Vibration device and method for manufacturing vibration device

Abstract

This vibration device comprises a first substrate, a second substrate, an intermediate layer, and an excitation electrode. The first substrate has a first surface. The second substrate has a second surface facing the first surface. The intermediate layer is located between the first surface and the second surface. The first surface has a first recess. The intermediate layer has a vibrating part and a frame part. The vibrating part has an excitation part in which the excitation electrode is located. The excitation part faces the first recess. The frame part surrounds the vibrating part in a plan view and is joined to the first surface and the second surface. The frame part includes a layer made of the same material as the layer included in the vibrating part. The outer edge of the vibrating part is separated from the frame part over the entire circumference thereof. The vibrating part is joined to the outer peripheral region of the first recess on the first surface.

Description

Vibration device and method for manufacturing the same

[0001] The present disclosure relates to a resonator device such as a quartz crystal resonator and a method for manufacturing the resonator device.

[0002] Known WLP (Wafer Level Package) type crystal units are formed by stacking a plate-shaped base, a crystal substrate, and a plate-shaped lid in this order (see, for example, Patent Documents 1 to 4). In plan view, the crystal substrate has a vibrating portion and a frame surrounding the vibrating portion. The vibrating portion is provided with an excitation electrode for vibrating the vibrating portion. The frame is bonded to the base and the lid. The base, frame, and lid form a package that houses the vibrating portion in a sealed space.

[0003] In Patent Documents 1 to 3, the vibrating section has a part or all of its outer periphery connected to the frame, and is thereby supported by a package made up of the base, frame, and lid.

[0004] In Patent Document 4, unlike Patent Documents 1 to 3, the vibrating section is separated from the frame section along its entire periphery. Instead, the vibrating section is bonded to the top surface of the base via bumps. As a result, the vibrating section is supported by the package in a state where it is floating above the top surface of the base.

[0005] JP 2000-138554 A, WO 2020 / 137830 A, WO 2022-38150 A, WO 2015 / 162958 A

[0006] A vibration device according to one aspect of the present disclosure comprises a first substrate, a second substrate, an intermediate layer, and an excitation electrode. The first substrate has a first surface. The second substrate has a second surface opposite the first surface. The intermediate layer is located between the first surface and the second surface. The first surface has a first recess. The intermediate layer has a vibration portion and a frame portion. The vibration portion has an excitation portion in which the excitation electrode is located. The excitation portion faces the first recess. The frame portion surrounds the vibration portion in a planar view and is bonded to the first surface and the second surface. The frame portion includes a layer made of the same material as a layer included in the vibration portion. The outer edge of the vibration portion is separated from the frame portion along its entire periphery. The vibration portion is bonded to the outer peripheral region of the first recess in the first surface.

[0007] The method for manufacturing the vibration device includes a first bonding step, an etching step, and a second bonding step. In the first bonding step, the intermediate layer, with the vibration section and the frame section integrated together, is bonded to the first surface having the first recess. In the etching step, after the first bonding step, the intermediate layer is etched to separate the outer edge of the vibration section from the frame section along its entire periphery. In the second bonding step, after the etching step, the second surface is bonded to the intermediate layer.

[0008] 1. An exploded perspective view showing the configuration of a quartz crystal resonator according to an embodiment. An exploded perspective view of the quartz crystal resonator of FIG. 1, seen from a different direction than FIG. 1. A cross-sectional view taken along line III-III in FIG. 1. A cross-sectional view similar to FIG. 3, showing another example of a metal layer. A perspective view showing the configuration of a vibrating portion of the quartz crystal resonator of FIG. 1. FIG. 6A is a cross-sectional view taken along line VIa-VIa in FIG. 5, FIG. 6B is a cross-sectional view taken along line VIb-VIb in FIG. 5, and FIG. 6C is a cross-sectional view showing another example of electrical continuity between the front and rear surfaces of the vibrating portion. A plan view showing another example of the relationship between the first recess and the vibrating portion. FIG. 8A is a plan view showing yet another example of the relationship between the first recess and the vibrating portion, and a cross-sectional view taken along line VIIIb-VIIIb in FIG. 8A. A plan view showing another example of the first substrate of a quartz crystal resonator. An enlarged view of region X in FIG. 2. An enlarged view of a portion including the second pad electrode in FIG. 3. FIGS. 12A, 12B, and 12C are schematic cross-sectional views illustrating an example of a method for manufacturing the quartz crystal resonator of FIG. 1. 13A, 13B, and 13C are cross-sectional views showing a continuation of FIG. 12C. 14A, 14B, and 14C are cross-sectional views showing processes performed in parallel with the procedure of FIG. 12A, etc. 15A, 15B, and 15C are cross-sectional views showing a continuation of FIG. 13C and FIG. 14C. 16 is a plan view showing yet another example of the relationship between the first recess and the vibrating portion. 17A is a plan view showing another example of the intermediate layer and the metal layer, and 17B is a plan view showing another example of the second substrate and the metal layer corresponding to FIG. 17A. 17B is an exploded perspective view showing another example of the support for the vibrating portion. 18 is an exploded perspective view of the quartz crystal unit of FIG. 18 viewed from a different direction than FIG. 18. 18 is a cross-sectional view taken along the line XX-XX of FIG. 18.

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The drawings used in the following description are schematic. Therefore, for example, the dimensional ratios in the drawings do not necessarily correspond to the actual ones. Furthermore, the dimensional ratios may not match between drawings. Certain shapes and / or dimensions may be exaggerated, and details may be omitted. However, the above does not deny that the actual shapes and / or dimensions may be as shown in the drawings, or that features of shapes and / or dimensions may be extracted from the drawings.

[0010] In the description of multiple aspects, for the aspects described later, basically, only the differences from the aspects described earlier will be described. Matters not specifically mentioned may be considered to be the same as the aspects described earlier or may be inferred from the aspects described earlier. Furthermore, for convenience, components that correspond to each other in multiple aspects may be given the same reference numerals even if there are differences. Conversely, for convenience, even if the components are the same, different reference numerals may be given. For convenience, in the description of the embodiments, the description may be made on the assumption that the configuration of the vibration device (such as the shape and dimensions of each part) is that illustrated in the figures, unless otherwise specified.

[0011] 1 and 2 are exploded perspective views showing the configuration of a quartz crystal resonator 1 (an example of a resonator device) according to an embodiment. Fig. 3 is a cross-sectional view taken along line III-III in Fig. 1. In Figs. 1 and 2, hatching indicates the placement of a relatively thin layer (e.g., a metal layer (conductor layer)) (i.e., it does not represent a cross section).

[0012] For convenience, the drawings are shown with a Cartesian coordinate system D1D2D3. In the following, unless otherwise specified, a plan view or a plan perspective view refers to a view in the D3 direction. The vibrator 1 may be used with either direction considered to be the upside. However, for convenience, the +D3 side may be considered to be the upside, and terms such as "directly below" or "directly above" may be used.

[0013] The quartz crystal resonator 1 (hereinafter sometimes simply referred to as "resonator 1") is an electronic component configured by stacking three layers shown in FIGS. 1 to 3 on top of each other. When an AC voltage is applied to the resonator 1, the vibrating portion 9 contained within the resonator 1 vibrates. This vibration is used, for example, to generate an oscillation signal. The oscillation signal is, for example, a signal whose signal level (e.g., voltage) oscillates at a constant frequency.

[0014] The vibrator 1 has, as the three layers, a first substrate 3, an intermediate layer 7, and a second substrate 5, in that order from the -D3 side. In a plan view, the intermediate layer 7 has the vibration portion 9 and a frame portion 11 that surrounds the vibration portion 9. The frame portion 11 and the vibration portion 9 are made of the same material. In a broader concept, taking into account the aspect in which the frame portion 11 and / or the vibration portion 9 have a laminated structure, the frame portion 11 includes layers made of the same material as the layers included in the vibration portion 9. The vibration portion 9 and the frame portion 11 are formed, for example, by etching layers (members) that are integrally formed from the same material.

[0015] A first excitation electrode 13A and a second excitation electrode 13B (hereinafter, sometimes referred to as "excitation electrodes 13" without distinction) for exciting the vibration unit 9 are located on the front and back sides (the +D3 side and the -D3 side) of the vibration unit 9, respectively. In the example of FIG. 2, the -D3 side surface of the vibration unit 9 is entirely covered with a metal layer (multi-function electrode 33). In this embodiment, for example, the region of the metal layer that overlaps with the first excitation electrode 13A on the +D3 side (indicated by a dashed line in FIG. 2) may be regarded as the second excitation electrode 13B on the -D3 side.

[0016] In the vibrating portion 9, the region where the pair of excitation electrodes 13 overlap in a plan view is referred to as the excitation portion 9a. Note that in Figures 1 and 2, the excitation portion 9a is hidden by the pair of excitation electrodes 13 and is not shown, so for convenience, the reference numeral of the excitation portion 9a is given to the position where it overlaps with the excitation electrodes 13. Similarly, for convenience, the reference numerals indicating each part of the first substrate 3, the second substrate 5, and the intermediate layer 7 may be given to the conductor layers that overlap the respective parts. The excitation portion 9a is the region where vibration is intended. As described above, the vibration of the excitation portion 9a is used to generate an oscillation signal.

[0017] The frame portion 11 is bonded around the entire periphery to the first surface 3a on the intermediate layer 7 side (+D3 side) of the first substrate 3. The frame portion 11 is also bonded around the entire periphery to the second surface 5a on the intermediate layer 7 side (-D3 side) of the second substrate 5. This forms an enclosed space surrounded by the first substrate 3, frame portion 11, and second substrate 5. Consequently, the vibrating portion 9 is sealed. The inside of the enclosed space (around the vibrating portion 9) is, for example, in a vacuum state (actually a state lower than atmospheric pressure) or in a state where an appropriate gas (for example, an inert gas such as nitrogen) is present.

[0018] The first surface 3a has a first recess 14. The vibration unit 9 is overlaid on the first surface 3a so that the excitation unit 9a faces the first recess 14. The vibration unit 9 (more specifically, the region outside the excitation unit 9a) is joined to an outer peripheral region 3b of the first surface 3a that is located on the outer peripheral side of the first recess 14. The outer edge of the vibration unit 9 is separated from the frame portion 11 along its entire periphery.

[0019] As described above, the portion involved in vibration (vibration portion 9) and the portion involved in sealing (frame portion 11) are completely separated. Therefore, for example, the likelihood of vibration from the vibration portion 9 leaking to the frame portion 11 is reduced. In the vibration portion 9, the excitation portion 9a is separated from the first surface 3a by the first recess 14. This facilitates vibration of the excitation portion 9a. Therefore, for example, the need to use a conductive bump to raise the excitation portion 9a above the first surface 3a is reduced. Because at least some of the layers of the frame portion 11 and the vibration portion 9 share the same material, for example, the two can be formed from an integrated layer (member). In this case, for example, the integrated layer can be formed parallel to the first substrate 3, which is expected to reduce warping and / or deflection of the vibration portion 9 and stabilize the characteristics of the vibrator 1. Furthermore, for example, the vibration portion 9 can be supported (joined) at any position on the periphery of the first recess 14, thereby improving design freedom. For example, the vibrating section 9 may be joined to the outer peripheral region 3b over the entire periphery of the first recess 14. Furthermore, the vibrating section 9 may be joined to the outer peripheral region 3b over the entire outside of the region facing the first recess 14. In such a case, for example, warping and / or bending of the vibrating section 9 is reduced, and the characteristics of the vibrator 1 are expected to become more stable.

[0020] The area of ​​the vibrating part 9 facing the first recess 14 in a plan view may be smaller than the area of ​​the outer peripheral region 3b in a plan view. For example, it may be half or less. Such an outer peripheral region 3b can stably hold the vibrating part 9.

[0021] The above is an overview of the embodiment. Below, the embodiment will be roughly described in the following order: 1. Vibrator in general (Figs. 1 to 3) 1.1. Shape and dimensions of vibrator 1.2. Mounting mode of vibrator 1.3. Bonding of first substrate, intermediate layer, and second substrate 2. Vibrating section (Figs. 1 to 3) 2.1. Vibrating section in general 2.2. Shape and dimensions of vibrating section 2.3. Conductors located in the vibrating section 2.3.1. Conductors located in the vibrating section in general 2.3.2. Excitation electrode 2.3.3. Pad electrode 2.3.4. Inspection electrode 2.3.5. Multi-function electrode 2.3.6. Material of conductors located in the vibrating section 2.4. Conduction between the front and back of the vibrating section 2.4.1. Conduction at the through-hole (Figs. 5, 6A, and 6B) 2.4.2. Conduction at the outer peripheral surface (Fig. 6C) 3. 1. Material, shape, and dimensions of the frame 3.2. Conductors located on the frame 4. First substrate (Figs. 1 to 3, 4, 9) 4.1. Material, shape, and dimensions of the first substrate 4.2. Conductors located on the first substrate 5. Second substrate (Figs. 1 to 4) 5.1. Material, shape, and dimensions of the second substrate 5.2. Conductors located on the second substrate 6. Positional relationships between components 6.1. Relationship between the first recess and the vibrating portion (Figs. 1 to 3, 7, 8A, and 8B) 6.2. Gap between the vibrating portion and the frame 6.3. Relationship between the dimensions of various layers 7. Details of electrical connection between the vibrating portion and the second substrate (Figs. 10 and 11) 7.1. Groove in the second substrate 7.2. Positional relationship between the first through-hole and the second through-hole 8. Other examples of support structures (FIGS. 18 to 20) 9. Method for manufacturing a vibrator (FIGS. 12A to 15C) 10. Summary of embodiments

[0022] (1. Vibrator in General) (1.1. Shape and Dimensions of Vibrator) The shape of the vibrator 1 (the shape when the first substrate 3, intermediate layer 7, and second substrate 5 are stacked) is arbitrary. In the illustrated example, the shape of the vibrator 1 is roughly a thin rectangular parallelepiped (the length in the D3 direction is shorter than the lengths in other directions). The shape in plan view is a rectangle with the D2 direction as the longitudinal direction. Other shapes of the vibrator 1 include, for example, a thin shape with a roughly constant thickness in the D3 direction, and a circular, elliptical, square, or polygonal (excluding rectangular) shape in plan view. Note that in the description of this disclosure, unless otherwise specified, a rectangle does not include a square. Similarly, unless otherwise specified, an ellipse does not include a circle.

[0023] The specific dimensions of the vibrator 1 are also arbitrary. Examples of relatively small dimensions of the vibrator 1 are given below. In plan view, the maximum length in the longitudinal direction (e.g., the length of the long side) and the maximum length in the lateral direction (e.g., the length of the short side) are, for example, 0.5 mm or more and 2 mm or less. The thickness (D3 direction) is, for example, 0.1 mm or more and 0.3 mm or less.

[0024] (1.2. Mounting Method of Vibrator) The mounting method of the vibrator 1 to an external element (e.g., a circuit board) is also arbitrary. For example, the mounting method may be surface mounting or through-hole mounting. From another perspective, the configuration of the external electrodes (external terminals) related to the mounting of the vibrator 1 is arbitrary. For example, the external electrodes of the vibrator 1 may be pad-shaped for surface mounting (as in the illustrated example), or may be pin-shaped for surface mounting or through-hole mounting.

[0025] In the illustrated example, the vibrator 1 has a first external electrode 15A and a second external electrode 15B (hereinafter, these may be simply referred to as "external electrodes 15") that are exposed to the outside on the +D3 side. The external electrodes 15 have a surface facing the +D3 side and are pad-shaped at least in appearance. Although not specifically illustrated, the external electrodes 15 may contribute to mounting, for example, as follows.

[0026] For example, the −D3 side surface of the vibrator 1 may be bonded to the mounting surface of an external element with an adhesive, and the external electrode 15 may be electrically connected to a pad of the external element or a pad of another electronic component mounted on the external element with a bonding wire.

[0027] Alternatively, the vibrator 1 may be arranged such that the external electrode 15 faces a pad provided on the mounting surface of an external element. The pad and the external electrode 15 may then be joined by a conductive bonding material (e.g., solder) interposed between the pad and the external electrode 15. In this embodiment, in addition to the two external electrodes 15, a dummy electrode or an electrode to which a reference potential is applied may be provided on the +D3 side surface of the vibrator 1 to stabilize support of the vibrator 1 by the external element. In particular, if the electrode to which a reference potential is applied is formed so as to straddle the second recess 39 (described below) and the frame portion 11 in a plan view, the strength of the second substrate 5 can be increased. Furthermore, by substantially covering (e.g., covering 70% or more) the +D3 side surface of the second substrate 5 while being electrically isolated from the external electrode 15, the vibrator 1 can be reduced in the influence of external electromagnetic waves. In particular, if the electrode to which the reference potential is applied is formed so as to be connected to the reference potential electrode formed on the -D3 side surface of the first substrate 3 via the side surface of the second substrate 5, the side surface of the intermediate layer 7, and the side surface of the first substrate 3, the influence of external electromagnetic waves can be further suppressed.

[0028] The position, shape, and dimensions of the external electrodes 15 are arbitrary. For example, unlike the illustrated example, the external electrodes 15 may be located on the -D3 side of the vibrator 1 (on the first substrate 3 from another perspective). The positions of the external electrodes 15 in plan view are also arbitrary. In the illustrated example, the two external electrodes 15 are aligned in a direction (diagonal direction) inclined relative to the longitudinal and lateral directions of the vibrator 1 in plan view, and are relatively far from the outer edge of the vibrator 1. Unlike the illustrated example, for example, the external electrodes 15 may be located at one of the four corners of the vibrator 1 in plan view. In that case, the external electrodes 15 may be routed on the +D3 side of the second substrate 5 and a pad may be provided on the outside of the vibrating portion 9. This configuration reduces the transmission of stress to the vibrating portion 9 during mounting. In particular, when the external electrodes 15 are arranged symmetrically across the first recess 14 in plan view, the bias of stress during mounting can be reduced. Furthermore, for example, the external electrode 15 may be rectangular (as shown in the example), circular, elliptical, or polygonal (excluding rectangular).

