Resonator and Resonance Device

Abstract

Provided are a resonator and a resonating device which make it possible to suppress occurrence of a combination of main mode vibration and spurious mode vibration.　A resonator 10 is provided with: a vibration unit 110 including three or more of vibration arms 121 which respectively have fixed ends, and at least two of which are bent out of plane in different phases, and including a base 130 having one end to which the fixed ends of the vibration arms 121 are connected and the other end opposite to the one end; a holding unit 140 configured to hold the vibration unit 110; and a support arm 151 connected, at one end thereof, to the holding unit 140 and connected, at the other end thereof, to the other end of the base 130. The support arm 151 has a reduction membrane LM configured to reduce a Q-factor of vibration of the support arm 151.

Description

Technical Field

[0001] The present invention relates to a resonator and a resonance device in which a plurality of vibrating arms vibrate in an out-of-plane bending vibration mode.

Background Art

[0002] Conventionally, a resonance device using MEMS (Micro Electro Mechanical Systems) technology has been used, for example, as a timing device. This resonance device is mounted on a printed circuit board incorporated in an electronic device such as a smartphone. The resonance device includes a lower substrate, an upper substrate that forms a cavity with the lower substrate, and a resonator disposed in the cavity between the lower substrate and the upper substrate.

[0003] For example, Patent Document 1 discloses a resonator that changes the resonance frequency by over-exciting a vibrating arm and causing an adjustment film at the tip of the vibrating arm to collide with the upper substrate or the lower substrate in a frequency adjustment process for finely adjusting the resonance frequency of the resonator.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] On the other hand, when the vibrating arm vibrates in the main mode, spurious mode vibrations occur in parts other than the vibrating arm, such as the support arm. When certain conditions are met, the main mode vibration and the spurious mode vibration may combine.

[0006] When the combination of the main mode vibration and the spurious mode vibration occurs, there are risks such as, for example, a large fluctuation in the resonance frequency or an increase in the equivalent series resistance.

[0007] The present invention has been made in view of such circumstances, and one of its objects is to provide a resonator and a resonance device capable of suppressing the occurrence of the coupling between the vibration of the main mode and the vibration of the spurious mode.

Means for Solving the Problems

[0008] A resonator according to one aspect of the present invention includes a plurality of vibrating arms having three or more, each having a fixed end, wherein at least two of the vibrating arms bend out of the plane in different phases, a vibrating portion including a base having one end to which the fixed ends of the plurality of vibrating arms are connected and the other end facing the one end, a holding portion configured to hold the vibrating portion, and a support arm having one end connected to the holding portion and the other end connected to the other end of the base, and the support arm has a reduction film configured to reduce the Q value in the vibration of the support arm.

[0009] A resonance device according to one aspect of the present invention includes the resonator described above.

Effects of the Invention

[0010] According to the present invention, the occurrence of the coupling between the vibration of the main mode and the vibration of the spurious mode can be suppressed.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

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Figure 10

Figure 11

Mode for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described. In the following description of the drawings, the same or similar components are denoted by the same or similar reference numerals. The drawings are illustrative, and the dimensions and shapes of each part are schematic, and the technical scope of the present invention should not be construed as being limited to the embodiments.

[0013] First, with reference to FIGS. 1 and 2, the schematic configuration of a resonance device according to an embodiment will be described. FIG. 1 is a perspective view schematically showing the appearance of a resonance device 1 in an embodiment. FIG. 2 is an exploded perspective view schematically showing the structure of the resonance device 1 shown in FIG. 1.

[0014] The resonance device 1 includes a lower lid 20, a resonator 10, and an upper lid 30. That is, the resonance device 1 is configured by laminating the lower lid 20, the resonator 10, a joint portion 40 described later, and the upper lid 30 in this order. The lower lid 20 and the upper lid 30 are arranged so as to face each other with the resonator 10 interposed therebetween. The upper lid 30 corresponds to an example of the "lid body" of the present invention.

[0015] Hereinafter, each component of the resonance device 1 will be described. In the following description, the side where the upper lid 30 is provided in the resonance device 1 is defined as the upper (or front) side, and the side where the lower lid 20 is provided is defined as the lower (or back) side for explanation.

[0016] The resonator 10 is a MEMS oscillator manufactured using MEMS technology. This MEMS oscillator is applied to, for example, timing devices, RF filters, duplexers, ultrasonic transducers, angular velocity sensors (gyro sensors), acceleration sensors, etc. It may also be used for piezoelectric mirrors with actuator functions, piezoelectric gyros, piezoelectric microphones with pressure sensor functions, ultrasonic vibration sensors, etc. Furthermore, it may be applied to electrostatic MEMS oscillators, electromagnetic drive MEMS oscillators, and piezoresistive MEMS oscillators.

[0017] The resonator 10, the lower lid 20, and the upper lid 30 are joined so that the resonator 10 is sealed and a vibration space for the resonator 10 is formed. Also, the resonator 10, the lower lid 20, and the upper lid 30 are each formed using a silicon (Si) substrate (hereinafter referred to as the "Si substrate"), and the Si substrates are joined to each other. Note that the resonator 10, the lower lid 20, and the upper lid 30 may each be formed using a SOI (Silicon On Insulator) substrate on which a silicon layer and a silicon oxide film are laminated.

[0018] The lower lid 20 includes a rectangular flat bottom plate 22 provided along the XY plane, and side walls 23 extending in the Z-axis direction from the peripheral edge of the bottom plate 22, that is, in the stacking direction of the lower lid 20 and the resonator 10. In the lower lid 20, a recess 21 defined by the surface of the bottom plate 22 and the inner surface of the side walls 23 is formed on the surface facing the resonator 10. The recess 21 forms at least a part of the vibration space of the resonator 10. Note that the lower lid 20 may have no recess 21 and may have a flat plate configuration. Also, a getter layer may be formed on the surface of the recess 21 of the lower lid 20 on the side of the resonator 10.

[0019] Further, the lower cover 20 includes a protrusion 50 formed on the surface of the bottom plate 22. Details of the protrusion 50 will be described later.

[0020] The upper cover 30 includes a rectangular flat bottom plate 32 provided along the XY plane, and side walls 33 extending in the Z-axis direction from the peripheral edge of the bottom plate 32 A recess 31 defined by the surface of the bottom plate 32 and the inner surface of the side wall 23 is formed on the surface of the upper cover 30 facing the resonator 10. The recess 31 forms at least a part of the vibration space in which the resonator 10 vibrates. Note that the upper cover 30 may have no recess 31 and may have a flat plate-like configuration. Also, a getter layer may be formed on the surface of the recess 31 of the upper cover 30 on the side of the resonator 10.

[0021] By joining the upper cover 30, the resonator 10, and the lower cover 20, the vibration space of the resonator 10 is hermetically sealed and a vacuum state is maintained. This vibration space may be filled with a gas such as an inert gas.

