is opposite to the configuration of the driving electrodes and the detecting electrodes on the inner vibration arms.

[0009] In the piezoelectric resonator provided in the embodiment of the present application, if the vibration arm is bent out of plane, the base and the connecting beam are bent along with the vibration arm in the direction of the out-of-plane bending.

[0010] In the piezoelectric resonator provided in the embodiment of the present application, one end of the connecting beam is connected to the rear end portion of the base.

[0011] In the piezoelectric resonator provided in an embodiment of the present application, the anchor has a first fixing portion and a second fixing portion that are arranged opposite to each other, the first fixing portion and the second fixing portion are arranged in an area opposite to the side walls of the multiple vibration arms, and the multiple vibration arms are located between the first fixing portion and the second fixing portion; the connecting beam includes a first connecting portion and a second connecting portion, one end of the first connecting portion is connected to the rear end portion of the base, and the other end is connected to the first fixing portion; one end of the second connecting portion is connected to the rear end portion of the base, and the other end is connected to the second fixing portion.

[0012] In the piezoelectric resonator provided in the embodiment of the present application, the first connection portion includes a first rear retaining arm and a first retaining side arm, the first rear retaining arm extends from the rear end portion of the base along the Y-axis direction, is bent and extends along the X-axis direction toward the side where the first fixed portion is located, and the first retaining side arm extends from the end portion of the first rear retaining arm along the Y-axis direction toward the side where the free end of the vibration arm is located, is bent and connected to the first fixed portion. The second connection portion includes a second rear retaining arm and a second retaining side arm, the second rear retaining arm extends from the rear end portion of the base along the Y-axis direction, is bent and extends along the X-axis direction toward the side where the second fixed portion is located, and the second retaining side arm extends from the end portion of the second rear retaining arm along the Y-axis direction toward the side where the free end of the vibration arm is located, is bent and connected to the second fixed portion.

[0013] In the piezoelectric resonator provided in the embodiment of the present application, the first connecting portion and the second connecting portion are symmetrically arranged.

[0014] In the piezoelectric resonator provided in the embodiment of the present application, the first holding side arm and the second holding side arm are both spaced apart from the adjacent vibration arm, and the interval between the first holding side arm and the adjacent vibration arm is smaller than the preset interval, and the interval between the second holding side arm and the adjacent vibration arm is smaller than the preset interval.

[0015] In summary, the piezoelectric resonator provided in the embodiment of the present application includes a resonator, and the resonator includes a vibration part, a connecting beam and an anchor, wherein the vibration part includes a base and at least three vibration arms, each vibration arm extends along the Y-axis direction, and is arranged side by side in the X-axis direction at a preset interval, and has at least two vibration arms that can bend outward in opposite directions, and the width of the two vibration arms located on the outermost sides in the X-axis direction is smaller than the width of the vibration arms located on the inner side in the X-axis direction. One end of the connecting beam is connected to the base, and the other end is connected to the anchor. This solution improves the Q value of the piezoelectric resonator and reduces the motion impedance by optimizing the structure of the vibration part and the connecting beam. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 It is a schematic diagram of the top view of the structure of the resonator of the piezoelectric resonator provided in the embodiment of the present application.

[0018] Figure 2 yes Figure 1 Schematic diagram of the vibration mode of the resonator of the medium piezoelectric resonator.

[0019] Figure 3 1 is a flow chart of a method for manufacturing a piezoelectric resonator according to an embodiment of the present application.

[0020] Figure 4-Figure 10 It is a schematic diagram of the structure of the piezoelectric resonator according to the embodiment of the present application when it is in a corresponding process flow. DETAILED DESCRIPTION

[0021] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0022] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used in this application and in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used in this application includes any and all combinations of one or more related listed items.

[0023] It should be understood that when an element or layer is referred to as "on ...", "adjacent to ...", "connected to" or "coupled to" other elements or layers, it can be directly on, adjacent to, connected to or coupled to other elements or layers, or there can be intervening elements or layers. On the contrary, when an element is referred to as "directly on ...", "directly adjacent to ...", "directly connected to" or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present application, the first element, component, region, layer or part discussed below can be represented as a second element, component, region, layer or part.

