Piezoelectric vibration piece and piezoelectric vibration device

Abstract

In the crystal vibration piece (10), the inner wall surface (12g) of the outer frame portion (12) is configured to be a rectangular ring shape in plan view; a notch portion (18) recessed to the outer frame portion (12) side is formed at a corner portion (12h) of the inner wall surface (12g); an internal wiring (19) for extending an electrode on one main surface of a substrate to the other main surface side is formed in the notch portion (18), the notch portion (18) has a first inner wall portion (18a) connected to a part of the inner wall surface (12g) in an approximately straight line shape, and a second inner wall portion (18b) in which the internal wiring (19) is formed, the second inner wall portion (18b) is not configured to be connected to a part of the inner wall surface (12g) in an approximately straight line shape, and an inclined surface (18c) having an included angle (θ1) between one main surface or the other main surface of the substrate of an obtuse angle is formed in the second inner wall portion (18b).

Description

Technical Field

[0001] The present invention relates to a piezoelectric vibrating sheet and a piezoelectric vibrating device having the piezoelectric vibrating sheet. Background Technology

[0002] In recent years, the operating frequencies of various electronic devices have been continuously increasing, and the packages have been continuously miniaturizing (especially becoming thinner). Therefore, with the increase in frequency and miniaturization of packages, crystal oscillators (such as crystal resonators and crystal oscillators) are also required to adapt to the trend of increasing frequency and miniaturization of packages.

[0003] As a crystal oscillator suitable for miniaturization and thinning, a crystal oscillator known as a sandwich structure is known. The housing of a sandwich structure crystal oscillator is constructed of an approximately cuboid package. This package includes, for example, a first sealing member and a second sealing member made of glass or quartz crystal, and a crystal oscillator plate with excitation electrodes formed on two main surfaces. The first sealing member and the second sealing member are stacked and joined via the crystal oscillator plate. Thus, the vibrating portion of the crystal oscillator plate disposed inside the package (internal space) is hermetically sealed by the first sealing member and the second sealing member (for example, see Patent Document 1).

[0004] In the piezoelectric vibrator described above, if a through hole is to be provided in the outer frame to connect an electrode formed on one main surface to an electrode formed on another main surface, space must be reserved for the through hole, making miniaturization difficult. On the other hand, if miniaturization results in a smaller distance between the vibrating part and the outer frame, the vibrating part may come into contact with the wiring formed on the outer frame, potentially causing wire breakage. Furthermore, when wet etching is performed on piezoelectric vibrators such as crystal vibrators, the difference in etching rate caused by the anisotropy of the quartz crystal can lead to the formation of tilted surfaces, resulting in sharp-edged shapes. Therefore, such areas must be avoided when wiring.

[0005] [Patent Document 1]: Japanese Patent Application Publication No. 2010-252051 Summary of the Invention

[0006] In view of the above, the object of the present invention is to provide a piezoelectric vibrator that can be miniaturized and has stable electrical characteristics, and a piezoelectric vibrating device having the piezoelectric vibrator.

[0007] As a technical solution to the above-mentioned technical problems, the present invention adopts the following structure. That is, the present invention provides a piezoelectric vibrating sheet, which is a piezoelectric vibrating sheet in which electrodes are formed on one main surface and another main surface of a substrate. The vibrating sheet is characterized by: including a vibrating portion, an outer frame portion surrounding the periphery of the vibrating portion, and a holding portion connecting a portion of the vibrating portion to a portion of the outer frame portion; a cut-out portion formed by hollowing out the substrate is provided between the vibrating portion and the outer frame portion; the inner wall surface of the outer frame portion is configured as a rectangular ring in plan view, and a notch portion recessed into the outer frame portion is formed in the corner region of the inner wall surface in plan view; internal wiring extending the electrodes formed on one main surface to the other main surface is formed in the notch portion; the notch portion has a first inner wall portion configured to be approximately linearly connected to a portion of the inner wall surface, and a second inner wall portion having the internal wiring formed thereon, wherein the second inner wall portion is not configured to be approximately linearly connected to a portion of the inner wall surface, and an inclined surface is formed in the second inner wall portion, the angle between the inclined surface and one or the other main surface of the substrate being an obtuse angle. Here, the electrodes formed on one main surface and the other main surface of the substrate can be lead-out electrodes derived from the first excitation electrode and the second excitation electrode formed on the vibrating part of the piezoelectric vibrator; electrodes of an annular sealing part (sealing path) that hermetically seals the vibrating part of the piezoelectric vibrator; grounded wiring electrodes; wiring electrodes connected to the integrated circuit (IC) of the piezoelectric oscillator, etc.

[0008] Based on the piezoelectric vibrator with the above structure, by forming an internal wiring through the inclined surface of the second inner wall portion of the notch provided on the inner wall surface of the outer frame, the internal wiring can be led out at the gently obtuse angle of the inner wall surface, thereby achieving a structure in which the internal wiring is not easily broken. Furthermore, by configuring the first inner wall portion of the notch portion to be connected approximately linearly to a portion of the inner wall surface of the outer frame, the junction between the first inner wall portion of the notch portion and the inner wall surface of the outer frame portion is free of sharp angles or steps, thereby forming a stable notch portion that is not easily affected by etching depressions caused by anisotropy. Simultaneously, since the notch portion is located in the region of the widest part of the outer frame portion when viewed from above, and is configured to be recessed into the outer frame side, the effective area of ​​the vibrating portion is ensured, achieving a miniaturized piezoelectric vibrator with stable electrical characteristics. Moreover, since the internal wiring is not exposed on the outer surface (outer side and edges) of the package of the piezoelectric vibrating device using this piezoelectric vibrator, it is possible to prevent the internal wiring from breaking or being worn due to contact during assembly and transportation.