[0022] Next, with reference to FIG. 3, a schematic configuration of the resonator according to the first embodiment will be described. FIG. 3 is a plan view schematically showing the structure of the resonator 10 shown in FIG. 2.

[0023] As shown in FIG. 3, the resonator 10 is a MEMS oscillator manufactured using MEMS technology, and vibrates with an out-of-plane bending vibration mode as the main vibration (hereinafter, also referred to as the "main mode") in the XY plane in the orthogonal coordinate system of FIG. 3.

[0024] The resonator 10 includes a vibrating portion 110, a holding portion 140, and a support arm 151.

[0025] The vibrating part 110 has a rectangular contour that extends along the XY plane in the orthogonal coordinate system of FIG. 3. The vibrating part 110 is disposed inside the holding part 140, and a space is formed between the vibrating part 110 and the holding part 140 at a predetermined interval. In the example of FIG. 3, the vibrating part 110 includes an exciting part 120 composed of four vibrating arms 121A to 121D (hereinafter also collectively referred to as "vibrating arms 121") and a base part 130. Note that the number of vibrating arms is not limited to four, and is set to an arbitrary number of three or more, for example. In the present embodiment, the exciting part 120 and the base part 130 are integrally formed.

[0026] The vibrating arms 121A, 121B, 121C, and 121D each extend along the Y-axis direction and are provided in parallel at a predetermined interval in the X-axis direction in this order. One end of the vibrating arm 121A is a fixed end connected to the front end part 131A of the base part 130 described later, and the other end of the vibrating arm 121A is an open end provided away from the front end part 131A of the base part 130. The vibrating arm 121A includes a weight part 122A formed on the open end side and an arm part 123A that extends from the fixed end and is connected to the weight part 122A. Similarly, the vibrating arms 121B, 121C, and 121D also include weight parts 122B, 122C, and 122D and arm parts 123B, 123C, and 123D, respectively. Note that the arm parts 123A to 123D each have a width of about 25 μm in the X-axis direction and a length of about 246 μm in the Y-axis direction, for example.

[0027] In the excitation unit 120 of the present embodiment, in the X-axis direction, two vibration arms 121A and 121D are arranged on the outside, and two vibration arms 121B and 121C are arranged on the inside. The width of the gap (hereinafter referred to as "release width") W1 formed between the respective arm portions 123B and 123C of the two inner vibration arms 121B and 121C is, for example, larger than the release width W2 between the respective arm portions 123A and 123B of the adjacent vibration arms 121A and 121B in the X-axis direction, and the release width W2 between the respective arm portions 123D and 123C of the adjacent vibration arms 121D and 121C in the X-axis direction. The release width W1 is, for example, about 38 μm, and the release width W2 is, for example, about 17 μm. By setting the release width W1 to be larger than the release width W2 in this way, the vibration characteristics and durability of the vibration unit 110 are improved. Note that, in order to miniaturize the resonance device 1, the release width W1 may be set to be smaller than the release width W2, or may be set at equal intervals.

[0028] The weight portions 122A to 122D (hereinafter also collectively referred to as "weight portion 122") are each provided with a mass addition film 125A to 125D (hereinafter also collectively referred to as "mass addition film 125") on its surface. Therefore, the weight per unit length of each of the weight portions 122A to 122D (hereinafter simply referred to as "weight") is heavier than the weight of each of the arm portions 123A to 123D. Thereby, while miniaturizing the vibration unit 110, the vibration characteristics can be improved. In addition, the mass addition films 125A to 125D not only function to increase the weight of the tip portions of the vibration arms 121A to 121D, but also have a function as a so-called frequency adjustment film that adjusts the resonance frequency of the vibration arms 121A to 121D by removing a part thereof.

[0029] In this embodiment, the width along the X-axis direction of each of the weight portions 122A to 122D is, for example, about 46 μm, which is larger than the width along the X-axis direction of each of the arm portions 123A to 123D. Thereby, the weight of each of the weight portions 122A to 122D can be made even larger. For miniaturization of the resonator 10, it is preferable that the width along the X-axis direction of each of the weight portions 122A to 122D is 1.5 times or more the width along the X-axis direction of each of the arm portions 123A to 123D. However, the weight of each of the weight portions 122A to 122D only needs to be larger than the weight of each of the arm portions 123A to 123D, and the width along the X-axis direction of each of the weight portions 122A to 122D is not limited to the example of this embodiment. The width along the X-axis direction of each of the weight portions 22A to 122D may be equal to or less than the width along the X-axis direction of each of the arm portions 123A to 123D.

[0030] When the resonator 10 is viewed from above in a plan view (hereinafter simply referred to as "plan view"), each of the weight portions 122A to 122D has a substantially rectangular shape and has a curved surface shape with rounded corners at the four corners, for example, a so-called R shape. Similarly, each of the arm portions 123A to 123D has a substantially rectangular shape and has an R shape near the fixed end connected to the base portion 130 and near the connection portion connected to each of the weight portions 122A to 122D. However, the shape of each of the weight portions 122A to 122D and the arm portions 123A to 123D is not limited to the example of this embodiment. For example, the shape of each of the weight portions 122A to 122D may be a substantially trapezoidal shape or a substantially L-shaped. Also, the shape of each of the arm portions 123A to 123D may be a substantially trapezoidal shape or a substantially L-shaped. Each of the weight portions 122A to 122D and the arm portions 123A to 123D may be formed with a bottomed groove portion having an opening on either the front surface side or the back surface side, or a hole portion having openings on both the front surface side and the back surface side. The groove portion and the hole portion may be away from the side surface connecting the front surface and the back surface, or may have an opening on the side surface side.

[0031] The base 130 has, in plan view, a front end portion 131A, a rear end portion 131B, a left end portion 131C, and a right end portion 131D. As described above, the fixed ends of the respective vibration arms 121A to 121D are connected to the front end portion 131A. A support arm 151 is connected to the rear end portion 131B.

[0032] The front end portion 131A, the rear end portion 131B, the left end portion 131C, and the right end portion 131D are each a part of the outer edge of the base 130. Specifically, the front end portion 131A and the rear end portion 131B are each an end portion extending in the X-axis direction, and the front end portion 131A and the rear end portion 131B are arranged to face each other. The left end portion 131C and the right end portion 131D are each an end portion extending in the Y-axis direction, and the left end portion 131C and the right end portion 131D are arranged to face each other. Both ends of the left end portion 131C are connected to one end of the front end portion 131A and one end of the rear end portion 131B, respectively. Both ends of the right end portion 131D are connected to the other end of the front end portion 131A and the other end of the rear end portion 131B, respectively.