[0024] In the description of the present application, it should be noted that the terms "upper", "lower", "left", "right", "inner", "outer", "front", "back", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0025] Current piezoelectric resonators have high motion impedance and low quality factor (Q value).

[0026] Based on this, the embodiment of the present application provides a piezoelectric resonator. The technical solution shown in the present application will be described in detail through specific embodiments below. It should be noted that the description order of the following embodiments is not intended to limit the priority order of the embodiments.

[0027] See also Figure 1 , Figure 1 The top view of the structure of the resonator of the piezoelectric resonator provided by the present application is a schematic diagram. The piezoelectric resonator includes a resonator 1, which is generally a flat plate structure. In addition, in order to facilitate a detailed description of the structure of the resonator 1, in the embodiment of the present application, the thickness direction of the resonator 1 is the Z axis, the width direction of the resonator 1 is the X axis, and the length direction of the resonator 1 is the Y axis, and a spatial rectangular coordinate system as shown in the figure is established.

[0028] The resonator 1 may include a vibrating portion 11 for vibrating, an anchor 12 for fixing, and a connecting beam 13 for connecting the vibrating portion 11 and the anchor 12. For example, the anchor 12 may form a frame surrounding the vibrating portion 11, and the connecting beam 13 may be formed in a gap between the vibrating portion 11 and the anchor 12 to connect the vibrating portion 11 to the anchor 12. It is understood that the piezoelectric resonator may also include a cover for encapsulating the resonator 1, which is not the focus of the application and will not be described in detail.

[0029] In this embodiment, the vibration part 11 may include a base 111 and at least three vibration arms, such as vibration arms 112A, 112B, and 112C. Hereinafter, the vibration arm 112 refers to any vibration arm.

[0030] Each vibration arm 112 extends along the Y-axis direction and is arranged side by side in the X-axis direction at a preset interval. Each vibration arm 112 may have a free end and a fixed end connected to the base 111 .

[0031] In this embodiment, the vibration arm 112 is formed as one body with the base 111. The free end of the vibration arm 112 is the end of the vibration arm 112 away from the base 111. Optionally, each vibration arm 112 is formed in a prism shape extending along the Y-axis direction.

[0032] In some embodiments, see Figure 1 , the width of the two vibration arms located on the outermost side (such as vibration arms 112A and 112C) in the X-axis direction is smaller than the width of the vibration arm 112B located on the inner side in the X-axis direction. Optionally, the widths of the two vibration arms located on the outermost side (such as vibration arms 112A and 112C) in the X-axis direction are the same. The lengths of the vibration arms in the Y-axis direction may be the same or different. For example, see Figure 1 For the vibration arms 112A, 112B, and 112C, the width of the vibration arms 112A and 112C in the X-axis direction is 30 to 50 μm, and the length in the Y-axis direction is 480 to 500 μm; the width of the vibration arm 112B in the X-axis direction is 60 to 100 μm, and the length in the Y-axis direction is 480 to 500 μm.

[0033] Optionally, the preset intervals between two adjacent vibration arms may be the same. For example, the preset interval between the vibration arm 112A and the vibration arm 112B is 40 to 60 μm. Optionally, the sum of the widths of the two outermost vibration arms in the X-axis direction is substantially the same as the sum of the widths of the inner vibration arms in the X-axis direction. It should be noted that, in this application, the two outermost vibration arms are collectively referred to as outer vibration arms, and the other vibration arms located between the outer vibration arms are collectively referred to as inner vibration arms.

[0034] For example, see Figure 1The outer vibration arms are vibration arms 112A and 112C, and only one inner vibration arm is vibration arm 112B. The sum of the widths of the vibration arms 112A and 112C in the X-axis direction is equal to the width of the vibration arm 112B in the X-axis direction.

[0035] In some other embodiments, when the number of the inner vibration arms is greater than two, the width of each inner vibration arm in the X-axis direction may be smaller than the width of each outer vibration arm in the X-axis direction.