[0009] In the piezoelectric vibrator with the above structure, it is preferable that the piezoelectric vibrator is an AT-cut quartz wafer, and the first inner wall portion is provided along the Z' end face of the inner wall surface of the outer frame portion. Based on this structure, there are no corners protruding towards the Z' direction side (if the +Y direction side is the main surface, then it is the +Z' direction side; if the -Y direction side is the main surface, then it is the -Z' direction side) and the +X direction side on the inner wall surface of the outer frame portion. As a result, etching depressions caused by corners can be avoided, and an obtuse-angled inclined surface that is not easy to break internal wiring can be easily formed.

[0010] In the piezoelectric vibrator with the above structure, it is preferable to have only one retaining portion, which is formed near the inner wall surface facing the side where the first inner wall portion is formed. Based on this structure, the bonding strength at the connection between the retaining portion and the outer frame portion is not reduced, thereby preventing breakage of the retaining portion. Simultaneously, the wiring for extending the electrode along the inner wall surface perpendicular to the inner wall surface where the first inner wall portion is formed can be configured more stably and kept as short as possible. Furthermore, since only one retaining portion is provided, the effects of vibration leakage can be suppressed.

[0011] In the piezoelectric vibrator with the above structure, preferably, the outer frame portion, viewed from above, has a shape with a long side and a short side, and the width of the short side is greater than the width of the long side, with the notch formed in the wider short side region. Based on this structure, by providing the notch in the wider short side region, the effective area of ​​the vibrating portion can be ensured, thereby enabling a miniaturized piezoelectric vibrator with stable electrical characteristics.

[0012] Furthermore, the present invention also provides a piezoelectric vibrating device comprising a piezoelectric vibrating plate having the above-described structure, characterized in that: a first sealing member covering one main surface side of the piezoelectric vibrating plate and a second sealing member covering the other main surface side of the piezoelectric vibrating plate are provided; the first sealing member is engaged with the piezoelectric vibrating plate, and the second sealing member is engaged with the piezoelectric vibrating plate, thereby the vibrating portion of the piezoelectric vibrating plate is airtightly sealed.

[0013] Based on the piezoelectric vibrating device with the above structure, the same effect as that of the piezoelectric vibrating plate described above can be obtained. Furthermore, since the internal wiring is not exposed on the outer surface of the piezoelectric vibrating device's package, it is possible to avoid the internal wiring from breaking or being worn due to contact during assembly and transportation. Therefore, an ideal structure suitable for miniaturization of the piezoelectric vibrating device can be realized.

[0014] In the piezoelectric vibrating device having the above structure, preferably, a portion of the notch overlaps with the wiring pattern formed on the first sealing member when viewed from above. Based on this structure, even if there is a slight deviation in the engagement position between the wiring pattern of the first sealing member and the wiring pattern of the piezoelectric vibrating sheet when viewed from above, stable wiring can be achieved using internal wiring.

[0015] In a piezoelectric vibrating device having the above-described structure, preferably, an external terminal is formed on the second sealing member, and a through hole is formed to connect the external terminal to an electrode formed on its opposite side. This through hole is positioned so as not to overlap with the notch and the retaining portion when viewed from above. Based on this structure, the width of the outer frame portion is not narrowed, and a sealing pattern that seals the vibrating part can be stably formed without reducing the area, thereby improving the stability of the hermetic seal of the vibrating part in the piezoelectric vibrating device.

[0016] <The Effects of the Invention> Based on the piezoelectric vibrating sheet and piezoelectric vibrating device of the present invention, both miniaturization and stable electrical characteristics can be achieved. Attached Figure Description

[0017] Figure 1 is a schematic diagram showing the outline structure of the crystal resonator according to this embodiment.

[0018] Figure 2 is a schematic top view of the first main surface side of the first sealing member of the crystal resonator.

[0019] Figure 3 is a schematic top view of the second main surface side of the first sealing member of the crystal resonator.

[0020] Figure 4 is a schematic top view of the first main surface of the crystal oscillator according to this embodiment.

[0021] Figure 5 is a schematic top view of the second main surface of the crystal oscillator according to this embodiment.

[0022] Figure 6 is a schematic top view of the first main surface side of the second sealing member of the crystal resonator.

[0023] Figure 7 is a schematic top view of the second main surface side of the second sealing member of the crystal resonator.

[0024] Figure 8 is a cross-sectional view along line X1-X1 in Figure 4.

[0025] Figure 9 is the equivalent of Figure 4 to the crystal vibrator involved in the modified example.

[0026] Figure 10 is a diagram corresponding to Figure 5 of the crystal vibrating plate involved in the modified example. Detailed Implementation

[0027] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following embodiments, the case where the piezoelectric resonator of the present invention is a crystal resonator will be described.

[0028] First, the basic structure of the crystal resonator 100 according to this embodiment will be described. As shown in FIG1, the crystal resonator 100 is configured to include a crystal vibrating plate (piezoelectric vibrating plate) 10, a first sealing member 20, and a second sealing member 30. In this crystal resonator 100, the crystal vibrating plate 10 is joined to the first sealing member 20, and the crystal vibrating plate 10 is joined to the second sealing member 30, thereby forming an encapsulated body with an approximately rectangular sandwich structure. That is, in the crystal resonator 100, the first sealing member 20 and the second sealing member 30 are respectively joined to the two main surfaces of the crystal vibrating plate 10, thereby forming an internal space (cavity) of the encapsulated body, and the vibrating part 11 (see FIG4 and FIG5) is hermetically sealed in this internal space.

