Piezoelectric vibration device

Abstract

Provided is a crystal vibrator 100, wherein: a protrusion 21 is formed on a first main surface 201 of a first seal member 20; and the protrusion 21 is formed at a position that, in plan view, overlaps with an upper-surface-side seal part of a first main surface 101 of a crystal diaphragm 10, a lower-surface-side seal part of a second main surface 102 of the crystal diaphragm 10; a first seal member-side seal part of a second main surface 202 of the first seal member 20, and a second seal member-side seal part of a first main surface 301 of a second seal member 30, and that, in plan view, does not overlap with first and second excitation electrodes 111, 112 of a vibration part 11 of the crystal diaphragm 10.

Description

Piezoelectric vibration device

[0001] The present invention relates to a piezoelectric vibration device.

[0002] In recent years, the operating frequencies of various electronic devices have been increasing, and the packages have been miniaturized (especially made thinner). Therefore, along with the increase in frequency and miniaturization of the package, piezoelectric vibration devices (such as crystal resonators, crystal oscillators, etc.) are also required to cope with the increase in frequency and miniaturization of the package.

[0003] As a piezoelectric vibration device suitable for miniaturization and thinning, a so-called sandwich-structured piezoelectric vibration device is known. The housing of the sandwich-structured piezoelectric vibration device is composed of a package having a substantially rectangular parallelepiped shape. This package is composed of, for example, a first sealing member and a second sealing member made of glass or crystal, and a crystal vibration plate having excitation electrodes formed on both main surfaces. The first sealing member and the second sealing member are laminated and joined via the crystal vibration plate. And the vibrating portion of the crystal vibration plate arranged inside the package (internal space) is hermetically sealed by the first sealing member and the second sealing member (see, for example, Patent Document 1).

[0004] Japanese Unexamined Patent Application Publication No. 2020-123906

[0005] In the above-described piezoelectric vibration device, the vibrating portion of the piezoelectric vibration plate is hermetically sealed by an annular sealing portion (seal path). The annular sealing portion is formed by joining annular metal films provided on the piezoelectric vibration plate, the first sealing member, and the second sealing member to each other. In this case, by applying a pressing force (pressurizing force) in the vertical direction to perform the joining, it is possible to firmly join the annular metal films, but it is required to pressurize the annular metal films as uniformly as possible to surely ensure the airtightness of the vibrating portion of the piezoelectric vibration plate.

[0006] Here, a plurality of electrical wiring paths are provided around the annular sealing portion, and these wiring paths are also formed by joining metal films provided on the piezoelectric vibration plate, the first sealing member, and the second sealing member to each other. Therefore, in order to ensure the airtightness of the vibrating portion of the piezoelectric vibration plate, it is necessary to consider not only the annular sealing portion but also the arrangement of the electrical wiring paths.

[0007] This invention has been made in consideration of the circumstances described above, and aims to provide a piezoelectric vibration device that can more reliably and sufficiently hermetically seal the vibrating portion of a piezoelectric diaphragm with an annular sealing portion.

[0008] The present invention provides the following means for solving the above-mentioned problems. That is, the present invention comprises a piezoelectric diaphragm having a vibrating part on which a first excitation electrode and a second excitation electrode are formed, and an outer frame part surrounding the vibrating part, and having an annular upper side sealing part and a lower side sealing part formed of a metal film on the outer periphery of both the upper and lower main surfaces of the outer frame part, a first sealing member that covers the upper surface of the piezoelectric diaphragm and has an annular first sealing member side sealing part formed of a metal film on the outer periphery of the lower surface, and a second sealing member that covers the lower surface of the piezoelectric diaphragm and has a plurality of external terminals formed on the lower surface and an annular second sealing member side sealing part formed of a metal film on the outer periphery of the upper surface, and the front of the first sealing member In a piezoelectric vibration device in which the vibrating portion of the piezoelectric diaphragm is hermetically sealed by joining the sealing portion on the first sealing member side and the sealing portion on the upper surface side of the piezoelectric diaphragm, and joining the sealing portion on the second sealing member side of the second sealing member and the sealing portion on the lower surface side of the piezoelectric diaphragm, a projection is formed on the upper surface of the first sealing member at a position that overlaps with the sealing portion on the upper surface side, the sealing portion on the lower side, the sealing portion on the first sealing member side, and the sealing portion on the second sealing member side in a plan view, but does not overlap with the first and second excitation electrodes in a plan view.

[0009] With the above configuration, the projection of the first sealing member, the upper sealing portion, the lower sealing portion, the sealing portion on the first sealing member side, and the sealing portion on the second sealing member side overlap in a plan view. Therefore, when manufacturing a piezoelectric vibration device package by pressure diffusion bonding or the like, a substantially uniform pressing force can be sufficiently transmitted to the substrate (first sealing member, piezoelectric diaphragm, second sealing member) in the overlapping portions in a plan view (upper sealing portion, lower sealing portion, sealing portion on the first sealing member side, sealing portion on the second sealing member side) without causing tilting or bending. As a result, the overlapping portions in a plan view can be pressed as uniformly as possible, and the vibrating portion can be sufficiently hermetically sealed by the annular sealing portion.

[0010] In the piezoelectric vibration device with the above configuration, it is preferable that the vibrating portion is formed in a rectangular shape in plan view and the protrusion is formed in an annular shape. With this configuration, when manufacturing the package of the piezoelectric vibration device by pressure diffusion bonding or the like, the upper sealing portion, lower sealing portion, first sealing member side sealing portion, and second sealing member side sealing portion that overlap with the protrusion in plan view can be pressed as uniformly as possible around the entire circumference, and the hermetically sealed vibrating portion by the annular sealing portion can be reliably and sufficiently achieved.

[0011] In the piezoelectric vibration device with the above configuration, it is preferable that the first sealing member's wiring portion is formed of a metal film on the inner circumference of the upper sealing portion of the piezoelectric diaphragm, the lower sealing portion is formed of a metal film on the inner circumference of the lower sealing portion of the piezoelectric diaphragm, the first sealing member's wiring portion is formed of a metal film on the inner circumference of the first sealing member's sealing portion of the lower sealing portion of the first sealing member, the second sealing member's wiring portion is formed of a metal film on the inner circumference of the second sealing member's sealing portion of the upper sealing portion of the second sealing member, the first sealing member's wiring portion of the first sealing member and the upper sealing portion of the piezoelectric diaphragm are joined together, and the second sealing member's wiring portion of the second sealing member and the lower sealing portion of the piezoelectric diaphragm are joined together. In this case, it is preferable that the protrusions overlap the upper wiring portion, the lower wiring portion, the first sealing member side wiring portion, and the second sealing member side wiring portion in a plan view. With these configurations, when manufacturing a piezoelectric vibration device package by pressure diffusion bonding or the like, the upper wiring portion, lower wiring portion, first sealing member side wiring portion, and second sealing member side wiring portion that overlap the protrusions in a plan view can be pressed as uniformly as possible, and the joining of the wiring portions that constitute the electrical wiring paths inside the package can be reliably achieved. In particular, in the overlapping portions in a plan view (upper wiring portion, lower wiring portion, first sealing member side wiring portion, and second sealing member side wiring portion), a substantially uniform pressing force can be sufficiently transmitted to the substrate (first sealing member, piezoelectric diaphragm, second sealing member) without causing tilting or bending. As a result, the overlapping portions in a plan view can be pressed as uniformly as possible, and the joining of the wiring portions can be reliably achieved.

[0012] A piezoelectric vibration device having the above configuration, wherein the second sealing member has a plurality of through-holes formed in the region of the wiring portion on the second sealing member side, penetrating the second sealing member in the thickness direction, and the projections are provided so as to overlap, in a plan view, the portion of the wiring portion on the second sealing member side surrounding each through-hole and the wiring portion on the lower surface side. With this configuration, the connection between the wiring portion on the second sealing member side surrounding each through-hole and the wiring portion on the lower surface side can be reliably made, and the portion around each through-hole can be sealed more reliably, thereby suppressing airtightness defects caused by the provision of each through-hole.

[0013] In the piezoelectric vibration device with the above configuration, it is preferable that the upper sealing portion, the lower sealing portion, the first sealing member side sealing portion, and the second sealing member side sealing portion are located within the area of ​​the projection in a plan view. With this configuration, since the upper sealing portion, the lower sealing portion, the first sealing member side sealing portion, and the second sealing member side sealing portion are located within the area of ​​the projection in a plan view, the entire surfaces of the upper sealing portion, the lower sealing portion, the first sealing member side sealing portion, and the second sealing member side sealing portion are pressurized by the projection, allowing for a more uniform and sufficient transmission of pressure.

[0014] A piezoelectric vibration device having the above configuration, characterized in that the upper wiring section, the lower wiring section, the first sealing member side wiring section, and the second sealing member side wiring section are provided within the area of ​​the projection in a plan view. With this configuration, since the upper wiring section, the lower wiring section, the first sealing member side wiring section, and the second sealing member side wiring section are provided within the area of ​​the projection in a plan view, the entire surface of the upper wiring section, the lower wiring section, the first sealing member side wiring section, and the second sealing member side wiring section is pressurized by the projection, allowing for a more uniform and sufficient transmission of pressure.

[0015] In the piezoelectric vibration device with the above configuration, it is preferable that the plurality of external terminals are arranged in the corner region of the lower surface of the second sealing member, and that the protrusions are provided so as to overlap each external terminal substantially uniformly in a plan view. With this configuration, the overlapping portion between each external terminal and the protrusion is also made uniform, which allows for even more uniform transmission of applied pressure, and ensures that the vibrating part is reliably and sufficiently airtightly sealed by the annular sealing portion.

[0016] In the piezoelectric vibration device with the above configuration, it is preferable that the piezoelectric diaphragm comprises a holding portion connecting the outer peripheral wall of the vibrating portion and the inner peripheral wall of the outer frame portion, and a cutout portion provided between the vibrating portion and the outer frame portion and formed by cutting out the piezoelectric diaphragm in the thickness direction. With this configuration, stress and other forces associated with the pressure applied during pressure diffusion bonding are not directly transmitted to the vibrating portion, so that fluctuations in the characteristics of the vibrating portion are less likely to occur before and after pressure diffusion bonding, and the electrical characteristics of the quartz diaphragm can be stabilized.