[0036] In this embodiment, the base 111 may include a front end portion 111A connected to the fixed end of the vibration arm 112 and a rear end portion opposite to the front end portion 111A.

[0037] The base 111 also has a left end 111C and a right end 111D. It can be understood that the front end 111A, the rear end 111B, the left end 111C and the right end 111D are respectively part of the outer edge of the base 111. Specifically, the front end 111A and the rear end 111B are opposite to each other in the Y-axis direction. The left end 111C and the right end 111D are opposite to each other in the X-axis direction.

[0038] The shape of the base 111 is a generally rectangular shape with the front end 111A and the rear end 111B as short sides and the left end 111C and the right end 111D as long sides. Figure 1 The rectangular shape shown in the figure may also be other shapes. For example, the shape of the base 111 may also be a trapezoidal shape in which one of the front end 111A and the rear end 111B is longer than the other. In addition, at least one of the front end 111A, the rear end 111B, the left end 111C, and the right end 111D may be bent or curved.

[0039] Preferably, the base 111 is formed in a rectangular shape, and the left end portion 111C and the right end portion 111D are respectively flush with the outer side walls 112a and 112a' of the two outermost vibration arms 112 connected to the base 111. Figure 1 , the left end 111C and the right end 111D of the base 111 are respectively flush with the outer side walls 112a and 112a' of the two outermost vibration arms 112A and 112C connected to the base 111. In other words, the width of the base 111 in the X-axis direction can be determined by the width of each vibration arm 112A, 112B, 112C in the X-axis direction and the preset interval between the vibration arms 112A, 112B, 112C. For example, the width of the base 111 in the X-axis direction is 200 to 320 μm, and the length of the base 111 in the Y-axis direction is 50 to 80 μm.

[0040] In this embodiment, the anchor 12 is disposed around the vibration part 11 and is used to fix the vibration part 11. The shape of the anchor 12 is not described in detail, and it only needs to be able to fix the vibration part 11. For example, it can be formed into a rectangular frame structure surrounding the vibration part 11 along the XY plane, or the anchor 12 is at least a part disposed around the vibration part 11.

[0041] In this embodiment, the anchor 12 is spaced apart from the vibration part 11, and the connecting beam 13 is disposed between the anchor 12 and the vibration part 11. The vibration part 11 is connected to the anchor 12 via the connecting beam 13. In some embodiments, one end of the connecting beam 13 is connected to the base 111, and the other end is connected to the anchor 12. Optionally, one end of the connecting beam 13 is connected to the rear end 111B of the base 111, and the other end is connected to the anchor 12. Of course, it is not limited to this, and one end of the connecting beam 13 can also be connected to the left end 111C or the right end 111D of the base 111, and the other end is connected to the anchor 12. In some embodiments, the connecting beam 13 is spaced apart from the vibration part 11.

[0042] In some embodiments, see Figure 1 , the anchor 12 includes a first fixing portion 12A and a second fixing portion 12B. The connecting beam 13 includes a first connecting portion 131A and a second connecting portion 131B. The first connecting portion 131A connects the base 111 with the corresponding first fixing portion 12A, and the second connecting portion 131B connects the base 111 with the corresponding second fixing portion 12B. Optionally, the first fixing portion 12A and the second fixing portion 12B are arranged opposite to each other. The first connecting portion 131A and the second connecting portion 131B are arranged symmetrically.

[0043] In this application, for the convenience of description, according to Figure 1 As shown, the side facing the free end of the vibration arm 112 is defined as the front side, and the side opposite thereto is defined as the rear side; the side facing the outer arm 112a of the outermost vibration arm 112A is defined as the left side, and the side opposite thereto is defined as the right side.

[0044] In some embodiments, the first fixing portion 12A and the second fixing portion 12B are disposed in a region opposite to the sidewalls of the plurality of vibration arms 112. The plurality of vibration arms 112 are located between the first fixing portion 12A and the second fixing portion 12B. Figure 1 , the first fixing portion 12A and the second fixing portion 12B are disposed on the left and right sides of the plurality of vibration arms 112. For example, if the anchor 12 is formed as a rectangular frame surrounding the vibration portion 11 along the XY plane, the first fixing portion 12A and the second fixing portion 12B correspond to the left frame arm and the right frame arm of the anchor 12, respectively.