[0029] (1.3. Bonding of First Substrate, Intermediate Layer, and Second Substrate) The bonding between the first substrate 3 and the intermediate layer 7, and the bonding between the intermediate layer 7 and the second substrate 5 may be variously performed.

[0030] 3, the first substrate 3 and the intermediate layer 7 are bonded to each other by a first metal layer 17 interposed therebetween. When attention is focused on the manufacturing process, a metal layer overlapping the first surface 3a of the first substrate 3 (first substrate-side layer 21; see also FIG. 1) and a metal layer overlapping the surface of the intermediate layer 7 facing the first substrate 3 (first intermediate-side layer 25; see also FIG. 2) are bonded to each other.

[0031] 3, the intermediate layer 7 and the second substrate 5 are bonded to each other by a second metal layer 19. When attention is paid to the manufacturing process, a metal layer (second substrate-side layer 23; see also FIG. 2) overlapping the second surface 5a of the second substrate 5 is bonded to a metal layer (second intermediate-side layer 27; see also FIG. 1) overlapping the surface of the intermediate layer 7 facing the second substrate 5.

[0032] Examples of bonding modes other than those shown include a mode in which the first substrate 3 and the intermediate layer 7 are bonded via an insulating layer interposed therebetween, and a mode in which the first substrate 3 and the intermediate layer 7 are bonded in direct contact with each other (direct bonding). The insulating layer is made of an inorganic material (e.g., SiO ２ ), or may be an organic material (e.g., resin). Furthermore, a metal layer and an insulating layer may be in close contact with each other between the first substrate 3 and the intermediate layer 7. Naturally, these other bonding modes may also be applied to the bonding between the second substrate 5 and the intermediate layer 7.

[0033] The bonding mode between the first substrate 3 and the intermediate layer 7 may be different from the bonding mode between the first substrate 3 and the intermediate layer 7. For example, the bonding between the substrate on which the external electrode 15 is provided (the second substrate 5 in the illustrated example) and the intermediate layer 7 may be achieved by a metal layer, while the bonding between the other substrate (the first substrate 3 in the illustrated example) and the intermediate layer 7 may be achieved by an insulating layer or direct bonding.

[0034] The bonding mode between the substrate (3 or 5) and the intermediate layer 7 may be different between different regions in a plan view. For example, the bonding between the vibrating section 9 and the substrate on which the external electrode 15 is provided (the second substrate 5 in the illustrated example) may be achieved by a metal layer, while the bonding between the frame section 11 and the substrate may be achieved by an insulating layer or direct bonding.

[0035] The first metal layer 17 and the second metal layer 19 will be described in detail later together with the first substrate 3, the intermediate layer 7, and the second substrate 5.

[0036] (2. Vibration Unit) (2.1. Vibration Unit in General) The vibration mode of the vibration unit 9 (vibration intended for use unless otherwise specified) may be various. From another perspective, the configurations of the vibration unit 9 and the excitation electrode 13 may be various.

[0037] For example, the vibration modes include thickness shear vibration, thickness longitudinal vibration, expansion vibration, longitudinal vibration, bending vibration, torsional vibration, and contour shear vibration. The vibration mode may also be one that generates an elastic wave (e.g., a surface acoustic wave (SAW)). As can be understood from the example of a SAW, the vibration mode is not limited to one that vibrates over the entire thickness direction of the vibrating portion 9, but may also be one in which only a portion of the thickness direction of the vibrating portion 9 vibrates.

[0038] As can be understood from the examples of the vibration modes described above, the material of the vibration unit 9 may be, for example, an integrally formed piezoelectric material throughout (as in the illustrated example), or may be a material that is only partially formed of a piezoelectric material. An example of the latter is a mode in which the vibration unit 9 is formed of a piezoelectric layer through which elastic waves propagate and another layer laminated on the piezoelectric layer.

[0039] The specific material of the piezoelectric body may also vary depending on the vibration mode to be used. For example, the material of the piezoelectric body may be single crystal or polycrystalline. Examples of the former include quartz, single crystal of lithium tantalate, and single crystal of lithium niobate. Examples of the latter include various ceramics.

[0040] The cut angle of the single crystal is also arbitrary. For example, examples of cut angles of quartz crystal include AT cut, SC cut, and BT cut, which are used for thickness shear vibration, and CT cut and DT cut, which are used for contour shear vibration.

[0041] Furthermore, for example, as can be understood from the examples of the vibration modes already described, the pair of excitation electrodes 13 may be opposed to each other across the vibration unit 9 in the thickness direction or other directions (as in the illustrated example), or may be located together on one surface (plane) of the vibration unit 9. An example of the latter is a pair of comb-shaped electrodes that excite elastic waves.

[0042] For convenience, the description of the embodiment will be given using an AT-cut quartz crystal blank that utilizes thickness-shear vibration as the vibrating unit 9. To be clear, thickness-shear vibration is a vibration mode in which two surfaces facing opposite each other in the thickness direction (D3 direction) vibrate by sliding against each other. Furthermore, the AT-cut quartz crystal blank has a cut angle such that when the axes rotated by 35° to 36° (e.g., 35°.15') from the Z-axis (optical axis) and Y-axis (mechanical axis) around the X-axis (electrical axis) are defined as the Z'-axis and Y'-axis, the thickness direction is the Y'-axis (from another perspective, the front and back surfaces are parallel to the X-axis and Z'-axis).

[0043] The relationship between the direction of vibration (or, from another perspective, the direction of crystal) and the configuration of the vibrator 1 (vibration unit 9) is arbitrary. For example, the direction of thickness-shear vibration (X-axis direction) may be the D1 direction, the D2 direction, or a direction inclined to these. However, in the description of the embodiments, for convenience, an example in which the D2 direction is the direction of thickness-shear vibration may be taken without any particular mention.

[0044] (2.2. Shape and Dimensions of Vibration Section) The shape of the vibration section 9 is arbitrary. For example, the vibration section 9 may be flat with a uniform thickness throughout (as shown in the example), or may be a so-called mesa or inverted mesa type. Here, the flat shape and / or uniform thickness means, for example, that the difference between the average thickness of the excitation section 9a and the average thickness of the overlapping region (or the junction region where the vibration section 9 and the periphery (peripheral region 3b) of the first recess 14 described later overlap each other) is within ±5% of the average thickness of the excitation section 9a, and / or the difference between the minimum and maximum thicknesses of the vibration section 9 is within ±5% of the average thickness of the excitation section 9a. The mesa type is, for example, a shape in which a region (mesa portion) roughly corresponding to the region where the excitation electrode 13 is disposed is thicker than its peripheral region. Specifically, for example, the difference between the average thickness of the mesa portion and the average thickness of its peripheral region may be greater than 5% and / or less than 40%. The inverted mesa type has a shape in which, for example, a region (inverted mesa portion) including the region where the excitation electrode 13 is arranged is thinner than the region around it. The specific shapes of the mesa portion and the inverted mesa portion (planar shape, inclination of the side surface, number of steps of height change, etc.) are also arbitrary.

[0045] The planar shape of the vibrating unit 9 is also arbitrary. For example, the planar shape of the vibrating unit 9 may be rectangular (e.g., rectangular or square) (as shown in the example), or may be circular, elliptical, or polygonal (excluding rectangular). From another perspective, the vibrating unit 9 may have a shape having a longitudinal direction and a lateral direction (e.g., rectangular or elliptical), or may have a shape in which such distinction is not possible (e.g., circular or square). The ratio of the longitudinal length to the lateral length is also arbitrary. For example, the ratio of the former to the latter may be 1.14 to 1.39:1, or 1.26:1.

[0046] The relationship between the shape of the vibrating section 9 and the crystal direction (vibration direction) is arbitrary. For example, in an embodiment in which the vibrating section 9 has a longitudinal direction and a lateral direction in a plan view, the direction of thickness-shear vibration (X-axis direction) may be the longitudinal direction or the lateral direction, or may be a direction inclined relative to the longitudinal direction. The ratio of the longitudinal length to the lateral length in the previous paragraph may be applied to an embodiment in which the direction of thickness-shear vibration coincides with the longitudinal direction.

[0047] The dimensions of the vibrating part 9 are also arbitrary. However, the dimensions that affect the resonant frequency of the vibrating part 9 are set based on the frequency that is intended to be used. The dimensions that affect the resonant frequency differ depending on the vibration mode. For example, in the case of thickness-shear vibration, the resonant frequency is determined by the thickness of the vibrating part 9 (more specifically, the excitation part 9a). When an nth-order wave is used in the AT-cut vibrating part 9, it is known that the resonant frequency f0 (MHz) can be approximated by f0 = 1.67 × n / t, where t (mm) is the thickness of the excitation part 9a.

[0048] As will be described later, the vibrator 1 can be packaged by stacking three layers (3, 5, and 7) in a wafer state. In other words, the vibrator 1 may be a WLP type. In this case, processing for adjusting the thickness of the vibrating portion 9 can be performed in a wafer state. As a result, for example, the thickness of the vibrating portion 9 can be processed to an extremely thin thickness using plasma CVM (Chemical Vaporization Machining), which is capable of processing with high precision (for example, ±5 nm).

[0049] As understood from the previous paragraph, the vibrating section 9 may be relatively thin. For example, the vibrating section 9 may be 5 μm or more and 10 μm or less, or 5 μm or more and 6 μm or less. When thickness-shear vibration is used, the thinner the vibrating section 9, the higher the resonant frequency. Therefore, from another perspective, the vibrating section 9 may be intended for use at a relatively high frequency. For example, when the above dimensions are applied to the formula for the resonant frequency of the AT cut described above, the resonant frequency is approximately 167 MHz or more and 334 MHz or less, or 278 MHz or more and 334 MHz or less.

[0050] (2.3. Conductors Located in the Vibrating Section) (2.3.1. General Conductors Located in the Vibrating Section) The vibrating section 9 has, for example, the following conductor layers (metal layers) located therein. The pair of excitation electrodes 13 already described. A pair of pad electrodes 29 (first pad electrode 29A and second pad electrode 29B), a pair of testing electrodes 31 (first testing electrode 31A and second testing electrode 31B), and two wiring sections 35 located on the +D3 side of the vibrating section 9. A multi-function electrode 33 located on the -D3 side of the vibrating section 9 and including the second excitation electrode 13B.

[0051] The pair of pad electrodes 29 contributes, for example, to connecting the pair of excitation electrodes 13 and the pair of external electrodes 15. The pair of inspection electrodes 31 contributes, for example, to connecting an inspection device that inspects the characteristics of the vibration unit 9 during the manufacturing process to the pair of excitation electrodes 13. The multi-function electrode 33, for example, has a portion that functions as the second excitation electrode 13B, and another portion that contributes to electrical connection between the second excitation electrode 13B and the conductor on the +D3 side of the vibration unit 9 and to joining the vibration unit 9 to the first substrate 3.

[0052] The various conductors (13A, 29, 31, and 35) located on the +D3 side of the vibrating part 9 are included in the already-described second intermediate side layer 27. The multi-function electrode 33 located on the -D3 side is included in the already-described first intermediate side layer 25.

[0053] (2.3.2. Excitation Electrode) The shape and dimensions of the first excitation electrode 13A (and consequently the second excitation electrode 13B) are arbitrary. For example, the shape of the first excitation electrode 13A may be circular (the example of FIG. 1), elliptical (see FIG. 7), rectangular (e.g., rectangular or square; see FIG. 8A), or polygonal (except rectangular). From another perspective, the first excitation electrode 13A may have a shape having a longitudinal direction and a lateral direction (e.g., rectangular or elliptical), or may have a shape in which such distinction is not possible (e.g., circular or square). The ratio of the longitudinal length to the lateral length is also arbitrary. For example, the ratio of the former to the latter may be 1.14 to 1.39:1, or 1.26:1.

[0054] The relationship between the shape of the first excitation electrode 13A and the crystal direction (vibration direction) is arbitrary. Usually, when the first excitation electrode 13A has a longitudinal direction and a lateral direction, the direction of thickness-shear vibration (X-axis direction) is the longitudinal direction. The ratio of the longitudinal length to the lateral length in the previous paragraph may be applied to such an embodiment.

[0055] The positional relationship between the first excitation electrode 13A and the vibration unit 9 is also arbitrary. For example, the geometric center of the first excitation electrode 13A may coincide with or be deviated from the geometric center of the vibration unit 9 (as in the illustrated example). In an aspect in which the first excitation electrode 13A and the vibration unit 9 each have a longitudinal direction and a lateral direction, the longitudinal direction of the first excitation electrode 13A may coincide with or be misaligned with the longitudinal direction of the vibration unit 9 (as in the examples of FIGS. 7 and 8A ). In an aspect in which the vibration unit 9 has a mesa portion or an inverted mesa portion, the positional relationship of the first excitation electrode 13A with respect to the mesa portion and the inverted mesa portion (such as whether they are the same in shape and / or size, or which is larger when the sizes are different) is also arbitrary.

[0056] (2.3.3. Pad Electrodes) The pair of pad electrodes 29 are electrically connected to the pair of excitation electrodes 13. Furthermore, both of the pair of pad electrodes 29 face the second substrate 5 side (+D3 side) and can be joined to a conductor (e.g., the second substrate side layer 23) of the second substrate 5. With this configuration, the pair of excitation electrodes 13 and the pair of external electrodes 15 of the second substrate 5 are electrically connected to each other.

[0057] The first pad electrode 29A is connected to the first excitation electrode 13A. Specifically, since both are located on the +D3 side of the vibrating part 9, they are connected by a wiring part 35 located on the +D3 side of the vibrating part 9.

[0058] The second pad electrode 29B is connected to the second excitation electrode 13B. Specifically, the two are connected via a region (outer electrode 33a) other than the second excitation electrode 13B of the multi-function electrode 33. The conduction between the outer electrode 33a and the second excitation electrode 13B (conduction between the front and back of the vibrating part 9) will be described later (Section 2.4).

[0059] The shape and position of the pair of pad electrodes 29 are arbitrary. For example, the shape of the pad electrodes 29 may be rectangular (in the illustrated example) or circular. Furthermore, the pad electrodes 29 may be spaced apart from the outer edge of the vibrating section 9 (in the example of FIG. 1 ), or may extend to the outer edge of the vibrating section 9 (see FIG. 8A ). The shape, size, and position of the pair of pad electrodes 29 may be rotationally symmetric with respect to the center of the vibrating section 9 (in the example of FIG. 1 ), or may be line-symmetric with respect to the center line of the vibrating section 9 that is parallel to the D1 direction or the D2 direction (see FIG. 8A ), or such a relationship does not necessarily have to be established.

[0060] Furthermore, for example, the pair of pad electrodes 29 may be located on both sides of the pair of excitation electrodes 13 in the predetermined direction (example of FIG. 1 ), or may be located on one side of the pair of excitation electrodes 13 in the predetermined direction (see FIG. 8A ). From another perspective, the arrangement direction of the pair of pad electrodes 29 is arbitrary. The predetermined direction is also arbitrary. In the example of FIG. 1 , the predetermined direction may be understood to be the vibration direction and / or the longitudinal direction of the vibrating unit 9 in a rough view, or may be understood to be a direction (diagonal direction) intersecting the vibration direction and / or the longitudinal direction of the vibrating unit 9 in a more detailed view. Furthermore, the predetermined direction is not limited to the longitudinal direction, and may be the lateral direction.

[0061] Generally, the positions of the pair of pad electrodes 29 are positions that restrict the vibration of the vibrating section 9, and are therefore likely to affect the vibration characteristics. On the other hand, in this embodiment, the vibrating section 9 is fixed to the first substrate 3 over, for example, almost the entire surface that is on the outer periphery side of the first recess 14. Therefore, the influence of the positions of the pair of pad electrodes 29 on the vibration is relatively low. From another perspective, there is a high degree of freedom in designing the pair of pad electrodes 29 in relation to the vibration characteristics.

[0062] (2.3.4. Testing Electrodes) The pair of testing electrodes 31 are electrically connected to the pair of excitation electrodes 13. Furthermore, both of the pair of testing electrodes 31 face the +D3 side. Therefore, for example, before bonding the second substrate 5 to the intermediate layer 7, a voltage can be applied to the pair of excitation electrodes 13 by bringing a probe into contact with the pair of testing electrodes 31. This allows the characteristics of the vibration section 9 to be tested.

[0063] The first testing electrode 31A is connected to the first excitation electrode 13A. Specifically, since both are located on the +D3 side of the vibrating part 9, they are connected by a wiring part 35 located on the +D3 side of the vibrating part 9.

[0064] The second testing electrode 31B is connected to the second excitation electrode 13B. Specifically, the two are connected via a region (outer electrode 33a) of the multi-function electrode 33 other than the second excitation electrode 13B.

[0065] The shape and position of the testing electrode 31 are arbitrary. The above description of the shape and position of the pad electrode 29 may be applied to the shape and position of the testing electrode 31. The shape, dimensions, and position of the testing electrode 31 may be symmetrical with those of the pad electrode 29 about a center line of the vibrating part 9 parallel to the D1 direction or the D2 direction (example of FIG. 1 ), or may be rotationally symmetrical with respect to the center of the vibrating part 9, or such a relationship may not hold.

[0066] The pair of testing electrodes 31 does not necessarily have to be provided (see FIG. 8A). In this case, testing is still possible by bringing the probes into contact with the pad electrodes 29. Unlike the pad electrodes 29, the testing electrodes 31 are not bonded to the conductors of the second substrate 5. However, bonding may be performed.

[0067] (2.3.5. Multifunctional Electrode) The multifunctional electrode 33, for example, extends over substantially the entire surface on the −D3 side of the vibrating unit 9. From another perspective, the multifunctional electrode 33 has a so-called solid pattern. A solid pattern is, for example, a pattern that extends over a relatively wide area, essentially without any gaps. With this configuration, the multifunctional electrode 33 has the second excitation electrode 13B and an outer electrode 33a that contributes to conduction and bonding. Specifically, the outer electrode 33a contributes to conduction between the second excitation electrode 13B and the conductors (the second pad electrode 29B and the second testing electrode 31B) on the +D3 side of the vibrating unit 9, and also contributes to bonding between the vibrating unit 9 and the first substrate 3.

[0068] However, the multi-function electrode 33 does not have to be a solid pattern that extends over the entire surface of the vibrating section 9 on the −D3 side.

