阅读说明：本技术 谐振装置 (Resonance device ) 是由 井上义久 维莱·卡亚卡里 河合良太 于 2020-02-03 设计创作，主要内容包括：本发明提供一种谐振装置,其降低了施加于支承臂与保持部的连接部分的应力。谐振装置具备：谐振器,包括基部、从该基部的一端沿着第一方向延伸的振动臂、配置于振动臂的周围的至少一部分并将振动臂保持为能够振动的保持部、以及将基部与保持部连接的支承臂；和第一基板,包括形成谐振器的振动空间的至少一部分的第一凹部、以及在厚度方向上与支承臂空开第一距离地设置的第一限制部,第一距离小于在第一基板的厚度方向上第一凹部的底面与振动臂之间的距离。(The invention provides a resonance device which reduces stress applied to a connecting portion of a support arm and a holding portion. The resonance device is provided with: a resonator including a base portion, a vibrating arm extending from one end of the base portion in a first direction, a holding portion arranged around at least a part of the vibrating arm and holding the vibrating arm so as to be capable of vibrating, and a support arm connecting the base portion and the holding portion; and a first substrate including a first recess forming at least a part of the vibration space of the resonator, and a first restriction portion provided with a first distance from the support arm in a thickness direction, the first distance being smaller than a distance between a bottom surface of the first recess and the vibration arm in the thickness direction of the first substrate.)

1. A resonance device is provided with:

a resonator including a base portion, a vibration arm extending from one end of the base portion in a first direction, a holding portion arranged around at least a part of the vibration arm and holding the vibration arm so as to be capable of vibrating, and a support arm connecting the base portion and the holding portion; and

a first substrate including a first recess forming at least a part of a vibration space of the resonator and a first restriction portion provided at a first distance from the support arm in a thickness direction,

the first distance is smaller than a distance between a bottom surface of the first recess and the vibration arm in a thickness direction of the first substrate.

2. The resonating device of claim 1,

a frequency ratio Fs/Fm of a frequency Fs of the vibration of the spurious mode generated in the support arm to a frequency Fm of the vibration of the primary mode generated in the vibrating arm satisfies: 2.1 < Fs/Fm.

3. The resonance device according to claim 1 or 2,

the connecting position of the support arm and the holding portion is offset from the center of the vibration arm and the base in the first direction toward the base portion in a plan view.

4. The resonance device according to any one of claims 1 to 3,

the support arm includes a support side arm extending in the first direction and a support rear arm protruding from the other end of the base and extending in a second direction,

the first restriction portion is provided with the first distance from at least the support rear arm of the support arms in the thickness direction of the first substrate.

5. The resonance device according to any one of claims 1 to 3,

the support arm includes a support side arm extending along the first direction,

the first regulating portion is provided with the first distance in the thickness direction of the first substrate from at least the support-side arm of the support arms.

6. The resonance device according to any one of claims 1 to 5,

the first distance is greater than 1/10 of the distance and less than the distance.

7. The resonance device according to any one of claims 1 to 6,

the first restriction portion includes a step.

8. The resonance device according to any one of claims 1 to 7,

the resonator comprises a plurality of said vibrating arms,

the first substrate further includes a protrusion portion that is disposed between adjacent two of the plurality of vibration arms and protrudes from the first recess portion.

9. The resonance device according to any one of claims 1 to 8,

the resonator further includes a second substrate arranged to face the first substrate with the resonator interposed therebetween, and including: a second recess forming at least a part of a vibration space of the resonator; and a second limiting part arranged with a second distance to the supporting arm in the thickness direction,

the second distance is smaller than a distance between a bottom surface of the second recess and the vibration arm in a thickness direction of the second substrate.

10. The resonance device according to any one of claims 1 to 8, further comprising:

a second substrate configured to be opposed to the first substrate with the resonator interposed therebetween and including a second recess portion forming at least a part of a vibration space of the resonator; and

a joining section joining the resonator and the second substrate, the joining section being spaced apart by a second distance in a thickness direction of the second substrate between a surface of the second substrate facing the resonator and the support arm,

the second distance is smaller than a distance between the vibration arm and a bottom surface of the second recess in a thickness direction of the second substrate.

11. A resonance device is provided with:

a resonator including a base portion, a vibration arm extending from one end of the base portion in a first direction, a holding portion arranged around at least a part of the vibration arm and holding the vibration arm so as to be capable of vibrating, and a support arm connecting the base portion and the holding portion;

a first substrate including a first recess forming at least a part of a vibration space of the resonator;

a second substrate configured to be opposed to the first substrate with the resonator interposed therebetween and including a second recess portion forming at least a part of a vibration space of the resonator; and

a bonding portion that bonds the resonator to the second substrate, the bonding portion being spaced apart from the support arm by a predetermined distance in a thickness direction of the second substrate, the surface of the second substrate facing the resonator,

the predetermined distance is smaller than a distance between the vibrating arm and a bottom surface of the second recess in a thickness direction of the second substrate.

Technical Field

The present invention relates to a resonance device that vibrates in a contour vibration mode.

Background

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

For example, patent document 1 discloses a resonance device including a resonator including: a first electrode and a second electrode; a piezoelectric film which is provided between the first electrode and the second electrode, has an upper surface facing the first electrode, and vibrates in a predetermined vibration mode when a voltage is applied between the first electrode and the second electrode; a protective film which is provided so as to face the upper surface of the piezoelectric film with the first electrode interposed therebetween and is made of an insulator; and a frequency adjustment film which is provided so as to face the upper surface of the piezoelectric film with the protective film interposed therebetween and is composed of a conductor, wherein the frequency adjustment film is electrically connected to either one of the first electrode and the second electrode.

Patent document 1: international publication No. 2017/2085683139274

In the resonance device of patent document 1, the vibration portion of the resonator is connected to the holding portion via the support arm. In such a resonator device, ultrasonic vibration is often applied to the resonator by ultrasonic welding, ultrasonic cleaning, or the like.

When ultrasonic vibration is applied, the resonator may strongly vibrate the arm up and down due to a parasitic mode existing in a frequency region of the ultrasonic vibration. As a result, a large stress is applied to the connecting portion between the support arm and the holding portion, and this portion or the periphery thereof may be broken or broken.

Disclosure of Invention

The present invention has been made in view of such circumstances, and an object thereof is to provide a resonance device capable of reducing stress applied to a connecting portion between a support arm and a holding portion.

A resonance device according to one aspect of the present invention includes:

a resonator including a base portion, a vibrating arm extending from one end of the base portion in a first direction, a holding portion arranged around at least a part of the vibrating arm and holding the vibrating arm so as to be capable of vibrating, and a support arm connecting the base portion and the holding portion; and

a first substrate including a first recess forming at least a part of a vibration space of the resonator and a first restriction portion provided at a first distance from the support arm in a thickness direction,

the first distance is smaller than a distance between a bottom surface of the first recess and the vibration arm in a thickness direction of the first substrate.

A resonance device according to another aspect of the present invention includes:

a resonator including a base portion, a vibrating arm extending from one end of the base portion in a first direction, a holding portion arranged around at least a part of the vibrating arm and holding the vibrating arm so as to be capable of vibrating, and a support arm connecting the base portion and the holding portion;

a first substrate including a first recess forming at least a part of a vibration space of the resonator;

a second substrate configured to be opposed to the first substrate with the resonator interposed therebetween and including a second recess portion forming at least a part of a vibration space of the resonator; and

a joint part for jointing the resonator and the second substrate, wherein a surface of the second substrate opposite to the resonator and the supporting arm are spaced with a predetermined distance in the thickness direction of the second substrate,

the prescribed distance is smaller than the distance between the vibrating arm and the bottom surface of the second recess in the thickness direction of the second substrate.

According to the present invention, stress applied to the connecting portion between the support arm and the holding portion can be reduced.

Drawings

Fig. 1 is a perspective view schematically showing an external appearance of a resonance device according to a first embodiment.

Fig. 2 is an exploded perspective view schematically showing the structure of the resonance device shown in fig. 1.

Fig. 3 is a plan view schematically showing the structure of the resonator shown in fig. 2.

Fig. 4 is a cross-sectional view along the X axis schematically showing the laminated structure of the resonator device shown in fig. 1.

Fig. 5 is a cross-sectional view along the Y-axis schematically showing the laminated structure of the resonator device shown in fig. 1.