[0045] Of course, it is not limited to this. In other embodiments, the first fixing portion 12A and the second fixing portion 12B are disposed in a region opposite to the free ends of the plurality of vibration arms 112. That is, the first fixing portion 12A and the second fixing portion 12B are disposed in a front region of the free ends of the vibration arms 112. For example, if the anchor 12 is formed as a rectangular frame surrounding the vibration portion 11 along the XY plane, the first fixing portion 12A and the second fixing portion 12B correspond to the front frame arms of the anchor 12.

[0046] In some embodiments, the rear end portion 111B of the base 111 is connected to the first fixing portion 12A via the first connecting portion 131A, and the rear end portion 111B of the base 111 is connected to the second fixing portion 12B via the second connecting portion 131B.

[0047] Specifically, the first connecting portion 131A includes a first rear holding arm 132A and a first side holding arm 133A. The first rear holding arm 132A extends from the rear end portion 111B of the base 111 toward the rear side along the Y-axis direction, and is bent and toward the side where the first fixing portion 12A is located (such as Figure 1 The first holding side arm 133A extends from the end portion of the first holding rear arm 132A toward the left side along the Y-axis direction toward the front side, and is bent and connected to the first fixing portion 12A.

[0048] Similarly, the second connecting portion 131B may include a second rear holding arm 132B and a second side holding arm 133B. The second rear holding arm 132B extends from the rear end portion 111B of the base 111 toward the rear side along the Y-axis direction, and is bent and toward the side where the second fixing portion 12B is located (such as Figure 1 The second holding side arm 133B extends from the end of the second holding rear arm 132B toward the right side along the Y-axis direction toward the front side, and is bent and connected to the second fixing portion 12B. Optionally, the first connecting portion 131A and the second connecting portion 131B are symmetrically arranged.

[0049] In some embodiments, the first retaining side arm 133A and the second retaining side arm 133B are respectively spaced apart from adjacent vibration arms. The interval between the first retaining side arm 133A and the adjacent vibration arm is smaller than the preset interval between the two adjacent vibration arms, and the interval between the second retaining side arm 133B and the adjacent vibration arm is smaller than the preset interval between the two adjacent vibration arms.

[0050] Specifically, see Figure 1The first holding side arm 133A is adjacent to the outermost vibration arm 112A, and the two are arranged in parallel and spaced apart. The interval between the first holding side arm 113A and the outer arm 112a of the vibration arm 112A is 5 to 10 μm. The second holding side arm 133B is adjacent to the outermost vibration arm 112C, and the two are arranged in parallel and spaced apart. The interval between the second holding side arm 133B and the outer arm 112a' of the vibration arm 112C is 5 to 10 μm.

[0051] The connection beam 13 is not limited to the above-mentioned configuration. For example, the connection beam 13 may be connected to the left end 111C and the right end 111D of the base 111. In addition, the connection beam 13 may be connected to the front side frame of the anchor 12 in the form of a ring frame.

[0052] In some embodiments, the width of the connecting beam 13 may be no greater than the width of the vibration arm 112. For example, the widths of the first rear holding arm 132A and the first side holding arm 133A in the first connecting portion 131A are both 20-30 μm, which is smaller than the widths of the outermost vibration arms 112A and 112C.

[0053] In some embodiments, the resonator 1 may include a resonator body and a driving function layer G disposed on the resonator body. Fig.10 The resonator body may be a substrate F1 described later, and the driving function layer G includes a piezoelectric film F2 and a first metal film E1 and a second metal film E2 that are disposed opposite to each other with the piezoelectric film F2 sandwiched therebetween.