[0017] In the piezoelectric vibration device with the above configuration, it is preferable that the protrusions are formed of a metal film. With this configuration, since the protrusions are formed of a metal film, the protrusions can be easily formed on the upper surface of the first sealing member by thin-film technology or the like. In this case, it is preferable that the protrusions are formed of the same metal material as the upper sealing portion, the lower sealing portion, the first sealing member side sealing portion, and the second sealing member side sealing portion. This not only improves the productivity of the piezoelectric vibration device, but also makes the film stress similar because the piezoelectric diaphragm and the metal films formed on the first sealing member and the second sealing member are the same, thereby reducing the effects of warping of the quartz diaphragm and the first and second sealing members.

[0018] In the piezoelectric vibration device with the above configuration, it is preferable that the width of the portion of the inner circumferential wall of the outer frame of the piezoelectric diaphragm that is parallel to the short side of the piezoelectric diaphragm is greater than the width of the portion parallel to the long side of the piezoelectric diaphragm. With this configuration, a relatively large area can be secured at both ends of the outer frame of the piezoelectric diaphragm in the long side direction, and wiring paths can be easily and effectively formed with a metal film or the like. Furthermore, even if through holes or notches are formed at both ends of the outer frame of the piezoelectric diaphragm in the long side direction, the strength of the outer frame can be maintained, thus mitigating the congestion of wiring paths that occurs with miniaturization due to through holes or notches.

[0019] According to the piezoelectric vibration device of the present invention, when manufacturing the package of the piezoelectric vibration device, the overlapping portions in a plan view can be pressed more uniformly, and the hermetically sealed portion of the piezoelectric diaphragm by the annular sealing portion can be performed more reliably and sufficiently.

[0020] Figure 1 is a schematic diagram illustrating the configuration of a quartz crystal oscillator according to this embodiment. Figure 2 is a schematic plan view of the first main surface side of the first sealing member of the quartz crystal oscillator. Figure 3 is a schematic plan view of the second main surface side of the first sealing member of the quartz crystal oscillator. Figure 4 is a schematic plan view of the first main surface side of the quartz crystal diaphragm of the quartz crystal oscillator. Figure 5 is a schematic plan view of the second main surface side of the quartz crystal diaphragm of the quartz crystal oscillator. Figure 6 is a schematic plan view of the first main surface side of the second sealing member of the quartz crystal oscillator. Figure 7 is a schematic plan view of the second main surface side of the second sealing member of the quartz crystal oscillator. Figure 8 is a diagram corresponding to Figure 1 of a quartz crystal oscillator according to another embodiment 1. Figure 9 is a diagram corresponding to Figure 1 of a quartz crystal oscillator according to another embodiment 2. Figure 10 is a diagram corresponding to Figure 1 of a quartz crystal oscillator according to another embodiment 3. Figure 11 is a diagram corresponding to Figure 1 of a quartz crystal oscillator according to another embodiment 4. Figure 12 is a diagram corresponding to Figure 4 of the quartz crystal diaphragm of a quartz crystal oscillator according to another embodiment 5. Figure 13 is a diagram corresponding to Figure 5 of the quartz crystal diaphragm of a quartz crystal oscillator according to another embodiment 5.

[0021] Embodiments of the present invention will be described in detail below with reference to the drawings. In the following embodiments, the case in which the piezoelectric vibration device to which the present invention is applied is a quartz crystal oscillator will be described.

[0022] First, the basic structure of the crystal oscillator 100 according to this embodiment will be described. As shown in Figure 1, the crystal oscillator 100 is composed of a crystal diaphragm (piezoelectric diaphragm) 10, a first sealing member 20, and a second sealing member 30. In this crystal oscillator 100, the crystal diaphragm 10 and the first sealing member 20 are joined together, and the crystal diaphragm 10 and the second sealing member 30 are joined together to form a roughly rectangular sandwich-structure package. That is, in the crystal oscillator 100, the first sealing member 20 and the second sealing member 30 are joined to each of the two main surfaces of the crystal diaphragm 10 to form an internal space (cavity) of the package, and the vibrating part 11 (see Figures 4 and 5) is hermetically sealed in this internal space.

[0023] The crystal oscillator 100 in this embodiment has a package size of, for example, 1.0 × 0.8 mm, achieving miniaturization and a low profile. Furthermore, the crystal oscillator 100 is electrically connected to an external circuit board (not shown) via solder.

[0024] Next, the crystal diaphragm 10, the first sealing member 20, and the second sealing member 30 of the crystal oscillator 100 described above will be explained with reference to Figures 1 to 7. Here, we will explain each component as a separate unit that is not joined together. Figures 2 to 7 merely show one example configuration of the crystal diaphragm 10, the first sealing member 20, and the second sealing member 30, and these do not limit the present invention.

[0025] As shown in Figures 4 and 5, the quartz diaphragm 10 is a piezoelectric substrate made of quartz, and both of its upper and lower main surfaces (first main surface 101, second main surface 102) are formed as flat, smooth surfaces (mirror finish). In this embodiment, an AT-cut quartz plate that performs thickness-sliding vibration is used as the quartz diaphragm 10. In the quartz diaphragm 10 shown in Figures 4 and 5, both main surfaces 101 and 102 of the quartz diaphragm 10 are considered to be the XZ' plane. In this XZ' plane, the direction parallel to the short side of the quartz diaphragm 10 is considered to be the X-axis direction, and the direction parallel to the long side of the quartz diaphragm 10 is considered to be the Z' axis direction. Note that AT cutting is a processing method in which artificial quartz is cut at an angle of 35°15′ inclined around the X-axis with respect to the Z-axis, which is one of the three crystal axes of artificial quartz: the electrical axis (X-axis), the mechanical axis (Y-axis), and the optical axis (Z-axis). In an AT-cut quartz plate, the X-axis coincides with the crystal axis of the quartz. The Y' and Z' axes coincide with axes that are approximately 35°15′ inclined from the Y and Z axes of the quartz crystal axis, respectively (this cutting angle may be slightly modified within the range of adjusting the frequency-temperature characteristics of the AT-cut quartz diaphragm). The Y' and Z' axis directions correspond to the cutting direction when cutting the AT-cut quartz plate.

[0026] A pair of excitation electrodes (first excitation electrode 111, second excitation electrode 112) are formed on both main surfaces 101 and 102 of the quartz crystal diaphragm 10. The quartz crystal diaphragm 10 has a vibrating portion 11 formed in a substantially rectangular shape, an outer frame portion 12 surrounding the outer circumference of the vibrating portion 11, and a holding portion 13 that holds the vibrating portion 11 by connecting the vibrating portion 11 and the outer frame portion 12. In other words, the quartz crystal diaphragm 10 has a configuration in which the vibrating portion 11, the outer frame portion 12, and the holding portion 13 are integrally provided. The holding portion 13 extends (projects) from only one corner of the vibrating portion 11 located in the +X direction and the -Z' direction to the outer frame portion 12 in the -Z' direction. A cutout portion 10a formed by cutting out the quartz crystal diaphragm 10 is provided between the vibrating portion 11 and the outer frame portion 12. In this embodiment, the crystal diaphragm 10 is provided with only one holding portion 13 that connects the vibrating portion 11 and the outer frame portion 12, and the cutout portion 10a is continuously formed to surround the outer circumference of the vibrating portion 11. In this embodiment, the outer frame portion 12 of the crystal diaphragm 10 is not provided with through holes or castellations. The crystal diaphragm 10 is configured not to have any through-holes other than the cutout portion 10a.

[0027] The first excitation electrode 111 is provided on the first main surface 101 side (upper surface side) of the vibrating section 11, and the second excitation electrode 112 is provided on the second main surface 102 side (lower surface side) of the vibrating section 11. Lead-out wiring (lead-out electrodes) for connecting these excitation electrodes to external electrode terminals is connected to the first excitation electrode 111 and the second excitation electrode 112. The first lead-out wiring 113 is led out from the first excitation electrode 111, and via the holding section 13, is connected to a connection joint pattern (upper surface wiring section) 12a formed on the first main surface 101 side of the outer frame section 12. Furthermore, the connection joint pattern 12a is connected via internal wiring 12g formed on the inner wall surface of the outer frame section 12 to a connection joint pattern (lower surface wiring section) 12e formed on the second main surface 102 side of the outer frame section 12. The internal wiring 12g is located on the inner wall surface of the outer frame portion 12, specifically on the inner wall surface aligned with the X-axis direction, and on the inner wall surface in the -Z' direction. The second lead-out wiring 114 is led out from the second excitation electrode 112 and connected via the holding portion 13 to the connecting joint pattern (lower side wiring portion) 12d formed on the second main surface 102 side of the outer frame portion 12.

[0028] Furthermore, connection joining patterns (upper wiring section) 12b and 12c are formed on the first main surface 101 side of the outer frame portion 12, and a connection joining pattern (lower wiring section) 12f is formed on the second main surface 102 side of the outer frame portion 12. The connection joining patterns 12a, 12b, and 12c are provided on the first main surface 101 side of the outer frame portion 12 around the outer peripheral edge of the cutout portion 10a, that is, around the inner peripheral edge of the outer frame portion 12. The connection joining patterns 12d, 12e, and 12f are provided on the second main surface 102 side of the outer frame portion 12 around the outer peripheral edge of the cutout portion 10a, that is, around the inner peripheral edge of the outer frame portion 12. The connection joining patterns 12a and 12e are formed in a vertically elongated shape that extends in the X-axis direction along the outer peripheral edge on the -Z' direction side of the cutout portion 10a.