[0029] The crystal resonator 100 described in this embodiment has a package size of 1.0 × 0.8 mm, achieving miniaturization and thinness. Furthermore, the crystal resonator 100 is electrically connected to an external circuit board (not shown) via solder.

[0030] Hereinafter, referring to FIGS. 1 to 7, the individual components of the crystal resonator 100, the crystal oscillator 10, the first sealing member 20, and the second sealing member 30 will be described. Here, the individual components that are not yet joined are described as single-unit structures. FIGS. 2 to 7 only show one structural example of each of the crystal oscillator 10, the first sealing member 20, and the second sealing member 30, and are not intended to limit the present invention.

[0031] As shown in Figures 4 and 5, the crystal oscillator 10 is a piezoelectric substrate made of quartz crystal, and its two main surfaces (first main surface 101 and second main surface 102) are processed (mirror-finished) into flat and smooth surfaces. In this embodiment, the crystal oscillator 10 is an AT-cut quartz wafer subjected to thickness shearing vibration. In the crystal oscillator 10 shown in Figures 4 and 5, the two main surfaces (101, 102) of the crystal oscillator 10 are located in the XZ' plane. In this XZ' plane, the direction parallel to the width direction (short side direction) of the crystal oscillator 10 is the X-axis direction, and the direction parallel to the length direction (long side direction) of the crystal oscillator 10 is the Z' axis direction. In addition, AT cutting refers to a processing method in which the crystal is cut around the X-axis at an angle of 35°15′ relative to the Z-axis among the three crystal axes of the artificial quartz crystal, namely, the electrical axis (X-axis), the mechanical axis (Y-axis), and the optical axis (Z-axis). In AT-cut quartz wafers, the X-axis aligns with the crystal axis of the quartz. The Y' and Z' axes are approximately tilted by 35°15′ relative to the crystal axis of the quartz crystal (this cutting angle can be slightly varied within the range of adjusting the frequency-temperature characteristics of the AT-cut crystal oscillator). The Y' and Z' axes correspond to the cutting directions when cutting AT-cut quartz wafers.

[0032] A pair of excitation electrodes (first excitation electrode 111 and second excitation electrode 112) are formed on the two main surfaces (101, 102) of the crystal oscillator 10. The crystal oscillator 10 has a vibrating portion 11 configured as approximately rectangular, an outer frame portion 12 surrounding the outer periphery of the vibrating portion 11, and a holding portion 13 that holds the vibrating portion 11 by connecting the vibrating portion 11 to the outer frame portion 12. That is, the crystal oscillator 10 adopts a structure in which the vibrating portion 11, the outer frame portion 12, and the holding portion 13 are configured as a single unit. The holding portion 13 extends (protrudes) from only one corner located in the +X direction and -Z' direction of the vibrating portion 11 towards the -Z' direction to the outer frame portion 12. Furthermore, between the vibrating portion 11 and the outer frame portion 12, there is a cut-out portion 10a obtained by cutting (hollowing out) the crystal oscillator 10. In this embodiment, only one holding portion 13 is formed on the crystal oscillator 10 to connect the vibrating portion 11 to the outer frame portion 12, and the cut-out portion 10a is continuously formed to surround the outer periphery of the vibrating portion 11. In this embodiment, a structure is adopted in which no through holes or crenellations are provided on the outer frame portion 12 of the crystal oscillator 10.

[0033] A first excitation electrode 111 is disposed on the first main surface 101 side of the vibration section 11, and a second excitation electrode 112 is disposed on the second main surface 102 side of the vibration section 11. Lead-out wires (lead-out electrodes) for connecting these excitation electrodes to external electrode terminals are connected to the first excitation electrode 111 and the second excitation electrode 112. A first lead-out wire 113 extends from the first excitation electrode 111, passes through the holding portion 13, and connects to a connection engagement pattern 12a formed on the first main surface 101 side of the outer frame section 12. Furthermore, the connection engagement pattern 12a connects to a connection engagement pattern 12e formed on the second main surface 102 side of the outer frame section 12 via an internal wiring 19 disposed within a notch 18 formed on the inner wall surface 12g of the outer frame section 12. Additionally, a second lead-out wire 114 extends from the second excitation electrode 112, passes through the holding portion 13, and connects to a connection engagement pattern 12d formed on the second main surface 102 side of the outer frame section 12. Thus, the internal wiring 19 within the notch 18 is used as the transfer wiring for the first excitation electrode 111.

[0034] On the two main surfaces (first main surface 101 and second main surface 102) of the crystal oscillator 10, oscillator-side sealing portions for engaging the crystal oscillator 10 with the first sealing member 20 and the second sealing member 30 are respectively provided. The oscillator-side sealing portion of the first main surface 101 has a first engagement pattern 121; the oscillator-side sealing portion of the second main surface 102 has a second engagement pattern 122. The first engagement pattern 121 and the second engagement pattern 122 are provided on the outer frame portion 12 and are formed in a ring shape when viewed from above. The outer periphery of the first engagement pattern 121 is positioned close to the outer periphery of the first main surface 101 of the crystal oscillator 10 (outer frame portion 12). The outer periphery of the second engagement pattern 122 is positioned close to the outer periphery of the second main surface 102 of the crystal oscillator 10 (outer frame portion 12). In this embodiment, the first bonding pattern 121 on the vibrator side and the second bonding pattern 122 on the vibrator side are connected by an internal wiring 17 formed on the inner wall surface of the outer frame portion 12. The internal wiring 17 is provided on an inner wall surface of the outer frame portion 12 that is parallel to the Z' axis direction and located on the -X direction side (and is an inner wall surface perpendicular to the inner wall surface where the aforementioned internal wiring 19 is provided). In addition, on the first main surface 101 side of the outer frame portion 12, bonding patterns 12b and 12c for connection are formed; on the second main surface 102 side of the outer frame portion 12, bonding pattern 12f for connection is formed. Thus, in addition to serving as a transition wiring for the first excitation electrode 111 and the second excitation electrode 112, the internal wiring 17 is also used as a transition wiring for grounding connection in this embodiment.