[0069] For example, the multifunctional electrode 33 may have a solid pattern, but part or all of its outer edge may be separated from the outer edge of the vibrating part 9. In this case, the solid pattern may include, for example, a region overlapping almost the entire excitation electrode 13 and a region overlapping part of the outer peripheral region 3b around the first recess 14, and may occupy 80% or more of the area of ​​the vibrating part 9.

[0070] Furthermore, for example, the multi-function electrode 33 may have a second excitation electrode 13B, an outer electrode (33a) surrounding the second excitation electrode 13B and spaced from the outer edge of the second excitation electrode 13B, and a wiring portion connecting the two. From another perspective, a ring-shaped slit (partially interrupted by the wiring portion) may be formed between the second excitation electrode 13B and the outer electrode 33a. In such an embodiment, the second excitation electrode 13B may have a shape that generally corresponds to the shape of the first excitation electrode 13A in a planar perspective view, for example.

[0071] Furthermore, for example, the multi-function electrode 33 may have a portion that contributes to the electrical connection between the second excitation electrode 13B and the second pad electrode 29B (and / or the second testing electrode 31B) and a portion that contributes to the bonding of the vibration part 9 to the first substrate 3 separated from each other and electrically disconnected. In this case, the latter may be electrically floating or may be provided with a reference potential.

[0072] (2.3.6. Materials of conductors located in the vibrating portion) The multi-function electrode 33 on the -D3 side of the vibrating portion 9 is included in the already-described first intermediate side layer 25. Furthermore, the various conductor layers (13A, 29, 31, and 35) on the +D3 side of the vibrating portion 9 are included in the second intermediate side layer 27. Therefore, in the explanation in this section, for convenience, the terms first intermediate side layer 25 and second intermediate side layer 27 may be used.

[0073] The various conductor layers (13A, 29, 31, and 35) located on the +D3 side of the vibrating part 9 may be made of the same material and have the same thickness (see the example of FIG. 3), or may be made of different materials and / or have different thicknesses (see FIG. 13C). An example of the latter mode is a mode in which the pad electrode 29 (and the testing electrode 31) has the same metal layer as the metal layer constituting the first excitation electrode 13A, but has another metal layer on the metal layer that is not included in the first excitation electrode 13A.

[0074] Similarly, the multi-function electrode 33 located on the -D3 side of the vibrating part 9 may be made of the same material and thickness throughout (the example in FIG. 3), or may have different materials and / or thicknesses depending on the region. An example of the latter embodiment is one in which the second excitation electrode 13B and the outer electrode 33a are made of different materials and / or thicknesses, similar to the +D3 side.

[0075] In an embodiment in which the conductor layers on the +D3 side and the −D3 side are made of the same material and have the same thickness throughout, the conductor layers (13A, 29, 31, and 35) on the +D3 side and the conductor layer (33) on the −D3 side may be made of the same material and thickness (example in FIG. 3 ), or may be made of different materials and / or thicknesses. Even in an embodiment in which the conductor layers on at least one of the +D3 side and the −D3 side are not made of the same material and thickness throughout, when comparing predetermined regions (for example, excitation electrodes 13, or other regions), the materials and / or thicknesses may be the same or different.

[0076] It should be noted that the thickness of the excitation electrode 13 (e.g., the first excitation electrode 13A) may be finely adjusted after being bonded to the first substrate 3, for example, to adjust the frequency. The influence of such fine adjustment is ignored when determining whether the thicknesses are the same. In addition, the influence of pressure and heat applied when bonding the three layers (3, 5, and 7) is also ignored. The same applies to the conductor layers of the first substrate 3 and the second substrate 5.

[0077] The first intermediate layer 25 and the second intermediate layer 27 may be made of any material. For example, each layer (25 or 27) may be made of one metal layer or two or more metal layers (see the example in FIG. 3). When a given layer (e.g., 25 or 27) is made of two or more metal layers (or insulating layers) and the material is the same across a given region, the number of stacked metal layers and the material of each metal layer (and even the ratio of thicknesses of the metal layers) may be the same. The same applies to the other layers.

[0078] 3, the first intermediate layer 25 has a lower layer 25a that contacts (directly overlaps) the vibrating section 9 and an upper layer 25b that overlaps the lower layer 25a. The upper layer 25b is made of, for example, a material that is more conductive than the material of the lower layer 25a and is thicker than the lower layer 25a. The lower layer 25a contributes to improving the bonding strength between the upper layer 25b and the vibrating section 9, for example. However, the laminated structure may be intended to have a function different from that described above.

[0079] The specific materials of the lower layer 25 a and the upper layer 25 b are not limited. For example, the lower layer 25 a may be made of chromium (Cr), titanium (Ti), nickel (Ni), or an alloy containing one or more of these as a main component. The upper layer 25 b may be made of gold (Au), silver (Ag), platinum (Pt), aluminum (Al), or an alloy containing one or more of these as a main component.

[0080] 3, the second intermediate layer 27 has, in order from the vibration section 9 side, a lower layer 27a, an upper layer 27b, a first bonding layer 27e, and a second bonding layer 27f. The first excitation electrode 13A and the wiring section 35 are, for example, composed of only the lower layer 27a and the upper layer 27b out of the above four layers. The pad electrode 29, the testing electrode 31, and the portion of the second intermediate layer 27 that overlaps with the frame section 11 are, for example, composed of the above four layers.

[0081] The above-mentioned explanation about the material of the first intermediate side layer 25 may be applied to the second intermediate side layer 27 by replacing the terms "first intermediate side layer 25," "lower layer 25a," and "upper layer 25b" with the terms "second intermediate side layer 27," "lower layer 27a," and "upper layer 27b," respectively, within the scope of no contradiction, etc. Furthermore, the above-mentioned explanation about the material of the first intermediate side layer 25 may be applied to the second intermediate side layer 27 by replacing the terms "first intermediate side layer 25," "lower layer 25a," and "upper layer 25b" with the terms "second intermediate side layer 27," "first bonding layer 27e," and "second bonding layer 27f," respectively, within the scope of no contradiction, etc.

[0082] (2.4. Conduction between the front and back of the vibrating part) (2.4.1. Conduction at the through hole) Fig. 5 is a perspective view of the vibrating part 9. In this figure, the conductor on the +D3 side of the vibrating part 9 is also shown by a dotted line. Fig. 6A is a cross-sectional view taken along line VIa-VIa in Fig. 5. Fig. 6B is a cross-sectional view taken along line VIb-VIb in Fig. 5.

[0083] As shown in these figures, the vibrating section 9 has a first through-hole 9h. By arranging a connecting conductor 37 in this first through-hole 9h, the conductor layer on the +D3 side of the vibrating section 9 and the conductor layer on the −D3 side of the vibrating section 9 are electrically connected.

[0084] The connecting conductor 37 may have any configuration. For example, it may be a columnar conductor filling the first through hole 9h (as shown in the example), or it may be a layered conductor overlapping the inner surface of the first through hole 9h. The columnar conductor may be entirely made of one material, or may be made of two or more materials. An example of the latter is a configuration in which the outer surface and the interior are made of different materials (as shown in the example of Figure 3). Similarly, the layered conductor may be entirely made of one material, or may be made of two or more materials. An example of the latter is a configuration in which a layer contacting the inner surface of the first through hole 9h and another layer overlapping the layer are provided. The material of the connecting conductor 37 may be the same as or different from the material of the conductor layer on the +D3 side and / or the -D3 side.

[0085] The explanation in the previous paragraph may be applied to the second through hole 5h and the extraction conductor 41 located therein, which will be described later. In this case, the terms "first through hole 9h" and "connection conductor 37" are replaced with the terms "second through hole 5h" and "extraction conductor 41," respectively.

[0086] 3 illustrates a configuration in which the connecting conductor 37 has an outer circumferential layer made of the same material as the first bonding layer 27 e and an internal columnar portion made of the same material as the second bonding layer 27 f. Similarly to the above, FIG. 3 illustrates a configuration in which the extracting conductor 41 (described later) has the same material as the materials of two or more conductor layers overlapping the +D3 side surface of the second substrate 5.

[0087] 5 , the position, shape, and dimensions of the first through hole 9h (or, from another perspective, the connection conductor 37) are arbitrary. For example, in the illustrated example, focusing on the first through hole 9h that contributes to electrical connection between the second pad electrode 29B and the multi-function electrode 33, the first through hole 9h is located directly below the second pad electrode 29B, and more specifically, for example, closer to the excitation electrode 13 than the geometric center of the second pad electrode 29B (more specifically, for example, closer to the excitation electrode 13 than the geometric center of the second pad electrode 29B with respect to the longitudinal direction and / or vibration direction of the vibrating unit 9). Furthermore, in the illustrated example, the first through hole 9h associated with the second pad electrode 29B has a slit shape extending in a direction intersecting (for example, perpendicular to) the arrangement direction of the second pad electrode 29B and the excitation electrode 13 (from another perspective, the longitudinal direction and / or vibration direction of the vibrating unit 9).

[0088] By positioning the first through hole 9h directly below the second pad electrode 29B, for example, the pattern of the conductor layer on the +D3 side is simplified and the area of ​​the conductor layer can be easily reduced. Furthermore, by positioning the first through hole 9h relatively closer to the excitation electrode 13, for example, the first through hole 9h acts to block the transmission of stress between the pad electrode 29 and the excitation portion 9a, thereby reducing the influence of the fixation of the pad electrode 29 to the second substrate 5 on the vibration of the excitation portion 9a. This effect is enhanced by the first through hole 9h having a slit shape extending in a direction intersecting the arrangement direction of the second pad electrode 29B and the excitation electrode 13. Furthermore, by having the first through hole 9h slit-shaped, it is easy to ensure the length of the inner circumferential surface of the first through hole 9h in a plan view, which makes it easy to ensure the conduction area between the connection conductor 37 in the first through hole 9h and the conductor layer on the +D3 side or the −D3 side.

[0089] However, the position, shape, and dimensions of the first through hole 9h may be different from those described above. Examples are given below. For example, the first through hole 9h does not have to be located directly below the second pad electrode 29B. In this case, the connection conductor 37 and the second pad electrode 29B may be connected, for example, by a wiring portion located on the +D3 side. Furthermore, the first through hole 9h may be located at the geometric center of the second pad electrode 29B or on the opposite side of the excitation electrode 13 from the geometric center in the arrangement direction of the second pad electrode 29B and the excitation electrode 13 (from another perspective, the longitudinal direction and / or vibration direction of the vibrating portion 9). Furthermore, the shape of the first through hole 9h in a planar view may be circular, elliptical (difficult to be perceived as a slit), square, or rectangular (difficult to be perceived as a slit).

[0090] Although the first through hole 9h relating to the second pad electrode 29B has been described, the above description of the position, shape and dimensions of the first through hole 9h may be applied to the first through hole 9h relating to the second testing electrode 31B as appropriate.

[0091] The shape and dimensions of the longitudinal cross section of the first through hole 9h (the cross section shown in FIGS. 6A and 6B) are also arbitrary. These figures illustrate a tapered shape in which the diameter decreases toward the -D3 side. Unlike the illustrated example, the longitudinal cross section of the first through hole 9h may have, for example, a constant diameter, a shape in which the diameter decreases toward the center in the thickness direction of the vibrating portion 9 (a shape having two tapered shapes), or a multi-step shape. Furthermore, the tapered shape may be formed due to the anisotropy of the material of the vibrating portion 9 with respect to etching, or may be formed intentionally by adjusting the irradiation pattern of the laser light, for example.

[0092] A supplementary note regarding the slit shape of the first through-hole 9h can be made. The slit shape can be said to be a shape in which the length in a first direction (D1 direction) is longer than the length in a second direction (D2 direction) perpendicular to the first direction. For example, the slit shape may extend with a basically constant width (excluding the ends). The ratio of the length (first direction) to the width (second direction) of the slit may be set appropriately, but for example, the length may be two or more times, three or more times, or five or more times the width.

[0093] When the vertical cross section of the slit-shaped first through hole 9h is tapered, the taper angle (the angle formed by two inner surfaces) of the tapered shape in the vertical cross section perpendicular to the longitudinal direction (D1 direction) is defined as θ1. The taper angle of the tapered shape in the vertical cross section perpendicular to the lateral direction (D2 direction) is defined as θ2. In this case, θ1 may be larger than θ2. From another perspective, the inclination angle of the inner surface of the first through hole 9h relative to the +D3 side surface of the vibrating unit 9 may be smaller, as an average of the two inner surfaces, in the vertical cross section perpendicular to the longitudinal direction (D1 direction) than in the vertical cross section perpendicular to the lateral direction. This can be expressed by the following equation: (180°-θ1) / 2<(180°-θ2) / 2. The operation of this configuration will be described in the summary of the embodiments (Section 10) below.

[0094] As described later in Section 9, the first through-hole 9h may be formed by one-sided etching from the +D3 side of the vibrating portion 9. In this case, the tapered shape is formed due to the anisotropy of the material of the vibrating portion 9 with respect to etching. For example, if the vibrating portion 9 is made of a single crystal, a crystal plane appears as a result of etching, forming the inner surface of the first through-hole 9h. The angle that the crystal plane makes with the +D3 side plane is determined by the crystal structure. As the etching progresses, a new crystal plane may appear, existing alongside or replacing the previously-appeared crystal plane. When a tapered shape is formed by a crystal plane in this way, to obtain the configuration described in the previous paragraph, the orientation of the slit must be appropriately set to match the direction of the crystal.

[0095] For example, in the AT cut, as described above, the D1, D2, and D3 directions correspond to the Z'-axis, X-axis, and Y'-axis directions, respectively. In this case, as shown in the example, the longitudinal direction of the slit may be the D1 direction (Z'-axis direction). In this case, the taper angles θ1 and θ2 may be, for example, θ1 = approximately 82° and θ2 = approximately 57°, or θ1 = approximately 113° and θ2 = approximately 72° (or approximately 91°), depending on the progress of etching. From another perspective, θ1 may be larger than θ2 by 20° or more. In addition, when crystal planes are not clearly visible at the ends (short sides) of the slit, it may be determined whether the taper angle of the inner surface corresponding to the long sides of the slit is set to be relatively large based on the crystal planes of the side surfaces of the vibrating portion 9.

[0096] (2.4.2. Conduction on the Outer Surface) Fig. 6C is a cross-sectional view showing another example of conduction between the front and back of the vibration part 9, and is a view corresponding to Fig. 6A. For convenience, the vibration part 9 relating to this conduction mode may be referred to as the vibration part 9A. In addition, in this figure, the first testing electrode 31A is not shown (or is not actually provided).

[0097] In the vibrating portion 9A, the front and back of the vibrating portion 9A are electrically connected by a layered connecting layer 38 that overlaps the outer peripheral surface (side surface) of the vibrating portion 9A. Unlike the example shown in the figure, the electrical connection at the first through-hole 9h and the electrical connection at the side surface of the vibrating portion 9 may be used in combination.

[0098] Specifically, the connection layer 38 includes a region that extends from the edge on the +D3 side to the edge on the −D3 side in a partial region of the outer circumferential surface of the vibrating part 9A in a plan view, thereby connecting the second pad electrode 29B and the multifunction electrode 33. The connection layer 38 may have only the region located on the outer circumferential surface of the vibrating part 9A, or may include, in addition to this region, a region located on the +D3 side of the vibrating part 9A and / or a region located on the −D3 side of the vibrating part 9A.

[0099] Although not specifically shown, a connection layer 38 is also provided that connects the second testing electrode 31B and the multi-function electrode 33. Note that, although only the connection layer 38 that connects the second pad electrode 29B and the multi-function electrode 33 will be described below, this description may be applied to the connection layer 38 that connects the second testing electrode 31B and the multi-function electrode 33 as appropriate.

[0100] The position, shape, and dimensions of the connection layer 38 are arbitrary. For example, the connection layer 38 may be located on any one or more of the side surfaces on the -D2 side, +D2 side, +D1 side, and -D1 side of the outer peripheral surface. From another perspective, the relationship between the side surface on which the connection layer 38 is located and the longitudinal direction and / or vibration direction of the vibrating section 9A is arbitrary. In the example of FIG. 3 , the connection layer 38 has a region located on the side surface on the +D2 side. The +D2 side side can be referred to as the side surface (end face) on one end side of the vibrating section 9A in the longitudinal direction and / or vibration direction, and / or the side surface on which the second pad electrode 29B (and the second testing electrode 31B) are located relative to the excitation electrode 13. In addition to or instead of the +D2 side side, the connection layer 38 may also include a region located on the side surface on the +D1 side (the side on which the second pad electrode 29B is located in the lateral direction of the vibrating section 9A).

[0101] Furthermore, for example, the D1 direction range of the region located on the +D2 side surface of the connection layer 38 and the D1 direction range of the second pad electrode 29B may be the same, or the former may be located in a part of the latter, or the latter may be located in a part of the former, or they may be offset from each other. From another perspective, for example, the connection layer 38 may have a shape that extends the second pad electrode 29B to the +D2 side, or may have a shape that extends from the second pad electrode 29B like the wiring portion 35. Although the +D2 side surface is taken as an example, the same applies to the +D1 side surface.

[0102] The material and thickness of the connection layer 38 are also arbitrary. For example, the material and / or thickness of the connection layer 38 may be the same as or different from the material and / or thickness of a part or all of the region of the conductor layer on the +D3 side (and / or −D3 side) of the vibrating unit 9 in plan view.

[0103] A supplementary note will be made regarding the side surface of the vibrating unit 9 on which the connection layer 38 is located. The side surface on which the connection layer 38 is located may be an inclined surface that is inclined so that it is positioned further outward from the vibrating unit 9 as it approaches the -D3 side (the first substrate 3 side). In this case, for example, the reliability of the connection between the conductor layers at the ridge between the side surface on the +D2 side and the surface on the +D3 side is improved. The inclination of the side surface of the vibrating unit 9 as described above may be formed due to the anisotropy of the material of the vibrating unit 9 with respect to etching, as with the inner circumferential surface of the first through hole 9h, or may be formed intentionally by adjusting the irradiation pattern of the laser light, for example.