[0033] In plan view, the base 130 has a substantially rectangular shape with the front end portion 131A and the rear end portion 131B as the long sides and the left end portion 131C and the right end portion 131D as the short sides. The base 130 is formed substantially symmetric with respect to a virtual plane defined along the center line CL1 in the X-axis direction, which is the perpendicular bisector of each of the front end portion 131A and the rear end portion 131B. That is, it can also be said that the base 130 is formed substantially line-symmetric with respect to the center line CL1. Note that the shape of the base 130 is not limited to the rectangular shape shown in FIG. 3, and other shapes that constitute substantially line-symmetry with respect to the center line CL1 may also be acceptable. For example, the shape of the base 130 may be a trapezoidal shape in which one of the front end portion 131A and the rear end portion 131B is longer than the other. Also, at least one of the front end portion 131A, the rear end portion 131B, the left end portion 131C, and the right end portion 131D may be bent or curved.

[0034] The virtual plane corresponds to the plane of symmetry of the entire vibrating portion 110, and the center line CL1 corresponds to the center line in the X-axis direction of the entire vibrating portion 110. Therefore, the center line CL1 is also a line passing through the centers of the vibrating arms 121A to 121D in the X-axis direction and is located between the vibrating arm 121B and the vibrating arm 121C. Specifically, each of the adjacent vibrating arms 121A and 121B is symmetrically formed with respect to each of the adjacent vibrating arms 121D and 121C across the center line CL1.

[0035] In the base portion 130, the base length, which is the longest distance in the Y-axis direction between the front end portion 131A and the rear end portion 131B, is, for example, about 25 μm. Also, the base width, which is the longest distance in the X-axis direction between the left end portion 131C and the right end portion 131D, is, for example, about 172 μm. In the example shown in FIG. 3, the base length corresponds to the length of the left end portion 131C or the right end portion 131D, and the base width corresponds to the length of the front end portion 131A or the rear end portion 131B.

[0036] The holding portion 140 is configured to hold the vibrating portion 110. More specifically, the holding portion 140 is configured such that the vibrating arms 121A to 121D can vibrate. Specifically, the holding portion 140 is formed symmetrically with respect to the virtual plane defined along the center line CL1. The holding portion 140 has a rectangular frame shape in plan view and is arranged to surround the outside of the vibrating portion 110 along the XY plane. In this way, by having the holding portion 140 have a frame shape in plan view, the holding portion 140 surrounding the vibrating portion 110 can be easily realized.

[0037] Note that the holding portion 140 only needs to be arranged at at least a part of the periphery of the vibrating portion 110 and is not limited to a frame shape. For example, the holding portion 140 may be arranged around the vibrating portion 110 to hold the vibrating portion 110 and also to be joined to the upper lid 30 and the lower lid 20.

[0038] In the present embodiment, the holding portion 140 includes frame bodies 141A to 141D that are integrally formed. As shown in FIG. 3, the frame body 141A is provided with its longitudinal direction parallel to the X-axis facing the open ends of the vibrating arms 121A to 121D. The frame body 141B is provided with its longitudinal direction parallel to the X-axis facing the rear end portion 131B of the base portion 130. The frame body 141C is provided with its longitudinal direction parallel to the Y-axis facing the left end portion 131C of the base portion 130 and the vibrating arm 121A, and is connected to one end of the frame body 141A at both ends thereof. 141B The frame body 141D is provided with its longitudinal direction parallel to the Y-axis facing the right end portion 131D of the base portion 130 and the vibrating arm 121A, and is connected to the other ends of the frame bodies 141A and 141B at both ends thereof. The frame body 141A and the frame body 141B face each other in the Y-axis direction with the vibrating portion 110 interposed therebetween. The frame body 141C and the frame body 141D face each other in the X-axis direction with the vibrating portion 110 interposed therebetween.

[0039] The support arm 151 is disposed inside the holding portion 140 and connects the base portion 130 and the holding portion 140. The support arm 151 is not line-symmetric with respect to the center line CL1 in plan view, that is, it is formed asymmetrically. Specifically, the support arm 151 includes a support rear arm 152 and a support side arm 153.

[0040] The support side arm 153 extends in parallel with the vibrating arm 121D between the vibrating arm 121D and the holding portion 140. Specifically, the support side arm 153 extends from one end (the right end or the end on the frame body 141D side) of the support rear arm 152 toward the frame body 141A in the Y-axis direction, bends in the X-axis direction, and is connected to the frame body 141D. That is, one end of the support arm 151 is connected to the holding portion 140.

[0041] The support rear arm 152 extends between the rear end portion 131B of the base portion 130 and the holding portion 140. Specifically, the support rear arm 152 extends from one end (the lower end or the end on the frame body 141B side) of the support side arm 153 toward the frame body 141C in the X-axis direction. Then, the support rear arm 152 bends in the Y-axis direction near the center in the X-axis direction in the base portion 130, and extends parallel to the center line CL1 from there and is connected to the rear end portion 131B of the base portion 130. That is, the other end of the support arm 151 is connected to the rear end portion 131B of the base portion 130.

[0042] The protrusion 50 protrudes into the vibration space from the recess 21 of the lower lid 20. The protrusion 50 is disposed between the arm portion 123B of the vibration arm 121B and the arm portion 123C of the vibration arm 121C in a plan view. The protrusion 50 extends in the Y-axis direction parallel to the arm portions 123B and 123C and is formed in a prism shape. The length of the protrusion 50 in the Y-axis direction is about 200 μm, and the length in the X-axis direction is about 15 μm. Note that the number of the protrusions 50 is not limited to one, and may be two or more. In this way, since the protrusion 50 is disposed between the vibration arm 121B and the vibration arm 121C and protrudes from the bottom plate 22 of the recess 21, the rigidity of the lower lid 20 can be increased, and the deflection of the resonator 10 formed on the lower lid 20 and the warping of the lower lid 20 can be suppressed.

[0043] Next, with reference to FIGS. 4 and 5, the laminated structure and operation of the resonance device according to the first embodiment will be described. FIG. 4 is a cross-sectional view taken along the X-axis schematically showing the laminated structure of the resonance device 1 shown in FIG. 1. FIG. 5 is a cross-sectional view taken along the Schematic Y-axis shown in FIG. 1. The cross-section of FIG. 5 is parallel to the frame body 141D and is a cross-section passing through the vibration arm 121D.

[0044] As shown in FIGS. 4 and 5, in the resonance device 1, the holding portion 140 of the resonator 10 is joined to the side wall 23 of the lower lid 20, and further, the holding portion 140 of the resonator 10 and the side wall 33 of the upper lid 30 are joined. In this way, the resonator 10 is held between the lower lid 20 and the upper lid 30, and a vibration space in which the vibrating portion 110 vibrates is formed by the lower lid 20, the upper lid 30, and the holding portion 140 of the resonator 10.