[0035] As shown in Figures 2 and 3, the first sealing member 20 is a cuboid substrate made of an AT-cut quartz wafer. The second main surface 202 of the first sealing member 20 (the surface that engages with the crystal resonator 10) is machined (mirror-finished) into a flat and smooth surface. Although the first sealing member 20 does not have a vibrating part, by using an AT-cut quartz wafer, similar to the crystal resonator 10, the thermal expansion rates of the crystal resonator 10 and the first sealing member 20 are the same, thereby suppressing thermal deformation of the crystal resonator 100. Furthermore, the X-axis, Y-axis, and Z'-axis directions of the first sealing member 20 are also the same as those of the crystal resonator 10. In this embodiment, the first sealing member 20 adopts a structure without through holes or crenellations, thus significantly shortening the manufacturing process of the first sealing member 20. Additionally, by eliminating the penetration path of moisture into the internal space of the package, the corrosion resistance of the first sealing member 20 is improved.

[0036] On the second main surface 202 of the first sealing member 20, a first sealing member-side first sealing portion for engaging with the crystal oscillator 10 is formed, with a first engagement pattern 24 on the sealing member side. The first engagement pattern 24 on the sealing member side is configured to be annular when viewed from above. The outer periphery of the first engagement pattern 24 on the sealing member side is set to be close to the outer periphery of the second main surface 202 of the first sealing member 20. In addition, on the second main surface 202 of the first sealing member 20, connection engagement patterns 22a, 22b, and 22c are formed for engaging with connection engagement patterns 12a, 12b, and 12c formed on the first main surface 101 of the outer frame portion 12 of the crystal oscillator 10.

[0037] As shown in Figures 6 and 7, the second sealing member 30 is a cuboid substrate made of an AT-cut quartz wafer. The first main surface 301 of the second sealing member 30 (the surface that engages with the crystal oscillator 10) is machined (mirror-finished) into a flat and smooth surface. Preferably, the second sealing member 30 also uses the same AT-cut quartz wafer as the crystal oscillator 10, and the directions of the X-axis, Y-axis, and Z'-axis are also the same as those of the crystal oscillator 10.

[0038] On the first main surface 301 of the second sealing member 30, a second sealing pattern 31 is formed as a second sealing portion for engaging with the crystal oscillator 10. The second sealing pattern 31 is configured to be annular when viewed from above. The outer periphery of the second sealing pattern 31 is positioned close to the outer periphery of the first main surface 301 of the second sealing member 30. Furthermore, on the first main surface 301 of the second sealing member 30, connection patterns 34a, 34b, and 34c are formed for engaging with connection patterns 12d, 12e, and 12f formed on the second main surface 102 of the outer frame portion 12 of the crystal oscillator 10. Connection patterns 34a and 34c are connected by a wiring pattern 35 extending along the Z' axis.

[0039] On the second main surface 302 (the outer main surface not facing the crystal resonator 10) of the second sealing member 30, four external electrode terminals 32 are provided for electrical connection to an external circuit board disposed outside the crystal resonator 100. The external electrode terminals 32 are configured to be approximately rectangular and are located at the four corners (corners) of the second main surface 302 of the second sealing member 30. When viewed from above, the external electrode terminals 32 are positioned overlapping with the outer frame portion 12 of the crystal resonator 10.

[0040] As shown in Figures 6 and 7, three through holes (33a, 33b, 33c) are formed on the second sealing member 30, passing through the first main surface 301 and the second main surface 302. The through holes 33a, 33b, and 33c are located at the four corners (corner areas) of the second sealing member 30. Through holes 33a, 33b, and 33c, through electrodes are formed along the inner wall surfaces of each through hole, enabling communication between the electrodes formed on the first main surface 301 and the second main surface 302. Through the through electrodes formed on the inner wall surfaces of the through holes 33a, 33b, and 33c, the electrode (connecting pattern) formed on the first main surface 301 is connected to the external electrode terminal 32 formed on the second main surface 302. Furthermore, the middle portion of each of the through holes 33a, 33b, and 33c forms a hollow through portion passing between the first main surface 301 and the second main surface 302.

[0041] In a crystal resonator 100 comprising a crystal oscillator 10, a first sealing member 20, and a second sealing member 30 having the above-described structure, the crystal oscillator 10 and the first sealing member 20 are diffusely bonded in a state where the first bonding pattern 121 on the oscillator side and the first bonding pattern 24 on the sealing member side overlap, and the crystal oscillator 10 and the second sealing member 30 are diffusely bonded in a state where the second bonding pattern 122 on the oscillator side and the second bonding pattern 31 on the sealing member side overlap, thereby forming a sandwich structure package as shown in FIG1. ​​Thus, the internal space of the package, i.e., the containment space of the vibrating part 11, is hermetically sealed.