[0054] The first metal film E1 and the second metal film E2 respectively have an excitation electrode for exciting the vibration arm 112 and an extraction electrode for electrically connecting the excitation electrode to an external power supply or a ground potential. Specifically, the portions of the first metal film E1 and the second metal film E2 that function as excitation electrodes are opposed to each other on the vibration arm 112 via the piezoelectric film F2; the portions of the first metal film E1 and the second metal film E2 that function as extraction electrodes connect the base 111 to the anchor 12 via the connecting beam 13, so as to extract the excitation electrode to the anchor 12.

[0055] It should be noted that the vibration mode and vibration direction of the vibration part 11 are closely related to the piezoelectric properties of the piezoelectric film F2 thereon and the arrangement of the electrodes. In the embodiment of the present application, the piezoelectric resonator is configured as an out-of-plane vibration mode. Specifically, see Figure 2, the vibration arm 112 is configured to bend outside the XY plane. For example, the vibration arm 112A uses the connection with the base 111 as a node and bends and vibrates along the Z-axis direction. The base 111 will bend in the Z-axis direction under the action of the vibration arm 112A and the vibration arm 112B. As the base 111 bends, the connecting beam 13 will also bend in the Z-axis direction. The setting of the connecting beam 13 can further reduce the transmission of force, reduce the anchor loss, and improve the Q value.

[0056] It should be noted that the vibration part 11, the connecting beam 13, and the anchor 12 are integrally formed by the same process. Specifically, a substrate F1 (such as a Si substrate or an upper silicon layer in an SOI substrate) is provided, a driving function layer G is formed on the substrate F1, and a corresponding etching process is performed to form the vibration part 11, the connecting beam 13, and the anchor 11, and the vibration part 11 is released, that is, Fig.10 The vibrating part 11 in the middle faces the cavity K below.

[0057] In the embodiment of the present application, at least two of the multiple vibration arms can be bent outward in opposite directions. Specifically, the outer vibration arms (such as vibration arms 112A and 112C) located on the outermost sides have the same vibration direction, and the inner vibration arms (such as vibration arm 112B) located on the inner sides have the same vibration direction, and the vibration direction of the outer vibration arms is opposite to the vibration direction of the inner vibration arms.

[0058] In this embodiment, the first metal film E1, the piezoelectric film F2 and the second metal film E2 may be patterned and configured with electrodes so that the corresponding vibration arms have opposite vibration directions. The excitation electrodes may include driving electrodes and detection electrodes.

[0059] For example, the first metal film E1 on one of the two vibration arms vibrating in opposite directions is configured as a driving electrode, and the second metal film E2 is configured as a detection electrode; the first metal film E1 on the other vibration arm is configured as a detection electrode, and the second metal film E2 is configured as a driving electrode. In this way, the two vibration arms can vibrate in opposite directions.

[0060] The above embodiment will be described in detail below with the assumption that the number of the vibration arms 112 is three ( 112A, 112B, and 112C).

[0061] At this time, the electrode configuration on the inner vibration arm 112B is opposite to the electrode configuration on the two outermost vibration arms 112A / 112C, so that the vibration direction of the inner vibration arm 112B is opposite to the vibration direction of the two outermost vibration arms 112A / 112C. Specifically, the configuration of the driving electrodes and the detection electrodes on the two outermost vibration arms 112A / 112C is opposite to the configuration of the driving electrodes and the detection electrodes on the inner vibration arm 112B.

[0062] At this time, the electrodes on the vibration arm 112A, the vibration arm 112B and the vibration arm 112C may be configured as follows:

[0063] For example, the first metal film E1 on the vibration arm 112A is configured as a driving electrode, and the second metal film E2 is configured as a detection electrode, so that the vibration arm 112A vibrates up and down along the Z-axis direction. Of course, it is not limited to this, and the arrangement of the second metal film E2 and the first metal film E1 is reversed, which is also applicable. That is, the first metal film E1 on the vibration arm 112A is configured as a detection electrode, and the second metal film E2 is configured as a driving electrode.