Fig. 6 is a graph showing a relationship between the frequency ratio and the DLD deviation.

Fig. 7 is a plan view showing a modification of the lower cover shown in fig. 2.

Fig. 8 is a plan view schematically showing the structure of a resonator according to the second embodiment.

Fig. 9 is a plan view schematically showing a first example of the lower cover in the second embodiment.

Fig. 10 is a plan view schematically showing a second example of the lower cover in the second embodiment.

Fig. 11 is a plan view schematically showing a third example of the lower cover in the second embodiment.

Fig. 12 is a cross-sectional view along the Y axis schematically showing the laminated structure of the resonator device in the third embodiment.

Fig. 13 is a cross-sectional view along the Y axis schematically showing the laminated structure of the resonator device in the fourth embodiment.

Fig. 14 is a cross-sectional view along the Y axis schematically showing the laminated structure of the resonator device in the fifth embodiment.

Detailed Description

Hereinafter, embodiments of the present invention will be described. In the description of the drawings below, the same or similar components are denoted by the same or similar reference numerals. The drawings are examples, and the sizes and shapes of the respective portions are schematic, and should not be construed as limiting the technical scope of the present invention to the embodiment.

[ first embodiment ]

First, a schematic configuration of a resonance device according to a first embodiment of the present invention will be described with reference to fig. 1 and 2. Fig. 1 is a perspective view schematically showing an external appearance of a resonance device 1 according to a first embodiment. Fig. 2 is an exploded perspective view schematically showing the structure of the resonance device 1 shown in fig. 1.

The resonance device 1 includes a lower cover 20, a resonator 10, and an upper cover 30. That is, the resonance device 1 is configured by stacking the lower cover 20, the resonator 10, and the upper cover 30 in this order. The lower cover 20 and the upper cover 30 are disposed to face each other with the resonator 10 interposed therebetween. The lower cover 20 corresponds to an example of the "first substrate" of the present invention, and the upper cover 30 corresponds to an example of the "second substrate" of the present invention.

Hereinafter, each configuration of the resonator device 1 will be described. In the following description, the side of the resonance device 1 on which the upper cover 30 is provided is referred to as the upper side (or the front side), and the side on which the lower cover 20 is provided is referred to as the lower side (or the back side).

The resonator 10 is a MEMS resonator manufactured using MEMS technology. The resonator 10 is coupled with the lower cover 20 and the upper cover 30 so as to seal the resonator 10 and form a vibration space of the resonator 10. The resonator 10, the lower cover 20, and the upper cover 30 are each formed using a silicon (Si) substrate (hereinafter, referred to as "Si substrate"), and the Si substrates are bonded to each other. The resonator 10, the lower lid 20, and the upper lid 30 may be formed using an SOI (Silicon On Insulator) substrate in which a Silicon layer and a Silicon oxide film are stacked.

The lower cover 20 includes a rectangular flat plate-shaped bottom plate 22 provided along the XY plane, and a side wall 23 extending from the peripheral edge of the bottom plate 22 in the Z-axis direction, that is, in the stacking direction of the lower cover 20 and the resonator 10. In lower cover 20, a recess 21 defined by the surface of bottom plate 22 and the inner surface of side wall 23 is formed on the surface facing resonator 10. The recess 21 forms at least a part of the vibration space of the resonator 10.

The lower cover 20 includes a regulating portion 25 provided on the surface of the bottom plate 22 and a protrusion 50 formed on the surface of the bottom plate 22. The detailed structure of the regulating portion 25 and the projecting portion 50 will be described later.

The upper cover 30 includes a rectangular flat plate-like bottom plate 32 provided along the XY plane, and a side wall 33 extending in the Z-axis direction from the peripheral edge of the bottom plate 22. In the upper cover 30, 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 facing the resonator 10. The recess 31 forms at least a part of a space in which the resonator 10 vibrates, that is, a vibration space.

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

Next, a schematic configuration of a resonator according to a first embodiment of the present invention will be described with reference to fig. 3. Fig. 3 is a plan view schematically showing the structure of the resonator 10 shown in fig. 2.

As shown in fig. 3, the resonator 10 is a MEMS resonator manufactured by using MEMS technology, and vibrates in the XY plane in the orthogonal coordinate system of fig. 3 with an out-of-plane bending vibration mode as a main vibration (hereinafter, also referred to as a "main mode"). The resonator 10 is not limited to a resonator using an out-of-plane bending vibration mode. The resonator of the resonator device 1 may use, for example, an extensional vibration mode, a thickness longitudinal vibration mode, a lamb wave vibration mode, an in-plane bending vibration mode, or a surface wave vibration mode. These transducers are applied to, for example, timing devices, RF filters, duplexers, ultrasonic transducers, gyro sensors, acceleration sensors, and the like. In addition, the present invention can be applied to piezoelectric microscopes having an actuator function, piezoelectric gyroscopes, optical scanning MEMS mirrors, piezoelectric microphones having a pressure sensor function, ultrasonic vibration sensors, and the like. In addition, the present invention can be applied to electrostatic MEMS elements, electromagnetic MEMS elements, and piezoresistive MEMS elements. Further, the present invention can be applied to a MHz oscillator.

The resonator 10 includes a vibrating portion 110, a holding portion 140, and a support arm 150.

The vibrating portion 110 has a rectangular outline extending along the XY plane in the orthogonal coordinate system of fig. 3. The vibration part 110 is disposed inside the holding part 140, and a space is formed between the vibration part 110 and the holding part 140 at a predetermined interval. In the example of fig. 3, the vibrating portion 110 includes an exciting portion 120 including four vibrating arms 121A to 121D (hereinafter, collectively referred to as "vibrating arms 121") and a base portion 130. The number of vibrating arms is not limited to four, and may be set to any number of two or more, for example. In the present embodiment, the excitation portion 120 is formed integrally with the base portion 130.

The vibrating arms 121A, 121B, 121C, and 121D extend in the Y-axis direction and are arranged in parallel at predetermined intervals in the X-axis direction in this order. One end of the vibrating arm 121A is a fixed end connected to a distal end portion 131A of the base 130 described later, and the other end of the vibrating arm 121A is an open end provided apart from the distal end portion 131A of the base 130. The vibrating arm 121A includes a mass attaching portion 122A formed on the open end side and an arm portion 123A extending from the fixed end and connected to the mass attaching portion 122A. Similarly, the vibration arms 121B, 121C, and 121D also include mass adding portions 122B, 122C, and 122D and arm portions 123B, 123C, and 123D, respectively. The arm portions 123A to 123D have a width in the X-axis direction of about 50 μm and a length in the Y-axis direction of about 465 μm, for example.

In the excitation unit 120 of the present embodiment, two vibrating arms 121A and 121D are disposed on the outer side and two vibrating arms 121B and 121C are disposed on the inner side in the X-axis direction. The width (hereinafter, referred to as "release width") W1 of the gap formed between the arm portions 123B, 123C of the inner two vibration arms 121B, 121C is set larger than, for example, the release width W2 between the arm portions 123A, 123B of the vibration arms 121A, 121B adjacent in the X-axis direction and the release width W2 between the arm portions 123D, 123C of the vibration arms 121D, 121C adjacent in the X-axis direction. The width W1 is, for example, about 25 μm, and the width W2 is, for example, about 10 μm. By setting the free width W1 to be larger than the free width W2, the vibration characteristics and durability of the vibrating portion 110 are improved. The width W1 may be set to be smaller than the width W2 or may be set at equal intervals so that the resonator device 1 can be downsized.

The mass-adding portions 122A to 122D have mass-adding films 125A to 125D on the surfaces thereof, respectively. Therefore, the weight per unit length (hereinafter, also simply referred to as "weight") of each of the mass adding portions 122A to 122D is larger than the weight of each of the arm portions 123A to 123D. This makes it possible to reduce the size of the vibrating portion 110 and improve the vibration characteristics. The mass-added films 125A to 125D have not only a function of increasing the weight of the tip portions of the vibrating arms 121A to 121D but also a function of adjusting the resonance frequencies of the vibrating arms 121A to 121D by cutting off a part thereof, so-called a frequency adjusting film.