[0042] At this time, the aforementioned bonding patterns also diffuse and bond together in an overlapping state. Thus, through the bonding of the bonding patterns, electrical conduction between the first excitation electrode 111, the second excitation electrode 112, and the external electrode terminal 32 can be achieved in the crystal resonator 100. Specifically, the first excitation electrode 111 is connected to the external electrode terminal 32 sequentially via the first lead wire 113, the internal wiring 19, and the through electrode of the through hole 33a; the second excitation electrode 112 is connected to the external electrode terminal 32 sequentially via the second lead wire 114, the wiring pattern 35, and the through electrode of the through hole 33b.

[0043] In the crystal resonator 100, preferably, the various bonding patterns are formed by stacking multiple layers on a quartz wafer and depositing or sputtering a Ti (titanium) layer and an Au (gold) layer from the bottommost layer side. Furthermore, preferably, other wiring or electrodes formed on the crystal resonator 100 also employ the same structure as the bonding patterns, thereby enabling the bonding patterns, wiring, and electrodes to be patterned simultaneously.

[0044] In the crystal resonator 100 having the above structure, the sealing portions (sealing paths) 15 and 16 that hermetically seal the vibrating portion 11 of the crystal oscillator 10 are configured as annular in plan view. Sealing path 15 is formed by diffusion bonding (gold-to-gold bonding) of the first bonding pattern 121 on the oscillator side and the first bonding pattern 24 on the sealing member side. The outer edge of sealing path 15 is approximately rectangular, and its outer periphery is positioned close to the outer periphery of the package. Similarly, sealing path 16 is formed by diffusion bonding (gold-to-gold bonding) of the second bonding pattern 122 on the oscillator side and the second bonding pattern 31 on the sealing member side. The outer edge of sealing path 16 is approximately rectangular, and its outer periphery is positioned close to the outer periphery of the package. Sealing paths 15 and 16 are not electrically connected to the electrical conduction path between the first excitation electrode 111, the second excitation electrode 112, and the external electrode terminal 32. Specifically, sealing path 15 is connected to sealing path 16 via internal wiring 17. Furthermore, sealing path 16 is grounded via through electrode through through hole 33c (in the grounding path, a portion of external electrode terminal 32 is utilized).

[0045] In the crystal resonator 100, where sealing paths 15 and 16 are formed through such diffusion bonding, there is a gap of less than 1.00 μm between the first sealing member 20 and the crystal oscillator 10, and a gap of less than 1.00 μm between the second sealing member 30 and the crystal oscillator 10. That is, the thickness of the sealing path 15 between the first sealing member 20 and the crystal oscillator 10 is less than 1.00 μm, and the thickness of the sealing path 16 between the second sealing member 30 and the crystal oscillator 10 is less than 1.00 μm (specifically, in the Au-Au bonding of this embodiment, it is 0.15 μm to 1.00 μm). Furthermore, as a comparative example, when using conventional Sn metal paste encapsulation materials, the thickness is 5 μm to 20 μm.

[0046] In this embodiment, the crystal oscillator 10 having the above-described structure has an inner wall surface 12g of the outer frame portion 12 configured as a rectangular ring when viewed from above; a notch 18 recessed into the outer frame portion 12 is formed at a corner 12h of the inner wall surface 12g; and an internal wiring 19 for extending an electrode on one main surface of the substrate to the other main surface is formed in the notch 18. The notch 18 has a first inner wall portion 18a and a second inner wall portion 18b provided with the internal wiring 19, wherein the first inner wall portion 18a is configured to be connected to a portion of the inner wall surface 12g in an approximately straight line and does not have internal wiring; the second inner wall portion 18b is not configured to be connected to a portion of the inner wall surface 12g in an approximately straight line. An inclined surface 18c is formed in the second inner wall portion 18b, and the angle θ1 between the inclined surface 18c and one or the other main surface of the substrate is an obtuse angle. This will be described in detail below with reference to Figures 4, 5, and 8.

[0047] As shown in Figures 4 and 5, the inner wall surface 12g of the outer frame portion 12 of the crystal oscillator 10 is configured as a rectangular ring when viewed from above, and a notch 18 recessed into the outer frame portion 12 is formed at the corner 12h (the area at the corner when viewed from above). This notch 18 is configured as approximately rectangular when viewed from above and is provided in the inner wall surface 12g of the outer frame portion 12, extending along the X-axis and located on the -Z' direction side. The notch 18 is recessed into the outer frame portion 12; in other words, the space of the notch 18 protrudes outwards into the outer frame portion 12.

[0048] The notch 18 is configured to communicate with the cut-off portion 10a of the crystal oscillator 10. The corner 12h refers to the corner of the inner wall surface 12g of the outer frame portion 12 located on the -X direction side and the -Z' direction side when the notch 18 is not formed. By providing such a notch 18, at the position of this corner 12h, the inner wall surface 12g of the outer frame portion 12 (the inner wall surface on the -X direction side) is connected to the first inner wall portion 18a (the wall portion on the -X direction side) of the notch 18 in an approximately straight line. That is, the first inner wall portion 18a is provided along the Z' end face (the end face parallel to the Z' axis direction) of the inner wall surface 12g of the outer frame portion 12. No internal wiring 19 is formed on this first inner wall portion 18a.

[0049] On the other hand, the second inner wall portion 18b (the wall portion on the -Z' direction side and the wall portion on the +X direction side) of the notch portion 18 and the inner wall surface 12g (the inner wall surface on the -Z' direction side) of the outer frame portion 12 are not formed on the same straight line. The second inner wall portion 18b is also not provided along the X end face (the end face parallel to the X-axis direction) of the inner wall surface 12g of the outer frame portion 12. On this second inner wall portion 18b, an internal wiring 19 is formed for extending the connecting joint pattern 12a formed on the first main surface 101 side of the outer frame portion 12 to the second main surface 102 side. Through this internal wiring 19, the connecting joint pattern 12a formed on the first main surface 101 side of the outer frame portion 12 is connected to the connecting joint pattern 12e formed on the second main surface 102 side of the outer frame portion 12.