[0104] Also, consider a configuration in which the connection layer 38 has a region located on one side (the +D2 side) in a predetermined direction (e.g., the longitudinal direction and / or the vibration direction of the vibrating unit 9A) and does not have a region located on the other side (the -D2 side) in the predetermined direction. In this case, for example, the inclination angle θ3 of the +D2 side surface with respect to the normal to the +D3 side surface of the vibrating unit 9 may be larger than the inclination angle θ4 of the -D2 side surface with respect to the normal. In this case, the effect described in the previous paragraph is improved compared to when the relationship between the angles θ3 and θ4 is reversed (this configuration is also included in the technology related to the present disclosure).

[0105] In an embodiment in which the inclined side surface of the vibrating portion 9 is a crystal plane that appears due to etching, the orientation of each part of the vibrating portion 9A (in other words, the orientation of the Cartesian coordinate system D1D2D3) may be set according to the crystal orientation, thereby establishing the above-described angular relationship. For example, in an embodiment in which the outer peripheral surface of the AT-cut vibrating portion 9A is formed by one-sided etching from the +D3 side (Y'-axis direction), the +D2 side (the side where the connecting layer 38 is located) may be the -Z' side. In this case, depending on the progress of etching, for example, θ3 is approximately 56° and θ4 is approximately 32°. From another perspective, θ3 may be larger than θ4 by a difference of 15° or more. Note that the first through-hole 9h does not have to have a uniformly inclined surface in the D3 direction. That is, the first through hole 9h may include a first tapered portion in which the opening gradually narrows from the surface on the first substrate 3 side toward the second substrate 5 side, and a second tapered portion in which the opening gradually narrows as it moves away from the surface on the second substrate 5 side toward the first substrate 3 side.

[0106] In addition, the influence of the inclination of the side surfaces as described above is basically ignored in the description of the shape and dimensions of the vibrating section 9 etc. Therefore, for example, the shape and dimensions in a planar view may be applied to each of the +D3 side surface and the −D3 side surface, or may be applied to the maximum shape or maximum dimension when both are viewed in a planar view.

[0107] (3. Frame) (3.1. Material, shape, and dimensions of frame) As described above, the frame 11 surrounds the vibrating unit 9 in a plan view and is spaced apart from the outer edge of the vibrating unit 9 all around. As long as this requirement is met, the material, shape, and dimensions of the frame 11 are arbitrary.

[0108] For example, the material of the frame portion 11 may be the same as or different from the material of the vibration portion 9. When the frame portion 11 and the vibration portion 9 are made of the same material, it tends to be easier to form them from an integrated layer (member). The thickness of the frame portion 11 may be (substantially) the same as the thickness of the vibration portion 9 (as in the illustrated example), or may be different. An example of a mode in which the thicknesses of the frame portion 11 and the vibration portion 9 are different is a mode in which the thickness of the vibration portion 9 (for example, the maximum thickness if not a constant thickness) is thinner than the thickness of the frame portion 11 (for example, the maximum thickness if not a constant thickness).

[0109] Regardless of whether the material of the frame portion 11 is the same as the material of the vibration portion 9, the description of the material of the vibration portion 9 may be applied to the material of the frame portion 11. Furthermore, in an embodiment in which the material of the frame portion 11 is different from the material of the vibration portion 9, the frame portion 11 may not include a piezoelectric material, or may include a piezoelectric material of a different type (and cut angle) from the type (and cut angle) of the piezoelectric material of the vibration portion 9. For specific examples of the material of the frame portion 11 that is different from the material of the vibration portion 9, the descriptions of the specific examples of the materials of the first substrate 3 and the second substrate 5 may be applied.

[0110] For example, in a plan view, the frame portion 11 surrounds the vibrating portion 9 over its entire circumference (over 360°). However, the frame portion 11 may be partially interrupted. This interrupted portion may be used, for example, to arrange a conductor that connects the inside and outside of the vibrator 1 in a manner different from the example shown in the drawings. The frame portion 11 may be considered to surround the vibrating portion 9 if it extends over at least ¾ of the circumference (270°), at least 7 / 8 of the circumference (315°), or at least 15 / 16 of the circumference (337.5°), based on the length of the outer edge of the vibrating portion 9 (or the angular range around the geometric center of the vibrating portion 9).

[0111] In plan view, the shape of the inner edge of the frame portion 11 may be similar or similar to the shape of the outer edge of the vibrating portion 9 (as in the illustrated example), or may be a completely different shape. An example of the former is a mode in which the shape of the outer edge of the vibrating portion 9 and the shape of the inner edge of the frame portion 11 are both rectangular (as in the illustrated example), circular, elliptical, or polygonal (excluding rectangular). An example of the latter is a mode in which the shape of the outer edge of the vibrating portion 9 and the shape of the inner edge of the frame portion 11 are circular-rectangular, or elliptical-rectangular. From another perspective, in plan view, the distance d1 between the inner edge of the frame portion 11 and the outer edge of the vibrating portion 9 may or may not be approximately constant around the entire circumference.

[0112] The shape and dimensions of the outer edge of the frame portion 11 are, for example, generally the same as the shape and dimensions (already described) of the outer edge of the vibrator 1 in a planar view. Furthermore, the description in the previous paragraph about the relationship between the outer edge of the vibrating portion 9 and the inner edge of the frame portion 11 may be applied to the relationship between the outer edge of the vibrating portion 9 and the outer edge of the frame portion 11 by replacing the term "inner edge of the frame portion 11" with the term "outer edge of the frame portion 11." Furthermore, the description in the previous paragraph about the relationship between the outer edge of the vibrating portion 9 and the inner edge of the frame portion 11 may be applied to the relationship between the inner edge of the frame portion 11 and the outer edge of the frame portion 11 by replacing the term "outer edge of the vibrating portion 9" with the term "inner edge of the frame portion 11" and the term "inner edge of the frame portion 11" with the term "outer edge of the frame portion 11." As can be understood from this, the width of the frame portion 11 (the distance from the inner edge to the outer edge) may be constant or may vary in the circumferential direction.

[0113] The thickness of the frame 11 is, for example, generally constant throughout. From another perspective, the front and back surfaces of the frame 11 are flat. However, for example, a recess or a protrusion may be provided on part of the front and / or back surface of the frame 11.

[0114] (3.2. Conductors Located in the Frame Portion) For example, the above-mentioned first intermediate side layer 25 and second intermediate side layer 27 (areas thereof excluding the area located in the vibrating section 9) are located on the front and back surfaces (the surface on the +D3 side and the surface on the -D3 side) of the frame portion 11. For example, no conductors (e.g., conductor layers) are located on the inner and outer peripheral surfaces of the frame portion 11. From another perspective, the areas of the first intermediate side layer 25 and the second intermediate side layer 27 located in the frame portion 11 are not connected to each other.

[0115] However, a conductor may be located on part or all of the inner circumferential surface and / or the outer circumferential surface in the circumferential direction. This may allow the regions of the first intermediate side layer 25 and the second intermediate side layer 27 located in the frame portion 11 to be electrically connected to each other. Such a conductor may be, for example, a conductor layer overlapping the inner circumferential surface and / or the outer circumferential surface. Castellations may be provided at corners of the first substrate 3 in a plan view, and electrical connection may be achieved by the conductors arranged on the castellations. Furthermore, a through hole, such as the first through hole 9h, may be provided in the frame portion 11 to electrically connect the regions of the first intermediate side layer 25 and the second intermediate side layer 27 located in the frame portion 11 to each other.

[0116] The first intermediate side layer 25 and the second intermediate side layer 27 are each disposed on the frame portion 11 over the entire circumference (360° around the vibration portion 9) in a plan view. More specifically, the first intermediate side layer 25 and the second intermediate side layer 27 each extend over the entire front and back surfaces of the frame portion 11, for example. However, the first intermediate side layer 25 and the second intermediate side layer 27 may have a portion that is separated from the inner edge and / or outer edge of the frame portion 11 over the entire or part of the circumferential direction of the frame portion 11. Furthermore, for example, the first intermediate side layer 25 (or the second intermediate side layer 27) may have two or more patterns extending parallel to each other along the frame portion 11, thereby forming a region where the first intermediate side layer 25 is not disposed, which is surrounded by the first intermediate side layer 25.

[0117] In each of the first intermediate side layer 25 and the second intermediate side layer 27, the region located in the frame portion 11 (part or all of it) and the region located in the vibration portion 9 (part or all of it) may be made of the same material and have the same thickness (example in Figure 3), or at least one of the material and thickness may be different. In either case, the description of the material of the first intermediate side layer 25 and the second intermediate side layer 27 given in the description of the conductor located in the vibration portion 9 may be applied to the material of the region of the first intermediate side layer 25 and the second intermediate side layer 27 located in the frame portion 11.

[0118] (4. First Substrate) Fig. 4 is a cross-sectional view showing an example of a specific aspect of the first substrate-side layer 21 and the second substrate-side layer 23 that is different from that shown in Fig. 3. Also, Fig. 9 is a plan view showing an example of a specific aspect of the first substrate 3 and the first substrate-side layer 21 that is different from that shown in Fig. 1. In the following description, Figs. 4 and 9 may be referenced in addition to Figs. 1 to 3.

[0119] (4.1. Material, Shape, and Dimensions of First Substrate) The first substrate 3 is, for example, a flat plate-like member having a substantially constant thickness, except for the first recess 14 being formed therein. However, the first substrate 3 may have appropriate recesses and / or protrusions on the +D3 side or the −D3 side in addition to the first recess 14. The shape and dimensions of the first substrate 3 in a planar view are, for example, generally the same as the shape and dimensions (already described) of the vibrator 1 in a planar view. The thickness of the first substrate 3 is arbitrary. In the example of FIG. 3 , the thickness of the first substrate 3 is thicker than the thickness of the second substrate 5 and the thickness of the intermediate layer 7. An example of the thickness of the first substrate 3 in a relatively small vibrator 1 is 50 μm or more and 200 μm or less.

[0120] If the thickness of the first substrate 3 is greater than the thickness of the second substrate 5 and the thickness of the intermediate layer 7, the intermediate layer 7 can be stably maintained when thinning it, as described below. However, the thickness of the first substrate 3 is not limited to this relationship. For example, if the thickness is the same as that of the second substrate 5, the stress balance in the entire vibrator 1 can be adjusted, and warping can be suppressed. Furthermore, the influence of stress when mounting the vibrator 1 can be reduced.

[0121] The material of the first substrate 3 is arbitrary. For example, the first substrate 3 may be integrally formed of the same material as the intermediate layer 7, or an insulator or semiconductor, or may be formed by laminating different materials. An example of the latter embodiment includes a first layer made of an insulator or semiconductor and a metal layer (from another perspective, a shield and / or reinforcing material) overlapping the first layer on the -D3 side. Another example is a embodiment in which the first substrate 3 is formed of a multilayer substrate. The insulator may be an inorganic material (for example, quartz or ceramic) or an organic material (for example, resin). Examples of the semiconductor include silicon (Si) or germanium (Ge).

[0122] The semiconductor constituting the first substrate 3 is, for example, an intrinsic semiconductor that does not contain lattice defects (in a broad sense). For example, the semiconductor is essentially free of impurities and / or disorder in the atomic arrangement. However, the semiconductor may contain lattice defects. For example, in a mode different from the illustrated example, a portion of the first substrate 3 may be made of a p-type semiconductor or n-type semiconductor containing impurities, and may constitute an electronic element or contribute to electrical conduction between the inside and outside of the vibrator 1.

[0123] The shape and dimensions of the first recess 14 in a plan view are arbitrary. For example, the planar shape of the first recess 14 may be identical, similar, or similar to the shape of the first excitation electrode 13A (see the example of FIG. 1 ), or may be completely different (see FIG. 7 ). Furthermore, in a planar perspective view, the first recess 14 and the first excitation electrode 13A may coincide with each other, the former may be contained within a portion of the latter, the latter may be contained within a portion of the former (see the example of FIG. 3 ), or each may have a non-overlapping area. In a planar perspective view, the geometric center of the first recess 14 and the geometric center of the first excitation electrode 13A may or may not coincide with each other.

[0124] In any of the embodiments described in the preceding paragraph, the description of the shape and dimensions of the first excitation electrode 13A may be used to describe the shape and dimensions of the first recess 14 in a planar view, unless a contradiction arises. To be sure, some of the descriptions that may be used are excerpted and rewritten as follows: The planar shape of the first recess 14 may be circular (as in the example of FIG. 1), elliptical (as in the example of FIG. 9), rectangular (e.g., rectangular or square; see FIGS. 7 and 8A), or polygonal (excluding rectangular). The ratio of the length in the longitudinal direction to the length in the lateral direction may be, for example, 1.14 to 1.39:1, or 1.26:1. This ratio may be applied, for example, to an embodiment in which the direction of thickness-shear vibration (X-axis direction) is the longitudinal direction.

[0125] The shape and dimensions (e.g., depth) of the vertical cross section (cross section parallel to the D3 direction) of the first recess 14 are also arbitrary. For example, in the vertical cross section of the first recess 14, the side surface of the first recess 14 may be approximately parallel to the D3 direction or may be inclined with respect to the D3 direction. Depending on the inclined side surface, the diameter of the first recess 14 may increase or decrease toward the +D3 side. The depth of the first recess 14 may be, for example, a minimum depth that prevents the second excitation electrode 13B from contacting the bottom surface of the first recess 14 (more specifically, in the illustrated example, the region of the first substrate-side layer 21 located at the bottom surface of the first recess 14) under the intended usage conditions, or it may be deeper. Furthermore, for example, the depth of the first recess 14 may be less than half the thickness of the first substrate 3 or may be greater than half the thickness of the first substrate 3.

[0126] (4.2. Conductor Located on First Substrate) For example, the above-mentioned first substrate side layer 21 is located on the surface on the +D3 side (intermediate layer 7 side) of the first substrate 3. For example, no conductor (e.g., conductor layer) is located on the outer peripheral surface (side surface) and the surface on the −D3 side of the first substrate 3.

[0127] However, a conductor other than the first-substrate-side layer 21 may be located on the first substrate 3. For example, a metal layer functioning as a shield and / or reinforcing material may overlap the surface on the -D3 side (as described above, the metal layer may be considered part of the first substrate 3). Furthermore, for example, castellations may be formed at corners of the first substrate 3 in a planar view, and a conductor may be located on the castellations. Furthermore, as described above, an external electrode 15 may be provided on the first substrate 3, and the external electrode 15 may be exposed on the surface on the -D3 side. Note that, when the external electrode 15 is provided on the first substrate 3, the thickness of the first substrate 3 may be thinner than that of the second substrate 5 in terms of forming a through hole. In this case, the configuration of the conductor on the -D3 side of the vibrating section 9 and the conductor on the first substrate 3 can be inferred from the configuration of the conductor on the +D3 side of the vibrating section 9 and the conductor on the second substrate 5 in the illustrated example.

[0128] The first substrate side layer 21 contributes to, for example, bonding of the vibrating section 9 to the first substrate 3. Furthermore, the first substrate side layer 21 also bonds the frame section 11 and the first substrate 3 around the entire periphery of the frame section 11, contributing to sealing of the vibrating section 9. The shape and dimensions of the first substrate side layer 21 in a plan view are arbitrary as long as they achieve the above-mentioned functions.

[0129] 1, the first-substrate-side layer 21 is separated into an inner region 21e that contributes to the bonding (and conduction) between the vibration section 9 and the first substrate 3, and an outer region 21f that contributes to the bonding between the frame section 11 and the first substrate 3. This reduces the likelihood of unintended conduction between the multi-function electrode 33 and other conductors, for example. However, the first-substrate-side layer 21 does not have to be separated into the inner region 21e and the outer region 21f, as in another example shown in FIG. 9. In other words, the entire first-substrate-side layer 21 may be formed by a single solid pattern.

[0130] The inner region 21e has, for example, a shape that generally matches the vibration unit 9 in a planar perspective view (for example, a shape in which 90% or more of the area of ​​each overlaps with the other). However, the inner region 21e may, for example, extend outside the vibration unit 9 within a range that does not overlap with the frame 11 (or the region of the first intermediate layer 25 that is located in the frame 11) in a planar perspective view, or may be located inside the outer edge of the vibration unit 9 while maintaining an overlap with the multi-function electrode 33. In any of the above embodiments, the description of the shape and dimensions of the vibration unit 9 in a planar view may be used for the shape and dimensions of the inner region 21e, unless a contradiction or the like arises.

[0131] The outer region 21f has, for example, a shape that generally matches the frame portion 11 in a planar perspective view (for example, a shape in which 90% or more of the area of ​​each overlaps with each other). However, the outer region 21f may, for example, extend inward from the inner edge of the frame portion 11 or extend outward from the outer edge of the frame portion 11 within a range that does not overlap with the vibration unit 9 (or the multi-function electrode 33) in a planar perspective view. In any of the above embodiments, the description of the shape and dimensions of the frame portion 11 in a planar view may be used for the shape and dimensions of the outer region 21f, as long as no contradictions or the like arise.

[0132] 1 is spaced apart from the outer edge of the first substrate 3 along the entire periphery. This reduces the likelihood of unintended electrical connection between the multi-functional electrode 33 and other conductors, for example. However, the first substrate side layer 21 may extend to the outer edge of the first substrate 3, as in another example shown in FIG. 9.

[0133] The first substrate-side layer 21 (inner region 21 e) may or may not have a portion overlapping the inner surface of the first recess 14. Examples of the former embodiment include an embodiment in which the first substrate-side layer 21 is located on the bottom surface of the first recess 14 (e.g., the entire bottom surface) (examples of FIGS. 1 and 3 ), an embodiment in which the first substrate-side layer 21 is located on the bottom surface and outer peripheral surface of the inner surface of the first recess 14 (e.g., the entire bottom surface and the entire outer peripheral surface) (example of FIG. 4 ), and an embodiment in which the first substrate-side layer 21 is located on the outer peripheral surface of the first recess 14 (e.g., the entire outer peripheral surface).