In the present embodiment, the width of each of the mass adding portions 122A to 122D along the X axis direction is, for example, about 70 μm, which is larger than the width of each of the arm portions 123A to 123D along the X axis direction. This can further increase the weight of each of the mass adding portions 122A to 122D. However, the width of each of the mass adding portions 122A to 122D along the X axis direction is not limited to the example of the present embodiment as long as the weight of each of the mass adding portions 122A to 122D is larger than the weight of each of the arm portions 123A to 123D. The width of each of the mass adding portions 122A to 122D along the X axis direction may be equal to or less than the width of each of the arm portions 123A to 123D along the X axis direction.

When resonator 10 is viewed from above in a plan view (hereinafter simply referred to as "plan view"), each of mass-adding portions 122A to 122D has a substantially rectangular shape and a curved surface shape with rounded corners, for example, a so-called arc shape. Similarly, the arm portions 123A to 123D each have a substantially rectangular shape, and have an arc shape in the vicinity of a fixed end connected to the base portion 130 and in the vicinity of a connection portion connected to each of the mass adding portions 122A to 122D. However, the shapes of the mass adding portions 122A to 122D and the arm portions 123A to 123D are not limited to the example of the present embodiment. For example, the mass-adding portions 122A to 122D may have a substantially trapezoidal shape or a substantially L-shaped shape. The arm portions 123A to 123D may have a substantially trapezoidal shape. The mass-adding portions 122A to 122D and the arm portions 123A to 123D may be formed with bottomed groove portions having openings on either the front side or the back side, and hole portions having openings on both the front side and the back side, respectively. The groove and the hole may be separated from a side surface connecting the front surface and the back surface, or may have an opening on the side surface.

The base 130 has a front end 131A, a rear end 131B, a left end 131C, and a right end 131D in plan view. The front end 131A, the rear end 131B, the left end 131C, and the right end 131D are part of the outer edge of the base 130. Specifically, the front end 131A and the rear end 131B are ends extending in the X-axis direction, and the front end 131A and the rear end 131B are disposed to face each other. The left end 131C and the right end 131D are ends extending in the Y axis direction, and the left end 131C and the right end 131D are disposed to face each other. Both ends of left end portion 131C are connected to one end of front end portion 131A and one end of 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. The vibrating arms 121A to 121D are connected to the front end 131A, and a left support arm 151A and a right support arm 151B, which will be described later, are connected to the rear end 131B.

In a plan view, the base 130 has a substantially rectangular shape with a front end 131A and a rear end 131B as long sides and a left end 131C and a right end 131D as short sides. The base portion 130 is formed to be substantially plane-symmetrical with respect to an imaginary plane P defined along a perpendicular bisector of each of the front end portion 131A and the rear end portion 131B. The shape of the base 130 is not limited to the rectangular shape shown in fig. 3, and may be another shape that is substantially plane-symmetrical with respect to the virtual plane P. 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. At least one of the front end 131A, the rear end 131B, the left end 131C, and the right end 131D may be bent or curved.

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

In the base 130, the longest distance in the Y axis direction between the front end 131A and the rear end 131B, that is, the base length, is, for example, about 40 μm. The base width, which is the longest distance in the X axis direction between the left end 131C and the right end 131D, is, for example, about 300 μm. In the example shown in fig. 3, the base length corresponds to the length of the left end 131C or the right end 131D, and the base width corresponds to the length of the front end 131A or the rear end 131B.

The holding portion 140 is configured to hold the vibrating arms 121A to 121D so as to be capable of vibrating. Specifically, the holding portion 140 is formed to be plane-symmetric with respect to the virtual plane P. The holding portion 140 has a rectangular frame shape in a plan view, and is disposed so as to surround the outside of the vibrating portion 110 along the XY plane. As described above, since the holding portion 140 has a frame shape in a plan view, the holding portion 140 surrounding the vibrating portion 110 can be easily realized.

The holding portion 140 is not limited to the frame shape as long as it is disposed at least partially around the vibration portion 110. For example, the holding portion 140 may be disposed around the vibrating portion 110 to such an extent that it can hold the vibrating portion 110 and be joined to the upper cover 30 and the lower cover 20.

In the present embodiment, the holding portion 140 includes integrally formed housings 141A to 141D. As shown in fig. 3, frame 141A is provided so as to face the open ends of vibrating arms 121A to 121D, and the longitudinal direction thereof is parallel to the X axis. The frame 141B is disposed to face the rear end 131B of the base 130, and the longitudinal direction thereof is parallel to the X axis. The frame 141C is disposed to face the left end 131C of the base 130 and the vibrating arm 121A, and has a longitudinal direction parallel to the Y axis, and both ends thereof are connected to one ends of the frames 141A and 141D, respectively. The frame 141D is disposed to face the right end 131D of the base 130 and the vibrating arm 121A, and has a longitudinal direction parallel to the Y axis, and both ends thereof are connected to the other ends of the frames 141A and 141B, respectively. The frame 141A and the frame 141B face each other in the Y axis direction through the vibrating portion 110. The frame 141C and the frame 141D face each other in the X-axis direction through the vibrating portion 110.

The support arm 150 is disposed inside the holding portion 140 and connects the base portion 130 and the holding portion 140. The support arm 150 is formed to be plane-symmetric with respect to the imaginary plane P. Specifically, the support arm 150 includes a left support arm 151A and a right support arm 151B in a plan view. The left support arm 151A connects the rear end 131B of the base 130 to the frame 141C of the holding portion 140. The right support arm 151B connects the rear end 131B of the base 130 to the frame 141D of the holding portion 140.

The left support arm 151A includes a support rear arm 152A and a support side arm 153A, and the right support arm 151B includes a support rear arm 152B and a support side arm 153B. The support rear arms 152A, 152B extend from the rear end 131B of the base 130 between the rear end 131B of the base 130 and the holding portion 140. Specifically, one end of the support rear arm 152A is connected to the rear end 131B of the base 130, and extends therefrom toward the frame 141B. Then, the support rear arm 152A is bent in the X-axis direction and extends toward the frame 141C. One end of the support rear arm 152B is connected to the rear end 131B of the base 130, and extends therefrom toward the frame 141B. Then, the support rear arm 152B is bent in the X-axis direction and extends toward the frame 141D.

Support side arm 153A extends between vibration arm 121A and holding unit 140 in parallel with vibration arm 121A. Support-side arm 153B extends between vibration arm 121D and holding unit 140 in parallel with vibration arm 121D. Specifically, the support side arm 153A extends from the other end (end on the side of the frame 141C) of the support rear arm 152A toward the frame 141A in the Y-axis direction, and is bent in the X-axis direction and connected to the frame 141C. The support side arm 153B extends from the other end (end on the frame 141D side) of the support rear arm 152B toward the frame 141A in the Y-axis direction, and is bent in the X-axis direction and connected to the frame 141D.

The support side arms 153A and 153B are connected to the frame 141C and the frame 141D at positions facing the arm portions 123A to 123D in the X axis direction, respectively. In other words, in a plan view, the connection position between the support-side arm 153A and the frame 141C and the connection position between the support-side arm 153B and the frame 141D are shifted from the center line CL in the Y axis direction of the vibrating unit 110, that is, the vibrating arms 121A to 121D and the base 130, toward the base 130. This shortens the length of the support arms 153A and 153B in the Y axis direction.

The protrusion 50 protrudes from the recess 21 of the lower cover 20 into the vibration space. In a plan view, the protrusion 50 is disposed between the arm portion 123B of the vibrating arm 121B and the arm portion 123C of the vibrating arm 121C. The projection 50 extends in the Y-axis direction in parallel with the arm portions 123B and 123C, and is formed in a prismatic shape. The length of the projection 50 in the Y-axis direction is about 240 μm, and the length in the X-axis direction is about 15 μm. The number of the protrusions 50 is not limited to one, and may be two or more. In this way, by disposing protrusion 50 between vibrating arm 121B and vibrating arm 121C and protruding from bottom plate 22 of recess 21, the rigidity of lower cover 20 can be improved, and the occurrence of bending of resonator 10 formed in lower cover 20 and warping of lower cover 20 can be suppressed.

Next, a laminated structure and an operation of the resonance device according to the first embodiment of the present invention will be described with reference to fig. 4 and 5. Fig. 4 is a cross-sectional view along the X axis schematically showing the laminated structure of the resonator device 1 shown in fig. 1. Fig. 5 is a cross-sectional view along the Y axis schematically showing the laminated structure of the resonator device 1 shown in fig. 1.