[0045] In the resonator 10, the vibrating portion 110, the holding portion 140, and the support arm 151 are integrally formed by the same process. The resonator 10 has a metal film E1 laminated on an Si substrate F2 which is an example of a substrate. Then, a piezoelectric film F3 is laminated on the metal film E1 so as to cover the metal film E1, and further, a metal film E2 is laminated on the piezoelectric film F3. A protective film F5 is laminated on the metal film E2 so as to cover the metal film E2. In the weight portions 122A to 122D, the above-described mass addition films 125A to 125D are further laminated on the protective film F5, respectively. The outer shapes of the vibrating portion 110, the holding portion 140, and the support arm 151 are formed by removing and patterning a laminate composed of the above-described Si substrate F2, metal film E1, piezoelectric film F3, metal film E2, protective film F5, etc. by dry etching.

[0046] In this embodiment, an example in which the resonator 10 includes the metal film E1 is shown, but the present invention is not limited thereto. For example, in the resonator 10, by using a degenerate silicon substrate having a low resistance for the Si substrate F2, the Si substrate F2 itself can also serve as the metal film E1, and the metal film E1 may be omitted.

[0047] The Si substrate F2 is formed of, for example, a degenerated n-type silicon (Si) semiconductor having a thickness of about 6 μm and can contain phosphorus (P), arsenic (As), antimony (Sb), etc. as n-type dopants. Further, the resistance value of the degenerated silicon (Si) used for the Si substrate F2 is, for example, less than 1.6 mΩ·cm, more preferably 1.2 mΩ·cm or less. Further, on the lower surface of the Si substrate F2, a silicon oxide layer F21 such as SiO2 is formed as an example of a temperature characteristic correction layer. Thereby, it becomes possible to improve the temperature characteristics.

[0048] In the present embodiment, the silicon oxide layer F21 refers to a layer having a function of reducing the temperature coefficient of the frequency in the vibrating portion 110 when a temperature correction layer is formed on the Si substrate F2, that is, the change rate per temperature, at least in the vicinity of normal temperature, as compared with the case where the silicon oxide layer F21 is not formed on the Si substrate F2. By the vibrating portion 110 having the silicon oxide layer F21, for example, in the resonance frequency of the laminated structure of the Si substrate F2, the metal films E1 and E2, the piezoelectric film F3, and the silicon oxide layer F21, the change associated with temperature can be reduced. The silicon oxide layer may be formed on the upper surface of the Si substrate F2 or may be formed on both the upper surface and the lower surface of the Si substrate F2.

[0049] It is desirable that the silicon oxide layers F21 of the weight portions 122A to 122D be formed with a uniform thickness. Note that the uniform thickness means that the variation in the thickness of the silicon oxide layer F21 is within ±20% from the average value of the thickness.

[0050] The metal films E1 and E2 each include excitation electrodes that excite the vibrating arms 121A to 121D, and lead electrodes that electrically connect the excitation electrodes to an external power source. The portions of the metal films E1 and E2 that function as excitation electrodes face each other across the piezoelectric film F3 at the arm portions 123A to 123D of the vibrating arms 121A to 121D. The portions of the metal films E1 and E2 that function as lead electrodes are led out from the base portion 130 to the holding portion 140 via, for example, the support arm 151. The metal film E1 is electrically continuous across the entire resonator 10. The metal film E2 is electrically separated at the portions formed on the vibrating arms 121A and 121D and the portions formed on the vibrating arms 121B and 121C.

[0051] The thicknesses of the metal films E1 and E2 are each, for example, about 0.1 μm or more and 0.2 μm or less. After film formation, the metal films E1 and E2 are patterned into excitation electrodes, lead electrodes, etc. by removal processing such as etching. The metal films E1 and E2 are formed of, for example, a metal material having a body-centered cubic crystal structure. Specifically, the metal films E1 and E2 are formed using Mo (molybdenum), tungsten (W), etc. Thus, by using a metal having a body-centered cubic crystal structure as the main component of the metal films E1 and E2, the metal films E1 and E2 suitable for the lower electrode and the upper electrode of the resonator 10 can be easily realized.

[0052] The piezoelectric film F3 is a thin film formed of a type of piezoelectric material that mutually converts electrical energy and mechanical energy. The piezoelectric film F3 expands and contracts in the Y-axis direction within the XY plane in response to an electric field formed in the piezoelectric film F3 by the metal films E1 and E2. Due to the expansion and contraction of the piezoelectric film F3, the vibrating arms 121A to 121D each displace their open ends toward the bottom plate 22 of the lower lid 20 and the bottom plate 32 of the upper lid 30. Thereby, the resonator 10 vibrates in an out-of-plane bending vibration mode.

[0053] The thickness of the piezoelectric film F3 is, for example, about 1 μm, but it may be about 0.2 μm to 2 μm. The piezoelectric film F3 is formed of a material having a crystal structure of a wurtzite-type hexagonal crystal structure. For example, it can be mainly composed of nitrides or oxides such as aluminum nitride (AlN), scandium aluminum nitride (ScAlN), zinc oxide (ZnO), gallium nitride (GaN), indium nitride (InN), and the like. Note that scandium aluminum nitride is a material in which part of the aluminum in aluminum nitride is replaced by scandium, and instead of scandium, it may be replaced by two elements such as magnesium (Mg) and niobium (Nb), or magnesium (Mg) and zirconium (Zr). Thus, by using a piezoelectric body having a wurtzite-type hexagonal crystal structure as the main component of the piezoelectric film F3, the piezoelectric film F3 suitable for the resonator 10 can be easily realized.

[0054] The protective film F5 protects the metal film E2 from oxidation. Note that if the protective film F5 is provided on the upper lid 30 side, it does not have to be exposed to the bottom plate 32 of the upper lid 30. For example, a parasitic capacitance reduction film or the like that reduces the capacitance of the wiring formed on the resonator 10 may be formed so as to cover the protective film F5. The protective film F5 is formed of, for example, an insulating film such as silicon nitride (SiN), silicon oxide (SiO2), aluminum oxide (Al2O3), tantalum pentoxide (Ta2O5), in addition to a piezoelectric film such as aluminum nitride (AlN), scandium aluminum nitride (ScAlN), zinc oxide (ZnO), gallium nitride (GaN), indium nitride (InN). The thickness of the protective film F5 is formed to be half or less of the thickness of the piezoelectric film F3. In this embodiment, for example, it is about 0.2 μm. Note that a more preferable thickness of the protective film F5 is about one-fourth of the thickness of the piezoelectric film F3. Further, when the protective film F5 is formed of a piezoelectric body such as aluminum nitride (AlN), it is preferable to use a piezoelectric body having the same orientation as the piezoelectric film F3.

[0055] It is desirable that the protective films F5 of the weight portions 122A to 122D be formed with a uniform thickness. Note that the uniform thickness means that the variation in the thickness of the protective film F5 is within ±20% from the average value of the thickness.