[0134] The material, thickness, and thickness direction configuration of the first substrate side layer 21 are also arbitrary. For example, the first substrate side layer 21 may be made of the same material and thickness throughout its entirety (example of FIG. 3 ), or may have different materials and / or thicknesses depending on the region. An example of the latter embodiment is a region overlapping the vibration section 9 and a region overlapping the frame section 11 (e.g., an inner region 21 e and an outer region 21 f) that are made of different materials and / or thicknesses.

[0135] Furthermore, for example, the first substrate-side layer 21 may be composed of one metal layer, or may be composed of two or more metal layers (example of FIG. 3). In the example of FIG. 3, the first substrate-side layer 21 has a lower layer 21a that contacts (directly overlaps) the first substrate 3, and an upper layer 21b that overlaps the lower layer 21a. The description of the lower layer 25a and upper layer 25b of the first intermediate-side layer 25 may be applied to the lower layer 21a and upper layer 21b by replacing the reference numeral "25" with "21" and replacing the term "vibration section 9" with "first substrate 3".

[0136] The materials of the layers (upper layer 25b and upper layer 21b in the example of FIG. 3 ) that constitute the surfaces of the first substrate-side layer 21 and the first intermediate-side layer 25 that are joined together may be the same or different. In the former embodiment, in the completed vibrator 1, the boundary between the first substrate-side layer 21 and the first intermediate-side layer 25 (upper layer 25b and upper layer 21b) may or may not be identifiable by observation with a TEM (Transmission Electron Microscope) or the like. The description in this paragraph may also be applied to the second substrate-side layer 23 and the second intermediate-side layer 27.

[0137] (5. Second Substrate) (5.1. Material, Shape, and Dimensions of Second Substrate) The second substrate 5 is, for example, a substantially flat member. The shape and dimensions of the second substrate 5 in a planar view are, for example, substantially the same as the shape and dimensions (already described) of the vibrator 1 in a planar view.

[0138] 2 and 3, the second substrate 5 has a second recess 39 on the second surface 5a on the -D3 side. The second recess 39 faces the excitation portion 9a of the vibration portion 9, similar to the first recess 14, for example, thereby facilitating vibration of the excitation portion 9a. The second recess 39 is also formed in an area wider than the area facing the excitation portion 9a. This reduces the bonding area between the second surface 5a and the intermediate layer 7, for example, and can increase the contact pressure when bonding the two.

[0139] However, the second surface 5a may be planar without the second recess 39. Furthermore, the second substrate 5 may have appropriate recesses and / or protrusions on the +D3 side or the −D3 side in addition to the second recess 39. In an embodiment in which the second surface 5a is planar, the likelihood of contact between the excitation portion 9a and the second surface 5a may be reduced by various methods. Examples are given below. The excitation portion 9a may be thinner on the −D3 side than the frame portion 11. The region of the second intermediate layer 27 that contributes to the bonding between the intermediate layer 7 and the second surface 5a may be thicker than the first excitation electrode 13A (see the example in Figure 3). Furthermore, for example, in an embodiment in which the vibration portion 9 utilizes a SAW that propagates on the −D3 side, the +D3 side surface of the excitation portion 9a may be bonded to the second surface 5a.

[0140] 2, the second surface 5a has a frame-shaped region 5aa bonded to the frame portion 11, a second recess 39 surrounded by the frame-shaped region 5aa, and a pedestal portion 5ab surrounded by the second recess 39. The top surface (the surface on the -D3 side) of the pedestal portion 5ab includes a pad region 5ac bonded to the pad electrode 29. The shapes and dimensions of each portion are, for example, as follows:

[0141] For example, in a planar perspective, the frame-shaped region 5aa has a shape that overlaps substantially the entire frame portion 11 (e.g., 90% or more). Part or all of the inner edge of the frame-shaped region 5aa (or, from another perspective, the edge of the second recess 39) may coincide with the inner edge of the frame portion 11, may be located inside the frame portion 11 within a range that does not overlap with the vibration portion 9 (or the excitation portion 9a), or may be located outside the frame portion 11 within a range that maintains the overlap between the frame-shaped region 5aa and the frame portion 11. Furthermore, part or all of the outer edge of the frame-shaped region 5aa (or, from another perspective, the outer edge of the second substrate 5) may coincide with the outer edge of the frame portion 11, or may be located inside the frame portion 11 within a range that maintains the overlap between the frame-shaped region 5aa and the frame portion 11, or may be located outside the frame portion 11. In any of the above embodiments, the description of the shape and dimensions of the frame portion 11 in a planar perspective may be applied to the shape and dimensions of the frame portion 5aa, as long as no contradictions arise.

[0142] The pedestal portion 5ab has a shape and dimensions that, for example, roughly overlap with the pad electrode 29 in a planar perspective view. Looking at it in more detail, part or all of the outer edge of the pedestal portion 5ab may coincide with the outer edge of the pad electrode 29, may be located outside (as in the example of FIG. 3), or may be located inside. In any case, the description of the shape and dimensions of the pad electrode 29 in a planar view may be applied to the shape and dimensions of the pedestal portion 5ab, as long as no contradictions arise. Furthermore, the position in the D3 direction of the top surface (the surface on the -D3 side) of the pedestal portion 5ab is the same as the position in the D3 direction of the surface on the -D3 side of the frame portion 11, for example. However, the two may be different.

[0143] A description of the shape and dimensions of the second recess 39 in a planar view will be omitted because it would contradict the above description of the shape and dimensions of the frame region 5aa and the pedestal portion 5ab in a planar view. Furthermore, the side surfaces of the second recess 39 may be generally parallel to the D3 direction or may be inclined relative to the D3 direction. Depending on the inclined side surfaces, the diameter of the second recess 39 may increase or decrease toward the -D3 side. The depth of the second recess 39 is arbitrary. For example, the depth of the second recess 39 may be minimal enough so that the first excitation electrode 13A does not contact the bottom surface of the second recess 39 (more specifically, in the illustrated example, the region of the second substrate-side layer 23 located at the bottom surface of the second recess 39) under the intended usage conditions, or it may be deeper. Furthermore, for example, the depth of the second recess 39 may be less than half the thickness of the second substrate 5 or greater than half.

[0144] The vibration unit 9 and the second substrate 5 are joined only at the base 5ab. With this configuration, the space between the +D3 side of the excitation unit 9a and the second recess 39 is connected to the space between the outside of the vibration unit 9 and the inner circumferential surface of the frame 11. This makes it possible to prevent dust and other foreign matter from adhering to the excitation unit 9a.

[0145] The second substrate 5 may have any thickness. In the example of Fig. 3, the thickness of the second substrate 5 is greater than the thickness of the intermediate layer 7 and less than the thickness of the first substrate 3. An example of the thickness of the second substrate 5 in a relatively small vibrator 1 is 20 µm or more and 100 µm or less.

[0146] In this example, the external electrodes 15 are disposed on the second substrate 5, and therefore through holes are formed through the second substrate 5 in the direction D3. By making the second substrate 5 thinner than the first substrate 3, the formation of the through holes becomes easier, improving productivity. In addition, the continuity of the extraction conductors 41 located within the through holes can be improved.

[0147] The material of the second substrate 5 is arbitrary. The above-mentioned explanation about the material of the first substrate 3 may be applied to the second substrate 5. Just to be sure, some of the descriptions that may be applied are excerpted and rewritten as follows: The second substrate 5 may be integrally formed of an insulator or a semiconductor, or may be formed by laminating different materials. The insulator may be an inorganic material (e.g., quartz or ceramic) or an organic material (e.g., resin). Examples of semiconductors include silicon (Si) and germanium (Ge).

[0148] (5.2. Conductors Located on Second Substrate) The following conductors are located on the second substrate 5, as shown in FIGS. 1 to 3, for example. A second-substrate-side layer 23 located on the surface on the -D3 side (the intermediate layer 7 side) of the second substrate 5. An external electrode 15 located on the surface on the +D3 side of the second substrate 5. An extraction conductor 41 disposed in a second through-hole 5h penetrating the second substrate 5, and electrically connecting the second-substrate-side layer 23 and the external electrode 15.

[0149] However, a conductor other than the above may be disposed on the second substrate 5. For example, castellations may be formed at corners of the second substrate 5 in a plan view, and conductors may be disposed on the castellations. This conductor may contribute to electrical conduction between the second-substrate-side layer 23 and the external electrode 15, and may be provided instead of or in addition to the extraction conductor 41.

[0150] The second substrate side layer 23 extends, for example, over substantially the entire second surface 5a. From another perspective, the second substrate side layer 23 has a region overlapping the frame region 5aa, a region overlapping the bottom surface of the second recess 39, and a region overlapping the top surface of the pedestal portion 5ab (from another perspective, the pad region 5ac). The second substrate side layer 23 does not have to overlap the side surface of the second recess 39 (example of FIG. 3), but may overlap (example of FIG. 4).

[0151] The region overlapping the frame-shaped region 5aa contributes to the bonding between the frame portion 11 and the second substrate 5. The region overlapping the top surface of the pedestal portion 5ab contributes to the bonding between the vibrating portion 9 and the second substrate 5, and also contributes to the electrical connection between the pad electrode 29 and the external electrode 15. The region overlapping the bottom surface (and side surface) of the second recess 39 can function as, for example, a shield and / or a reinforcing material.

[0152] The second substrate side layer 23 does not have to extend over the entire second surface 5 a. For example, the second substrate side layer 23 may have a region overlapping the frame region 5 aa and a region overlapping the pad region 5 ac, but may not have a region overlapping the bottom surface of the second recess 39. Furthermore, for example, the second substrate side layer 23 may be spaced apart from the edge of the second surface 5 a.

[0153] The material, thickness, and thickness direction configuration of the second substrate side layer 23 are also arbitrary. For example, the second substrate side layer 23 may be made of the same material and thickness throughout (the example of FIG. 3 ), or may have different materials and / or thicknesses in different regions. An example of the latter embodiment is one in which the material and / or thickness differs between the region bonded to the intermediate layer 7 and the region not bonded to it.

[0154] Furthermore, for example, the second substrate-side layer 23 may be composed of one metal layer, or may be composed of two or more metal layers (example of FIG. 3). In the example of FIG. 3, the second substrate-side layer 23 has a lower layer 23a that contacts (directly overlaps) the second substrate 5 and an upper layer 23b that overlaps the lower layer 23a. The description of the lower layer 25a and upper layer 25b of the first intermediate-side layer 25 may be incorporated into the lower layer 23a and upper layer 23b by replacing the reference numeral "25" with "23" and replacing the term "vibration section 9" with "second substrate 5".

[0155] The position, shape, and dimensions (seen from the outside) of the external electrode 15 were described in the description of the mounting mode of the vibrator in Section 1.2. The external electrode 15 may be configured by a conductor layer overlapping the +D3 side surface of the second substrate 5, or may be configured by the +D3 side surface of the columnar extraction conductor 41 penetrating the second substrate 5, or may have a configuration in which such a distinction is difficult to make.

[0156] In an embodiment in which the external electrode 15 includes a conductor layer overlapping the surface on the +D3 side of the second substrate 5, the conductor layer may be composed of one metal layer or two or more metal layers (see the example in FIG. 3). In the example in FIG. 3, although not specifically designated by a reference numeral, the conductor layer portion of the external electrode 15 is composed of three metal layers. The specific materials are arbitrary. For example, the material of the layer closest to the +D3 side may be one of the materials exemplified for the upper layer 25b. Furthermore, the materials of the other two layers may be one of the materials exemplified for the lower layer 25a.

[0157] As already mentioned in the description of the connecting conductor 37, the extraction conductor 41 may have any configuration (for example, a columnar or layered configuration). The shape and dimensions of the extraction conductor 41 (second through hole 5h) are also arbitrary. For example, the second through hole 5h may have a straight columnar shape, or may have a tapered shape with a diameter that decreases toward the +D3 side or the −D3 side. The shape of the cross section (D1-D2 cross section) of the second through hole 5h may be, for example, a circle, an ellipse, a rectangle, or a polygon (excluding a rectangle).

[0158] The positions of the extraction conductor 41 and the external electrode 15 are also arbitrary. In the example of Figure 3, the extraction conductor 41 and the external electrode 15 are located on the second surface 5a of the second substrate 5, directly above the pad region 5ac that is bonded to the pad electrode 29. This, for example, simplifies the configuration of the second substrate 5. Also, for example, the second through hole 5h is located in a position that overlaps the vibrating portion 9 and does not overlap the frame portion 11, thereby reducing the likelihood that the second through hole 5h will reduce the sealing performance. Details of the positional relationship between the first through hole 9h and the second through hole 5h in the example of Figure 3 will be described in Section 7.2.

[0159] Unlike the illustrated example, the external electrode 15 (and the extraction conductor 41) may be disposed at a position other than directly above the pad region 5ac. Examples of other positions include a position that does not overlap the pad electrode 29 but overlaps the vibrating portion 9, a position that overlaps between the vibrating portion 9 and the frame portion 11, a position that overlaps the frame portion 11 and / or a position on the outer periphery of the frame portion 11. In an embodiment in which the external electrode 15 (and the extraction conductor 41) does not overlap the vibrating portion 9, for example, the likelihood that stress when the vibrator 1 is mounted on a circuit board (not shown) or the like will be transmitted to the vibrating portion 9 via the external electrode 15 and the extraction conductor 41 is reduced.

[0160] In the embodiment described in the previous paragraph, for example, the second substrate side layer 23 may have a pattern extending from a position overlapping the pad region 5ac to any position, and the extraction conductor 41 and the external electrode 15 may be provided at the any position. Alternatively, for example, the pattern may extend to the castellation, and the conductor arranged at the castellation may electrically connect the external electrode 15 and the pad electrode 29. Alternatively, the second substrate 5 may be formed of a multilayer substrate, and the external electrode 15 may be arranged at an appropriate position.

[0161] (6. Positional Relationships Between Components, etc.) (6.1. Relationship Between First Recess and Vibrating Section) The vibrating section 9 may, for example, face the entire first recess 14 (examples of FIGS. 1 to 3). Furthermore, the first substrate 3 and the vibrating section 9 may be joined around the entire periphery of the first recess 14, thereby blocking (sealing) the first recess 14.

[0162] However, the vibrating portion 9 does not have to cover the first recess 14, and does not have to face the entire first recess 14. An example will be shown below.

[0163] 7 is a plan view showing an example of an aspect in which the vibrating portion 9 does not seal the first recess 14. Specifically, this figure shows the first substrate 3 and the vibrating portion 9 as viewed from the +D3 side (the second substrate 5 and the frame portion 11 are not shown).

[0164] In this example, the vibrating section 9 does not face the entire first recess 14. Consequently, the first substrate 3 and the vibrating section 9 are not joined along the entire periphery of the first recess 14. In this embodiment, for example, the inside of the first recess 14 and the space on the +D3 side of the vibrating section 9 (for example, the inside of the second recess 39) are connected to each other, so that the air pressures therebetween are equal. As a result, for example, the influence of an air pressure difference on vibration is reduced.

[0165] In the case where the vibrating portion 9 does not face the entire first recess 14, the relationship between the shapes, dimensions, and positions of the two is arbitrary. From another perspective, the shapes and dimensions of the portions facing each other or the portions not facing each other are arbitrary. From yet another perspective, the shape and dimensions of the region where the vibrating portion 9 is supported (and / or bonded) to the first substrate 3 on the outer periphery of the first recess 14 are arbitrary.

[0166] For example, in the example of FIG. 7 , portions of the first recess 14 that are not covered by the vibrating portion 9 are provided in two locations on either side of the vibrating portion 9 in the D1 direction. From another perspective, the region of the first substrate 3 that supports the vibrating portion 9 is divided into two around the first recess 14. Unlike the example shown in the figure, the portion of the first recess 14 that is not covered by the vibrating portion 9 may be one location or three or more locations. Furthermore, the area of ​​the first recess 14 (more specifically, its opening (upper portion)) that is covered by the vibrating portion 9 (the area excluding the area of ​​the third through hole 9k when a third through hole 9k described later is provided) may be less than half the area of ​​the first recess 14, or may be, for example, at least half, at least two-thirds, at least four-fifths, or at least nine-tenths of the area of ​​the first recess 14.

[0167] Furthermore, for example, the circumferential range of the overlapping region where the outer periphery (outer peripheral region 3b) of the vibrating unit 9 and the first recess 14 overlap (or the joining region where the two are joined) can be any. For example, the overlapping region (jointing region) may extend over 30° or more, 45° or more, 75° or more, 100° or more, 150° or more, half a circumference (180°) or more, ¾ circumference (270°) or more, 7 / 8 circumference (315°) or more, or 15 / 16 circumference (337.5°) based on the length of the outer edge of the vibrating unit 9 or the first recess 14 (or the angular range around the geometric center of the vibrating unit 9 or the first recess 14). When the angle is 180° or more, the overlapping region (jointing region) may be considered to surround the center of the vibrating unit 9 or the first recess 14. In the example of FIG. 7, as indicated by two arrows a5, the overlapping region (joint region) does not need to be continuous, and the total of the regions may span an angular range of 180° or more.

[0168] Fig. 8A is a plan view similar to Fig. 7 showing another example of an embodiment in which the vibrating portion 9 does not seal the first recess 14. Fig. 8B is a cross-sectional view taken along line VIIIb-VIIIb in Fig. 8A (however, only a partial range including the first recess 14 is shown).

[0169] In this example, the vibrating portion 9 has a width that faces the entire first recess 14, and as a result, the vibrating portion 9 and the outer periphery (outer periphery region 3b) of the first recess 14 overlap (are joined) all around the center of the vibrating portion 9 (the first recess 14 from another perspective). However, the vibrating portion 9 is provided with a third through-hole 9k that penetrates the vibrating portion 9 in the thickness direction. This allows communication between the interior of the first recess 14 and the space on the +D3 side of the vibrating portion 9 (the second recess 39).

[0170] The number, position, shape, and dimensions of the third through holes 9k are arbitrary. For example, the third through holes 9k may be located in either the arrangement region or the non-arrangement region of the first intermediate side layer 25 and / or the second intermediate side layer 27. The third through holes 9k may or may not also serve as the first through holes 9h that contribute to electrical conduction. The shape of the third through holes 9k in a plan view does not have to be slit-shaped (as in the illustrated example), but may also be slit-shaped.