The resonance device 1 joins the holding portion 140 of the resonator 10 to the side wall 23 of the lower cover 20, and joins the holding portion 140 of the resonator 10 to the side wall 33 of the upper cover 30. In this way, resonator 10 is held between lower cover 20 and upper cover 30, and vibration space in which vibrating portion 110 vibrates is formed by lower cover 20, upper cover 30, and holding portion 140 of resonator 10.

The vibration part 110, the holding part 140, and the support arm 150 in the resonator 10 are integrally formed by the same process. The resonator 10 has a metal film E1 laminated on an Si substrate F2 as an example of a substrate. Then, a piezoelectric film F3 is stacked over the metal film E1 so as to cover the metal film E1, and a metal film E2 is further stacked over the piezoelectric film F3. A protective film F5 was laminated over the metal film E2 so as to cover the metal film E2. In the mass adding portions 122A to 122D, the mass adding films 125A to 125D are stacked on the protective film F5, respectively. The outer shapes of the vibration unit 110, the holding unit 140, and the support arm 150 are formed by removing and patterning a laminated body including the Si substrate F2, the metal film E1, the piezoelectric film F3, the metal film E2, the protective film F5, and the like by dry etching using an argon (Ar) ion beam, for example.

In the present embodiment, the 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, a degenerate silicon substrate having a low resistance is used as the Si substrate F2, so that the Si substrate F2 itself can also serve as the metal film E1, and the metal film E1 can be omitted.

The Si substrate F2 is formed of, for example, a degenerate n-type silicon (Si) semiconductor having a thickness of about 6 μm, and can include phosphorus (P), arsenic (As), antimony (Sb), and the like As an n-type dopant. The resistance value of the degenerate silicon (Si) used in the Si substrate F2 is, for example, less than 1.6m Ω · cm, and more preferably 1.2m Ω · cm or less. Further, SiO, for example, is formed on the lower surface of the Si substrate F2₂The silicon oxide layer F21 is used as an example of the temperature characteristic correction layer. This can improve the temperature characteristics.

In the present embodiment, the silicon oxide layer F21 is a layer having a function of reducing the temperature coefficient of the frequency at the vibrating portion 110, i.e., the rate of change per unit temperature, when the temperature correction layer is formed on the Si substrate F2, 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. Since the vibrating portion 110 includes the silicon oxide layer F21, for example, a change in resonance frequency associated with temperature can be reduced in a laminated structure including the Si substrate F2, the metal films E1 and E2, the piezoelectric film F3, and the silicon oxide layer F21. The silicon oxide layer may be formed on the upper surface of the Si substrate F2, or on both the upper surface and the lower surface of the Si substrate F2.

The silicon oxide layer F21 of the mass adding parts 122A to 122D is preferably formed to have a uniform thickness. The uniform thickness means that the thickness of the silicon oxide layer F21 is within ± 20% from the average value of the thicknesses.

The metal films E1 and E2 include excitation electrodes for exciting the vibration arms 121A to 121D, respectively, and extraction electrodes for electrically connecting the excitation electrodes to an external power supply. The portions of the metal films E1 and E2 that function as excitation electrodes face each other through 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 extraction electrodes are led out from the base 130 to the holding portion 140 via the support arm 150, for example. The metal film E1 is electrically continuous throughout the resonator 10. The metal film E2 is electrically separated between the portions formed on the vibrating arms 121A and 121D and the portions formed on the vibrating arms 121B and 121C.

The thicknesses of the metal films E1 and E2 are, for example, about 0.1 μm to 0.2 μm, respectively. After the formation of the metal films E1 and E2, the metal films are patterned into excitation electrodes, extraction electrodes, and the like by a removal process such as etching. The metal films E1, E2 are formed of, for example, a metal material having a crystal structure of a body-centered cubic structure. Specifically, the metal films E1 and E2 are formed using Mo (molybdenum), tungsten (W), or the like. In this way, the metal films E1 and E2 can easily realize metal films E1 and E2 suitable for the lower electrode and the upper electrode of the resonator 10 by having a crystal structure as a metal main component of a body-centered cubic structure.

The piezoelectric film F3 is a thin film formed of one of piezoelectric bodies that interconvert electrical energy and mechanical energy. The piezoelectric film F3 expands and contracts in the Y-axis direction among the in-plane directions of the XY plane in accordance with the electric field formed by the metal films E1, E2 in the piezoelectric film F3. By the expansion and contraction of the piezoelectric film F3, the vibrating arms 121A to 121D are displaced toward the bottom plate 22 of the lower cover 20 and the bottom plate 32 of the upper cover 30, respectively. Thus, the resonator 10 vibrates in an out-of-plane bending vibration mode.

The thickness of the piezoelectric film F3 is, for example, about 1 μm, but may be about 0.2 to 2 μm. The piezoelectric film F3 is made of a material having a crystal structure of wurtzite hexagonal crystal structure, and may be made of a nitride or an oxide, such as aluminum nitride (AlN), scandium aluminum nitride (ScAlN), zinc oxide (ZnO), gallium nitride (GaN), or indium nitride (InN), as a main component. Aluminum scandium nitride is a material obtained by replacing a part of aluminum in aluminum nitride with scandium, and may be replaced with two elements, such as magnesium (Mg) and niobium (Nb), or magnesium (Mg) and zirconium (Zr), instead of scandium. In this way, the piezoelectric film F3 mainly contains a piezoelectric body having a wurtzite hexagonal crystal structure, and thus the piezoelectric film F3 suitable for the resonator 10 can be easily realized.

The protective film F5 protects the metal film E2 from oxidation. The protective film F5 may not be exposed to the bottom plate 32 of the upper cover 30 as long as it is provided on the upper cover 30 side. For example, a parasitic capacitance reducing film or the like that reduces the capacitance of the wiring formed in the resonator 10 may be formed so as to cover the protective film F5. The protective film F5 is formed of, for example, a piezoelectric film such as aluminum nitride (AlN), scandium aluminum nitride (ScAlN), zinc oxide (ZnO), gallium nitride (GaN), or indium nitride (InN), and is further formed of silicon nitride (SiN) or silicon oxide (SiO)₂) Alumina (Al)₂O₃) Tantalum pentoxide (Ta)₂O₅) And the like are formed. The thickness of the protective film F5 is formed to be equal to or less than half the thickness of the piezoelectric film F3, and is, for example, about 0.2 μm in the present embodiment. Further, a more preferable thickness of the protective film F5 is about one-fourth of the thickness of the piezoelectric film F3. When the protective film F5 is made of a piezoelectric body such as aluminum nitride (AlN), it is preferable to use a piezoelectric body having the same orientation as that of the piezoelectric film F3.

The protective film F5 of the mass-added parts 122A to 122D is preferably formed to have a uniform thickness. The uniform thickness means that the variation in the thickness of the protective film F5 is within ± 20% from the average value of the thicknesses.

The mass adding films 125A to 125D constitute the surfaces of the mass adding portions 122A to 122D on the side of the upper cover 30, and correspond to the frequency adjusting films of the vibrating arms 121A to 121D. The frequency of the resonator 10 is adjusted by trimming processing for removing a part of each of the mass additional films 125A to 125D. From the viewpoint of the efficiency of frequency adjustment, the mass additional films 125A to 125D are preferably formed of a material having a higher mass reduction rate by etching than the protective film F5. The mass reduction rate is represented by the product of the etch rate and the density. The etching rate refers to the thickness removed per unit time. The protective film F5 and the mass added films 125A to 125D have arbitrary magnitude relationship of etching rate as long as the relationship of mass reduction rate is as described above. In addition, from the viewpoint of effectively increasing the weight of the mass-added parts 122A to 122D, the mass-added films 125A to 125D are preferably formed of a material having a large specific gravity. For these reasons, the mass additional films 125A to 125D are formed of a metal material such as molybdenum (Mo), tungsten (W), gold (Au), platinum (Pt), nickel (Ni), aluminum (Al), or titanium (Ti).

A part of the upper surface of each of the mass additional films 125A to 125D is removed by trimming in the step of adjusting the frequency. The trimming process of the mass added films 125A to 125D can be performed by, for example, dry etching by irradiation with an argon (Ar) ion beam. The ion beam can be irradiated over a wide range, and thus the processing efficiency is excellent, but the mass additional films 125A to 125D may be charged due to the charge. In order to prevent the vibration orbits of the vibrating arms 121A to 121D from changing and the vibration characteristics of the resonator 10 from deteriorating due to coulomb interaction caused by the electrification of the mass-added films 125A to 125D, it is preferable that the mass-added films 125A to 125D be grounded.