[0029] Both main surfaces (first main surface 101 and second main surface 102) of the crystal diaphragm 10 are provided with diaphragm-side sealing portions for joining the crystal diaphragm 10 to the first sealing member 20 and the second sealing member 30. A diaphragm-side first joining pattern (upper sealing portion) 121 is formed as the diaphragm-side sealing portion of the first main surface 101, and a diaphragm-side second joining pattern (lower sealing portion) 122 is formed as the diaphragm-side sealing portion of the second main surface 102. The diaphragm-side first joining pattern 121 and the diaphragm-side second joining pattern 122 are provided on the outer frame portion 12 and are formed in an annular shape in plan view. The outer edge of the diaphragm-side first joining pattern 121 is provided close to the outer edge of the first main surface 101 of the crystal diaphragm 10 (outer frame portion 12). The outer edge of the diaphragm-side second bonding pattern 122 is provided close to the outer edge of the second main surface 102 of the crystal diaphragm 10 (outer frame portion 12). In this embodiment, the diaphragm-side first bonding pattern 121 and the diaphragm-side second bonding pattern 122 are connected via internal wiring 17 formed on the inner wall surface of the outer frame portion 12. The internal wiring 17 is provided on the inner wall surface of the outer frame portion 12 that is aligned with the Z' axis direction and on the -X direction side, and is provided on an inner wall surface perpendicular to the inner wall surface on which the aforementioned internal wiring 12g is provided.

[0030] The diaphragm-side first bonding pattern 121 is provided on the outer periphery of the aforementioned connecting bonding patterns 12a, 12b, and 12c, and is provided at a predetermined distance from the connecting bonding patterns 12a, 12b, and 12c. The diaphragm-side second bonding pattern 122 is provided on the outer periphery of the aforementioned connecting bonding patterns 12d, 12e, and 12f, and is provided at a predetermined distance from the connecting bonding patterns 12d, 12e, and 12f. In this embodiment, the annular diaphragm-side first bonding pattern 121 and the connecting bonding patterns 12a, 12b, and 12c of the first main surface 101 of the crystal diaphragm 10 are provided as a first annular metal film portion formed on the outer frame portion 12. The annular diaphragm-side second bonding pattern 122 and the connecting bonding patterns 12d, 12e, and 12f of the second main surface 102 of the crystal diaphragm 10 are provided as a second annular metal film portion formed on the outer frame portion 12. The first annular metal film portion is a metal film that forms a seal path 15a and joints 15b and 15c by joining it with the third annular metal film portion of the first sealing member 20. The second annular metal film portion is a metal film that forms a seal path 16a and joints 16b and 16c by joining it with the fourth annular metal film portion of the second sealing member 30.

[0031] As shown in Figures 2 and 3, the first sealing member 20 is a rectangular substrate formed from a single AT-cut quartz plate, and the second main surface 202 (the surface that joins to the quartz diaphragm 10), which is the lower surface of the first sealing member 20, is formed as a flat, smooth surface (mirror finish). Although the first sealing member 20 does not have a vibrating part, by using an AT-cut quartz plate similar to the quartz diaphragm 10, the thermal expansion coefficients of the quartz diaphragm 10 and the first sealing member 20 can be made the same, thereby suppressing thermal deformation in the quartz resonator 100. In addition, the orientation of the X, Y, and Z' axes of the first sealing member 20 is the same as that of the quartz diaphragm 10. In this embodiment, since the first sealing member 20 does not have through holes or castellations, the manufacturing process of the first sealing member 20 can be significantly shortened. Furthermore, by eliminating the path for moisture to enter the internal space of the package in the first sealing member 20, corrosion resistance can be improved.

[0032] A first sealing member side first bonding pattern (first sealing member side sealing portion) 24 is formed on the second main surface 202 of the first sealing member 20, serving as a first sealing portion on the sealing member side for bonding to the crystal diaphragm 10. The first sealing member side first bonding pattern 24 is formed in an annular shape in plan view. The outer edge of the first sealing member side first bonding pattern 24 is provided close to the outer edge of the second main surface 202 of the first sealing member 20. In addition, connecting bonding patterns (first sealing member side wiring portions) 22a, 22b, and 22c are formed on the second main surface 202 of the first sealing member 20 for bonding to connecting bonding patterns 12a, 12b, and 12c formed on the first main surface 101 of the outer frame portion 12 of the crystal diaphragm 10. The connecting bonding patterns 22a, 22b, and 22c are provided around the outer peripheral edge of the cutout portion 10a of the crystal diaphragm 10, that is, around the inner peripheral edge of the outer frame portion 12, when bonded to the crystal diaphragm 10 as described above. The connecting bonding pattern 22a is provided on the -Z' side and is formed in a vertically elongated shape extending in the X-axis direction. The sealing member side first bonding pattern 24 is provided on the outer peripheral side of the connecting bonding patterns 22a, 22b, and 22c, and is provided at a predetermined distance from the connecting bonding patterns 22a, 22b, and 22c. In this embodiment, the annular sealing member side first bonding pattern 24 on the second main surface 102 of the first sealing member 20 and the connecting bonding patterns 22a, 22b, and 22c are provided as a third annular metal film portion formed in a position overlapping with the outer frame portion 12 of the crystal diaphragm 10 as described above. The third annular metal film portion is a metal film that forms a seal path 15a and joint portions 15b and 15c by joining it with the first annular metal film portion of the quartz diaphragm 10.

[0033] An annular projection 21 is formed on the first main surface 201, which is the upper surface of the first sealing member 20. In this embodiment, the projection 21 is formed of a metal film with substantially the same thickness. The outer periphery of the first main surface 201 on which the projection 21 is formed is higher than the central part of the first main surface 201 on which the projection 21 is not formed by the thickness of the metal film (approximately 0.1 to 0.3 μm). The upper surface of the projection 21 is formed of a flat surface and is parallel to the second main surface 202 of the first sealing member 20. The projection 21 is formed of the same metal material as the first bonding pattern 24 on the sealing member side and the connecting bonding patterns 22a, 22b, and 22c. The projection 21 is provided around the outer edge of the cutout portion 10a of the quartz crystal diaphragm 10, that is, around the inner edge of the outer frame portion 12, when joined to the quartz crystal diaphragm 10 as described above. The projection 21 serves as a pressing portion (pressure portion) for applying vertical pressing force (pressure) to the quartz crystal resonator 100 during the diffusion bonding of the first to fourth annular metal film portions, which will be described later. Details of the projection 21 will be described later.

[0034] As shown in Figures 6 and 7, the second sealing member 30 is a rectangular substrate formed from a single AT-cut quartz plate, and the first main surface 301 (the surface that joins to the quartz diaphragm 10), which is the upper surface of the second sealing member 30, is formed as a flat, smooth surface (mirror finish). It is desirable that the second sealing member 30 also uses an AT-cut quartz plate, similar to the quartz diaphragm 10, and that the orientation of the X, Y, and Z' axes is the same as that of the quartz diaphragm 10.

[0035] A second sealing member side bonding pattern (second sealing member side bonding portion) 31 is formed on the first main surface 301 of the second sealing member 30, which serves as a second sealing portion on the sealing member side for bonding to the crystal diaphragm 10. The second sealing member side bonding pattern 31 is formed in an annular shape in plan view. The outer edge of the second sealing member side bonding pattern 31 is provided close to the outer edge of the first main surface 301 of the second sealing member 30. In addition, connecting bonding patterns (second sealing member side wiring portions) 34a, 34b, and 34c are formed on the first main surface 301 of the second sealing member 30 for bonding to connecting bonding patterns 12d, 12e, and 12f formed on the second main surface 102 of the outer frame portion 12 of the crystal diaphragm 10. The connecting patterns 34a, 34b, and 34c are provided around the outer edge of the cutout portion 10a of the crystal diaphragm 10, that is, around the inner edge of the outer frame portion 12, when joined to the crystal diaphragm 10 as described above. The connecting pattern 34b is provided on the -Z' side and is formed in a vertically elongated shape extending in the X-axis direction. The connecting patterns 34a and 34c are connected by a horizontally elongated wiring pattern 35 extending in the Z' axis direction. The sealing member side second connecting pattern 31 is provided on the outer periphery side of the connecting patterns 34a, 34b, and 34c, and is provided at a predetermined distance from the connecting patterns 34a, 34b, and 34c. In this embodiment, the annular sealing member side second bonding pattern 31 and connecting bonding patterns 34a, 34b, and 34c on the first main surface 201 of the second sealing member 30 are provided as a fourth annular metal film portion formed in a position overlapping with the outer frame portion 12 of the crystal diaphragm 10 described above. The fourth annular metal film portion is a metal film that forms a seal path 16a and bonding portions 16b and 16c by bonding with the second annular metal film portion of the crystal diaphragm 10. Note that the wiring pattern 35 is not bonded to the second annular metal film portion of the crystal diaphragm 10 and does not contribute to the formation of the seal path 16a and bonding portions 16b and 16c, and is therefore not included in the fourth annular metal film portion.

[0036] The second main surface 302 (the outer main surface not facing the crystal diaphragm 10), which is the lower surface of the second sealing member 30, is provided with four external electrode terminals 32 that are electrically connected to an external circuit board provided outside the crystal oscillator 100. The external electrode terminals 32 are formed in a substantially L-shape and are located in the four corners (corner portions) of the second main surface 302 of the second sealing member 30.

[0037] As shown in Figures 6 and 7, the second sealing member 30 has three through-holes 33a, 33b, and 33c that penetrate between the first main surface 301 and the second main surface 302. Through electrodes are formed along the inner walls of the through-holes 33a, 33b, and 33c to ensure electrical conductivity between the electrodes formed on the first main surface 301 and the second main surface 302. The electrodes formed on the inner walls of the through-holes 33a, 33b, and 33c provide electrical conductivity between the electrode (connection pattern) formed on the first main surface 301 and the external electrode terminal 32 formed on the second main surface 302. Furthermore, the central portions of each through-hole 33a, 33b, and 33c are hollow through-holes that penetrate between the first main surface 301 and the second main surface 302.

[0038] In the quartz crystal oscillator 100, which includes the quartz crystal diaphragm 10, the first sealing member 20, and the second sealing member 30 as described above, the quartz crystal diaphragm 10 and the first sealing member 20 are diffusion-bonded with the diaphragm-side first bonding pattern 121 and the sealing member-side first bonding pattern 24 overlapping, and the quartz crystal diaphragm 10 and the second sealing member 30 are diffusion-bonded with the diaphragm-side second bonding pattern 122 and the sealing member-side second bonding pattern 31 overlapping, thereby manufacturing a sandwich-structured package as shown in Figure 1. As a result, the internal space of the package, that is, the space housing the vibrating part 11, is hermetically sealed.