[0171] The communication between the first recess 14 and the space on the +D3 side of the vibration unit 9 (the second recess 39) may be achieved by methods other than those described above. For example, in a configuration in which the vibration unit 9 faces the entire first recess 14, a slit extending from the edge of the first recess 14 to the outer edge of the vibration unit 9 may be provided in the multi-function electrode 33 and / or the first substrate-side layer 21 to communicate the first recess 14 with the space on the outer periphery of the vibration unit 9 (the gap between the vibration unit 9 and the frame 11). Alternatively, a slit SL formed integrally with the first recess 14 and extending to the outer edge of the vibration unit 9 may be provided in the first substrate 3 (see FIG. 16 ). Furthermore, the communication between the first recess 14 and the space on the +D3 side of the vibration unit 9 (the second recess 39) may be achieved outside the first recess 14 within the vibration unit 9 in a planar view. The first recess 14 may also be communicated with the outside by a cantilever-like support ( FIG. 20 ), which will be described later.

[0172] (6.2. Gap between vibrating portion and frame portion) The specific size of the distance d1 (FIG. 3) between the outer edge of the vibrating portion 9 and the inner edge of the frame portion 11 is arbitrary. For example, the distance d1 may be less than half the width of the frame portion 11 (the width from the inner edge to the outer edge), or may be equal to or greater than half the width. Furthermore, for example, the distance d1 may be set taking into consideration the wavelength of unwanted vibrations generated in the vibrating portion 9. Specifically, for example, it is as follows.

[0173] When an AC voltage is applied to the vibrating unit 9, unwanted vibrations other than the thickness-shear vibration intended for use occur in the vibrating unit 9. Examples of unwanted vibrations include bending vibration, thickness vibration (thickness longitudinal vibration), and contour-shear vibration. Bending vibration is, for example, vibration in which the vibrating unit 9 bends in the D3 direction. Thickness vibration is, for example, vibration in which the vibrating unit 9 expands and contracts in the thickness direction (D3 direction). Contour-shear vibration is, for example, vibration in which opposing side surfaces of the vibrating unit 9 slide against each other in a planar view.

[0174] The unwanted vibrations resonate at a frequency (wavelength) determined by the specific dimensions of the vibrating portion 9. From another perspective, the unwanted vibrations generate standing waves with nodes or antinodes at the ends of the vibrating portion 9 in the vibration direction. The wavelength of this standing wave is defined as λ (this may be any of various unwanted vibrations). In this case, the distance d1 may be n×λ / 4 (n is a natural number). When d1 is said to be equal to n×λ / 4, an error of ±λ / 16 or ±λ / 32 may exist.

[0175] In each of the various modes of unwanted vibration (bending vibration, thickness vibration, and contour shear vibration), standing waves of various orders may occur. The above λ is set to the wavelength that is most likely to couple with the thickness shear vibration of the target object among the various orders of standing waves propagating in the direction in which the distance d1 is measured. The wavelength λ of such a standing wave may be determined, for example, by simulation calculation or experiment. Furthermore, the relationship in the previous paragraph may be true, for example, over the entire circumference of the vibrating portion 9, or over a portion or most of the circumference (for example, more than half the circumference or more than three-quarters of the circumference).

[0176] As described above, the vibration unit 9 and the frame unit 11 are separated from each other along the entire periphery. In this regard, the gap between them is, for example, a space, and is in a vacuum state or a state where gas is present. However, a material that can allow relative displacement between the vibration unit 9 and the frame unit 11 may be interposed in the gap, rather than a configuration in which the vibration unit 9 and the frame unit 11 are integrally configured (or, from another perspective, connected to each other using the same material). This material has, for example, a modulus of elasticity (e.g., Young's modulus) lower than the modulus of elasticity of the materials of the vibration unit 9, the frame unit 11, and the first substrate 3.

[0177] (6.3. Relationship of Dimensions, etc. of Various Layers) The relationship of dimensions (for example, width and thickness) of various layers (for example, layers 3, 5, 7, 17, and 19) is arbitrary.

[0178] For example, in the example of Figure 3, in a planar perspective view, the outer edge of the first substrate 3 is located outside the outer edge of the second substrate 5 along its entire periphery (i.e., the former is wider than the latter), and the outer edge of the second substrate 5 is located outside the outer edge of the intermediate layer 7 along its entire periphery (i.e., the former is wider than the latter). Unlike the example of Figure 3, for example, the outer edge of the first substrate 3 may be located outside the outer edges of the intermediate layer 7 and the second substrate 5 along its entire periphery, while the outer edge of the intermediate layer 7 may be located outside the outer edge of the second substrate 5 along its entire periphery. Furthermore, the positional relationship between the outer edges of these three layers may differ depending on the circumferential position. The degree of difference in width is also arbitrary.

[0179] Here, when the outer edge of the first substrate 3 is located outside the outer edge of the intermediate layer 7, dicing can be performed outside the outer edge of the intermediate layer 7 during singulation, thereby preventing stress from being applied to the vibrating portion 9 at the joint between the intermediate layer 7 and the first substrate 3 during dicing. As a result, a highly reliable vibrator 1 can be obtained.

[0180] Also, for example, in the example of FIG. 3 , when the recesses (14 and 39) are ignored, the first substrate 3 is thicker than the second substrate 5, and the second substrate 5 is thicker than the intermediate layer 7. Unlike the example of FIG. 3 , for example, the second substrate 5 may be thicker than the first substrate 3. Also, for example, in the example of FIG. 3 , the first metal layer 17 and the second metal layer 19 are thinner than the first substrate 3, the second substrate 5, and the intermediate layer 7. Unlike the example of FIG. 3 , any metal layer may be thicker than the intermediate layer 7, etc. Also, for example, the thickness of the second metal layer 19 may be thicker than the thickness of the first metal layer 17 (example of FIG. 3 ), the same as, or thinner than the thickness of the first metal layer 17. When there is a difference in thickness between the various layers as described above, the degree of difference may be arbitrary.

[0181] In a planar perspective view, the geometric center of the first recess 14 may or may not coincide with the geometric center of the first substrate 3. Furthermore, the geometric center of the first substrate 3 and / or the first recess 14 may or may not coincide with the geometric center of the vibration unit 9 and / or the excitation unit 9a. When the wavelength of the thickness-shear vibration (in other words, the vibration intended for use) is λ, for example, if the distance between the geometric centers is λ / 4 or less, the two may be considered to coincide with each other.

[0182] (7. Details of the electrical connection between the vibration portion and the second substrate) (7.1. Groove on the second substrate) Figure 10 is an enlarged view of region X in Figure 2. Figure 11 is an enlarged view of a portion including the second pad electrode 29B in Figure 3. Note that in Figure 11, the lower layer 21a of the first metal layer 17 is not shown (or the lower layer 21a is not actually provided). Also, the distinction between the lower layer 27a, upper layer 27b, and first bonding layer 27e is not shown (or one layer is actually provided instead of these three layers). Note that while the connection of the second pad electrode 29B is taken as an example here, the connection of the second testing electrode 31B is similar.

[0183] As shown in these figures, an annular groove 43 may be provided on the top surface of the pedestal portion 5ab, surrounding a pad region 5ac connected to the second pad electrode 29B. The second substrate side layer 23 is not provided inside the groove 43. This separates the portion of the second substrate side layer 23 located in the pad region 5ac from the other portions of the second substrate side layer 23, making it possible to apply different potentials to these portions.

[0184] In a planar perspective view, the outer edge of the top surface of the pedestal portion 5ab may be located, for example, outside the outer edge of the second pad electrode 29B over the entire periphery (i.e., the top surface may be wider than the second pad electrode 29B). Furthermore, as shown by arrow a1 in Fig. 11 , the inner edge of the groove 43 may be located, for example, outside the outer edge of the second pad electrode 29B over the entire periphery (i.e., the area surrounded by the groove 43 may be wider than the second pad electrode 29B). This positional relationship (area size relationship) reduces, for example, the likelihood that portions of the second substrate-side layer 23 to which different potentials should be applied will be short-circuited by the second pad electrode 29B.

[0185] The specific shape and dimensions of the groove 43 are arbitrary. For example, the groove 43 may have a shape similar or similar to the outer edge of the top surface of the pedestal portion 5ab and / or the outer edge of the pad electrode 29, or may have a completely different shape. Furthermore, for example, the distance between the outer edge of the groove 43 and the outer edge of the pedestal portion 5ab and the distance between the inner edge of the groove 43 and the second pad electrode 29B are arbitrary. The depth of the groove 43 may be the same as the depth of the second recess 39 (in the illustrated example), or may be different. The width of the groove 43 may be constant or may not be constant. The side surface of the groove 43 may be parallel to or inclined with respect to the D3 direction.

[0186] 4, the groove 43 may be formed around the periphery of the pedestal portion 5ab. Alternatively, the groove 43 may not be provided. Even if the groove 43 is not provided, the portion bonded to the second pad electrode 29B can be separated from the other portions by patterning the second substrate side layer 23.

[0187] (7.2. Positional Relationship Between First Through Hole and Second Through Hole) As shown in FIG. 11 , a configuration is assumed in which the second through hole 5h is provided directly above the pad region 5ac. In this case, as indicated by arrows a2 and a3, the first through hole 9h and the second through hole 5h may each have a portion that does not overlap with each other in a planar perspective view. In this case, it is expected that the structural strength of the configuration consisting of the vibrating section 9 and the second substrate 5 will be improved compared to, for example, a configuration in which one through hole fits into the other through hole (this configuration is also included in the technology disclosed herein). It is to be noted that in a configuration in which one through hole fits into the other through hole, electrical loss is expected to be reduced.

[0188] The direction and amount of offset between the first through hole 9 h and the second through hole 5 h are arbitrary. In the illustrated example, the first through hole 9 h and the second through hole 5 h overlap each other in some parts. However, the first through hole 9 h and the second through hole 5 h may be offset from each other so as not to completely overlap each other.

[0189] (8. Other Examples of Support Structure) As described in Section 6.1, the range of the circumferential direction of the bonded region where the vibrating part 9 and the outer periphery (outer periphery region 3b) of the first recess 14 are bonded is arbitrary. As can be deduced from this, the vibrating part 9 may be supported, for example, in a cantilevered manner. An example is shown below.

[0190] Fig. 18 is an exploded perspective view showing a quartz crystal vibrator 201 in which a vibrating portion 9 is supported in a cantilevered manner, and corresponds to Fig. 1. Fig. 19 is an exploded perspective view of the vibrator 201 viewed from a different direction than Fig. 18, and corresponds to Fig. 2. Fig. 20 is a cross-sectional view taken along line XX-XX in Fig. 18.

[0191] The first intermediate side layer 25 overlapping the surface of the intermediate layer 7 facing the first substrate 3 has two connection electrodes 33b located on one end side in a predetermined direction (for example, the longitudinal direction D2 direction) of the vibration part 9 ( FIGS. 19 and 20 ). From another perspective, the portion of the first intermediate side layer 25 that overlaps the vibration part 9 and faces the outer circumferential region 3b of the first recess 14 is not provided so as to surround the first recess 14, but is provided only on one end side of the vibration part 9.

[0192] Furthermore, the first substrate side layer 21 overlapping the first surface 3a on the vibrating unit 9 side of the first substrate 3 has two connection pads 21h facing the two connection electrodes 33b (FIGS. 18 and 20). From another perspective, the portion of the first substrate side layer 21 overlapping the outer circumferential region 3b and facing the vibrating unit 9 is not provided so as to surround the first recess 14, but is provided only on one end side of the vibrating unit 9.

[0193] The connection electrodes 33b and the connection pads 21h are then bonded. The vibrating portion 9 faces the outer peripheral region 3b, for example, along the entire periphery of the first recess 14. However, the vibrating portion 9 and the outer peripheral region 3b are separated by approximately the thickness of these conductor layers, except for the areas where the connection electrodes 33b and the connection pads 21h are arranged. As a result, the vibrating portion 9 is supported on the first substrate 3 in a cantilevered manner.

[0194] Although the support by the first substrate 3 has been described, the support by the second substrate 5 is also cantilevered. From another perspective, the vibrating section 9 is supported in a cantilevered manner by being sandwiched between the first substrate 3 and the second substrate 5 at one end side.

[0195] Specifically, in the second intermediate layer 27 overlapping the surface of the intermediate layer 7 facing the second substrate 5, the two pad electrodes 29 are located at one end of the vibrating section 9 ( FIGS. 18 and 20 ), and no testing electrode 31 is provided. The two pad electrodes 29 are then bonded to areas of the second substrate-side layer 23 that overlap the two pad areas 5ac. As a result, the vibrating section 9 is supported in a cantilevered manner, separated from the second substrate 5 by the thickness of the pad electrodes 29 and the second substrate-side layer 23.

[0196] In the illustrated example, the pedestal portion 5ab is not provided. From another perspective, the second recess 39 does not surround the pedestal portion 5ab, and has a shape and size that generally coincide with the first recess 14 in a planar perspective. Regardless of whether the first recess 14 and the second recess 39 coincide with each other in a planar perspective, the description of the shape, dimensions, etc. of the first recess 14 may be applied to the second recess 39. Note that the pedestal portion 5ab may be provided in the vibrator 201, and conversely, the pedestal portion 5ab may be omitted in the vibrator 1.

[0197] One of the two connection electrodes 33b is connected to the second excitation electrode 13B via a wiring portion (reference numeral omitted). Furthermore, the one connection electrode 33b is connected to the second pad electrode 29B directly above it via a connection conductor 37 (FIG. 20). The other connection electrode 33b may be connected to the first excitation electrode 13A via the connection conductor 37 and the first pad electrode 29A directly above it, or may be connected to the second excitation electrode 13B instead of the first excitation electrode 13A, or may be a dummy electrode that is not connected to any of the excitation electrodes 13.

[0198] As can be seen from the above, the specific number, position, shape, etc. of the connection electrodes 33b for cantilevered support are arbitrary. For example, unlike the illustrated example, only one connection electrode 33b extending in the D1 direction may be provided. In the illustrated example, the conductors (including the connection conductor 37) in the vibrating portion 9 are configured with 180° rotational symmetry about a center line parallel to the D2 direction as the axis of symmetry. This makes it easier to ensure vibration symmetry. Note that, regardless of whether they are 180° rotationally symmetric, the descriptions of the position, shape, dimensions, etc. of the pad electrodes 29 and the wiring portion 35 may be applied to the connection electrodes 33b and the wiring portion connected to the connection electrodes 33b.

[0199] The specific number, positions, shapes, etc. of the connection pads 21h are also arbitrary. In the illustrated example, the number, positions, shapes, etc. of the connection pads 21h are similar to those of the connection electrodes 33b. However, for example, if the connection electrodes 33b that are not connected to the second excitation electrode 13B are dummy electrodes, one connection pad 21h may be provided across the two connection electrodes 33b.

[0200] In the illustrated example, when viewed in the D3 direction, the vibrating portion 9 overlaps the entire first recess 14. From another perspective, when viewed in the D3 direction, the vibrating portion 9 extends from the outside of one side of the first recess 14 to the outside of the other side of the first recess 14 in the direction from one end supported in a cantilevered manner to the other end (free end). From yet another perspective, when viewed in the D3 direction, the first recess 14 does not overlap the other end (free end) of the vibrating portion 9. However, unlike the illustrated example, the first recess 4 may overlap the free end and / or the first recess 14 may overlap both edge portions of the vibrating portion 9 in the D1 direction as illustrated in FIG.

[0201] Unlike the illustrated example, the vibrating portion 9 may not be sandwiched between the first substrate 3 and the second substrate 5, but may be entirely separated from the second substrate 5. In this case, for example, the second substrate side layer 23 does not have a portion overlapping the pad region 5ac, and the vibrating portion 9 is not bonded to the second substrate 5. The second recess 39 may be made wider than the vibrating portion 9, so that the second substrate 5 is separated from the vibrating portion 9. Then, two extraction conductors 41 and two external electrodes 15 are provided on the first substrate 3 directly below the two connection pads 21h.

[0202] The various features shown in the examples of Figures 18 to 20 may be applied as appropriate to vibrators having support structures other than a cantilever-shaped support structure. For example, in the examples of Figures 18 to 20, the conductor layer located on the underside of the vibrating section 9 is not a solid pattern (multi-function electrode 33), but is a pattern including the second excitation electrode 13B, a wiring section, and a connection electrode 33b. This type of configuration may also be applied to a vibrating section 9 that is supported at both ends. For example, the two connection electrodes 33b may be located on both sides of the second excitation electrode 13B in the direction D2.

[0203] (9. Manufacturing Method of Vibrator) The vibrator 1 (and 201) having the above configuration may be manufactured by various manufacturing methods. An example is shown below.

[0204] 12A to 15C are schematic cross-sectional views illustrating an example of a method for manufacturing the vibrator 1. The manufacturing process basically proceeds in order from FIG. 12A to FIG. 15C.

[0205] 12A to 15C show, for example, processing steps for a wafer including a plurality of first substrates 3, a wafer including a plurality of second substrates 5, and a wafer including a plurality of intermediate layers 7. However, for convenience, these figures only show one first substrate 3, one second substrate 5, and one intermediate layer 7. For convenience, please refer to other drawings for some of the reference numerals described below.

[0206] These figures show an example in which the vibrating section 9 is supported around the entire periphery of the first recess 14. The electrical continuity between the front and back of the vibrating section 9 is shown as the electrical continuity on the side surface of the vibrating section 9 shown in Figure 6C. Also, the second intermediate layer 27 has regions with different thicknesses. Note that manufacturing methods for embodiments not shown here can be inferred from the manufacturing methods described below.

[0207] As shown in FIG. 12A , first, a wafer including a plurality of first substrates 3 and a wafer including an intermediate layer 7 are bonded together using a first metal layer 17 (an example of a first bonding step). More specifically, for example, as shown in FIG. 3 , the first substrate-side layer 21 and the first intermediate-side layer 25 are bonded together using pressure and heat. At this stage, the vibration section 9 and the frame section 11 are integrated in the intermediate layer 7, and no conductors other than the first intermediate-side layer 25 are disposed thereon. The first substrate-side layer 21 also extends over the entire surface (first surface 3 a) of the first substrate 3 facing the intermediate layer 7. Note that in the case of the vibrator 201, rather than the vibrator 1, the first substrate-side layer 21 and the first intermediate-side layer 25 are patterned before bonding.