Lead lines C1, C2, and C3 are formed on the protective film F5 of the holding portion 140. The lead wire C1 is electrically connected to the metal film E1 through the 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 the through hole 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 the through hole formed in the protective film F5. The lead wires C1 to C3 are made of a metal material such as aluminum (Al), germanium (Ge), gold (Au), or tin (Sn).

In the present embodiment, although fig. 4 shows an example in which the arm portions 123A to 123D, the lead lines C2 and C3, and the through-electrodes V2 and V3 are located on the same plane in cross section, they are not necessarily located on the same plane in cross section. For example, the through electrodes V2 and V3 may be formed at positions separated from the cross-section of the cutting arm portions 123A to 123D in the Y-axis direction, the positions being parallel to the ZX plane defined by the Z axis and the X axis.

Similarly, in the present embodiment, although fig. 5 shows an example in which the mass adding part 122A, the arm part 123A, the lead lines C1, C2, the through-electrodes V1, V2, and the like are located on the same plane cross section, they are not necessarily located on the same plane cross section.

The bottom plate 22 and the side walls 23 of the lower cover 20 are integrally formed of an Si substrate P10. The Si substrate P10 is made of silicon which is not degenerated, and has a resistivity of, for example, 10 Ω · cm or more. Inside the recess 21 of the lower cover 20, the Si substrate P10 is exposed. A silicon oxide layer F21 is formed on the upper surface of the protrusion 50. However, from the viewpoint of suppressing the electrification of the protrusion 50, the Si substrate P10 having a resistivity lower than that of the silicon oxide layer F21 may be exposed on the upper surface of the protrusion 50, or a conductive layer may be formed.

The thickness of the lower cover 20 defined in the Z-axis direction is about 150 μm, and the depth D1 of the recess 21 defined in the same manner is about 50 μm. Since the amplitude of each of vibration arms 121A to 121D is limited to depth D1, the maximum amplitude on the lower cover 20 side is about 50 μm.

The restricting portion 25 is provided with a first distance d1 from the support arm 150 of the resonator 10 in the thickness direction of the lower cover 20 along the Z-axis direction. Specifically, the restricting portion 25 includes a step forming a step difference with the bottom surface of the recess 21, and is formed integrally with the lower cover 20. The restricting portion 25 is provided at a position facing the support rear arms 152A, 152B of the support arm 150. Therefore, in the case where the support arm 150 vibrates in the Z-axis direction, the maximum amplitude of the lower cover 20 side is limited to the first distance d 1. The first distance d1 is, for example, about 5 μm to 15 μm.

Further, the lower cap 20 can also be regarded as a part of the SOI substrate. When the resonator 10 and the lower cover 20 are regarded as a MEMS substrate formed of an integrated SOI substrate, the Si substrate P10 of the lower cover 20 corresponds to a support substrate of the SOI substrate, the silicon oxide layer F21 of the resonator 10 corresponds to a BOX layer of the SOI substrate, and the Si substrate F2 of the resonator 10 corresponds to an active layer of the SOI substrate. In this case, various semiconductor elements, circuits, and the like may be formed outside the resonator device 1 using a part of a continuous MEMS substrate.

The bottom plate 32 and the side wall 33 of the upper cover 30 are integrally formed of an Si substrate Q10. The front surface and the back surface of the upper lid 30 and the inner surface of the through hole are preferably covered with the silicon oxide film Q11. The silicon oxide film Q11 is formed on the surface of the Si substrate Q10 by, for example, oxidation of the Si substrate Q10, Chemical Vapor Deposition (CVD). Inside the recess 31 of the upper cover 30, the Si substrate Q10 is exposed. Further, a suction layer may be formed on the surface of recess 31 of upper cover 30 on the side facing resonator 10. The getter layer is formed of, for example, titanium (Ti) or the like, and adsorbs exhaust gas released from the joint 40 or the like described later, thereby suppressing a decrease in the degree of vacuum of the vibration space. The air intake layer may be formed on the surface of the recess 21 of the lower cover 20 facing the resonator 10, or on the surface of both the recess 21 of the lower cover 20 and the recess 31 of the upper cover 30 facing the resonator 10.

The thickness of the upper cover 30 defined in the Z-axis direction is about 150 μm, and the depth D2 of the concave portion 31 defined in the same manner is about 50 μm. Since the amplitude of each of the vibrating arms 121A to 121D is limited to the depth D2, the maximum amplitude on the upper cover 30 side is about 50 μm.

Terminals T1, T2, and T3 are formed on the upper surface (the surface opposite to the surface facing resonator 10) of upper cover 30. The terminal T1 is a mounting terminal for grounding the metal film E1. The terminal T2 is a mounting terminal for electrically connecting the metal film E2 of the vibrating arms 121A and 121D to an external power supply. The terminal T3 is a mounting terminal for electrically connecting the metal film E2 of the vibrating arms 121B and 121C to an external power supply. The terminals T1 to T3 are formed by plating a metallization layer (base layer) of chromium (Cr), tungsten (W), nickel (Ni), or the like with nickel (Ni), gold (Au), silver (Ag), Cu (copper), or the like, for example. In addition, a dummy terminal electrically insulated from the resonator 10 may be formed on the upper surface of the upper cover 30 for the purpose of adjusting the parasitic capacitance and balancing the mechanical strength.

Through-electrodes V1, V2, and V3 are formed inside the side wall 33 of the upper lid 30. The through-electrode V1 electrically connects the terminal T1 to the lead wire C1, the through-electrode V2 electrically connects the terminal T2 to the lead wire C2, and the through-electrode V3 electrically connects the terminal T3 to the lead wire C3. The through-electrodes V1 to V3 are formed by filling conductive materials in through-holes that penetrate the side wall 33 of the upper lid 30 in the Z-axis direction. The conductive material to be filled is, for example, polysilicon (Poly-Si), copper (Cu), gold (Au), or the like.

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 is joined to the resonator 10 by the joint portion 40. The bonding portion 40 is formed in a closed ring shape surrounding the vibrating portion 110 in the XY plane so as to hermetically seal the vibrating space of the resonator 10 in a vacuum state. The bonding portion 40 is formed of, for example, a metal film formed by stacking an aluminum (Al) film, a germanium (Ge) film, and an aluminum (Al) film in this order and eutectic bonding. The bonding portion 40 may be formed by a combination of films appropriately selected from gold (Au), tin (Sn), copper (Cu), titanium (Ti), silicon (Si), and the like. In order to improve the adhesion, the bonding portion 40 may include a metal compound such as titanium nitride (TiN) or tantalum nitride (TaN) between films.

In the present embodiment, the terminal T1 is grounded, and alternating voltages of mutually opposite phases are applied to the terminal T2 and the terminal T3. Therefore, the phase of the electric field formed in the piezoelectric film F3 of the resonating arms 121A and 121D and the phase of the electric field formed in the piezoelectric film F3 of the resonating arms 121B and 121C are opposite to each other. Thereby, outer vibrating arms 121A and 121D and inner vibrating arms 121B and 121C are displaced in opposite directions to each other. For example, when the mass adding portions 122A and 122D of the vibrating arms 121A and 121D are displaced toward the inner surface of the upper cover 30, the mass adding portions 122B and 122C of the vibrating arms 121B and 121C are displaced toward the inner surface of the lower cover 20. In this way, between the adjacent vibration arm 121A and vibration arm 121B, the vibration arm 121A and vibration arm 121B vibrate in the up-down opposite directions around the central axis r1 extending in the Y-axis direction. Further, between the adjacent vibration arm 121C and vibration arm 121D, the vibration arm 121C and vibration arm 121D vibrate in the up-down opposite directions around the central axis r2 extending in the Y-axis direction. As a result, torsional moments in opposite directions are generated in the center axis r1 and the center axis r2, and bending vibration is generated in the base 130. The maximum amplitude of vibration arms 121A to 121D is about 50 μm, and the amplitude during normal driving is about 10 μm.