[0039] In the crystal oscillator 100 configured as described above, the sealing portions (seal paths) 15a and 16a that hermetically seal the vibrating portion 11 of the crystal diaphragm 10 are formed in annular shape in plan view. The seal path 15a is formed by diffusion bonding (Au-Au bonding) of the diaphragm-side first bonding pattern 121 and the sealing member-side first bonding pattern 24 described above. In this case, diffusion bonding is performed by applying vertical pressing force (pressure) to the wafer-state crystal oscillator 100 (pressure diffusion bonding). The outer edge shape of the seal path 15a is formed to be substantially rectangular, and the outer edge of the seal path 15a is positioned close to the outer edge of the package. Similarly, the seal path 16a is formed by diffusion bonding (pressure diffusion bonding) of the diaphragm-side second bonding pattern 122 and the sealing member-side second bonding pattern 31 described above. The outer edge shape of the seal path 16a is formed to be substantially rectangular, and the outer edge of the seal path 16a is positioned close to the outer edge of the package. The seal paths 15a and 16a are not electrically connected to the electrical conduction path between the first and second excitation electrodes 111 and 112 and the external electrode terminals 32 and 32. Specifically, the seal path 15a is connected to the seal path 16a via the internal wiring 17, and the seal path 16a is further connected to earth (ground connection, utilizing a portion of the external electrode terminal 32) via the through-hole electrode 33c.

[0040] Furthermore, the aforementioned connecting bonding patterns are diffusely bonded together while superimposed. As a result of the bonding of the connecting bonding patterns, bonding portions 15b and 15c are formed between the quartz diaphragm 10 and the first sealing member 20, and bonding portions 16b and 16c are formed between the quartz diaphragm 10 and the second sealing member 30 (see Figure 1). In other words, the bonding portion between the first annular metal film portion on the first main surface 101 of the quartz diaphragm 10 and the third annular metal film portion on the second main surface 202 of the first sealing member 20 becomes the seal path 15a and bonding portions 15b and 15c, and the bonding portion between the second annular metal film portion on the second main surface 102 of the quartz diaphragm 10 and the fourth annular metal film portion on the first main surface 301 of the second sealing member 30 becomes the seal path 16a and bonding portions 16b and 16c. The joints 15b and 15c are provided on the inner circumference side of the seal path 15a, and the joints 16b and 16c are provided on the inner circumference side of the seal path 16a. This allows electrical conductivity to be obtained between the first excitation electrode 111, the second excitation electrode 112 and the external electrode terminals 32, 32 in the quartz oscillator 100. Specifically, the first excitation electrode 111 is connected to the external electrode terminal 32 via the first lead wiring 113, the internal wiring 12g, and the through-hole electrode 33a in that order. The second excitation electrode 112 is connected to the external electrode terminal 32 via the second lead wiring 114, the wiring pattern 35, and the through-hole electrode 33b in that order.

[0041] In the quartz oscillator 100, it is preferable that the various bonding patterns consist of multiple layers stacked on a quartz plate, with the Ti (titanium) layer and Au (gold) layer formed from the bottom layer by vapor deposition or sputtering. Furthermore, if the other wiring and electrodes formed on the quartz oscillator 100 have the same configuration as the bonding patterns, the bonding patterns, wiring, and electrodes can be patterned simultaneously, which is preferable.

[0042] In the quartz crystal oscillator 100 in which seal paths 15a and 16a are formed by diffusion bonding as described above, the gap between the first sealing member 20 and the quartz crystal diaphragm 10 is 1.00 μm or less, and the gap between the second sealing member 30 and the quartz crystal diaphragm 10 is 1.00 μm or less. In other words, the thickness of the seal path 15a between the first sealing member 20 and the quartz crystal diaphragm 10 is 1.00 μm or less, and the thickness of the seal path 16a between the second sealing member 30 and the quartz crystal diaphragm 10 is 1.00 μm or less (specifically, 0.15 μm to 1.00 μm in the Au-Au bonding of this embodiment). For comparison, in conventional metal paste sealing materials using Sn, the gap is 5 μm to 20 μm.

[0043] In this embodiment, in the crystal oscillator 100 with the above configuration, the first sealing member side sealing portion and the first sealing member side wiring portion of the first sealing member 20 are joined to the upper surface side sealing portion and the upper surface side wiring portion of the crystal diaphragm 10, and the second sealing member side sealing portion and the second sealing member side wiring portion of the second sealing member 30 are joined to the lower surface side sealing portion and the lower surface side wiring portion of the crystal diaphragm 10, thereby providing an internal space in which the vibrating portion 11 of the crystal diaphragm 10 is hermetically sealed. A projection 21 is formed on the first main surface 201 of the first sealing member 20. The projection 21 is positioned so as to overlap in plan view with the first annular metal film portion on the upper surface of the quartz diaphragm 10, the second annular metal film portion on the lower surface of the quartz diaphragm 10, the third annular metal film portion on the lower surface of the first sealing member 20, and the annular sealing member side second bonding pattern 31 of the second sealing member 30, but so as not to overlap in plan view with the first and second excitation electrodes 111 and 112 of the vibrating portion 11 of the quartz diaphragm 10. This point will be explained below.

[0044] As described above, the first annular metal film portion on the first main surface 101, which is the upper surface of the crystal vibrating plate 10, is composed of an annular diaphragm-side first bonding pattern 121 along the outer peripheral edge of the first main surface 101 and connection bonding patterns 12a, 12b, 12c on its inner peripheral side. The second annular metal film portion on the second main surface 102, which is the lower surface of the crystal vibrating plate 10, is composed of an annular diaphragm-side second bonding pattern 122 along the outer peripheral edge of the second main surface 102 and connection bonding patterns 12d, 12e, 12f on its inner peripheral side. The third annular metal film portion on the second main surface 202, which is the lower surface of the first sealing member 20, is composed of an annular sealing member-side first bonding pattern 24 along the outer peripheral edge of the second main surface 202 and connection bonding patterns 22a, 22b, 22c on its inner peripheral side. The fourth annular metal film portion on the first main surface 201, which is the upper surface of the second sealing member 30, is composed of an annular sealing member-side second bonding pattern 31 along the outer peripheral edge of the first main surface 201 and connection bonding patterns 34a, 34b, 34c on its inner peripheral side. The thicknesses of the first to fourth annular metal film portions are formed to be substantially the same as the thickness of the protruding portion 21 described above (about 0.1 to 0.3 μm).

[0045] In the present embodiment, as shown in FIGS. 1 and 2, an annular protruding portion 21 is formed on the first main surface 201 of the first sealing member 20. The outer edge shape and the inner edge shape of the protruding portion 21 are formed in a substantially rectangular shape, and the outer peripheral edge of the protruding portion 21 is disposed close to the outer peripheral edge of the first main surface 201. The outer peripheral edge of the protruding portion 21 is provided at a position slightly closer to the inner peripheral side than the outer peripheral edge of the outer frame portion 12 of the crystal vibrating plate 10 in a plan view, and a slight gap is provided between the outer peripheral edge of the protruding portion 21 and the outer peripheral edge of the outer frame portion 12. The inner peripheral edge of the protruding portion 21 is provided along the outer peripheral edge of the cutout portion 10a of the crystal vibrating plate 10, that is, along the inner peripheral edge of the outer frame portion 12. The inner peripheral edge of the protruding portion 21 is provided at a position substantially coinciding with the inner peripheral edge of the outer frame portion 12 of the crystal vibrating plate 10 in a plan view.

[0046] Furthermore, the first annular metal film portion, the second annular metal film portion, the third annular metal film portion, and the fourth annular metal film portion are arranged so as to fit within the region of the projection portion 21 in a plan view. Specifically, as shown in Figures 1 and 2, if the straight lines along the four sides of the outer edge of the projection portion 21 are L11 to L14, and the straight lines along the four sides of the inner edge of the projection portion 21 are L21 to L24, then the positional relationship is as follows: Straight lines L11, L12, L21, and L22 are straight lines perpendicular to the Z' axis direction and pass through the XY plane. Straight lines L13, L14, L23, and L24 are straight lines perpendicular to the X axis direction and pass through the YZ' plane. The first, second, third, and fourth annular metal film portions described above are located within a rectangular area enclosed by lines L11 to L14, but outside a rectangular area enclosed by lines L21 to L24, in a plan view.

[0047] On the other hand, the vibrating portion 11 of the quartz diaphragm 10, including the first and second excitation electrodes 111 and 112, is located within a rectangular area enclosed by straight lines L21 to L24 in a plan view. Also, in a plan view, more than half of the external electrode terminals 32 of the second sealing member 30 are located within a rectangular area enclosed by straight lines L11 to L14 and outside the rectangular area enclosed by straight lines L21 to L24, while the remaining portion is located within the rectangular area enclosed by straight lines L21 to L24. The through-holes 33a, 33b, and 33c of the second sealing member 30 are located within a rectangular area enclosed by straight lines L11 to L14 and outside the rectangular area enclosed by straight lines L21 to L24 in a plan view.

[0048] According to this embodiment, since the annular protrusion 21 of the first sealing member 20 and the first annular metal film portion, the second annular metal film portion, the third annular metal film portion, and the sealing member side second bonding pattern 31 of the second sealing member 30, and the fourth annular metal film portion including the connection bonding patterns 34a, 34b, 34c overlap in a plan view, when manufacturing the package of the crystal oscillator 100 by pressure diffusion bonding or the like, in the overlapping portion (the first annular metal film portion, the second annular metal film portion, the third annular metal film portion, the fourth annular metal film portion) in a plan view, a substantially uniform pressing force (pressing pressure) can be sufficiently transmitted without applying inclination or deflection to the substrates (the first sealing member 20, the crystal vibrating plate 10, the second sealing member 30). As a result, the overlapping portion (the first annular metal film portion, the second annular metal film portion, the third annular metal film portion, the fourth annular metal film portion) in a plan view can be pressed as uniformly as possible, the airtight sealing of the vibrating portion 11 by the seal paths 15a, 16a can be sufficiently performed, and the bonding of the bonding portions (wiring portions) 15b, 15c, 16b, 16c can be surely performed. In particular, if the thickness of the protrusion 21 is 0.1 μm or more, a substantially uniform pressing force (pressing pressure) can be sufficiently transmitted without applying inclination or deflection to the substrates (the first sealing member 20, the crystal vibrating plate 10, the second sealing member 30), and it becomes a more desirable form. In this embodiment, the thickness of the protrusion 21 is set to about 1 / 2 of the thickness of the seal paths 15a, 16a and the bonding portions 15b, 15c, 16b, 16c in the Au-Au bonding. For example, the thickness of the seal paths 15a, 16a and the bonding portions 15b, 15c, 16b, 16c is set to about 0.4 μm, and the thickness of the protrusion 21 is set to about 0.2 μm.