[0056] The mass addition films 125A to 125D form the surfaces on the upper lid 30 side of each of the weight portions 122A to 122D and correspond to the frequency adjustment films of each of the vibrating arms 121A to 121D. The resonance frequency of the resonator 10 is adjusted by a trimming process of removing a part of each of the mass addition films 125A to 125D. From the viewpoint of the efficiency of frequency adjustment, it is preferable that the mass addition films 125A to 125D are formed of a material having a mass reduction rate by etching faster than that of the protective film F5. The mass reduction rate is represented by the product of the etching rate and the density. The etching rate is the thickness removed per unit time. The protective film F5 and the mass addition films 125A to 125D may have an arbitrary relationship in the magnitude of the etching rate as long as the relationship of the mass reduction rate is as described above. Also, from the viewpoint of efficiently increasing the weights of the weight portions 122A to 122D, it is preferable that the mass addition films 125A to 125D are formed of a material having a large specific gravity. For these reasons, the mass addition films 125A to 125D are formed of, for example, metal materials such as molybdenum (Mo), tungsten (W), gold (Au), platinum (Pt), nickel (Ni), aluminum (Al), titanium (Ti).

[0057] A part of the upper surface of each of the mass addition films 125A to 125D is removed by a trimming process in the step of adjusting the frequency. The trimming process of the mass addition films 125A to 125D can be performed, for example, by dry etching with irradiation of an argon (Ar) ion beam. Since the ion beam can be irradiated over a wide range, it has excellent processing efficiency, but since it has an electric charge, there is a risk of charging the mass addition films 125A to 125D. In order to prevent the vibration characteristics of the resonator 10 from deteriorating due to a change in the vibration orbit of the vibrating arms 121A to 121D caused by the Coulomb interaction due to the charging of the mass addition films 125A to 125D, it is preferable that the mass addition films 125A to 125D are grounded.

[0058] On the protective film F5 of the holding part 140, lead wires C1, C2, and C3 are formed. The lead wire C1 is electrically connected to the metal film E1 through through-holes formed in the piezoelectric film F3 and the protective film F5. The lead wire C2 is electrically connected to the portions of the metal film E2 formed on the vibrating arms 121A and 121D through through-holes formed in the protective film F5. The lead wire C3 is electrically connected to the portions of the metal film E2 formed on the vibrating arms 121B and 121C through through-holes formed in the protective film F5. The lead wires C1 to C3 are formed of a metal material such as aluminum (Al), germanium (Ge), gold (Au), tin (Sn), or the like.

[0059] In the present embodiment, in FIG. 4, an example is shown in which the arm portions 123A to 123D, the lead wires C2 and C3, the through electrodes V2 and V3, etc. are located on a cross-section of the same plane, but these are not necessarily located on a cross-section of the same plane. For example, the through electrodes V2 and V3 may be formed at a position away from the Y-axis direction from a cross-section that is parallel to the ZX plane defined by the Z-axis and the X-axis and cuts the arm portions 123A to 123D.

[0060] Similarly, in the present embodiment, in FIG. 5, Hammer part 122D, the arm portion 123D, the lead wires C1, C2, the through electrodes V1, V2, etc. are shown as being located on a cross-section of the same plane, but these are not necessarily located on a cross-section of the same plane.

[0061] The bottom plate 22 and the side wall 23 of the lower lid 20 are integrally formed by the Si substrate P10. The Si substrate P10 is formed of non-degenerate silicon, and its resistivity is, for example, 10 Ω·cm or more. Inside the recess 21 of the lower lid 20, the Si substrate P10 is exposed. On the upper surface of the protrusion 50, a silicon oxide layer F21 is formed. However, from the viewpoint of suppressing the charging of the protrusion 50, the Si substrate P10 having a lower electrical resistivity than the silicon oxide layer F21 may be exposed on the upper surface of the protrusion 50, or a conductive layer may be formed.

[0062] The thickness of the lower lid 20 defined in the Z-axis direction is about 150 μm, and the depth of the recess 21 defined similarly is about 50 μm.

[0063] The bottom plate 32 and the side wall 33 of the upper lid 30 are integrally formed by the Si substrate Q10. The front surface, back surface, and the inner surface of the through hole of the upper lid 30 are preferably covered with a silicon oxide film Q11. The silicon oxide film Q11 is formed on the surface of the Si substrate Q10, for example, by oxidizing the Si substrate Q10 or by chemical vapor deposition (CVD). Inside the recess 31 of the upper lid 30, the Si substrate Q10 is exposed. Note that a getter layer may be formed on the surface of the recess 31 of the upper lid 30 that faces the resonator 10. The getter layer is formed of, for example, titanium (Ti) or the like, adsorbs outgassing released from the joint portion 40 and the like described later, and suppresses a decrease in the degree of vacuum in the vibration space. Note that the getter layer may be formed on the surface of the recess 21 of the lower lid 20 that faces the resonator 10, or may be formed on the surfaces of both the recess 21 of the lower lid 20 and the recess 31 of the upper lid 30 that face the resonator 10.

[0064] The thickness of the upper lid 30 defined in the Z-axis direction is about 150 μm, and the depth of the recess 31 defined similarly is about 50 μm.

[0065] Terminals T1, T2, and T3 are formed on the upper surface of the upper lid 30 (the surface opposite to the surface facing the resonator 10). Terminal T1 is a mounting terminal for grounding the metal film E1. Terminal T2 is a mounting terminal for electrically connecting the metal films E2 of the vibrating arms 121A and 121D to an external power supply. Terminal T3 is a mounting terminal for electrically connecting the metal films E2 of the vibrating arms 121B and 121C to an external power supply. Terminals T1 to T3 are formed by plating, for example, nickel (Ni), gold (Au), silver (Ag), copper (Cu), etc. on a metallized layer (underlayer) such as chromium (Cr), tungsten (W), nickel (Ni). Note that dummy terminals electrically insulated from the resonator 10 may be formed on the upper surface of the upper lid 30 for the purpose of adjusting parasitic capacitance and mechanical strength balance.

[0066] Through electrodes V1, V2, and V3 are formed inside the side wall 33 of the upper cover 30. The through electrode V1 electrically connects the terminal T1 and the lead wire C1, the through electrode V2 electrically connects the terminal T2 and the lead wire C2, and the through electrode V3 electrically connects the terminal T3 and the lead wire C3. The through electrodes V1 to V3 are formed by filling a through hole penetrating the side wall 33 of the upper cover 30 in the Z-axis direction with a conductive material. The conductive material to be filled is, for example, polycrystalline silicon (Poly-Si), copper (Cu), gold (Au), or the like.

[0067] A joint portion 40 is formed between the side wall 33 of the upper cover 30 and the holding portion 140, and the upper cover 30 and the resonator 10 are joined by this joint portion 40. The joint portion 40 is formed in a closed annular shape surrounding the vibrating portion 110 in the XY plane so as to hermetically seal the vibration space of the resonator 10 in a vacuum state. The joint portion 40 is formed by, for example, a metal film in which an aluminum (Al) film, a germanium (Ge) film, and an aluminum (Al) film are laminated in this order and eutectically joined. Note that the joint portion 40 may be formed by an appropriate combination of films selected from gold (Au), tin (Sn), copper (Cu), titanium (Ti), silicon (Si), and the like. Further, in order to improve the adhesion, the joint portion 40 may contain a metal compound such as titanium nitride (TiN) or tantalum nitride (TaN) between the films.