[0064] It can be understood that the arrangement of the outermost vibration arm 112C is exactly the same as that of the vibration arm 112A; the selection and arrangement of the driving electrode and the detection electrode in the vibration arm 112B are opposite to those of the vibration arm 112A and the vibration arm 112C, that is, if the first metal film E1 is selected as the driving electrode and the second metal film E2 is configured as the detection electrode on the vibration arm 112A and the vibration arm 112C; then the second metal film E1 is selected as the detection electrode and the second metal film E2 is configured as the driving electrode on the vibration arm 112B; so that the vibration directions of the vibration arms 112A, 112C and the vibration arm 112B are opposite.

[0065] In this case, the forces acting on the base 111 when the vibration arms 112A, 112C and the vibration arm 112B vibrate are in opposite directions and can cancel each other out, thereby reducing the force transmitted from the base 111 to the anchor 12 via the connecting beam 13, and the design of the connecting beam 13 can further reduce the transmission of force, thereby reducing the anchor loss and improving the quality factor of the resonator. Moreover, by adopting the electrode driving method of this embodiment, the motion impedance of the piezoelectric resonator is significantly reduced, such as reduced to 4 to 5 times the original, and there is no interfering stray mode near the piezoelectric resonance frequency of the current design (about 5KHz before and after), and the desired resonance frequency can be obtained more stably.

[0066] For example, the existing electrode driving method is specifically as follows: the excitation electrode may include a driving electrode, a detection electrode and a grounding electrode, wherein the second metal film E2 on the vibration arm is patterned and then divided to form a driving electrode and a detection electrode, and the first metal film E1 on the vibration arm is formed as a grounding electrode; or, the first metal film E1 and the second metal film E2 are interchanged, that is, the metal film E1 is patterned and then divided to form a driving electrode and a detection electrode, and the metal film E2 is formed as a grounding electrode. Figure 1 The resonator 1 in the embodiment adopts two different electrode configurations, the present embodiment and the existing one. The impedance corresponding to the existing electrode configuration is 266KΩ, while the impedance corresponding to the electrode configuration of the present embodiment is 61KΩ, which is reduced by more than 4 times.

[0067] In one embodiment, the resonant frequency of the resonator 1 designed by the present application can be configured to be in the KHz range, specifically, about 32 KHz. For example, Figure 2 The resonator 1 is driven by the above electrode configuration, and the resonant frequency can reach 32.855KHz, and the Q value can reach 7.46e+05. The resonator 1 of the present application can meet the required resonant frequency requirements and has a high quality factor.

[0068] In summary, the piezoelectric resonator provided in the embodiment of the present application includes a resonator 1, which may include a vibration part 11, an anchor 12 and a connecting beam 13. Among them, the vibration part includes a base 111 and at least three vibration arms. One end of the connecting beam 13 is connected to the base 111; the anchor 12 is connected to the other end of the connecting beam 13. The present application improves the Q value of the piezoelectric resonator and reduces the motion impedance of the piezoelectric resonator by optimizing the structure of the vibration part 11 and the connecting beam 13, as well as the electrode configuration.

[0069] The present application also provides a method for manufacturing a piezoelectric resonator. Figure 3 The specific process of the manufacturing method of the piezoelectric resonator can be as follows:

[0070] S1. Provide a wafer.

[0071] See also Figure 4 The wafer may be a SOI wafer, wherein the upper silicon layer in the SOI wafer serves as the substrate F1.

[0072] S2. Forming a driving function layer G on the wafer.

[0073] In this step, see Figure 5 and Figure 6 The first metal film E1, the piezoelectric film F2 and the second metal film E2 are deposited on the substrate F1 and then patterned accordingly to form the driving function layer G. The driving function layer G is used to drive the vibration part 11 to vibrate after receiving a driving signal.

[0074] Specifically, a layer of metal material is deposited on the substrate F1 to form a first metal film E1, and a layer of piezoelectric material is deposited on the first metal film E1 to form a piezoelectric film F2; then, the piezoelectric film F2 is patterned by dry etching to form a piezoelectric layer; then, the first metal film E1 is patterned by dry etching or wet etching to form a bottom electrode (such as the ground electrode in the first electrode configuration, or the detection electrode in the second electrode configuration, etc.); then, a layer of metal material is deposited on the piezoelectric layer to form a second metal film E2, and photoresist is deposited on the second metal film E2, and the photoresist is patterned; then, the second metal film E2 is patterned using the patterned photoresist as a mask to form a top electrode (such as the driving electrode and the detection electrode in the first electrode configuration, or the driving electrode in the second electrode configuration, etc.), and the formed bottom electrode, piezoelectric layer and top electrode constitute a driving function layer G.