[0049] Furthermore, since the projection 21 is formed in an annular shape with substantially the same thickness, when manufacturing the package of the quartz oscillator 100 by pressure diffusion bonding or the like, the first annular metal film portion, the second annular metal film portion, the third annular metal film portion, and the fourth annular metal film portion that overlap with the projection 21 in a plan view can be pressed as uniformly as possible over their entire circumference, ensuring reliable and sufficient hermetically sealing of the vibrating portion 11 by the seal paths 15a and 16a. Moreover, since the first annular metal film portion, the second annular metal film portion, the third annular metal film portion, and the fourth annular metal film portion are located within the area of ​​the projection 21 in a plan view, the entire surface of the first annular metal film portion, the second annular metal film portion, the third annular metal film portion, and the fourth annular metal film portion are pressed by the projection 21, allowing for a more uniform and sufficient transmission of pressure.

[0050] More specifically, the projection 21 of the first sealing member 20, the diaphragm-side first bonding pattern 121 of the first annular metal film, the diaphragm-side second bonding pattern 122 of the second annular metal film, the sealing member-side first bonding pattern 24 of the third annular metal film, and the sealing member-side second bonding pattern 31 of the fourth annular metal film are superimposed in plan view. Therefore, when manufacturing the package of the quartz oscillator 100 by pressure diffusion bonding or the like, a substantially uniform pressing force can be sufficiently transmitted to the substrate (first sealing member 20, quartz diaphragm 10, second sealing member 30) in the superimposed parts in plan view (diaphragm-side first bonding pattern 121, diaphragm-side second bonding pattern 122, sealing member-side first bonding pattern 24, and sealing member-side second bonding pattern 31) without causing tilting or bending. As a result, the superimposed parts in plan view can be pressed as uniformly as possible, and the vibrating part 11 can be sufficiently hermetically sealed by the annular sealing paths 15a and 16a. In this case, since the first bonding pattern 121 on the diaphragm side of the first annular metal film portion, the second bonding pattern 122 on the diaphragm side of the second annular metal film portion, the first bonding pattern 24 on the sealing member side of the third annular metal film portion, and the second bonding pattern 31 on the sealing member side of the fourth annular metal film portion are provided within the area of ​​the projection 21 in a plan view, the entire surfaces of the first bonding pattern 121 on the diaphragm side, the second bonding pattern 122 on the diaphragm side, the first bonding pattern 24 on the sealing member side, and the second bonding pattern 31 on the sealing member side are pressurized by the projection 21, allowing for a more uniform and sufficient transmission of pressure.

[0051] Furthermore, since the projection 21 of the first sealing member 20 and the connecting bonding patterns 12a, 12b, 12c of the first annular metal film portion, the connecting bonding patterns 12d, 12e, 12f of the second annular metal film portion, the connecting bonding patterns 22a, 22b, 22c of the third annular metal film portion, and the connecting bonding patterns 34a, 34b, 34c of the fourth annular metal film portion are superimposed in a plan view, when manufacturing the package of the quartz oscillator 100 by pressure diffusion bonding or the like, a substantially uniform pressing force can be sufficiently transmitted to the substrate (first sealing member 20, quartz diaphragm 10, second sealing member 30) in the superimposed parts in a plan view (connecting bonding patterns 12a, 12b, 12c, connecting bonding patterns 12d, 12e, 12f, connecting bonding patterns 22a, 22b, 22c, connecting bonding patterns 34a, 34b, 34c) without causing tilting or bending. As a result, the overlapping portions in a plan view can be pressurized as uniformly as possible, ensuring reliable joining of the wiring portions that constitute the electrical wiring paths inside the package. In this case, since the connecting patterns 12a, 12b, 12c of the first annular metal film portion, 12d, 12e, 12f of the second annular metal film portion, 22a, 22b, 22c of the third annular metal film portion, and 34a, 34b, 34c of the fourth annular metal film portion are located within the area of ​​the projection 21 in a plan view, the entire surfaces of the connecting patterns 12a, 12b, 12c, 12d, 12e, 12f, 22a, 22b, 22c, and 34a, 34b, 34c are pressurized by the projection 21, allowing for more even and sufficient pressure to be transmitted.

[0052] In this embodiment, multiple external electrode terminals 32 are arranged in the corner region of the second main surface 302 of the second sealing member 30, and the projections 21 are provided so as to overlap each external electrode terminal 32 substantially uniformly in a plan view. By making the overlapping portion between each external electrode terminal 32 and the projections 21 uniform, the applied pressure can be transmitted even more uniformly, and the hermetically sealed portion 11 by the seal paths 15a and 16a can be reliably and sufficiently achieved.

[0053] Furthermore, the second sealing member 30 has two through-holes 33a and 33b that penetrate in the thickness direction within the area of ​​the connecting bonding patterns 34b and 34c, and the projection 21 is provided so as to overlap, in a plan view, the portion of the connecting bonding patterns 34b and 34c around each through-hole 33a and 33b, and the connecting bonding patterns 12e and 12f of the second annular metal film portion of the crystal diaphragm 10. This ensures reliable bonding between the connecting bonding patterns 34b and 34c around each through-hole 33a and 33b and the connecting bonding patterns 12e and 12f, and the portion of each through-hole 33a and 33b is more reliably sealed, thereby suppressing airtightness defects caused by the provision of each through-hole 33a and 33b. Similarly, the second sealing member 30 has a through-hole 33c formed in the thickness direction within the region of the sealing member side second bonding pattern 31, and the projection 21 is provided so as to overlap, in a plan view, the portion of the sealing member side second bonding pattern 31 around the through-hole 33c and the diaphragm side second bonding pattern 122 of the second annular metal film portion of the crystal diaphragm 10. This ensures reliable bonding between the sealing member side second bonding pattern 31 around the through-hole 33c and the diaphragm side second bonding pattern 122 of the crystal diaphragm 10, and the portion around the through-hole 33c is more reliably sealed, thereby suppressing airtightness defects caused by the provision of the through-hole 33c.

[0054] Furthermore, since the projection 21 is formed of a metal film, the projection 21 can be easily formed on the first main surface 201 of the first sealing member 20 using thin-film technology or the like. In this case, it is preferable that the projection 21 is formed of the same metal material as the first annular metal film portion, second annular metal film portion, third annular metal film portion, and fourth annular metal film portion described above. This not only improves the productivity of the quartz oscillator 100, but also approximates the film stress because the metal films formed on the quartz diaphragm 10, the first sealing member 20, and the second sealing member 30 are the same, thereby reducing the effects of warping of the quartz diaphragm 10, the first sealing member 20, and the second sealing member 30. When the projection 21 is a metal film, a visible transparent area can be formed in the central part of the first sealing member 20, making it possible to inspect the appearance of the vibrating portion 11 of the quartz diaphragm 10 inside the package from the outside of the quartz oscillator 100. Furthermore, it is desirable that the surface of the projection 21 be flat in order to transmit the applied pressure more uniformly. The shape of the projection 21 in plan view may be similar to or identical to the other metal film configurations (first annular metal film portion, second annular metal film portion, third annular metal film portion, and fourth annular metal film portion), and the film thickness may also be similar to or identical.

[0055] Furthermore, in this embodiment, the width of the portion of the inner circumferential wall of the outer frame portion 12 of the crystal diaphragm 10 parallel to the short side of the crystal diaphragm 10 (width in the X-axis direction) is larger than the width of the portion parallel to the long side of the crystal diaphragm 10 (width in the Z'-axis direction). Similarly, the width of the portion of the vibrating section 11 parallel to the short side of the crystal diaphragm 10 (width in the X-axis direction) is also larger than the width of the portion parallel to the long side of the crystal diaphragm 10 (width in the Z'-axis direction). This allows for relatively large areas to be secured at both ends of the outer frame portion 12 in the Z'-axis direction, making it easy and effective to form wiring paths using metal films or the like. Moreover, even if through-holes or notches are formed at both ends of the outer frame portion 12 in the Z'-axis direction, the strength of the outer frame portion 12 can be maintained, thus mitigating the congestion of wiring paths that occurs with miniaturization due to through-holes or notches. Furthermore, since the quartz diaphragm 10 includes a holding portion 13 that connects the outer peripheral wall of the vibrating portion 11 and the inner peripheral wall of the outer frame portion 12, and a cutout portion 10a provided between the vibrating portion 11 and the outer frame portion 12 and formed by cutting out the quartz diaphragm 10 in the thickness direction, stress and other forces associated with the pressure applied during pressure diffusion bonding are not directly transmitted to the vibrating portion 11. As a result, it is less likely for the characteristics of the vibrating portion 11 to fluctuate before and after pressure diffusion bonding, and the electrical characteristics of the quartz diaphragm 10 can be stabilized.

[0056] Herein, the manufacturing method of the quartz oscillator 100 according to this embodiment will be described. In the manufacturing process of the quartz oscillator 100, a wafer in which multiple packages are assembled is produced, and each package is separated into individual pieces by cutting, such as by dicing. Specifically, the manufacturing process includes a lamination step in which a quartz wafer (a laminate of wafers) is formed by stacking a first encapsulating member wafer formed in a first encapsulating member wafer formation step, a quartz diaphragm wafer formed in a quartz diaphragm wafer formation step, and a second encapsulating member wafer formed in a second encapsulating member wafer formation step, and a piece separation step in which the packages of the quartz oscillator 100 are separated from the quartz wafer by dicing, etc.