[0068] As shown in FIG. 5, the support arm 151 has a damping film LM. The damping film LM is configured to reduce the Q value in the vibration of the support arm 151. More specifically, the damping film LM is formed on both the upper support rear arm 152 and the upper support side arm 153.

[0069] The damping film LM is preferably made of a material with a low Q value of vibration. Specifically, the damping film LM is formed, for example, by tetraethyl orthosilicate (Si(OC2H5)4) (also referred to as "TEOS" (tetraethoxysilane)). Further, the damping film LM may have a plurality of layers laminated thereon. For example, a tetraethyl orthosilicate layer and an aluminum (Al) layer, or a tetraethyl orthosilicate layer, an aluminum (Al) layer, a titanium (Ti) layer, and an aluminum (Al) layer may be laminated in this order to form the damping film LM.

[0070] Also, the damping film LM preferably includes a layer made of the material of the joint portion 40. Specifically, for example, an aluminum (Al) film is formed on the holding portion 140 of the resonator 10, a germanium (Ge) film is formed on the side wall 33 of the upper lid 30, and when the aluminum (Al) film on the resonator 10 side and the germanium (Ge) film on the upper lid 30 side are eutectically joined to form the joint portion 40, the damping film LM is configured to include an aluminum (Al) layer. Thereby, when forming the layer constituting the joint portion 40, for example, by changing the shape of the mask or the like, it becomes possible to form the damping film LM. thing Therefore, the damping film LM can be easily formed without adding or changing the manufacturing process of the resonator 10.

[0071] As described above, the support arm 151 includes a silicon oxide layer F21, an Si substrate F2, a piezoelectric film F3, a metal film E2, and a protective film F5, and has substantially the same laminated structure as the arm portion 123 of the vibrating arm 121. Therefore, the thickness of the support arm 151 including the damping film LM is larger than the thickness of the arm portion 123 of the vibrating arm 121.

[0072] In this embodiment, the terminal T1 is grounded, and alternating voltages with opposite phases are applied to the terminals T2 and T3. Therefore, the phases of the electric fields formed in the piezoelectric films F3 of the vibrating arms 121A and 121D are opposite to the phases of the electric fields formed in the piezoelectric films F3 of the vibrating arms 121B and 121C. As a result, the outer vibrating arms 121A and 121D and the inner vibrating arms 121B and 121C are displaced in opposite directions.

[0073] For example, as shown in FIG. 4, when the weight portions 122A and 122D and the arm portions 123A and 123D of the vibrating arms 121A and 121D are displaced toward the inner surface of the upper lid 30, the weight portions 122B and 122C and the arm portions 123B and 123C of the vibrating arms 121B and 121C are displaced toward the inner surface of the lower lid 20. Although illustration is omitted, conversely, when the weight portions 122A and 122D and the arm portions 123A and 123D of the vibrating arms 121A and 121D are displaced toward the inner surface of the lower lid 20, the weight portions 122B and 122C and the arm portions 123B and 123C of the vibrating arms 121B and 121C are displaced toward the inner surface of the upper lid 30. Thus, at least two of the four vibrating arms 121A to 121D are bent out of the plane in different phases.

[0074] In this way, between the adjacent vibrating arms 121A and 121B, the vibrating arms 121A and 121B vibrate in the opposite vertical directions around the central axis r1 extending in the Y-axis direction. Also, between the adjacent vibrating arms 121C and 121D, the vibrating arms 121C and 121D vibrate in the opposite vertical directions around the central axis r2 extending in the Y-axis direction. As a result, torsional moments in opposite directions are generated by the central axis r1 and the central axis r2, and bending vibration occurs in the vibrating portion 110. The maximum amplitude of the vibrating arms 121A to 121D is about 50 μm, and the amplitude during normal driving is about 10 μm.

[0075] Next, with reference to FIG. 6, the dimensions of the vibrating portion in plan view will be described. FIG. 6 is a plan view for explaining the dimensions of the resonator 10 shown in FIG. 3. Note that in FIG. 6, a part of the resonator 10 is shown for simplification of explanation.

[0076] As shown in FIG. 6, in the resonator 10 of the present embodiment, the width WG, which is the length of each of the weight portions 122A to 122D along the X-axis direction, is, for example, 46 μm. Also, the vibrating arm width WA, which is the length of each of the vibrating arms 121A to 121D along the X-axis direction, is, for example, 25 μm, and the vibrating arm length LA, which is the length of each of the vibrating arms 121A to 121D along the Y-axis direction, is, for example, 410 μm.

[0077] Also, at the base 130, the base length LB, which is the length in the direction from the front end portion 131A to the rear end portion 131B, is, for example, 25 μm. On the other hand, the base width WB, which is the length in the direction from the left end portion 131C to the right end portion 131D, is, for example, 172 μm.

[0078] Also, the width of the support arm 151, specifically, the support arm width WS, which is the length in the direction along the X-axis of the support side arm 153, is, for example, 17 μm. Although not shown, the length in the direction along the Y-axis of the support rear arm 152 is also, similarly, 17 μm. Further, the length of the support arm 151, specifically, the support arm length LS, which is the length in the direction along the Y-axis of the support side arm 153, is, for example, 40 μm.

[0079] The other end of the support arm 151, specifically, the other end of the support rear arm 152, is connected to a position that is shifted 10 μm to the negative side in the X-axis direction, that is, to the left side, with respect to the position where the center line CL1 passes at the rear end portion 131B of the base 130. In the following description, unless otherwise specified, the position where the center line CL1 passes at the rear end portion 131B of the base 130 is taken as the origin (zero), and one side (right side) is represented as “+” (plus) and the other side (left side) is represented as “−” (minus). That is, in the example shown in FIG. 6, the other end of the support rear arm 152 is connected to a position of −10 μm with respect to the position where the center line CL1 passes at the rear end portion 131B of the base 130.

[0080] In the following description, unless otherwise specified, the dimensions of each part are those having the lengths described with reference to FIG. 6.

[0081] Next, while referring to FIGS. 7 and 8, the influence of the coupling between the main mode vibration and the spurious mode vibration will be described. FIG. 7 is a graph showing the relationship between the input voltage and the frequency change rate in a virtual resonator. FIG. 8 is a graph showing the relationship between the input voltage and the equivalent series resistance in a virtual resonator. Note that the virtual resonator is virtualized for comparison with the resonator 10 of the present embodiment, and has substantially the same configuration as the resonator 10 except that it does not have the reduction film LM. In FIGS. 7 and 8, the horizontal axis represents the input voltage (Vin) applied to each vibrating arm of the vibrating part. Also, in FIG. 7, the vertical axis represents the frequency change rate (df / f) with reference to the resonance frequency (f) when the input voltage is 0.01V. Further, in FIG. 8, the vertical axis represents the equivalent series resistance (ESR) of the vibrating part.