[0075] Of course, it is not limited to this. The present application may also adopt other process steps to form the driving function layer G. For example, the first metal film E1 may be patterned to form a bottom electrode, and then a piezoelectric film F2 may be formed on the bottom electrode and patterned to form a piezoelectric layer; then, a second metal film E2 is deposited on the piezoelectric layer, and a photoresist is deposited on the second metal film E2, and the photoresist is patterned; then, the second metal film E2 is patterned using the patterned photoresist as a mask to form a top electrode, such as forming a connecting hole 21 exposing the bottom electrode, and the first groove C and isolation groove L described above may be formed during the patterning process.

[0076] Optionally, the metal material may be molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or the like, and the piezoelectric material may be aluminum nitride, zinc oxide, PZT or the like.

[0077] In addition, in some embodiments, see Figure 7 A protective film F3 is grown on the second metal film E2 to protect the second metal film E2 and inhibit its oxidation.

[0078] Specifically, an insulating material can be deposited on the second metal film E2 to form a protective film F3, and then the protective film F3 is etched to selectively remove the insulating protective layer to form a number of electrical connection holes, which respectively expose the top electrode or the bottom electrode. The number of electrical connection holes may include a connection hole 21 and a via 22, etc.

[0079] See also Figure 8 Metal materials such as AL can be deposited in several electrical connection holes to form conductive members, such as the conductive member 21A disposed in the connection hole 21 and the conductive member 22B disposed in the via hole 22, so as to lead out the bottom electrode and the top electrode.

[0080] S3 , etching the wafer to form the vibration part 11 , the connecting beam 13 and the anchor 12 .

[0081] See also Fig. 9 , the substrate F1 in the SOI wafer is etched as a device layer, and the etching is performed from the side where the driving function layer G is located toward the SOI wafer, and the substrate F1 and the driving function layer G thereon are selectively removed to form the vibration part 11, the connecting beam 13 and the anchor 12. Specifically, the SOI wafer can have a connected main body area 1A and an anchor area 1B; the substrate F1 of the SOI wafer located in the main body area 1A is etched to form the vibration part 11 and the connecting beam 13, and the SOI wafer located in the anchor area 1B forms the anchor 12.

[0082] It is understandable that in order to protect the driving function layer G, the conductive parts, etc. from being damaged, a layer of insulating material can be deposited to form a protective layer before etching. After etching, a layer of protective material is deposited to facilitate the subsequent release of the vibration part 11. The protective material can fill the gap generated by etching to prevent part of the material from entering the etching gap when the vibration part 11 is released in step S4, thereby affecting the vibration part 11. After releasing the vibration part 11, the protective material and the protective layer are removed in turn.

[0083] S4. Release the vibration unit 11.

[0084] See also Fig.10 , the SOI wafer can be selectively removed from the back side of the SOI wafer, that is, the side away from the driving function layer G, to form a cavity K to release the vibration part 11.

[0085] Specifically, at least the SOI wafer below the substrate F1 of the main area 1A is etched to form a cavity K, so that the vibration part 11 is arranged opposite to the cavity K, that is, the cavity K is formed below the vibration part 11, so as to release the vibration part 11 and facilitate the operation of the vibration part 11. It can be understood that the outline size of the cavity K can be larger than the area size of the main area 1A, and the cavity K can cover the main area 1A in the projection on a horizontal plane.

[0086] In summary, the piezoelectric resonator formed by the piezoelectric resonator manufacturing method provided in the embodiment of the present application can improve the Q value of the piezoelectric resonator and reduce the motion impedance of the piezoelectric resonator by optimizing the structure of the vibration part 11 and the connecting beam 13, as well as the electrode configuration.