[0057] The wafer formation process for the first sealing member is a process of forming a wafer for the first sealing member, which consists of multiple first sealing members 20 assembled together as shown in Figures 2 and 3. The wafer formation process for the crystal diaphragm is a process of forming a wafer for the crystal diaphragm, which consists of multiple crystal diaphragms 10 assembled together as shown in Figures 4 and 5. The wafer formation process for the second sealing member is a process of forming a wafer for the second sealing member, which consists of multiple second sealing members 30 assembled together as shown in Figures 6 and 7.

[0058] In the lamination process, each first sealing member 20 of the first sealing member wafer, each crystal diaphragm 10 of the crystal diaphragm wafer, and each second sealing member 30 of the second sealing member wafer are laminated. The first annular metal film portion of each crystal diaphragm 10 of the crystal diaphragm wafer and the third annular metal film portion of each first sealing member 20 of the first sealing member wafer are overlapped and subjected to diffusion bonding by applying pressure and heating, and the second annular metal film portion of each crystal diaphragm 10 of the crystal diaphragm wafer and the fourth annular metal film portion of each second sealing member 30 of the second sealing member wafer are overlapped and subjected to diffusion bonding by applying pressure and heating.

[0059] Furthermore, in the lamination process, the diffusion bonding between the first annular metal film portion and the third annular metal film portion, and the diffusion bonding between the second annular metal film portion and the fourth annular metal film portion are performed by diffusion bonding under pressure (pressure diffusion bonding). Pressure diffusion bonding is performed by applying a vertical load from one side of either the upper surface of the wafer for the first sealing member or the lower surface of the wafer for the second sealing member. Since the annular projections 21 described above are formed on the upper surface of each first sealing member 20 of the wafer for the first sealing member, the vertical load can be concentrated and transmitted via each projection 21 to the joint portion between the first annular metal film portion and the third annular metal film portion, and to the joint portion between the second annular metal film portion and the fourth annular metal film portion. In other words, if the upper surface of each first sealing member 20 of the wafer for the first sealing member is a flat surface, the vertical load may be distributed to parts other than the joint portion, making it difficult to concentrate and transmit the load to the joint portion.

[0060] However, in this embodiment, an annular projection 21 is provided on the upper surface of each first sealing member 20 of the wafer for the first sealing member, and the annular projection 21 is provided in a position that overlaps with the first annular metal film portion, the second annular metal film portion, the third annular metal film portion, and the fourth annular metal film portion in a plan view. Therefore, during pressure diffusion bonding, the annular projection 21 can concentrate and transmit the vertical load to the joint portion between the first annular metal film portion and the third annular metal film portion, and the joint portion between the second annular metal film portion and the fourth annular metal film portion. During pressure diffusion bonding, a vertical load is first applied to the projection 21, and this load is transmitted to the joint portion provided directly below the projection 21, so the vertical load is less likely to be distributed to parts other than the joint portion. As a result, the bonding force of the seal paths 15a and 16a, and the bonding force of the joint portions 15b, 15c, 16b, and 16c can be made stronger.

[0061] The embodiments disclosed herein are illustrative in all respects and are not intended to be restrictive. Therefore, the technical scope of the present invention is not construed solely by the embodiments described above, but is defined by the claims. This includes all modifications within the meaning and scope of the equivalents of the claims.

[0062] In the above embodiment, the first sealing member 20 is provided with annular projections 21 that are continuously formed around the entire circumference of the outer periphery of the first main surface 201. However, the projections 21 may be partially arranged around the outer periphery of the first main surface 201. For example, projections may not be provided at the corners of the rectangular first main surface 201, but rather along the four sides of the outer periphery of the first main surface 201. In this case, arranging the projections point-symmetrically with respect to the center of the first sealing member 20 in plan view allows for as uniform a pressure as possible, which is preferable.

[0063] In the above embodiment, the first annular metal film portion of the first main surface 101 of the crystal diaphragm 10 is composed of an annular diaphragm-side first bonding pattern 121 along the outer peripheral edge of the first main surface 101 and connecting bonding patterns 12a, 12b, and 12c on its inner peripheral side. However, the first annular metal film portion may be composed only of the diaphragm-side first bonding pattern 121. Also, in the above embodiment, the second annular metal film portion of the second main surface 102 of the crystal diaphragm 10 is composed of an annular diaphragm-side second bonding pattern 122 along the outer peripheral edge of the second main surface 102 and connecting bonding patterns 12d, 12e, and 12f on its inner peripheral side. However, the second annular metal film portion may be composed only of the diaphragm-side second bonding pattern 122. Furthermore, in the above embodiment, the third annular metal film portion of the second main surface 202, which is the lower surface of the first sealing member 20, is composed of an annular sealing member-side first joining pattern 24 along the outer peripheral edge of the second main surface 202 and connecting joining patterns 22a, 22b, and 22c on its inner peripheral side. However, the third annular metal film portion may be composed only of the sealing member-side first joining pattern 24. Also, in the above embodiment, the fourth annular metal film portion of the first main surface 201, which is the upper surface of the second sealing member 30, is composed of an annular sealing member-side second joining pattern 31 along the outer peripheral edge of the first main surface 201 and connecting joining patterns 34a, 34b, and 34c on its inner peripheral side. However, the fourth annular metal film portion may be composed only of the sealing member-side second joining pattern 31.

[0064] In the above embodiment, all of the connecting bonding patterns 12a, 12b, and 12c of the first main surface 101 of the crystal diaphragm 10 are provided in a position that overlaps with the projection 21 in a plan view. However, some of the connecting bonding patterns 12a, 12b, and 12c may be provided in a position that overlaps with the projection 21 in a plan view. Also, in the above embodiment, all of the connecting bonding patterns 12d, 12e, and 12f of the second main surface 102 of the crystal diaphragm 10 are provided in a position that overlaps with the projection 21 in a plan view. However, some of the connecting bonding patterns 12d, 12e, and 12f may be provided in a position that overlaps with the projection 21 in a plan view. Furthermore, in the above embodiment, all of the connecting joining patterns 22a, 22b, and 22c of the second main surface 202 of the first sealing member 20 are provided in a position that overlaps with the projection 21 in a plan view, but some of the connecting joining patterns 22a, 22b, and 22c may be provided in a position that overlaps with the projection 21 in a plan view. Furthermore, in the above embodiment, all of the connecting joining patterns 34a, 34b, and 34c of the first main surface 301 of the second sealing member 20 are provided in a position that overlaps with the projection 21 in a plan view, but some of the connecting joining patterns 34a, 34b, and 34c may be provided in a position that overlaps with the projection 21 in a plan view.

[0065] In the above embodiment, the wiring pattern 35 connecting the connecting joining patterns 34a and 34c formed on the first main surface 301 of the second sealing member 30 is provided in a position that does not overlap with the projection 21 in a plan view. However, the wiring pattern 35 may also be provided in a position that overlaps with the projection 21 in a plan view. Furthermore, the wiring pattern 35 may not be provided on the first main surface 301 of the second sealing member 30. Alternatively, the second main surface 202 of the first sealing member 20 may be provided with a wiring pattern similar to the wiring pattern 35. In this case, the wiring pattern on the second main surface 202 of the first sealing member 20 may be provided in a position that overlaps with the projection 21 in a plan view, or it may be provided in a position that does not overlap with the projection 21 in a plan view.

[0066] In the above embodiment, the diaphragm-side first bonding pattern (upper sealing portion) 121 and the connecting bonding patterns (upper wiring portions) 12a, 12b, and 12c that constitute the first annular metal film portion of the first main surface 101 of the crystal diaphragm 10 both overlap the projection 21 in a plan view. However, it is sufficient that at least the diaphragm-side first bonding pattern 121 overlaps the projection 21 in a plan view. The connecting bonding patterns 12a, 12b, and 12c may partially overlap the projection 21 in a plan view, or they may not overlap the projection 21 in a plan view at all. Furthermore, the diaphragm-side second bonding pattern (lower sealing portion) 122 and the connecting bonding patterns (lower wiring portions) 12d, 12e, and 12f that constitute the second annular metal film portion of the second main surface 102 of the crystal diaphragm 10 both overlap with the projection 21 in a plan view, but it is sufficient that at least the diaphragm-side second bonding pattern 122 overlaps with the projection 21 in a plan view. The connecting bonding patterns 12d, 12e, and 12f may partially overlap with the projection 21 in a plan view, or they may not overlap with the projection 21 in a plan view at all.

[0067] Furthermore, in the above embodiment, the sealing member side first bonding pattern (first sealing member side sealing portion) 24 and the connecting bonding patterns (first sealing member side wiring portion) 22a, 22b, and 22c that constitute the third annular metal film portion of the second main surface 202 of the first sealing member 20 both overlap with the projection 21 in a plan view. However, it is sufficient that at least the sealing member side first bonding pattern 24 overlaps with the projection 21 in a plan view. The connecting bonding patterns 22a, 22b, and 22c may partially overlap with the projection 21 in a plan view, or they may not overlap with the projection 21 in a plan view at all. Furthermore, although the sealing member side second bonding pattern (second sealing member side sealing portion) 31 and the connecting bonding patterns (second sealing member side wiring portion) 34a, 34b, and 34c that constitute the fourth annular metal film portion of the first main surface 301 of the second sealing member 30 both overlap with the projection 21 in a plan view, it is sufficient that at least the sealing member side second bonding pattern 31 overlaps with the projection 21 in a plan view. The connecting bonding patterns 34a, 34b, and 34c may partially overlap with the projection 21 in a plan view, or they may not overlap with the projection 21 in a plan view at all.