[0082] As shown in FIG. 7, in the virtual resonator, when the input voltage Vin is changed from 0.01V to 0.05V by the impedance analyzer, the frequency change rate is substantially zero and hardly changes. On the other hand, when an input voltage from 0.05V to 0.08V is applied by the impedance analyzer, the frequency change rate changes greatly to a negative value. This means that when the input voltage exceeds 0.05V, the resonance frequency shifts in the negative direction.

[0083] Also, as shown in FIG. 8, in the virtual resonator, when the input voltage Vin is changed from 0.01V to 0.05V by the impedance analyzer, the equivalent series resistance is almost a constant value and does not change much. On the other hand, when an input voltage from 0.05V to 0.08V is applied by the impedance analyzer, the equivalent series resistance increases as the input voltage increases.

[0084] From these results, it is considered that in the virtual resonator, when an input voltage greater than 0.05V is applied, coupling (also referred to as "coupling") between the main mode vibration and the spurious mode vibration occurs.

[0085] Here, as described above, in the vibration of the main mode of the resonator 10 of the present embodiment, the vibrating arms 121A and 121D and the vibrating arms 121B and 121C perform out-of-plane bending vibrations with opposite phases to each other. Generally, any resonator has vibrations different from those of the main mode, that is, spurious mode vibrations (also referred to as "parasitic vibrations"). In the resonator 10 of the present embodiment, in the main mode, mainly the vibrating arm 121 vibrates, while in the spurious mode, mainly the base 130 and the support arm 151 vibrate. These are the same in the virtual resonator.

[0086] When the frequency of this spurious mode vibration is, for example, a predetermined multiple or 1 / predetermined number with respect to the frequency of the main mode vibration, that is, the resonance frequency, it is known that the main mode vibration and the spurious mode vibration tend to be easily combined.

[0087] Next, while referring to FIG. 9, the drive level at which the combination of the main mode vibration and the spurious mode vibration occurs will be described. FIG. 9 is a graph showing the relationship between the frequency ratio and the coupling drive level in a virtual resonator. In FIG. 9, the horizontal axis is the frequency ratio (Fs / Fm) of the spurious mode frequency (Fs) to the main mode frequency (Fm). Also, the vertical axis is the coupling drive level at which the combination of the main mode vibration and the spurious mode vibration occurs. The drive level is the value (Vin 2 ^2 / Rr) obtained by dividing the square of the input voltage (Vin) by the resonance resistance (Rr), and the unit is [μW]. The graph in FIG. 9 is a plot of the results of measuring the coupling drive level in each of a plurality of virtual resonators with the frequency ratio changed.

[0088] As shown in FIG. 9, in a virtual resonator, the higher the frequency ratio is above 2 times, the higher the coupling drive level tends to be. In other words, if the frequency in the spurious mode oscillation can be made sufficiently higher than twice the frequency of the main mode oscillation, it can be said that the coupling drive level increases and the coupling between the main mode oscillation and the spurious mode oscillation becomes difficult.

[0089] In the virtual resonator, for example, the average frequency ratio is 2.37 times, which is greater than 2 times. However, the coupling between the main mode oscillation and the spurious mode oscillation is not caused by the frequency ratio alone, and there are other factors. Therefore, in the virtual resonator, the average coupling drive level is 0.058 μW, which is a relatively low value. In addition, resonators have conventionally been required to be further miniaturized, and it is difficult to significantly increase the frequency ratio by changing dimensions and the like.

[0090] Here, the inventors of the present invention focused on the Q value of the spurious mode oscillation and found that the coupling drive level can be increased by reducing this Q value. More specifically, it was found that the support arm 151 preferably has a reduction film LM configured to reduce the Q value of the vibration in the support arm 151. Thereby, the Q value is reduced in the spurious mode oscillation in which the vibration of the support arm 151 is the main vibration.

[0091] Next, with reference to FIGS. 10 and 11, the laminated structure around the support arm according to an embodiment of the present invention will be described. FIG. 10 is a partial enlarged cross-sectional view schematically showing the configuration around the support rear arm 152 shown in FIG. 3. The graph in FIG. 11 is a graph showing the relationship between the configuration around the support arm and the coupling drive level. In FIG. 11, the vertical axis represents the coupling drive level at which the coupling between the main mode oscillation and the spurious mode oscillation occurs. The drive level is the value obtained by dividing the square of the input voltage (Vin) by the resonance resistance (Rr) (Vin 2It is (P0 / Pr), and the unit is [μW]. Also, "none" on the horizontal axis represents a virtual resonator in which the support arm does not have a reduction film, and "reduction film example 1" and "reduction film example 2" on the horizontal axis are reduction films LM of the support arm 151, and each represents a resonator 10 including a reduction film LM having a different configuration. The graph in Fig. 11 depicts (plots) the results of measuring the coupling drive level multiple times in each configuration of the virtual resonator and the resonator 10.

[0092] As shown in Fig. 10, unlike the virtual resonator, the support arm 151 of the present embodiment has a reduction film LM. Fig. 10 illustrates the reduction film LM of the support rear arm 152 among the support arms 151.

[0093] As described above, the support rear arm 152 includes an Si substrate F2 having a silicon oxide layer F21 formed on the lower surface, a piezoelectric film F3, and a protective film F5 laminated so as to cover the metal film E2. A reduction film LM is formed on the support rear arm 152.

[0094] The reduction film LM is preferably formed on at least the support rear arm 152 among the support arms 151. Here, the inventors of the present invention have found that the thickness, material, etc. of the connection portion with the base portion 130 among the support arms 151 are dominant factors in reducing the Q value in the vibration of the support arm 151. Therefore, by forming the reduction film LM on at least the support rear arm 152, the Q value of the spurious mode in which the vibration of the support arm 151 is the main vibration can be effectively and efficiently reduced.

[0095] Also, as described above, the thickness of the support rear arm 152 including the reduction film LM is larger than the thickness of the arm portion 123 of the vibration arm 121. Thereby, the Young's modulus of the support arm 151 including the reduction film LM can be increased, and the frequency of the spurious mode with respect to the frequency of the main mode can be increased.

[0096] The reduction film LM is composed of a first layer 41, a second layer 42, a third layer 43, and a fourth layer 44. The first layer 41 is a layer mainly composed of, for example, tetraethyl orthosilicate, and has a thickness of 1 μm. The second layer 42 is a layer mainly composed of, for example, aluminum (Al), and has a thickness of 0.7 μm. The third layer 43 is a layer mainly composed of, for example, titanium (Ti), and has a thickness of 0.1 μm. The fourth layer 44 is, like the second layer 42, a layer mainly composed of, for example, aluminum (Al), and has a thickness of 0.7 μm.