[0050] Additionally, as shown in FIG8, an inclined surface 18c is formed on the second inner wall portion 18b. The angle θ1 between the inclined surface 18c and the first main surface 101 of the outer frame portion 12 is an obtuse angle, and the internal wiring 19 is formed on the inclined surface 18c. FIG8 shows the inclined surface 18c formed on the wall portion on the +X direction side of the second inner wall portion 18b, but the same inclined surface is also formed on the wall portion on the -Z' direction side of the second inner wall portion 18b. In this embodiment, the angle θ1 is approximately 120°, but preferably 105° to 150°. The inclined surface 18c extends to the middle position in the depth direction of the notch portion 18, for example, extending to near the center in the depth direction of the notch portion 18. The upper half of the second inner wall portion 18b of the notch portion 18 is the inclined surface 18c, and the lower half of the second inner wall portion 18b is the inclined surface 18d. The internal wiring 19 is continuously provided along the inclined surfaces 18c and 18d of the second inner wall portion 18b. Furthermore, the notch 18 and the inclined surfaces 18c and 18d are formed during the wet etching process that forms the cut-off portion 10a of the crystal oscillator 10. Additionally, the angle between the second main surface 102 of the outer frame portion 12 and the inclined surface 18d is also approximately 120°.

[0051] Based on this embodiment, a miniaturized crystal oscillator 10 with stable electrical characteristics can be realized. Specifically, by forming an internal wiring 19 that passes through the inclined surface 18c of the second inner wall portion 18b of the notch portion 18 provided on the inner wall surface 12g of the outer frame portion 12, the internal wiring 19 can be led out in the portion of the inner wall surface with a gentle obtuse angle, thereby achieving a structure in which the internal wiring 19 is not easily broken. In addition, by configuring the first inner wall portion 18a of the notch portion 18 to be connected in an approximately straight line to a part of the edge (the edge parallel to the Z' axis direction) of the inner wall surface 12g of the outer frame portion 12, no edge or step appears at the junction of the first inner wall portion 18a and the inner wall surface 12g, thereby forming a stable notch portion 18 that is not easily affected by etching depressions caused by anisotropic wet etching. Meanwhile, the notch 18 is provided at the widest corner 12h of the outer frame 12 (viewed from above), and is recessed into the outer frame 12, thus ensuring the effective area of ​​the vibrating section 11 and achieving a miniaturized and electrically stable crystal resonator 10. Furthermore, since the internal wiring 19 is not exposed on the outer surface (outer side and edges) of the package of the crystal resonator 100 using this crystal resonator 10, it is possible to prevent the internal wiring 19 from breaking or being worn due to contact during assembly or transportation.

[0052] In this embodiment, the first inner wall portion 18a is provided along the Z' end face (the end face parallel to the Z' axis direction) of the inner wall surface 12g of the outer frame portion 12. As a result, the inner wall surface 12g of the outer frame portion 12 has a structure on the side of the first main surface 101 (the surface on the +Y' direction side) that does not have corners protruding to the +Z' direction side and the +X direction side, thereby preventing etching depressions caused by corners and making it easy to form an obtuse angled inclined surface that is not prone to breakage.

[0053] In this embodiment, only one retaining portion 13 is provided, and the retaining portion 13 is positioned in the X-axis direction, close to the inner wall surface 12g facing the inner wall surface 12g of the first inner wall portion 18a where the notch portion 18 is formed, when viewed from above. This prevents a decrease in the bonding strength of the connection between the retaining portion 13 and the outer frame portion 12, thus preventing breakage of the retaining portion 13. Simultaneously, wiring for electrode extension can be stably and as short as possible formed along the inner wall surface 12g perpendicular to the inner wall surface 12g of the first inner wall portion 18a where the notch portion 18 is formed. Furthermore, since only one retaining portion 13 is provided, the effects of vibration leakage can be suppressed.

[0054] Furthermore, when viewed from above, the outer frame 12 has a shape with a pair of long sides and a pair of short sides, and the width of each short side is greater than the width of each long side. A notch 18 is provided in the region of the wider short side. The pair of short sides of the outer frame 12 are parallel to the X-axis, and the pair of long sides of the outer frame 12 are parallel to the Z'-axis. The width of each short side in the Z'-axis direction is greater than the width of each long side in the X-axis direction. Therefore, by providing the notch 18 in the region of the wider short side, the effective area of ​​the vibrating section 11 can be ensured, achieving a miniaturized crystal oscillator 10 with stable electrical characteristics.

[0055] The crystal resonator 100 equipped with the aforementioned crystal oscillator 10 achieves the same technical effects as the crystal oscillator 10. Furthermore, since the internal wiring 19 is not exposed on the outer surface of the crystal resonator 100's package, it is possible to prevent the internal wiring 19 from breaking or being worn due to contact during assembly and transportation. Therefore, an ideal structure corresponding to a miniaturized crystal resonator 100 can be realized.

[0056] In this embodiment, when viewed from above, a portion of the notch 18 overlaps with the wiring pattern (here, the connection joint pattern 22a) formed on the second main surface 202 of the first sealing member 20. Therefore, even if there is a slight deviation in the joint position where the connection joint pattern 22a of the second main surface 202 of the first sealing member 20 joins the connection joint pattern 12a of the first main surface 101 of the crystal oscillator 10, stable wiring can be achieved using the internal wiring 19.