As described above, in a plan view, the connection positions of the support-side arms 153A and 153B and the holding unit 140 are shifted toward the base unit 130 from the center lines CL in the Y-axis direction of the vibration arms 121A to 121D and the base unit 130, and the lengths of the support-side arms 153A and 153B in the Y-axis direction are shortened. Thus, the support trailing arms 152A, 152B hardly vibrate in the vibration of the main mode, and the amplitude of the support trailing arms 152A, 152B in the Z-axis direction can be reduced.

Here, the relationship between the vibration of the resonator 10 and the depths of the recess 21 and the regulating portion 25 will be described.

Generally, ultrasonic welding is often used in the manufacturing process or installation of the resonator device 1. Ultrasonic welding is a processing technique in which thermoplastic resins are instantaneously melted and joined by, for example, fine ultrasonic vibration of about 20kHz to 40kHz and a pressing force. In addition, in flux cleaning after reflow mounting of solder, ultrasonic cleaning of about 28kHz to 45kHz, for example, is often used. Alternatively, when the electronic component including the resonance device 1 is mounted on a vehicle, ultrasonic vibration may be generated as spike noise in the electronic component when the vehicle travels on gravel, for example.

When such ultrasonic vibration is applied to the resonator 10, the support arm 150 may strongly vibrate in the vertical direction due to a parasitic mode existing in a frequency region of the ultrasonic vibration. As a result, a large stress is applied to the connecting portion between the support arm 150 and the holding portion 140, and the connecting portion or the periphery thereof may be broken, thereby damaging or destroying the resonator 10.

In contrast, in the present embodiment, as shown in fig. 5, restriction unit 25 is provided with first distance D1 from support arm 150, and first distance D1 is smaller than depth D1 between the bottom surface of recess 21 and vibration arms 121A to 121D in the thickness direction of lower cover 20. Thus, when ultrasonic vibration is applied to the resonator 10, the vibration of the support arm 150 in the Z-axis direction is restricted by the restricting portion 25, and therefore, the amplitude thereof is reduced as compared with the case where the restricting portion 25 is not provided. Therefore, stress applied to the connecting portion between support arm 150 and holding portion 140 can be reduced, and breakage or destruction of resonator 10 can be suppressed.

The first distance D1 is preferably 1/10 or more of the depth D1 and less than the depth D1, and more preferably 1/10 or more of the depth D1 and 3/10 or less of the depth D1. In this way, the first distance D1 is greater than or equal to 1/10 of the depth D1 and smaller than the depth D1, whereby the resonance device 1 that reduces stress applied to the connecting portion of the support arm 150 and the holding part 140 can be easily realized.

When the resonance device 1 operates, the vibrating arms 121A to 121D vibrate in the primary mode, and the left support arm 151A and the right support arm 151B vibrate in the parasitic mode. In the following description, the frequency of the main mode vibration generated in vibrating arms 121A to 121D is defined as frequency Fm, and the frequency of the spurious mode vibration generated in supporting arm 150 is defined as frequency Fs.

Next, a relationship between a ratio of the frequency of the spurious mode to the frequency of the main mode and a DLD (Drive Level Dependency) characteristic will be described with reference to fig. 6. Fig. 6 is a graph showing a relationship between the frequency ratio and the DLD deviation. In fig. 6, the horizontal axis represents the frequency ratio Fs/Fm of the frequency Fs of the spurious mode vibration to the frequency Fm of the primary mode vibration, and the vertical axis represents a value indicating the DLD deviation (DLD slope 3 σ).

As shown in fig. 6, as the frequency ratio Fs/Fm approaches 2, the DLD slope 3 σ becomes larger. The DLD slope 3 sigma in the range of the frequency ratio Fs/Fm of 1.8-2.2 (Fs/Fm is more than or equal to 1.8 and less than or equal to 2.2) is larger than the DLD slope 3 sigma in the range of the frequency ratio Fs/Fm of less than 1.8(Fs/Fm is less than 1.8) and the frequency ratio Fs/Fm of more than 2.2 (Fs/Fm is more than 2.2). Particularly, the DLD slope 3 sigma is particularly large in the range where the frequency ratio Fs/Fm is 1.8 to 2.2 (1.9. ltoreq. Fs/Fm. ltoreq.2.1). For example, in the example shown in FIG. 6, the DLD slope 3 σ in the range of 1.8. ltoreq. Fs/Fm. ltoreq.2.2 exceeds 10 ppm/0.2. mu.W, and the DLD slope 3 σ in the range of 1.9. ltoreq. Fs/Fm. ltoreq.2.1 exceeds 20 ppm/0.2. mu.W. Therefore, the frequency ratio Fs/Fm preferably satisfies Fs/Fm < 1.8, or 2.2 < Fs/Fm, more preferably Fs/Fm < 1.9, or 2.1 < Fs/Fm.

The change in the slope of the approximation curve in the range of 1.8-2.2 is greater than the change in the slope of the approximation curve in the ranges of Fs/Fm < 1.8 and Fs/Fm < 2.2, and is particularly greater in the range of 1.9-2.1. Here, the slope of the approximate curve is the amount of change in the DLD slope 3 σ with respect to the amount of change in the frequency ratio Fs/Fm. In other words, in the range of 1.8 ≦ Fs/Fm ≦ 2.2, when the frequency Fm or the frequency Fs changes due to manufacturing variations such as thickness variations of the piezoelectric film F3, the DLD slope 3 σ greatly changes. Therefore, the allowable ranges of the frequency Fs and the frequency Fm are smaller in the range of 1.8 ≦ Fs/Fm ≦ 2.2 than in the ranges of Fs/Fm < 1.8 and 2.2 < Fs/Fm. That is, in order to reduce the required processing accuracy and suppress the yield deterioration, the frequency ratio Fs/Fm preferably satisfies Fs/Fm < 1.8 or 2.2 < Fs/Fm, and more preferably satisfies Fs/Fm < 1.9 or 2.1 < Fs/Fm.

Thus, when the frequency ratio Fs/Fm satisfies 2.1 < Fs/Fm, the DLD deviation can be prevented from increasing.

In the present embodiment, the example in which the resonance device 1 includes the restriction portion 25 having the step-like shape including the step is shown, but the present invention is not limited thereto. For example, the restricting portion may have a shape having a slope or may have a shape subjected to arc chamfering in which corners are rounded. The restricting portion 25 may be provided at the first distance d1 from the support arm 150 in the thickness direction of the lower cover 20, and may have another form.

< modification example >

Fig. 7 is a plan view showing a modification of the lower cover 20 shown in fig. 2.

As shown in fig. 7, the lower cover 20' includes two restricting portions 25A and 25B. The regulating portions 25A and 25B protrude from the surface of the base plate 22, and each have a pentagonal shape in plan view.

The restricting portions 25A and 25B are provided with the first distance d1 from the support arm 150 in the thickness direction of the lower cover 20' along the Z-axis direction. Specifically, the restricting portion 25A is disposed with a first distance d1 between the connecting portion of the left support arm 151A that connects the support rear arm 152A to the rear end 131B of the base 130. Similarly, the restricting portion 25B is disposed with a first distance d1 between the connecting portion of the right support arm 151B that connects the rear end portion 131B of the support rear arm 152B to the base portion 130. In this way, by providing the restricting portions 25A and 25B with the first distance d1 in the thickness direction of the lower cover 20' along the Z-axis direction, and between at least the support rear arms 152A and 152B of the support arms 150, it is possible to reduce stress applied to the connecting portion between the support arms 150 and the holding portion 140, and to increase the volume of the recess 21.

[ second embodiment ]

Next, a resonator device according to a second embodiment of the present invention will be described with reference to fig. 8 to 11. In the following embodiments, the same or similar components as those in the first embodiment will be denoted by the same or similar reference numerals, and the points different from those in the first embodiment will be described. In addition, the same operational effects exerted by the same structures are not mentioned in order.

First, a schematic configuration of a resonator according to a second embodiment of the present invention will be described with reference to fig. 8. Fig. 8 is a plan view schematically showing the structure of the resonator 210 according to the second embodiment. Fig. 8 is a plan view corresponding to fig. 3 in the first embodiment.

The resonator 210 of the second embodiment is different from the resonator 10 of the first embodiment in that the left support arm 251A and the right support arm 251B are connected to the left end 231C and the right end 231D of the base 230, respectively.