[0068] In the above embodiment, the first annular metal film portion, the second annular metal film portion, the third annular metal film portion, and the fourth annular metal film portion are arranged so that they fit within the area of ​​the projection portion 21 in a plan view, and the outer and inner edges of the seal paths 15a, 16a and the joint portions 15b, 15c, 16b, 16c are provided at positions that substantially coincide with the outer and inner edges of the projection portion 21 (see Figure 1). However, the embodiment is not limited to this, and for example, as shown in Figure 8, the area of ​​the projection portion 21 in a plan view may be made larger than the area of ​​the first annular metal film portion, the second annular metal film portion, the third annular metal film portion, and the fourth annular metal film portion, with the outer edges of the seal paths 15a, 16a being located on the inner side of the outer edge of the projection portion 21, and the inner edges of the seal paths 15a, 16a and the joint portions 15b, 15c, 16b, 16c being located on the outer side of the inner edge of the projection portion 21.

[0069] Furthermore, as shown in Figure 9, the area of ​​the projection 21 in plan view may be made smaller than the area of ​​the first annular metal film portion, the second annular metal film portion, the third annular metal film portion, and the fourth annular metal film portion in plan view, with the outer edges of the seal paths 15a and 16a positioned further outward than the outer edge of the projection 21, and the inner edges of the seal paths 15a and 16a and the joint portions 15b, 15c, 16b, and 16c positioned further inward than the inner edge of the projection 21. In this case, in order to ensure hermetically sealed vibration portion 11 of the crystal diaphragm 10, it is preferable to arrange the first annular metal film portion, the second annular metal film portion, the third annular metal film portion, and the fourth annular metal film portion so that they fit within 120% of the area of ​​the projection 21 in plan view. For example, the distance between the outer edges of the seal paths 15a and 16a in Figure 9 and the inner edges of the joints 15b, 15c, 16b, and 16c should be within 1.2 times the width of the straight lines L11 and L21 (the width of the straight lines L12 and L22). In the above description, a projection 21 made of a metal film is formed on the outer periphery of the first main surface 201 of the first sealing member 20, and no metal film is formed on the central part of the first main surface 201. However, the description is not limited to this, and a projection 21 may also be formed on the first main surface 201 of the first sealing member 20 by forming a pattern of a metal film over the entire surface of the first main surface 201 of the first sealing member 20 and making the projection 21 thicker than the surrounding area.

[0070] In the above embodiment, the projection 21 was formed from a metal film, but the invention is not limited to this, and the projection 21 may be formed from other materials. For example, the projection 21 may be formed from an insulating film or the like. Alternatively, as shown in Figure 10, the projection 21 may be integrally formed on the first sealing member 20. In this case, the first sealing member 20 may be a quartz plate, and the annular projection 21 may be formed by wet etching to create a recess in the center of the first main surface 201 of the first sealing member 20.

[0071] In the above embodiment, the crystal diaphragm 10 was provided with only one holding portion 13 connecting the vibrating portion 11 and the outer frame portion 12, and the cutout portion 10a was formed continuously so as to surround the outer circumference of the vibrating portion 11. However, any configuration in which the cutout portion 10a is provided between the vibrating portion 11 and the outer frame portion 12 is acceptable, and the configuration of the crystal diaphragm 10 can be changed in various ways. For example, the crystal diaphragm 10 may be configured to have two or more holding portions 13 connecting the vibrating portion 11 and the outer frame portion 12. Also, the holding portion 13 may be configured to extend toward the outer frame portion 12 from a location other than the corner of the vibrating portion 11. In the above embodiment, the cutout portion 10a was provided continuously so as to surround the part of the outer circumference of the vibrating portion 11 other than the holding portion 13, but the cutout portion 10a may be provided partially (discontinuously). Also, as shown in Figure 11, the crystal diaphragm 10 may be configured without a cutout portion 10a. In this case, the inner circumference portion of the outer frame portion 12 of the crystal diaphragm 10 is made into a thin-walled portion 14 that is thinner than the outer frame portion 12, and the first and second excitation electrodes 111 and 112 of the vibrating portion 11 are formed in the central part of the thin-walled portion 14. In the example of Figure 11, the thickness of the vibrating portion 11 and the thickness of the thin-walled portion 14 surrounding it are the same, but the thickness of the vibrating portion 11 may be greater than or less than the thickness of the thin-walled portion 14 surrounding it.

[0072] Here, we will explain the case where the crystal diaphragm 10 is provided with two holding parts 13, referring to Figures 12 and 13. As shown in Figures 12 and 13, an AT-cut crystal plate that performs thickness-sliding vibration is used as the crystal diaphragm 10. In the crystal diaphragm 10 shown in Figures 12 and 13, both main surfaces 101 and 102 of the crystal diaphragm 10 are the XZ' plane. In this XZ' plane, the direction parallel to the short side direction of the crystal diaphragm 10 is the X-axis direction, and the direction parallel to the long side direction of the crystal diaphragm 10 is the Z' axis direction.

[0073] A pair of excitation electrodes (first excitation electrode 111, second excitation electrode 112) are formed on both main surfaces 101 and 102 of the quartz crystal diaphragm 10. The quartz crystal diaphragm 10 has a configuration comprising a vibrating section 11 formed in a substantially rectangular shape, an outer frame section 12 surrounding the outer peripheral wall of the vibrating section 11, a holding section 13 connecting the outer peripheral wall of the vibrating section 11 and the inner peripheral wall of the outer frame section 12, and cutout sections 14a and 14b formed by cutting out the space between the vibrating section 11 and the outer frame section 12 in the thickness direction. Both the inner peripheral wall of the outer frame section 12 and the outer peripheral wall of the vibrating section 11 are formed in a rectangular shape in plan view. Furthermore, the direction of the long side of the quartz crystal diaphragm 10 in plan view and the direction of the long side of the inner peripheral wall of the outer frame section 12 in plan view are arranged in a direction perpendicular to each other, and the direction of the long side of the inner peripheral wall of the outer frame section 12 in plan view and the direction of the long side of the vibrating section 11 in plan view are arranged in the same direction. In this embodiment, the outer frame portion 12 of the quartz diaphragm 10 is configured without through holes or castellations. The vibrating portion 11 is formed with a thicker outer periphery portion 11b side, where the first excitation electrode 111 and the second excitation electrode 112 are not formed, compared to the central portion 11a side, where the first excitation electrode 111 and the second excitation electrode 112 are formed, and annular steps 11c are formed on both main surfaces of the vibrating portion 11.

[0074] The holding portion 13 is provided one on the +X direction side and one on the -X direction side of the vibrating portion 11. The holding portion 13 is formed in a substantially T-shape in plan view and is composed of a vibrating holding portion 13a on the vibrating portion 11 side and an outer frame holding portion 13b on the outer frame portion 12 side. Specifically, the holding portion 13 is integrally formed with a vibrating holding portion 13a that extends linearly along the X-axis direction from the outer peripheral wall of the vibrating portion 11 and an outer frame holding portion 13b that extends linearly along the Z'-axis direction. The vibrating holding portion 13a and the outer frame holding portion 13b are connected in directions perpendicular to each other. The vibrating holding portion 13a extends toward the outer frame holding portion 13b side along the long side direction in plan view of the inner peripheral wall of the outer frame portion 12, and the outer frame holding portion 13b extends toward the inner peripheral wall side of the outer frame portion 12 along the short side direction in plan view of the inner peripheral wall of the outer frame portion 12. One end of the vibration-holding portion 13a is connected to the center of the vibration portion 11 in the Z' axis direction, and the other end of the vibration-holding portion 13a is connected to the center of the outer frame holding portion 13b in the Z' axis direction. The outer frame holding portion 13b is connected to the areas of the four corners in a plan view of the inner circumferential wall of the outer frame portion 12. One end of the outer frame holding portion 13b is connected to the inner circumferential wall of the outer frame portion 12 on the +Z' direction side, and the other end of the outer frame holding portion 13b is connected to the inner circumferential wall of the outer frame portion 12 on the -Z' direction side.

[0075] The retaining portion 13, configured as described above, divides the cutout formed between the outer circumferential wall of the vibrating portion 11 and the inner circumferential wall of the outer frame portion 12 into multiple (in this case, four) parts in a plan view. Specifically, the cutout portion 14a is the portion enclosed by the outer circumferential wall of the vibrating portion 11, the inner circumferential wall of the outer frame portion 12, and the vibrating retaining portion 13a and outer frame retaining portion 13b of the retaining portion 13, and is formed in a roughly U-shape in a plan view. The cutout portion 14b is the portion enclosed by the inner circumferential wall of the outer frame portion 12 and the outer frame retaining portion 13b of the retaining portion 13, and is formed in a straight line extending along the Z' axis in a plan view.

[0076] The first excitation electrode 111 is provided on the first main surface 101 side (upper surface side) of the vibrating section 11, and the second excitation electrode 112 is provided on the second main surface 102 side (lower surface side) of the vibrating section 11. Lead-out wiring (lead-out electrodes) for connecting these excitation electrodes to external electrode terminals is connected to the first excitation electrode 111 and the second excitation electrode 112. The first lead-out wiring 113 is led out from the first excitation electrode 111 in the +X direction and is connected to a connecting joint pattern 12a formed on the first main surface 101 side of the outer frame section 12 via a holding section 13 provided on the +X direction side of the vibrating section 11. The outer frame section 12 is formed to be thicker than the holding section 13, and a step is formed between the outer frame section 12 and the holding section 13. For this reason, the first lead-out wiring 113 is connected to the connecting joint pattern 12b via internal wiring 12g formed on the inner circumferential wall of the outer frame section 12. The connecting joint pattern 12a is also connected to the connecting joint pattern 12e formed on the second main surface 102 side of the outer frame 12 via internal wiring 12g formed on the inner circumferential wall of the outer frame 12. The internal wiring 12g is provided on the inner circumferential wall of the outer frame 12 that is aligned with the X-axis direction and is located on the inner circumferential wall on the +Z' side.

[0077] Furthermore, a connecting joint pattern 12b is formed on the first main surface 101 side of the outer frame portion 12. The connecting joint patterns 12a and 12b are provided on the first main surface 101 side of the outer frame portion 12 around the outer peripheral edge of the cutout portion 14a, that is, around the inner peripheral edge of the outer frame portion 12. The connecting joint patterns 12d and 12e are provided on the second main surface 102 side of the outer frame portion 12 around the outer peripheral edge of the cutout portion 14a, that is, around the inner peripheral edge of the outer frame portion 12.