[0057] In this embodiment, an external electrode terminal 32 is formed on the second main surface 302 of the second sealing member 30, and through holes 33a, 33b, and 33c are formed for connecting the external electrode terminal 32 to electrodes (here, connecting patterns 34a, 34b, and 34c) formed on the main surface on its opposite side. The through holes 33a, 33b, and 33c are positioned so as not to overlap with the notch 18 and the retaining portion 13 when viewed from above. As a result, the width of the outer frame portion 12 is not narrowed, and a sealing pattern can be stably formed on the outer frame portion 12 without reducing the area, thereby helping to improve the stability of the hermetic seal of the oscillating portion 11 in the crystal resonator 100.

[0058] The embodiments disclosed herein are examples of all aspects and do not constitute a basis for limiting interpretation. Therefore, the technical scope of this invention should not be interpreted solely by the above embodiments, but should be defined based on the description in the claims. Furthermore, all technical modifications with the same meaning and scope as the claims are included within the protection scope of this invention.

[0059] In the above embodiment, the top view shape of the notch 18 is approximately rectangular, but it is not limited to this. The shape of the notch 18 can also be V-shaped, trapezoidal, arc-shaped, elliptical arc-shaped or other shapes.

[0060] Furthermore, in the above embodiment, only one notch 18 and one internal wiring 19 are provided, but it is not limited to this; a structure with multiple notches 18 and multiple internal wirings 19 can also be adopted. In addition, in the above embodiment, the holding portion 13 extends to the outer frame portion 12 in the -Z' direction, and the notch 18 and internal wiring 19 are provided on the end face of the inner wall surface 12g of the outer frame portion 12 in the -Z' direction side, thereby allowing the electrode extending from the vibrating portion 11 via the holding portion 13 to be configured as short as possible. Meanwhile, in the above embodiment, the internal wiring 19 is formed only in the second inner wall portion 18b of the notch 18, while no internal wiring is formed in the first inner wall portion 18a of the notch 18; however, internal wiring can also be formed in the first inner wall portion 18a. However, by not forming internal wiring in the first inner wall portion 18a of the notch 18 as in the above embodiment, short circuits with the first bonding pattern 121 on the vibrating plate side and the second bonding pattern 122 on the vibrating plate side can be prevented, and stable wiring is also facilitated.

[0061] Alternatively, the aforementioned internal grounding wiring 17 can be provided in the short side region of the outer frame portion 12 of the crystal oscillator 10. In this case, it is preferable to provide a notch and an inclined surface with the same structure as in the above embodiment in the short side region of the outer frame portion 12, and to form the internal grounding wiring 17 on the inclined surface. For example, as shown in the modified examples of Figures 9 and 10, a notch 18 with the same structure as in the above embodiment is provided at the end of the Z' end face (the end face parallel to the Z' axis direction) of the inner wall surface 12g of the outer frame portion 12 in the -Z' direction, and an internal wiring 19 is formed. Based on this, a notch 17a is formed at the end of the Z' end face of the inner wall surface 12g of the outer frame portion 12 in the +Z' direction, and an internal grounding wiring 17 is formed.

[0062] The structure of the notch 17a is substantially the same as that of the notch 18 described above. Its top view shape is approximately rectangular, and it is located on the inner wall surface 12g of the outer frame portion 12, extending along the X-axis direction, specifically on the inner wall surface on the +Z' direction side. The notch 17a is recessed into the outer frame portion 12 and is configured to communicate with the cut-off portion 10a of the crystal oscillator 10. By providing such a notch 17a, the inner wall surface 12g (inner wall surface on the -X direction side) of the outer frame portion 12 is connected to the first inner wall portion 17b (wall portion on the -X direction side) of the notch 17a in an approximately straight line.

[0063] On the other hand, the second inner wall portion 17c (the wall portion on the +Z' direction side and the wall portion on the +X direction side) of the notch portion 17a and the inner wall surface 12g (the inner wall surface on the +Z' direction side) of the outer frame portion 12 are not connected in a straight line. The second inner wall portion 17c is also not provided along the X end face (the end face parallel to the X-axis direction) of the inner wall surface 12g of the outer frame portion 12. As a result, the inner wall surface 12g of the outer frame portion 12 does not have corners protruding to the -Z' direction side and the +X direction side on the second main surface 102 side (the surface on the -Y' direction side), thereby preventing the formation of etching depressions caused by corners.

[0064] On the second inner wall portion 17c, an internal wiring 17 is formed for extending the first bonding pattern 121 on the vibrating plate side formed on the first main surface 101 side of the outer frame portion 12 to the second main surface 102 side. Through this internal wiring 17, the first bonding pattern 121 on the vibrating plate side formed on the first main surface 101 side of the outer frame portion 12 connects with the second bonding pattern 122 on the second main surface 102 side of the outer frame portion 12. Additionally, although not shown, similar to the embodiment described above, an inclined surface with an obtuse angle between it and the second main surface 102 of the outer frame portion 12 is also formed on the second inner wall portion 17c (see FIG. 8), and the internal wiring 17 is formed on this inclined surface.

[0065] In addition to the notch 18 and internal wiring 19 described above, a through hole can be formed on the outer frame portion 12 of the crystal oscillator 10, and a through electrode can be formed in the through hole to enable conduction between the electrodes formed on the first main surface 101 and the second main surface 102. In this case, it is preferable to place the through hole near the center of the outer frame portion 12 and away from the holding portion 13 and the notch 18. For example, it is preferable to place the through hole near the center of the short side on the +Z' direction side of the outer frame portion 12.