As shown in fig. 8, resonator 210 includes resonating arms 221A to 221D, base 230, holding portion 240, and support arm 250, as in resonator 10 of the first embodiment. Each of the vibration arms 221A to 221D includes each of the mass adding portions 222A to 222D and each of the arm portions 223A to 223D. The base portion 230 includes a front end 231A, a rear end 231B, a left end 231C, and a right end 231D. The holding portion 240 includes housings 241A, 241B, 241C, and 241D. The support arm 250 includes a left support arm 251A and a right support arm 251B.

The left support arm 251A and the right support arm 251B include support side arms 253A and 253B, respectively, instead of the support rear arm of the first embodiment shown in fig. 3. Specifically, one end of the support-side arm 253A is connected to the left end 231C of the base 130, and extends therefrom toward the frame 241C in the X-axis direction. Then, the support side arm 253A is bent in the Y-axis direction, extends toward the frame 241A, and is bent in the X-axis direction and connected to the frame 241C. Similarly, one end of the support side arm 253B is connected to the right end 231D of the base 130, and extends therefrom toward the frame 241D in the X-axis direction. Then, the support side arm 253B is bent in the Y-axis direction, extends toward the frame 241A, and is bent in the X-axis direction and connected to the frame 241D.

Next, a schematic structure of a lower cover according to a second embodiment of the present invention will be described with reference to fig. 9 to 11. Fig. 9 is a plan view schematically showing a first example of the lower cover 220 in the second embodiment. Fig. 10 is a plan view schematically showing a second example of the lower cover 220 in the second embodiment. Fig. 11 is a plan view schematically showing a third example of the lower cover 220 in the second embodiment.

As shown in fig. 9, the lower cover 220 includes a bottom plate 222 and a side wall 223, as in the lower cover 20 of the first embodiment. In lower cover 220, a recess 221 defined by the surface of bottom plate 222 and the inner surface of sidewall 223 is formed on the surface facing resonator 210.

The protruding portion of the first embodiment is not formed on the surface of the bottom plate 222, and the restricting portion 225A is provided as in the first embodiment. The restriction portion 225A is provided with a first distance d1 in the thickness direction of the lower cover 220 along the Z-axis direction, between the restriction portion and at least the support side arms 253A and 253B of the support arm 150. Accordingly, stress applied to the connecting portion between the support arm 150 and the holding portion 140 can be reduced, and the support arms 253A and 253B are connected to the left end 231C and the right end 231D of the base 230, respectively, so that the space on the rear end 231B side of the base 230 can be reduced, and the resonance device can be downsized.

As in the first embodiment, the form of the restriction section 225A is not limited to the example shown in fig. 9.

For example, as shown in fig. 10, the lower cap 220 may include a columnar restricting portion 225B extending in the Y-axis direction.

As shown in fig. 11, the lower cover 220 may include two restricting portions 225C and 225D. In this case, the restriction portion 225C is disposed with a first distance d1 between the connection portion of the support side arm 253A of the left support arm 251A with the left end 231C of the base 130. Similarly, the restriction section 225D is disposed with a first distance D1 between the connection portion of the support side arm 253B of the right support arm 251B with the right end 231D of the base 130.

[ third embodiment ]

Next, a resonator device according to a third embodiment of the present invention will be described with reference to fig. 12. Fig. 12 is a cross-sectional view along the Y axis schematically showing the laminated structure of the resonator device 300 in the third embodiment. Fig. 12 is a cross-sectional view corresponding to fig. 5 in the first embodiment.

The resonance device 300 of the third embodiment is different from the resonance device 1 of the first embodiment in that the upper cover 330 includes the restricting part 335.

As shown in fig. 12, the upper cover 330 includes a bottom plate 332 and side walls 333, as in the upper cover 30 of the first embodiment. In addition, in the upper cover 330, a recess 331 defined by the surface of the bottom plate 332 and the inner surface of the side wall 333 is formed on the surface facing the resonator 10.

The upper cover 330 includes a restricting portion 335 provided on the surface of the bottom plate 332. The restricting portion 335 is provided with a second distance d2 from the support arm 150 of the resonator 10 in the thickness direction of the upper cover 330 along the Z-axis direction. Specifically, the restricting portion 335 includes a step that forms a step with the bottom surface of the recess 331, and is formed integrally with the upper cover 330. The restricting portion 335 is provided at a position facing the support rear arms 152A, 152B of the support arm 150. Therefore, in the case where the support arm 150 vibrates in the Z-axis direction, the maximum amplitude of the upper cover 330 side is limited to the second distance d 2. The second distance d2 is, for example, about 5 μm to 40 μm.

Second distance D2 is smaller than depth D2 between the bottom surface of recess 331 and vibration arms 121A to 121D in the thickness direction of upper cover 330. Thus, when ultrasonic vibration is applied to the resonator 10, the vibration of the support arm 150 in the Z-axis direction is restricted by the restricting portion 335, and therefore the amplitude thereof is reduced as compared with the case where the restricting portion 335 is not provided. Therefore, stress applied to the connecting portion between support arm 150 and holding portion 140 can be further reduced, and breakage or destruction of resonator 10 can be further suppressed.

[ fourth embodiment ]

Next, a resonator device according to a fourth embodiment of the present invention will be described with reference to fig. 13. Fig. 13 is a cross-sectional view along the Y axis schematically showing the laminated structure of the resonator device 400 in the fourth embodiment. Fig. 13 is a cross-sectional view corresponding to fig. 5 in the first embodiment.

The resonance device 400 of the fourth embodiment is different from the resonance device 1 of the first embodiment in that the size of the recess 431 of the upper cover 430 is reduced.

As shown in fig. 13, the upper cover 430 includes a bottom plate 432 and a side wall 433, as in the upper cover 30 of the first embodiment. In addition, in upper cover 430, a recess 431 defined by the surface of bottom plate 432 and the inner surface of side wall 433 is formed on the surface facing resonator 10.

Recess 431 has a smaller length in the Y direction in which resonating arms 121A to 121D of resonator 10 extend than recess 31 of the first embodiment.

The upper cover 430 is disposed with a second distance d2 in the thickness direction along the Z-axis direction between the lower surface of the upper cover 430 facing the resonator 10 and the support arm 150, via the joint 40. Therefore, in the case where the support arm 150 vibrates in the Z-axis direction, the maximum amplitude of the upper cover 430 side is limited to the second distance d 2. The second distance d2 is substantially the same as the thickness of the joint 40, and is, for example, about 5 μm.

Second distance D2 is smaller than depth D2 between the bottom surface of recess 431 and vibration arms 121A to 121D in the thickness direction of upper cover 430. Thus, when ultrasonic vibration is applied to the resonator 10, the vibration of the support arm 150 in the Z-axis direction is restricted by the lower surface of the upper cover 430 facing the resonator 10, and thus its amplitude is reduced. Therefore, stress applied to the connecting portion between support arm 150 and holding portion 140 can be further reduced, and breakage or destruction of resonator 10 can be further suppressed.

[ fifth embodiment ]

Next, a resonator device according to a fifth embodiment of the present invention will be described with reference to fig. 14. Fig. 14 is a cross-sectional view along the Y axis schematically showing the laminated structure of the resonator device 500 in the fifth embodiment. Fig. 14 is a cross-sectional view corresponding to fig. 5 in the first embodiment.

The resonator device 500 of the fifth embodiment is different from the resonator device 1 of the first embodiment in that the lower cover 520 does not have the restriction portion and in that the size of the concave portion 531 of the upper cover 530 is reduced.

As shown in fig. 14, the lower cover 520 includes a bottom plate 522 and side walls 523, as in the lower cover 20 of the first embodiment. In addition, in lower cover 520, a concave portion 521 defined by the surface of bottom plate 522 and the inner surface of side wall 523 is formed on the surface facing resonator 10.

The restricting portion of the first embodiment is not provided on the surface of the bottom plate 222. Therefore, in the thickness direction of the lower cover 520 along the Z-axis direction, the distance between the bottom surface of the concave portion 521 and the support arm 150 is the depth D1 of the concave portion 521.

The upper lid 530 includes a bottom plate 532 and side walls 533 as in the upper lid 30 of the first embodiment. In addition, in upper cover 530, a concave portion 531 defined by the surface of bottom plate 432 and the inner surface of side wall 433 is formed on the surface facing resonator 10. Recess 531 has a smaller length in the Y direction in which vibration arms 121A to 121D of resonator 10 extend, than recess 31 of the first embodiment.