[0097] Thus, it is preferable that the reduction film LM is composed of a material different from the material of the arm portion 123 of the vibrating arm 121. Thereby, while increasing the Q value in the vibration of the main mode, it becomes possible to reduce the Q value in the vibration of the spurious mode.

[0098] In the following description, unless otherwise specified, the reduction film LM shall have the configuration and thickness described with reference to FIG. 10.

[0099] As shown in FIG. 11, in the virtual resonator represented by "none", as described above, the average of the frequency ratios is 2.37 times, and the average of the coupling drive levels remains at 0.058 μW. At this time, the average Q value of the vibration of the spurious mode is 21,835.

[0100] On the other hand, in the resonator 10 having the reduction film LM with the configuration shown in FIG. 10 represented by "reduction film example 2", the average Q value of the vibration of the spurious mode is 4,860, which is reduced to 1 / 4 or less compared to the virtual resonator. Also, the average of the frequency ratios increases to 2.70 times, and the average of the coupling drive levels increases to 0.125 μW.

[0101] Also, the configuration of the reduction film LM represented by "reduction film example 1" includes only the first layer 41 shown in FIG. 10. Even in this case, the resonator 10 reduces the Q value of the vibration of the spurious mode compared to the virtual resonator, increases the average of the frequency ratios, and increases the average of the coupling drive levels.

[0102] Thus, the support arm 151 has a reduction film LM configured to reduce the Q value of the vibration in the support arm 151. As a result, the Q value of the spurious mode vibration, in which the vibration of the support arm 151 is the main vibration, is reduced, and the drive level at which the coupling between the main mode vibration and the spurious mode vibration occurs can be increased. Therefore, it becomes difficult for the main mode vibration and the spurious mode vibration to be coupled, and the occurrence of such coupling can be suppressed.

[0103] In the present embodiment, an example in which the vibrating portion 110 of the resonator 10 includes four vibrating arms 121A to 121D is used, but the present invention is not limited thereto. The vibrating portion 110 may include, for example, three or five or more vibrating arms. In this case, at least two vibrating arms bend out of plane with different phases.

[0104] Further, in the present embodiment, an example in which one end of the support arm 151 of the resonator 10 is connected to the frame 141D of the holding portion 140 is used, but the present invention is not limited thereto. One end of the support arm 151 may be connected to the frame 141C of the holding portion 140, for example.

[0105] As described above, the exemplary embodiments of the present invention have been described. In a resonator according to an embodiment, the support arm has a reduction film configured to reduce the Q value of the vibration in the support arm. As a result, the Q value of the spurious mode vibration, in which the vibration of the support arm is the main vibration, is reduced, and the drive level at which the coupling between the main mode vibration and the spurious mode vibration occurs can be increased. Therefore, it becomes difficult for the main mode vibration and the spurious mode vibration to be coupled, and the occurrence of such coupling can be suppressed.

[0106] Further, in a resonator according to an embodiment, the thickness of the support arm including the reduction film is larger than the thickness of the arm portion of the vibrating arm. As a result, the Young's modulus of the support arm including the reduction film can be increased, and the frequency of the spurious mode with respect to the frequency of the main mode can be increased.

[0107] Also, in a resonator according to an embodiment, the reduction film is made of a material different from that of the arm portion of the vibrating arm. Thereby, it becomes possible to increase the Q value in the vibration of the main mode while reducing the Q value in the vibration of the spurious mode.

[0108] Also, in a resonator according to an embodiment, the reduction film is formed on the supporting rear arm. Thereby, it is possible to effectively and efficiently reduce the Q value of the spurious mode in which the vibration of the supporting arm is the main vibration.

[0109] Also, a resonance device according to an embodiment includes the resonator described above. Thereby, it is possible to easily realize a resonance device that suppresses the occurrence of the coupling between the vibration of the main mode and the vibration of the spurious mode.

[0110] Also, in the resonance device described above, the reduction film includes a layer made of the material of the joint portion. Thereby, when forming the layer constituting the joint portion, for example, by changing the shape of the mask or the like, the reduction film can be formed. thing Since this becomes possible, the reduction film can be easily formed without adding or changing the manufacturing process of the resonator.

[0111] Note that each of the embodiments described above is for facilitating the understanding of the present invention and is not for limiting and interpreting the present invention. The present invention can be changed / improved without departing from its gist, and equivalents thereof are also included in the present invention. That is, even if those skilled in the art make appropriate design changes to the embodiments and / or modifications, as long as they have the features of the present invention, they are included in the scope of the present invention. For example, each element included in the embodiments and / or modifications, its arrangement, material, conditions, shape, size, etc. are not limited to those illustrated and can be changed as appropriate. Also, it goes without saying that the embodiments and modifications are examples, and partial substitution or combination of the configurations shown in different embodiments and / or modifications is possible, and these are also included in the scope of the present invention as long as they include the features of the present invention.

Description of Reference Numerals

[0112] 1… Resonance device, 10… Resonator, 20… Lower cover, 21… Recess, 22… Bottom plate, 23… Side wall, 30… Upper cover, 31… Recess, 32… Bottom plate, 33… Side wall, 40… Joint part, 41… First layer, 42… Second layer, 43… Third layer, 44… Fourth layer, 50… Protrusion part, 110… Vibration part, 120… Excitation part, 121, 121A, 121B , 121C, 121D… Vibration arms, 122, 122A, 122B, 122C, 122D… Hammer parts, 123, 123A, 123B, 123C, 123D… Arms, 125, 125A, 125B, 125C, 125D… Mass addition films, 130… Base part, 131A… Front end part, 131B… Rear end part, 131C… Left end part, 131D… Right end part, 140… Holding part, 141A, 141B, 141C, 141D… Frame bodies, 151… Support arm, 152… Support rear arm, 153… Support side arm.

Claims

1. A plurality of three or more vibrating arms each having a fixed end, wherein at least two of the plurality of vibrating arms bend out of plane with different phases, and a base having one end to which the fixed ends of the plurality of vibrating arms are connected and the other end facing the one end, a vibrating part including; A holding part configured to hold the vibrating part; A support arm having one end connected to the holding part and the other end connected to the other end of the base, The vibrating part is held by the holding part via the support arm, The support arm has a reduction film configured to reduce the Q value in the vibration of the support arm, The thickness of the support arm including the reduction film is greater than the thickness of each arm portion of the plurality of vibrating arms, Resonator.

2. The reduction film is made of a material different from the material of each arm portion of the plurality of vibrating arms, The resonator according to claim 1.

3. The support arm includes a support-side arm and a support rear arm having one end connected to the support-side arm and the other end connected to the other end of the base, The reduction film is formed on the support rear arm, The resonator according to claim 1.

4. Comprising the resonator according to claim 1, Resonance device.

5. A lid body; Further comprising a joining part that joins the resonator and the lid body, The reduction film includes a layer made of the material of the joining part, The resonance device according to claim 4.

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