[0066] In the above embodiment, the crystal oscillator 10 has only one holding portion 13 connecting the vibrating part 11 and the outer frame portion 12, and the cut portion 10a is configured to continuously surround the outer periphery of the vibrating part 11. However, as long as the cut portion 10a is provided between the vibrating part 11 and the outer frame portion 12, various modifications can be made to the structure of the crystal oscillator 10. For example, a structure with two or more holding portions 13 connecting the vibrating part 11 and the outer frame portion 12 can also be used. In addition, the holding portion 13 can also extend from the area other than the corner of the vibrating part 11 toward the outer frame portion 12.

[0067] In the above embodiment, an AT-cut quartz crystal oscillator 10 is used as the crystal oscillator 10, but other types of crystal oscillators (such as SC-cut quartz crystal oscillators, Z-cut quartz crystals, etc.) can also be used. Furthermore, in the above embodiment, an approximately rectangular crystal oscillator 10 is used as the crystal oscillator 10, but it is not limited to this; for example, a tuning fork-type crystal oscillator can also be used. Additionally, in the above embodiment, a through-hole is used to achieve electrical conduction with the external electrode terminal 32, but it is not limited to this; a castellan or similar structure can also be used to achieve electrical conduction with the external electrode terminal 32.

[0068] In the above embodiment, the number of external electrode terminals 32 on the second main surface 302 of the second sealing member 30 is four, but it is not limited to this; the number of external electrode terminals 32 may be, for example, two, six, or eight. Here, the application of the present invention to a crystal resonator 100 has been described, but it is not limited thereto; the present invention is also applicable to piezoelectric oscillators, such as crystal oscillators. In the case of a crystal oscillator, a structure can be adopted in which the wiring electrodes connected to the integrated circuit mounted on the crystal resonator are connected to the internal wiring 19.

[0069] In the above embodiments, both the first sealing member 20 and the second sealing member 30 are made of quartz wafers, but are not limited thereto. The first sealing member 20 and the second sealing member 30 may also be made of, for example, glass or resin.

[0070] Furthermore, while the above embodiments describe a piezoelectric vibrating device with a three-layer structure in which the crystal vibrator is sandwiched between a first sealing member and a second sealing member, the invention is not limited thereto. The invention is also applicable to piezoelectric vibrating devices with a structure in which the crystal vibrator is mounted inside a base made of ceramic or the like. Additionally, the invention is also applicable to double-sealed structures in which a three-layer piezoelectric vibrating device is housed within a package made of ceramic or the like.

[0071] This application claims priority based on Japanese Patent Application No. 2023-183390 filed on October 25, 2023, the entire contents of which are incorporated herein by reference.

[0072] <Explanation of Figure Labels> 10 Crystal Vibrating Plate 10a Resection section 11. Vibrating section 12 Outer frame 12g inner wall surface 12h corner 13. Holding section 18. Notch 18a First inner wall section 18b Second inner wall section 18c inclined surface 19 Internal wiring 100 Crystal Resonator 111 First excitation electrode 112 Second excitation electrode

Claims

1. A piezoelectric vibrating sheet, wherein electrodes are formed on one main surface and another main surface of a substrate, characterized in that: It includes a vibrating part, an outer frame part surrounding the outer periphery of the vibrating part, and a holding part connecting a portion of the vibrating part to a portion of the outer frame part. Between the vibrating part and the outer frame part, there is a cut-out part formed by hollowing out the substrate. The inner wall of the outer frame is configured as a rectangular ring when viewed from above, and a notch is formed in the corner area of ​​the inner wall when viewed from above, which is recessed into the side of the outer frame. In the notch, an internal wiring is formed that extends the electrode formed on one main surface to the other main surface side; The notch has a first inner wall portion that is configured to be connected to a portion of the inner wall surface in an approximately straight line, and a second inner wall portion on which the internal wiring is formed. The second inner wall portion is not configured to be connected to a portion of the inner wall surface in an approximately straight line. An inclined surface is formed on the second inner wall portion, and the angle between the inclined surface and one main surface or the other main surface of the substrate is an obtuse angle.

2. The piezoelectric vibrating sheet as described in claim 1, characterized in that: The piezoelectric vibrator is an AT-cut quartz wafer, and the first inner wall portion is disposed along the Z' end face of the inner wall surface of the outer frame portion.

3. The piezoelectric vibrating sheet as described in claim 1, characterized in that: Only one retaining portion is provided, and the retaining portion is formed on the inner wall surface near the side facing the inner wall surface on which the first inner wall portion is formed.

4. The piezoelectric vibration device as described in claim 1, characterized in that: The outer frame portion, viewed from above, has a shape with a long side and a short side, and the width of the short side is greater than the width of the long side. The notch portion is formed in the area of ​​the wider short side.

5. A piezoelectric vibration device comprising the piezoelectric vibrating plate according to any one of claims 1 to 4, characterized in that: The device is provided with a first sealing member covering one main surface side of the piezoelectric vibrating sheet and a second sealing member covering the other main surface side of the piezoelectric vibrating sheet; The first sealing member engages with the piezoelectric vibrating plate, and the second sealing member engages with the piezoelectric vibrating plate, thereby sealing the vibrating part of the piezoelectric vibrating plate in an airtight manner.

6. The piezoelectric vibration device as described in claim 5, characterized in that: When viewed from above, a portion of the notch overlaps with the wiring pattern formed on the first sealing member.

7. The piezoelectric vibration device as described in claim 5, characterized in that: An external terminal is formed on the second sealing member, and a through hole is formed to connect the external terminal to an electrode formed on its opposite side. The through hole is positioned so as not to overlap with the notch and the retaining portion when viewed from above.

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