[0087] The piezoelectric resonator provided in the present application is introduced in detail above. The principles and implementation methods of the present application are explained by using specific examples in the present application. The description of the above embodiments is only used to help understand the core idea of ​​the present application. At the same time, for technicians in this field, according to the idea of ​​the present application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A piezoelectric resonator, comprising a resonator, characterized in that: The resonator comprises: A vibration part, the vibration part comprising a base and at least three vibration arms; each vibration arm extends along the Y-axis direction and is arranged side by side in the X-axis direction at a preset interval, and the X-axis and the Y-axis constitute a plane rectangular coordinate system; each vibration arm can be bent outward relative to the XY plane, and at least two of the vibration arms can be bent outward in opposite directions; the width of the two vibration arms located on the outermost sides in the X-axis direction is smaller than the width of the vibration arms located on the inner side in the X-axis direction; each vibration arm has a fixed end and a free end, and the base has a front end connected to the fixed end of each vibration arm and a rear end opposite to the front end; An anchoring member, disposed around the vibrating portion and used to fix the vibrating portion; A connecting beam is arranged between the anchor and the vibration part, one end of the connecting beam is connected to the base, and the other end of the connecting beam is connected to the anchor.

2. The piezoelectric resonator according to claim 1, wherein The two outermost vibration arms have the same width in the X-axis direction.

3. The piezoelectric resonator according to claim 1, wherein The resonator includes a resonator body and a driving function layer arranged on the resonator body, the driving function layer has a piezoelectric film and a first metal film and a second metal film arranged opposite to each other with the piezoelectric film sandwiched therebetween; one of the first metal film and the second metal film on each vibration arm is configured as a driving electrode, and the other is configured as a detection electrode.

4. The piezoelectric resonator according to claim 3, wherein The configuration of the driving electrodes and the detecting electrodes on the two outermost vibration arms is opposite to the configuration of the driving electrodes and the detecting electrodes on the inner vibration arms.

5. The piezoelectric resonator according to claim 1, wherein If the vibration arm is bent out of plane, the base and the connecting beam will bend along with the vibration arm in the direction of the out-of-plane bending.

6. The piezoelectric resonator according to claim 1, wherein One end of the connecting beam is connected to the rear end portion of the base.

7. The piezoelectric resonator according to claim 1, wherein The anchor has a first fixing portion and a second fixing portion arranged opposite to each other, the first fixing portion and the second fixing portion are arranged in an area opposite to the side walls of the multiple vibration arms, and the multiple vibration arms are located between the first fixing portion and the second fixing portion; the connecting beam includes a first connecting portion and a second connecting portion, one end of the first connecting portion is connected to the rear end portion of the base, and the other end is connected to the first fixing portion; one end of the second connecting portion is connected to the rear end portion of the base, and the other end is connected to the second fixing portion.

8. The piezoelectric resonator according to claim 7, wherein The first connecting portion includes a first holding rear arm and a first holding side arm, the first holding rear arm extending from the rear end of the base along the Y-axis direction, being bent and extending along the X-axis direction toward the side where the first fixing portion is located, and the first holding side arm extending from the end of the first holding rear arm along the Y-axis direction toward the side where the free end of the vibration arm is located, being bent and connected to the first fixing portion; The second connecting portion includes a second retaining rear arm and a second retaining side arm, the second retaining rear arm extends from the rear end portion of the base along the Y-axis direction, is bent and extends along the X-axis direction toward the side where the second fixed portion is located, and the second retaining side arm extends from the end portion of the second retaining rear arm along the Y-axis direction toward the side where the free end of the vibration arm is located, is bent and connected to the second fixed portion.

9. The piezoelectric resonator according to claim 8, wherein The first connection portion and the second connection portion are symmetrically arranged.

10. The piezoelectric resonator according to claim 8, wherein The first holding side arm and the second holding side arm are both spaced apart from the adjacent vibration arm, and the interval between the first holding side arm and the adjacent vibration arm is smaller than the preset interval, and the interval between the second holding side arm and the adjacent vibration arm is smaller than the preset interval.

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