Upper cover 530 is disposed with second distance d2 in the thickness direction along the Z-axis direction between the lower surface of upper cover 530 facing resonator 10 and support arm 150, via joint 40. Therefore, in the case where the support arm 150 vibrates in the Z-axis direction, the maximum amplitude of the upper cover 530 side is limited to the second distance d 2. The second distance d2 is substantially the same as the thickness of the joint 40, and is, for example, about 5 μm.

The second distance D2 is smaller than the depth D2 between the bottom surface of the recess 531 and the vibration arms 121A to 121D in the thickness direction of the upper cover 530. Thus, when ultrasonic vibration is applied to resonator 10, the vibration of support arm 150 in the Z-axis direction is restricted by the lower surface of upper cover 530 facing resonator 10, and therefore its amplitude is reduced. Therefore, stress applied to the connecting portion between support arm 150 and holding unit 140 can be reduced inexpensively and easily, and breakage or breakage of resonator 10 can be suppressed.

The exemplary embodiments of the present invention have been described above. According to the resonance device of the one aspect of the present invention, the restricting portion is provided with the first distance from the support arm in the thickness direction of the lower cover, and the first distance is smaller than the depth between the bottom surface of the recess in the thickness direction of the lower cover and the vibrating arm. Thus, when ultrasonic vibration is applied to the resonator, the vibration of the support arm in the Z-axis direction is restricted by the restricting portion, and therefore the amplitude thereof is reduced as compared with the case where no restricting portion is provided. Therefore, stress applied to the connecting portion between the support arm and the holding portion can be reduced, and breakage or destruction of the resonator can be suppressed.

In the resonance device, the frequency ratio Fs/Fm satisfies 2.1 < Fs/Fm. This can suppress an increase in the DLD deviation.

In the resonator device, the connection position between the support-side arm and the holding portion is shifted toward the base portion from the center line of the vibrating arm and the base portion in the Y-axis direction in a plan view. This shortens the length of the support side arm in the Y-axis direction, and the support rear arm hardly vibrates in the main mode vibration, thereby reducing the amplitude of the support rear arm in the Z-axis direction.

In the resonance device, the restricting portion is provided with a first distance from at least one of the support arms in a thickness direction of the lower cover along the Z-axis direction. This reduces stress applied to the connecting portion between the support arm and the holding portion, and increases the volume of the recess.

In the resonance device, the restriction portion is provided with a first distance from at least one of the support arms in a thickness direction of the lower cover along the Z-axis direction. Accordingly, the stress applied to the connecting portion between the support arm and the holding portion can be reduced, and the support side arms are connected to the left end and the right end of the base portion, respectively, so that the space on the rear end side of the base portion can be reduced, and the resonance device can be downsized.

In the above resonance device, the first distance is not less than 1/10 of the depth and is less than the depth. This makes it possible to easily realize a resonance device that reduces stress applied to the connecting portion between the support arm and the holding portion.

In addition, in the above resonance device, the restriction portion includes a step. This makes it possible to easily realize a resonance device that reduces stress applied to the connecting portion between the support arm and the holding portion.

In the resonator device, the protrusion is disposed between the adjacent resonating arms and protrudes from the bottom plate of the recess. This can improve the rigidity of the lower cover, and suppress the occurrence of flexure of the resonator formed in the lower cover and warpage of the lower cover.

In the resonator device, the restricting portion is provided at a second distance from the support arm of the resonator in the thickness direction of the upper cover along the Z-axis direction, the second distance being smaller than the depth between the bottom surface of the recess in the thickness direction of the upper cover and the resonating arm. Thus, when ultrasonic vibration is applied to the resonator, the vibration of the support arm in the Z-axis direction is restricted by the restricting portion, and therefore the amplitude thereof is reduced as compared with the case where no restricting portion is provided. Therefore, stress applied to the connecting portion between the support arm and the holding portion can be further reduced, and breakage or destruction of the resonator can be further suppressed.

In the above resonance device, the joint portion is spaced apart by a second distance between the support arm and a lower surface of the upper cover facing the resonator in a thickness direction of the upper cover along the Z-axis direction, the second distance being smaller than a depth between the bottom surface of the recess in the thickness direction of the upper cover and the vibration arm. Thus, when ultrasonic vibration is applied to the resonator, the vibration of the support arm in the Z-axis direction is restricted by the lower surface of the upper cover facing the resonator, and therefore its amplitude is reduced. Therefore, stress applied to the connecting portion between the support arm and the holding portion can be further reduced, and breakage or destruction of the resonator can be further suppressed.

According to the resonator device in accordance with the other aspect of the present invention, the joint portion is spaced apart by a second distance between the support arm and a lower surface of the upper cover facing the resonator in the thickness direction of the upper cover along the Z-axis direction, and the second distance is smaller than the depth between the bottom surface of the recess in the thickness direction of the upper cover and the vibrating arm. Thus, when ultrasonic vibration is applied to the resonator, the vibration of the support arm in the Z-axis direction is restricted by the lower surface of the upper cover facing the resonator, and therefore its amplitude is reduced. Therefore, stress applied to the connecting portion between the support arm and the holding portion can be reduced inexpensively and easily, and breakage of the resonator can be suppressed.

The embodiments described above are intended to facilitate understanding of the present invention, and are not intended to limit the present invention. The present invention can be modified/improved without departing from the gist thereof, and the present invention also includes equivalents thereof. That is, those skilled in the art can appropriately modify the embodiments and/or the modifications, and the embodiments and/or modifications are included in the scope of the present invention as long as the features of the present invention are provided. For example, the elements provided in the embodiment and/or the modification, and the arrangement, materials, conditions, shapes, dimensions, and the like thereof are not limited to those illustrated in the examples, and can be appropriately modified. It is to be understood that the embodiments and the modifications are merely exemplary, and that partial substitutions and combinations of the configurations shown in the different embodiments and/or modifications are possible, and are included in the scope of the present invention as long as the features of the present invention are included.

Description of the reference numerals

1 … resonant device; 10 … resonator; 20 … lower cover; 20' … lower cover; 21 … recess; 22 … a bottom panel; 23 … side walls; 25. 25A, 25B … restricting parts; 30 …, covering; 31 … recess; a 32 … bottom panel; 33 … side walls; a 40 … joint; a 50 … projection; 110 … vibrating part; 120 … excitation part; 121. 121A, 121B, 121C, 121D … vibrating arms; 122A, 122B, 122C, 122D … mass additions; 123A, 123B, 123C, 123D … arm portions; 125A, 125B, 125C, 125D … mass additional films; 130 … a base portion; 131a … front end; 131B … rear end; 131C … left end; 131D … right end; 140 … holding part; 141A, 141B, 141C, 141D … housings; 150 … supporting an arm; 151a … left support arm; 151B … right support arm; 152A, 152B … support the rear arm; 153A, 153B … support side arms; 210 … resonator; 220 … lower cover; 221 … recess; 221A, 221B, 221C, 221D … vibrating arms; 222 … a bottom panel; 222A, 222B, 222C, 222D … mass additions; 223 … side walls; 223A, 223B, 223C, 223D … arm portions; 225A, 225B, 225C, 225D … restriction; 230 … a base portion; 231a … front end; 231B … rear end; 231C … left end; 231D … right end; 240 … holding part; 241A, 241B, 241C, 241D … casing; 250 … supporting arm; 251a … left support arm; 251B … right support arm; 253A, 253B … support side arms; a 300 … resonant device; 330 … covering; 331 … recess; 332 … a base plate; 333 … side walls; 335 … restriction; 400 … resonant device; 430 … upper cover; 431 … recess; 432 … a base plate; 433 … side walls; 500 … resonant device; 520, 520 … lower cover; 521 … concave part; 522 … bottom plate; 523 … side walls; 530, 530 …, covering; 531 … a recess; 532 … bottom plate; 533 … side wall; c1, C2 and C3 … leading-out wires; CL … centerline; d1, D2 … depth; d1 … first distance; d2 … a second distance; e1, E2 … metal films; f2 … Si substrate; f3 … piezoelectric film; f5 … protective film; f21 … silicon oxide layer; fm … frequency; fs … frequency; p … imaginary plane; a P10 … Si substrate; a Q10 … Si substrate; q11 … silicon oxide film; r1, r2 … central axis; t1, T2, T3 … terminals; v1, V2, V3 … through electrodes; w1, W2 … release width.