[0208] Next, as shown in FIG. 12B , the intermediate layer 7 is thinned. This process may include, for example, a large thinning process by polishing or wet etching, and a high-precision thinning process by plasma CVM. Through this thinning process, the intermediate layer 7 is brought to a final thickness that corresponds to the frequency that is intended to be used. Because the intermediate layer 7 is etched while still in the wafer state supported by the wafer of the first substrate 3, it is easy to process it to be extremely thin.

[0209] Next, as shown in FIG. 12C , the intermediate layer 7 is etched (e.g., wet etching; hereinafter, the same applies to other layers unless otherwise specified) to form the outer shapes of the vibrating section 9 and the frame section 11 (an example of an etching step). An electrode layer 27c that will become part of the second intermediate layer 27 is also formed. The electrode layer 27c may be configured to include, for example, the lower layer 27a and the upper layer 27b in the example of FIG. 3. At this stage, the electrode layer 27c has the same planar shape as the vibrating section 9 and the frame section 11. The etching of the vibrating section 9 and the frame section 11 and the patterning of the electrode layer 27c may be performed simultaneously, or the former may be performed before the latter.

[0210] 13A , a bonding layer 27d is formed to become another part of the second intermediate-side layer 27. The bonding layer 27d corresponds to, for example, the first bonding layer 27e and the second bonding layer 27f in the example of FIG. 3. The bonding layer 27d is, for example, a layer that is in direct contact with and bonded to the second substrate-side layer 23, and is made of a material that improves strength or functions as a barrier layer (for example, a Ti / Au laminate structure).

[0211] Next, as shown in FIG. 13B, the bonding layer 27d is removed by etching from the upper surface of the vibrating portion 9 in areas other than the areas that will become the pad electrodes 29 and the testing electrodes 31, thereby exposing the electrode layer 27c.

[0212] 13C , the electrode layer 27c, the bonding layer 27d, and / or the first metal layer 17 are removed by etching from the region of the vibrating section 9 where the second intermediate side layer 27 is not disposed, between the vibrating section 9 and the frame section 11, and outside the frame section 11. At this time, the first excitation electrode 13A and the wiring section 35 are patterned by the electrode layer 27c. In addition, the first substrate side layer 21 is separated into an inner region 21e and an outer region 21f.

[0213] 12A to 13C, a second substrate 5 is fabricated as shown in Fig. 14A. For example, a flat wafer is etched to form a second recess 39. Note that the shape of second recess 39 in plan view is such that frame-shaped region 5aa (the region bonded to frame portion 11) and pedestal portion 5ab are connected, and an additional frame-shaped region is formed outside frame-shaped region 5aa.

[0214] 14B , a metal layer 23c that will become part of the second-substrate-side layer 23 is deposited and patterned. In the illustrated example, unlike in FIG. 3 , the metal layer 23c is provided only in a region of the surface (second surface 5a) of the second substrate 5 that faces the intermediate layer 7 and is bonded to the intermediate layer 7. The metal layer 23c may include, for example, the lower layer 23a and upper layer 23b in the example of FIG. 3 , and may further include a barrier layer.

[0215] 14C , a bonding layer 23d is formed and patterned to form another part of the second substrate-side layer 23. In the illustrated example, the bonding layer 23d is provided only in the region to be bonded to the intermediate layer 7, similar to the metal layer 23c described above. The bonding layer 23d may be made of a material that is easy to bond, such as an AuSn alloy.

[0216] Although not particularly shown, the grooves 43 may be formed by etching after the formation of the second substrate side layer 23. At this time, the second substrate side layer 23 overlapping the region that will become the grooves 43 is also removed.

[0217] 15A , the intermediate layer 7 and the second substrate 5 are bonded together by the second metal layer 19 (an example of a second bonding step). More specifically, the second substrate-side layer 23 and the second intermediate-side layer 27 are bonded together by applying pressure and heat. The second substrate-side layer 23 and the second intermediate-side layer 27 may be bonded together at room temperature by activating the surfaces of the second substrate-side layer 23 and the second intermediate-side layer 27, for example.

[0218] 15B, the second substrate 5 is thinned by polishing or etching, so that the second substrate 5 has its final thickness.

[0219] 15C, second through holes 5h are formed in the second substrate 5, and extraction conductors 41 and external electrodes 15 are provided therein. After that, although not shown, the three-layer wafer is divided into individual pieces by dicing or the like. In this way, the vibrator 1 is fabricated.

[0220] In addition, a frame-shaped recess is also formed on the -D3 side surface of the second substrate 5, outside the frame-shaped region 5aa. When forming the second through-holes 5h, if a through-hole is formed from the +D3 side surface in the area that overlaps with this recess in a plan view, the second substrate 5 is separated into individual pieces. In this case, there is no need to dice the three-layer wafer together, which increases productivity. Furthermore, since stress is not applied to the joint between the second substrate 5 and the intermediate layer 7 during dicing, a highly reliable vibrator 1 can be obtained.

[0221] (10. Summary of the embodiment) As described above, the vibration device (quartz crystal vibrator 1) according to the embodiment has a first substrate 3, a second substrate 5, an intermediate layer 7, and an excitation electrode 13. The first substrate 3 has a first surface 3a. The second substrate 5 has a second surface 5a facing the first surface 3a. The intermediate layer 7 is located between the first surface 3a and the second surface 5a. The first surface 3a has a first recess 14. The intermediate layer 7 has a vibration portion 9 and a frame portion 11. The vibration portion 9 has an excitation portion 9a where the excitation electrode 13 is located. The excitation portion 9a faces the first recess 14 (at least a part thereof). The frame portion 11 surrounds the vibration portion 9 in a plan view and is bonded to the first surface 3a and the second surface 5a. The frame portion 11 includes layers made of the same material as layers included in the vibration portion 9. The entire outer edge of the vibrating portion 9 is separated from the frame portion 11. The vibrating portion 9 is joined to the outer peripheral region 3b of the first recess 14 on the first surface 3a.

[0222] Therefore, for example, as described in the description of the outline of the embodiment, the likelihood of the vibration of the vibrating unit 9 leaking to the frame unit 11 is reduced. Furthermore, since the vibrating unit 9 is supported by the outer peripheral region 3b, the support structure can be simplified and / or the degree of freedom in designing the support position can be improved.

[0223] The vibrating portion 9 may be joined to the outer peripheral region 3b over an angular range of 180° or more around the center (geometric center) of the vibrating portion 9 in a plan view.

[0224] In this case, it can be said that the vibrating portion 9 is supported over a wide range in the circumferential direction, and therefore, for example, it is expected that warping and / or bending of the vibrating portion 9 is reduced, and the characteristics of the vibrator 1 are stabilized.

[0225] The vibrating device (vibrator 1) may have a first metal layer 17 and a second metal layer 19. The first metal layer 17 may be interposed between the vibrating portion 9 and the first surface 3a to bond them together, or may be interposed between the frame portion 11 and the first surface 3a to bond them together. The second metal layer 19 may be interposed between the frame portion 11 and the second surface 5a to bond them together.

[0226] In this case, for example, the bonding is easier than in a case where direct bonding is performed. Also, for example, a metal layer used for an electrode such as the excitation electrode 13 can be used for bonding.

[0227] The vibration device (vibrator 1) may have a pad electrode 29. The pad electrode 29 may be located on the second surface 5a side of the vibration portion 9 and may be electrically connected to the excitation electrode 13. The second surface 5a may have a frame-shaped region 5aa, a pad region 5ac, and a second recess 39. The frame-shaped region 5aa may be bonded to the frame portion 11. The pad region 5ac may be bonded to the pad electrode 29. The second recess 39 may be surrounded by the frame-shaped region 5aa, surround the pad region 5ac, and face the excitation portion 9a.

[0228] In this case, for example, as described above, it is possible to facilitate the vibration of the excitation portion 9a and increase the contact pressure when bonding the pad electrode 29 and the second substrate side layer 23 together.

[0229] The second surface 5a may have a pedestal portion 5ab surrounded by the second recess 39. The pedestal portion 5ab may have a top surface including a pad region 5ac bonded to the pad electrode 29. The top surface of the pedestal portion 5ab or the bottom surface of the second recess 39 may have a groove 43 surrounding the pad region 5ac and the pad electrode 29 in a planar perspective view.

[0230] 4, 10, and 11, the likelihood of an unintended short circuit occurring is reduced. When combined with the pedestal portion 5ab, the effect of insulating the portion of the second substrate side layer 23 above the pad region 5ac from other portions of the second substrate side layer 23 is improved.

[0231] The vibration device (vibrator 1) may have a second metal layer 19 overlapping the second surface 5a. The second metal layer 19 may face the entire excitation portion 9a, and may also face the outer edge of the vibration portion 9, the frame portion 11, and the gap between the vibration portion 9 and the frame portion 11. From another perspective, for example, the second metal layer 19 may extend over substantially the entire second surface 5a.

[0232] In this case, for example, the second metal layer 19 is more likely to function as a shield and / or a reinforcing material. Also, the likelihood of gas being released from the second substrate 5 into the space around the vibrating portion 9 during the manufacturing process is reduced.

[0233] The vibrating device (vibrator 1) may have a first metal layer 17 and a second metal layer 19. The first metal layer 17 may be in contact with the vibrating portion 9 and the first surface 3a between them, or may be interposed between the frame portion 11 and the first surface 3a and in contact with them both. The second metal layer 19 may be in contact with the frame portion 11 and the second surface 5a between them. The thickness of the second substrate 5 may be thinner than the thickness of the first substrate 3. The thickness of the second metal layer 19 may be thicker than the thickness of the first metal layer 17.

[0234] In this case, for example, because the first substrate 3 is thicker than the second substrate 5, external stress is less likely to be transmitted to the vibrating portion 9 supported on the outer periphery of the first recess 14. As a result, the likelihood of the characteristics of the vibrating portion 9 deteriorating is reduced. From another perspective, by making the second substrate 5 thinner, it is possible to achieve a thinner vibrating portion 9 while maintaining its characteristics. Furthermore, the relatively thick second metal layer 19 reinforces the strength of the relatively thin second substrate 5. As a result, the strength of the vibrator 1 as a whole is improved.

[0235] The vibrating section 9 may have a constant thickness from the region facing the first recess 14 (at least a part thereof) to the region facing the outer peripheral region 3b (at least a part thereof). In other words, the vibrating section 9 may have a portion with a constant thickness that straddles the boundary between the first recess 14 and the outer peripheral region 3b. For example, the vibrating section 9 may have a constant thickness throughout. Note that, when saying this, unique parts of the vibrating section 9, such as the first through-hole 9h, may be ignored.

[0236] Stress concentration is likely to occur in the vibrating portion 9 at the boundary between the first recess 14 and the outer peripheral region 3b. On the other hand, in the configuration described in the previous paragraph, stress concentration at the boundary is alleviated compared to an embodiment in which the region of the vibrating portion 9 facing the first recess 14 is thinner than the region facing the outer peripheral region 3b (this embodiment is also included in the technology disclosed herein). As a result, for example, resistance to impact is improved. Also, changes in temperature characteristics due to stress can be reduced.

[0237] The vibration device (vibrator 1) may have a third metal layer (first intermediate side layer 25; from another perspective, multi-functional electrode 33) overlapping the first surface 3a side of the vibration section 9. The first intermediate side layer 25 may straddle the boundary between the first recess 14 and the outer peripheral region 3b in a planar perspective view, and the portion straddling the boundary may span an angular range of 30° or more, 45° or more, 75° or more, 100° or more, 150° or more, or 180° or more around the center (geometric center) of the first recess 14, and does not need to be continuous, and also includes an embodiment in which the total of the region spans the above-mentioned angular range.

[0238] In this case, for example, compared to an embodiment in which the multi-function electrode 33 is not a solid pattern and the wiring portion extending from the second excitation electrode 13B straddles the boundary between the first recess 14 and the outer peripheral region 3b (this embodiment is also included in the technology according to the present disclosure), the length of the first intermediate side layer 25 interposed between the boundary and the vibration unit 9 is longer. On the other hand, the first intermediate side layer 25 is expected to have the effect of alleviating stress caused in the vibration unit 9 by the boundary. Therefore, for example, the probability that unintended stress will be caused in the vibration unit 9 is reduced, which in turn has the effect of improving the characteristics of the vibration unit 9 and / or improving resistance to impact.

[0239] The vibration device (vibrator 1) may have a first metal layer 17 interposed between the intermediate layer 7 and the first surface 3a, bonding them together. The first metal layer 17 may include a third metal layer (e.g., the first intermediate layer 25 (or the lower layer 25a or upper layer 25b) in FIG. 3 ) overlapping the vibration section 9 and the frame section 11. The first intermediate layer 25 may be made of the same material and have the same thickness in the portion overlapping the vibration section 9 (the multi-function electrode 33) and the portion overlapping the frame section 11, and may also include a portion overlapping the excitation section 9a. Here, the term "same material" does not necessarily mean that the materials are completely identical, and includes unavoidable differences in material and manufacturing, as well as differences in impurity concentration. The term "same thickness" does not necessarily mean that the thickness of the portion overlapping the frame section 11 is different from the thickness of the portion overlapping the vibration section 9 (e.g., average value) within ±5% of the latter thickness.

[0240] In this case, for example, the first intermediate layer 25 (or the lower layer 25 a or the upper layer 25 b) used as the second excitation electrode 13B is also used to join the frame portion 11 and the first substrate 3. As a result, for example, the configuration is simplified.

[0241] The vibrating device (vibrator 1) may have a first metal layer 17 between the intermediate layer 7 and the first surface 3a in contact with both. The thickness of the first metal layer 17 may be thinner than the thickness of the excitation portion 9a.

[0242] In this case, for example, the vibrator 1 can be made thinner by thinning the first metal layer 17. In the embodiment, since the distance between the excitation portion 9a and the first surface 3a (the bottom surface of the first recess 14) is ensured by the first recess 14, there is no need to thicken the first metal layer 17 to ensure the distance between them, and the first metal layer 17 can be made thin. Note that, as described above, in an embodiment utilizing thickness-shear vibration, the excitation portion 9a corresponding to high frequencies is made extremely thin. When a first metal layer 17 thinner than such a thin excitation portion 9a is used, the above effect is enhanced.

[0243] The excitation electrode 13 (first excitation electrode 13A) may be located on the surface of the vibration section 9 on the side of the second substrate 5, and may be contained in the first recess 14 in a planar perspective view.

[0244] In this case, for example, the likelihood that the vibration of the excitation part 9a will be restricted by the edge of the first recess 14 is reduced, or the degree of restriction is reduced, resulting in, for example, improved characteristics of the vibration part 9.

[0245] The vibrating device (vibrator 1 ) may have a fourth metal layer (first substrate side layer 21 ) that overlaps the bottom surface of the first recess 14 .

[0246] In this case, for example, the effect of the first substrate side layer 21 as a shield and / or reinforcing material is improved. In addition, for example, the amount of gas released from the first substrate 3 into the space around the vibrating part 9 during the manufacturing process is reduced.

[0247] The vibrating device (vibrator 1) may have a fourth metal layer (first substrate side layer 21) that overlaps the first substrate 3 from the side surface of the first recess 14 to the outer peripheral region 3b (FIG. 4).

[0248] In this case, for example, the same effect as that already described when the first substrate side layer 21 overlaps the bottom surface of the first recess 14 is achieved. Furthermore, for example, by having the first substrate side layer 21 interposed between the edge of the first recess 14 and the vibrating part 9, it is expected that the stress generated in the vibrating part 9 due to the edge will be reduced.

[0249] In a planar perspective view, the outer edge of the frame portion 11 and the outer edge of the second substrate 5 may be located inside the outer edge of the first substrate 3 along the entire periphery.

[0250] In this case, for example, the outer peripheral surface of the first substrate 3 can protect the outer peripheral surfaces of the frame portion 11 and the second substrate 5 against contact from the outer peripheral side. Therefore, for example, by making the first substrate 3 relatively thick, not only can the likelihood of deformation of the vibrating portion 9 joined to the first substrate 3 be reduced as described above, but also the resistance of the vibrator 1 to contact from the outer peripheral side can be improved. Furthermore, for example, in the manufacturing process, dicing of the first substrate 3 from the second substrate 5 side can be facilitated.

[0251] The vibration portion 9 and the excitation electrode 13 may have a configuration that utilizes thickness-shear vibration. The first recess 14 may have an elliptical shape in plan view, with the direction of thickness-shear vibration as the longitudinal direction.

[0252] In this case, the first recess 14 has a shape similar to the shape in which the energy of thickness-shear vibration is trapped. Therefore, for example, the area of ​​the first recess 14 can be reduced while maintaining the characteristics of the vibrating portion 9, making it easier to ensure the strength of the first substrate 3.

[0253] The side surface of the vibration section 9 may have an inclined surface that is positioned closer to the outer periphery of the vibration section 9 as it approaches the first substrate 3 .

[0254] In this case, for example, it is possible to increase the bonding area between the vibrating section 9 and the first substrate 3. Also, for example, when forming a connection layer 38 (which may be formed together with the second intermediate side layer 27) that overlaps the side surface of the vibrating section 9 from the +D3 side of the vibrating section 9 and electrically connects the second intermediate side layer 27 and the first metal layer 17, it is easy to form the connection layer 38. From another perspective, the reliability of the conduction provided by the connection layer 38 is improved.

[0255] The distance between the vibration portion 9 and the frame portion 11 may be a length (n×λ / 4) obtained by multiplying a natural number by a quarter wavelength of at least one of the unnecessary vibrations in the excitation portion 9a, namely, bending vibration, thickness vibration, and contour shear vibration.

[0256] In this case, for example, it is possible to reduce the influence of unwanted vibrations. A part of the vibration of the vibrating part 9 reaches the frame part 11 via the first substrate 3. This vibration is reflected by the frame part 11 and returns to the vibrating part 9, thereby reducing vibration loss and enabling efficient vibration generation.

[0257] The vibrating section 9 may have a first through hole 9h in which a conductor (connection conductor 37) is located, providing electrical continuity between the first substrate 3 side of the vibrating section 9 and the second substrate 5 side of the vibrating section 9. One of the first substrate 3 or the second substrate 5 (the second substrate 5 in the illustrated example) may have a second through hole 5h in which a conductor (extraction conductor 41) is located, providing electrical continuity between the intermediate layer 7 side of the one substrate and the side of the one substrate opposite the intermediate layer 7. In a planar perspective view, the first through hole 9h and the second through hole 5h may have portions that do not overlap with each other.

[0258] In this case, as described with reference to FIG. 11, it is expected that the structural strength of the vibrator 1 will be improved.

[0259] The vibrating section 9 may have a first through hole 9h in which a conductor is located, electrically connecting the first substrate 3 side of the vibrating section 9 and the second substrate 5 side of the vibrating section 9. The first through hole 9h may have a shape in which the length in a first direction (direction D1) is longer than the length in a second direction (direction D2) perpendicular to the first direction, in a plan view of the vibrating section 9. The first through hole 9h may also have a tapered shape with a diameter that decreases toward the first substrate 3. A taper angle θ1 in a cross section perpendicular to the first direction may be larger than a taper angle θ2 in a cross section perpendicular to the second direction.

[0260] In this case, for example, as described above, with respect to the inclination angle of the inner surface of the first through hole 9h relative to the +D3 side surface of the vibrating portion 9, the average of the two inner surfaces in a vertical cross section perpendicular to the longitudinal direction (D1 direction) is made smaller than the average of the two inner surfaces in a vertical cross section perpendicular to the lateral direction. Therefore, for example, the inner surface in a vertical cross section perpendicular to the longitudinal direction is, on average, easier to form a conductor film on when forming a film from the +D3 side. By ensuring that the inner surface in such a vertical cross section is long in plan view, the reliability of electrical conduction is improved overall.

[0261] 17A, the vibrating section 9 may have a separate divided section SP. The divided section SP is bonded to the first substrate 3 in the same manner as the vibrating section 9 and the first substrate 3 in the other examples.

[0262] The first excitation electrode 13A has a narrow width extending outward from a portion overlapping with the first recess 14 in a plan view. A first pad electrode 29A is located on the +D3 side surface of the divided portion SP. The first pad electrode 29A is electrically connected to the first intermediate layer 25 via a first through-hole 9h.

[0263] 17B, ​​the pedestal portion 5ab corresponding to the first pad electrode 29A (i.e., the electrode electrically connected to the first excitation electrode 13A) has a larger area than the pedestal portion 5ab corresponding to the second pad electrode 29B. That is, the pedestal portion 5ab is formed continuously in the narrow portion and in the region corresponding to the first pad electrode 29A. The narrow portion and the first pad electrode 29A are electrically connected by the second substrate side layer 23 located on the pedestal portion 5ab.

[0264] This configuration allows the area of ​​the narrow width portion to be reduced, thereby reducing the capacitance formed by the first intermediate layer 25 and the narrow width portion, and providing a vibrator 1 with excellent characteristics.

[0265] Furthermore, in the above example, the intermediate layer 7 is thinned after being bonded to the first substrate 3, but by using a film-like intermediate layer 7 that has been thinned in advance, the thickness adjustment process after bonding can be omitted.

[0266] The manufacturing method of the quartz crystal resonator 1 may include, for example, a first bonding step ( FIG. 12A ), an etching step ( FIG. 12C ), and a second bonding step ( FIG. 15A ). In the first bonding step, the intermediate layer 7, in which the vibrating portion 9 and the frame portion 11 are integrated, is bonded to the first surface 3 a, which has the first recess 14. In the etching step, after the first bonding step, the intermediate layer 7 is etched to separate the outer edge of the vibrating portion 9 from the frame portion 11 along its entire periphery. In the second bonding step, after the etching step, the second surface 5 a is bonded to the intermediate layer 7.

[0267] In this case, for example, as described in the explanation of the outline of the embodiment, the intermediate layer 7 in which the vibrating portion 9 and the frame portion 11 are integrated is superimposed on the first substrate 3 and the vibrating portion 9 is processed, so that warping and / or bending of the vibrating portion 9 is reduced and the characteristics of the vibrator 1 are expected to be stabilized.

[0268] In the above embodiments, the quartz crystal resonator 1 is an example of a resonator device. The first intermediate side layer 25 is an example of a third metal layer. The first substrate side layer 21 is an example of a fourth metal layer. The D1 direction is an example of a first direction. The D2 direction is an example of a second direction.

[0269] The technology according to the present disclosure is not limited to the above-described embodiment and may be implemented in various modes.

[0270] For example, the vibration device is not limited to a vibrator. For example, the vibration device may be an oscillator having an oscillation circuit that applies a voltage to a vibration unit to generate an oscillation signal. In this case, for example, an integrated circuit (IC) may be mounted on the inside or outside of the vibration device relative to the first substrate and / or the second substrate. Alternatively, the oscillation circuit may be formed by injecting dopants into the first substrate and / or the second substrate made of semiconductor or by forming electrodes on the first substrate and / or the second substrate. Alternatively, the first substrate and / or the second substrate may be formed as a multilayer substrate and have an oscillation circuit built in. Furthermore, for example, the vibration device may be used for purposes other than generating an oscillation signal, such as filtering.

[0271] The following concepts can be extracted from the present disclosure: (Concept 1) A vibration device comprising: a first substrate having a first surface; a second substrate having a second surface opposite the first surface; an intermediate layer located between the first surface and the second surface; and an excitation electrode, wherein the first surface has a first recess, the intermediate layer has an excitation portion where the excitation electrode is located, the excitation portion facing the first recess, and a frame portion surrounding the vibration portion in a plan view and bonded to the first surface and the second surface, the frame portion including a layer made of the same material as a layer included in the vibration portion, the outer edge of the vibration portion is separated from the frame portion along the entire periphery, and the vibration portion is bonded to an outer peripheral region of the first recess in the first surface. (Concept 2) The resonator device according to Concept 1, comprising: a first metal layer interposed between the vibrating portion and the first surface to bond them together, and also interposed between the frame portion and the first surface to bond them together, and a second metal layer interposed between the frame portion and the second surface to bond them together. (Concept 3) The resonator device according to Concept 1 or 2, comprising: a pad electrode located on the second surface side of the vibrating portion and electrically connected to the excitation electrode, the second surface comprising: a frame-shaped region bonded to the frame portion; a pad region bonded to the pad electrode; and a second recess surrounded by the frame-shaped region, surrounding the pad region and facing the excitation portion. (Concept 4) The resonator device according to Concept 3, wherein the second surface has a pedestal portion surrounded by the second recess, the pedestal portion having a top surface including the pad region, and the top surface of the pedestal portion or a bottom surface of the second recess has a groove surrounding the pad region and the pad electrode in a planar perspective view. (Concept 5) A vibration device described in any one of Concepts 1 to 4, having a second metal layer overlapping the second surface, wherein the second metal layer faces the entire excitation section and also faces the outer edge of the vibration section, the frame section, and the gap between the vibration section and the frame section.(Concept 6) The resonator device according to any one of Concepts 1 to 5, comprising: a first metal layer in contact with both the vibrating portion and the first surface between them and also in contact with both the frame portion and the first surface between them; and a second metal layer in contact with both the frame portion and the second surface between them, wherein the thickness of the second substrate is thinner than the thickness of the first substrate, and the thickness of the second metal layer is thicker than the thickness of the first metal layer. (Concept 7) The resonator device according to any one of Concepts 1 to 6, wherein the vibrating portion has a constant thickness from a region facing the first recess to a region facing the outer circumferential region. (Concept 8) The resonator device according to any one of Concepts 1 to 7, comprising: a first metal layer interposed between the intermediate layer and the first surface to bond them together, wherein the first metal layer includes a third metal layer overlapping the vibrating portion and the frame portion, and wherein a portion of the third metal layer overlapping the vibrating portion and a portion overlapping the frame portion are made of the same material and have the same thickness, and includes a portion overlapping the excitation portion. (Concept 9) The resonator device according to any one of Concepts 1 to 8, further comprising a first metal layer in contact with both the intermediate layer and the first surface, wherein the thickness of the first metal layer is thinner than the thickness of the excitation portion. (Concept 10) The resonator device according to any one of Concepts 1 to 9, further comprising: a first metal layer located on the surface of the resonator portion facing the second substrate, and located within the first recess in a planar perspective view. (Concept 11) The resonator device according to any one of Concepts 1 to 10, further comprising: a fourth metal layer overlapping a bottom surface of the first recess. (Concept 12) The resonator device according to any one of Concepts 1 to 11, further comprising: a fourth metal layer overlapping the first substrate from a side surface of the first recess to the outer circumferential region. (Concept 13) The resonator device according to any one of Concepts 1 to 12, further comprising: a first metal layer located inside the first substrate along the entire periphery in a planar perspective view. (Concept 14) A vibration device described in any one of Concepts 1 to 13, wherein the vibration portion and the excitation electrode are configured to utilize thickness-shear vibration, and the first recess has an elliptical shape in a planar view with the direction of the thickness-shear vibration as its longitudinal direction.(Concept 15) The vibration device according to any one of Concepts 1 to 14, wherein a side surface of the vibration unit has an inclined surface that is positioned closer to the outer periphery of the vibration unit as it approaches the first substrate. (Concept 16) The vibration device according to any one of Concepts 1 to 15, wherein a distance between the vibration unit and the frame unit is a length obtained by multiplying a natural number by a quarter wavelength of at least one of bending vibration, thickness vibration, and contour shear vibration as unwanted vibrations in the excitation unit. (Concept 17) The vibration device according to any one of Concepts 1 to 16, wherein the vibration unit has a first through hole in which a conductor is located that provides electrical conduction between a side of the vibration unit facing the first substrate and a side of the vibration unit facing the second substrate, and one of the first substrate or the second substrate has a second through hole in which a conductor is located that provides electrical conduction between a side of the intermediate layer of the one substrate and a side of the one substrate opposite to the intermediate layer, and the first through hole and the second through hole each have a portion that does not overlap with each other in a planar perspective view. (Concept 18) The vibration device according to any one of Concepts 1 to 17, wherein the vibration part has a first through hole in which a conductor is located, which conducts electricity between a side of the vibration part facing the first substrate and a side of the vibration part facing the second substrate, the first through hole having a shape in which a length in a first direction is longer than a length in a second direction orthogonal to the first direction in a plan view of the vibration part, and a tapered shape having a diameter decreasing toward the first substrate, and a taper angle in a cross section orthogonal to the first direction being larger than a taper angle in a cross section orthogonal to the second direction. (Concept 19) The vibration device according to Concept 8, wherein the frame and the vibration part are made of the same material and have approximately the same thickness, the excitation electrodes are located on the first substrate side and the second substrate side of the vibration part, and the third metal layer includes one of the excitation electrodes located on the first substrate side. (Concept 20) The vibration device according to any one of Concepts 1 to 19, wherein the vibration portion is joined to the outer peripheral region over an angular range of 180° or more around a center of the vibration portion in a plan view.(Concept 21) A resonator device according to any one of Concepts 1 to 20, comprising a third metal layer overlapping the first surface side of the vibrating portion, wherein the third metal layer straddles the boundary between the first recess and the outer circumferential region in a planar perspective view, and the portion straddling the boundary extends over an angular range of 180 degrees or more around the center of the first recess. (Concept 22) A method for manufacturing a resonator device according to any one of Concepts 1 to 21, comprising: a first bonding step of bonding the intermediate layer, with the vibrating portion and the frame portion integrated together, to the first surface having the first recess; an etching step of etching the intermediate layer after the first bonding step to separate the outer edge of the vibrating portion from the frame portion along its entire periphery; and a second bonding step of bonding the second surface to the intermediate layer after the etching step.

[0272] From this disclosure, concepts other than those described above can be extracted. For example, while Concept 1 above requires that the frame and the vibrating part have layers made of the same material, concepts that do not require layers made of the same material may be extracted. Such extracted concepts may be characterized by, for example, Concepts 2 to 21.

[0273] 1...quartz crystal oscillator (oscillating device), 3...first substrate, 3a...first surface, 3b...peripheral region, 5...second substrate, 5a...second surface, 7...intermediate layer, 9...vibrating portion, 9a...excitation portion, 11...frame portion, 13...excitation electrode, 14...first recess.

Claims

1. a first substrate having a first surface; a second substrate having a second surface opposite to the first surface; an intermediate layer located between the first surface and the second surface; An excitation electrode; It has the first surface has a first recess; The intermediate layer is a vibration section having an excitation section in which the excitation electrode is located, the excitation section facing the first recess; a frame portion that surrounds the vibration portion in a plan view and is joined to the first surface and the second surface, the frame portion includes a layer made of the same material as a layer included in the vibration portion, an outer edge of the vibration portion is separated from the frame portion over the entire circumference; The vibration portion is joined to an outer peripheral region of the first recess in the first surface. Vibration devices.

2. a first metal layer interposed between the vibration portion and the first surface to bond them together and also between the frame portion and the first surface to bond them together; a second metal layer interposed between the frame portion and the second surface and bonding the two together; The vibration device according to claim 1 ,

3. a pad electrode located on the second surface side of the vibration portion and electrically connected to the excitation electrode; The second surface is A frame-shaped region joined to the frame portion; a pad region joined to the pad electrode; a second recess that is surrounded by the frame region, surrounds the pad region, and faces the excitation portion; The vibration device according to claim 1 .

4. the second surface has a base portion surrounded by the second recess, the base portion has a top surface including the pad area, The top surface of the base portion or the bottom surface of the second recess portion has a groove surrounding the pad region and the pad electrode in a plan view. The vibration device according to claim 3 .

5. a second metal layer overlying the second surface; The second metal layer faces the entire excitation portion, and also faces the outer edge of the vibration portion, the frame portion, and a gap between the vibration portion and the frame portion. The vibration device according to claim 1 .

6. a first metal layer in contact with both the vibration portion and the first surface between the vibration portion and the first surface and in contact with both the frame portion and the first surface between the frame portion and the first surface; a second metal layer between the frame and the second surface and in contact with both; It has the thickness of the second substrate is smaller than the thickness of the first substrate, The thickness of the second metal layer is greater than the thickness of the first metal layer. The vibration device according to claim 1 .

7. The vibration portion has a constant thickness from a region facing the first recess to a region facing the outer circumferential region. The vibration device according to claim 1 .

8. a first metal layer interposed between the intermediate layer and the first surface and bonding them together; the first metal layer includes a third metal layer overlapping the vibration portion and the frame portion, The third metal layer has a portion overlapping the vibration portion and a portion overlapping the frame portion, the portion being made of the same material and having the same thickness, and includes a portion overlapping the excitation portion. The vibration device according to claim 1 .

9. a first metal layer between and in contact with the intermediate layer and the first surface; The thickness of the first metal layer is smaller than the thickness of the excitation portion. The vibration device according to claim 1 .

10. The excitation electrode is located on a surface of the vibration part on the side of the second substrate, and is accommodated in the first recess in a plan view. The vibration device according to claim 1 .

11. a fourth metal layer overlying a bottom surface of the first recess; The vibration device according to claim 1 .

12. a fourth metal layer overlapping the first substrate from a side surface of the first recess to the outer circumferential region; The vibration device according to claim 1 .

13. In a planar perspective view, the outer edge of the frame portion and the outer edge of the second substrate are located inside the outer edge of the first substrate over the entire periphery. The vibration device according to claim 1 .

14. The vibration portion and the excitation electrode have a configuration utilizing thickness-shear vibration, The first recess has an elliptical shape in a plan view with the direction of thickness-shear vibration as a longitudinal direction. The vibration device according to claim 1 .

15. The side surface of the vibration part has an inclined surface located closer to the outer periphery of the vibration part as it approaches the first substrate. The vibration device according to claim 1 .

16. The distance between the vibration part and the frame part is a length obtained by multiplying a quarter wavelength of at least one of bending vibration, thickness vibration, and contour shear vibration as unwanted vibrations in the excitation part by a natural number. The vibration device according to claim 1 .

17. the vibration portion has a first through hole in which a conductor is positioned, the conductor electrically connecting a side of the vibration portion facing the first substrate and a side of the vibration portion facing the second substrate; one of the first substrate and the second substrate has a second through hole in which a conductor is located, the conductor electrically connecting a side of the one substrate facing the intermediate layer to a side of the one substrate opposite to the intermediate layer, In a planar perspective view, the first through hole and the second through hole each have a portion that does not overlap with each other. The vibration device according to claim 1 .

18. the vibration portion has a first through hole in which a conductor is positioned, the conductor electrically connecting a side of the vibration portion facing the first substrate and a side of the vibration portion facing the second substrate; The first through hole is In a plan view of the vibration section, the vibration section has a shape in which a length in a first direction is longer than a length in a second direction perpendicular to the first direction, The first substrate has a tapered shape having a smaller diameter toward the first substrate side, A taper angle in a cross section perpendicular to the first direction is larger than a taper angle in a cross section perpendicular to the second direction. The vibration device according to claim 1 .

19. The frame and the vibration section are made of the same material and have approximately the same thickness. the excitation electrodes are located on the first substrate side and the second substrate side of the vibration section, The vibration device according to claim 8 , wherein the third metal layer includes one of the excitation electrodes that is located on the first substrate side.

20. The vibration portion is joined to the outer circumferential region over an angular range of 180° or more around the center of the vibration portion in a plan view. The vibration device according to claim 1 .

21. a third metal layer overlapping the vibration portion on the first surface side, The third metal layer straddles the boundary between the first recess and the outer circumferential region in a planar perspective view, and the boundary-spanning portion extends over an angular range of 180° or more around a center of the first recess. The vibration device according to claim 1 .

22. A method for manufacturing a vibration device according to any one of claims 1 to 21, a first joining step of joining the intermediate layer, with the vibration section and the frame section being integrated together, to the first surface having the first recess; an etching step of etching the intermediate layer after the first bonding step to separate an outer edge of the vibration part from the frame part over its entire periphery; a second bonding step of bonding the second surface to the intermediate layer after the etching step; A method for manufacturing a vibration device having the above structure.