[0078] The second lead wire 114 is led out from the second excitation electrode 112 toward the -X direction and connected to a connecting joint pattern 12d formed on the second main surface 102 side of the outer frame 12 via a holding portion 13 provided on the -X direction side of the vibrating portion 11. As described above, a step is formed between the outer frame 12 and the holding portion 13, and the second lead wire 114 is connected to the connecting joint pattern 12d via internal wiring 12h formed on the inner circumferential wall of the outer frame 12. The internal wiring 12h is provided on the inner circumferential wall of the outer frame 12 that is aligned with the X-axis direction and is on the -Z' direction side. In this embodiment, since the first lead wire 113 and the second lead wire 114 are led out in different directions, the lead wires of each other are not arranged facing each other across the vibrating portion 11. Therefore, unnecessary excitation by the lead wires in the vibrating portion 11 is eliminated, and the stability of the characteristics can be improved.

[0079] Both main surfaces (first main surface 101 and second main surface 102) of the crystal diaphragm 10 are provided with diaphragm-side sealing portions for joining the crystal diaphragm 10 to the first sealing member 20 and the second sealing member 30. A diaphragm-side first joining pattern (upper sealing portion) 121 is formed as the diaphragm-side sealing portion of the first main surface 101, and a diaphragm-side second joining pattern (lower sealing portion) 122 is formed as the diaphragm-side sealing portion of the second main surface 102. The diaphragm-side first joining pattern 121 and the diaphragm-side second joining pattern 122 are provided on the outer frame portion 12 and are formed in an annular shape in plan view. The outer edge of the diaphragm-side first joining pattern 121 is provided close to the outer edge of the first main surface 101 of the crystal diaphragm 10 (outer frame portion 12). The outer edge of the diaphragm-side second bonding pattern 122 is provided close to the outer edge of the second main surface 102 of the crystal diaphragm 10 (outer frame portion 12). The diaphragm-side first bonding pattern 121 and the diaphragm-side second bonding pattern 122 are connected via internal wiring 17 formed in the inner circumferential wall of the outer frame portion 12. The internal wiring 17 is provided in the inner circumferential wall of the outer frame portion 12, specifically in the inner circumferential wall along the Z' axis direction, on the -X direction side, and is provided in the inner circumferential wall perpendicular to the inner circumferential wall where the aforementioned internal wirings 12g and 12h are provided.

[0080] The diaphragm-side first bonding pattern 121 is provided on the outer periphery of the above-described connecting bonding patterns 12a and 12b, and is provided at a predetermined distance from the connecting bonding patterns 12a and 12b. The diaphragm-side second bonding pattern 122 is provided on the outer periphery of the above-described connecting bonding patterns 12d and 12e, and is provided at a predetermined distance from the connecting bonding patterns 12d and 12e. In this embodiment, the annular diaphragm-side first bonding pattern 121 and the connecting bonding patterns (upper wiring portion) 12a and 12b of the first main surface 101 of the crystal diaphragm 10 are provided as a first annular metal film portion formed on the outer frame portion 12. The annular diaphragm-side second bonding pattern 122 and the connecting bonding patterns (lower wiring portion) 12d and 12e of the second main surface 102 of the crystal diaphragm 10 are provided as a second annular metal film portion formed on the outer frame portion 12. Similar to the above embodiment, the first annular metal film portion is a metal film that forms a seal path 15a and joint portions 15b, 15c (see Figure 1) by joining with the third annular metal film portion of the first sealing member 20 (see Figure 3). The second annular metal film portion is a metal film that forms a seal path 16a and joint portions 16b, 16c (see Figure 1) by joining with the fourth annular metal film portion of the second sealing member 30 (see Figure 6).

[0081] As described above, the first annular metal film portion of the first main surface 101, which is the upper surface of the crystal diaphragm 10, is composed of an annular diaphragm-side first bonding pattern 121 along the outer peripheral edge of the first main surface 101 and connecting bonding patterns 12a and 12b on its inner peripheral side. The second annular metal film portion of the second main surface 102, which is the lower surface of the crystal diaphragm 10, is composed of an annular diaphragm-side second bonding pattern 122 along the outer peripheral edge of the second main surface 102 and connecting bonding patterns 12d and 12e on its inner peripheral side. And, as in the above embodiment, the first annular metal film portion and the second annular metal film portion are arranged so as to fit within the area of ​​the projection 21 (see Figures 1 and 2) in a plan view. As a result, the same effects as in the above embodiment can be obtained with this embodiment as well.

[0082] In the above embodiment, an AT-cut quartz crystal diaphragm was used as the quartz crystal diaphragm 10, but other types of quartz crystal diaphragms (e.g., SC-cut quartz crystal diaphragms, tuning fork-type quartz crystal diaphragms, etc.) may also be used. Furthermore, when using an AT-cut quartz crystal diaphragm 10, the X-axis and Z'-axis directions of the quartz crystal diaphragm 10 in the above embodiment may be rotated 90° around the Y-axis.

[0083] In the above embodiment, the number of external electrode terminals 32 on the second main surface 302 of the second sealing member 30 is set to four, but the number is not limited to this, and the number of external electrode terminals 32 may be, for example, two, six, or eight. In the above embodiment, the shape of the external electrode terminals 32 is set to be approximately L-shaped, but the shape is not limited to this, and the shape of the external electrode terminals 32 may be, for example, rectangular. Furthermore, although the present invention has been described in the case where it is applied to a quartz crystal oscillator 100, the present invention is not limited to this, and the present invention may also be applied to piezoelectric oscillators such as quartz oscillators.

[0084] In the above embodiment, the first sealing member 20 and the second sealing member 30 were formed from a quartz plate, but the embodiment is not limited to this, and the first sealing member 20 and the second sealing member 30 may be formed from, for example, glass or resin.

[0085] This application claims priority under Japanese Patent Application No. 2024-206618, filed in Japan on November 27, 2024. By reference thereto, all its contents are incorporated into this application.

[0086] 10 Crystal diaphragm (piezoelectric diaphragm) 10a Cutout section 11 Vibrating section 12 Outer frame section 12a, 12b, 12c Connection bonding pattern (upper side wiring section) 12d, 12e, 12f Connection bonding pattern (lower side wiring section) 13 Holding section 20 First sealing member 21 Protrusions 22a, 22b, 22c Connection bonding pattern (first sealing member side wiring section) 24 First bonding pattern on sealing member side (first sealing member side sealing section) 30 Second sealing member 31 Second bonding pattern on sealing member side (second sealing member side sealing section) 32 External electrode terminals 34a, 34b, 34c Connection bonding pattern (second sealing member side wiring section) 100 Crystal oscillator (piezoelectric vibration device) 101 First main surface (upper surface of crystal diaphragm) 102 Second main surface (lower surface of crystal diaphragm) 111 First excitation electrode 112 Second excitation electrode 121 First bonding pattern on the diaphragm side (upper sealing portion) 122 Second bonding pattern on the diaphragm side (lower sealing portion) 202 Second main surface (lower surface of the first sealing member) 301 First main surface (upper surface of the second sealing member)

Claims

1. A piezoelectric vibration device comprising: a vibrating portion on which a first excitation electrode and a second excitation electrode are formed, and an outer frame portion surrounding the vibrating portion, wherein the outer frame portion has an annular upper sealing portion and a lower sealing portion formed of a metal film on the outer periphery of both the upper and lower main surfaces; a first sealing member covering the upper surface of the piezoelectric vibrating portion and having an annular first sealing member side sealing portion formed of a metal film on the outer periphery of the lower surface; and a second sealing member covering the lower surface of the piezoelectric vibrating portion and having a plurality of external terminals formed on the lower surface and an annular second sealing member side sealing portion formed of a metal film on the outer periphery of the upper surface, wherein the first sealing member side sealing portion of the first sealing member and the upper sealing portion of the piezoelectric vibrating portion are joined, and the second sealing member side sealing portion of the second sealing member and the lower sealing portion of the piezoelectric vibrating portion are joined, thereby providing an internal space in which the vibrating portion of the piezoelectric vibrating portion is hermetically sealed. A piezoelectric vibration device characterized in that a projection is formed on the upper surface of the first sealing member at a position that overlaps with the upper sealing portion, the lower sealing portion, the first sealing member side sealing portion, and the second sealing member side sealing portion in a plan view, but does not overlap with the first and second excitation electrodes in a plan view.

2. A piezoelectric vibration device according to claim 1, characterized in that the vibrating portion is formed in a rectangular shape in a plan view, and the projection portion is formed in an annular shape.

3. A piezoelectric vibration device according to claim 1 or 2, wherein an upper wiring portion formed of a metal film is formed on the inner circumference of the upper sealing portion of the piezoelectric diaphragm on the outer circumference of the upper surface of the outer frame portion of the piezoelectric diaphragm, a lower wiring portion formed of a metal film is formed on the inner circumference of the lower sealing portion of the outer surface of the piezoelectric diaphragm on the outer circumference of the lower surface of the piezoelectric diaphragm, a first sealing member side wiring portion formed of a metal film is formed on the inner circumference of the first sealing member side sealing portion of the lower surface of the first sealing member, a second sealing member side wiring portion formed of a metal film is formed on the inner circumference of the second sealing member side sealing portion of the upper surface of the second sealing member, the first sealing member side wiring portion of the first sealing member and the upper wiring portion of the piezoelectric diaphragm are joined, and the second sealing member side wiring portion of the second sealing member and the lower wiring portion of the piezoelectric diaphragm are joined.

4. A piezoelectric vibration device according to claim 3, characterized in that the projection is superimposed in a plan view on the upper wiring portion, the lower wiring portion, the first sealing member side wiring portion, and the second sealing member side wiring portion.

5. A piezoelectric vibration device according to claim 4, wherein the second sealing member has a plurality of through-holes formed in the region of the wiring portion on the second sealing member side, penetrating the second sealing member in the thickness direction, and the projection is provided so as to overlap, in a plan view, the portion of the wiring portion on the second sealing member side with the portion around each through-hole and the wiring portion on the lower surface side.

6. A piezoelectric vibration device according to claim 1 or 2, characterized in that the upper sealing portion, the lower sealing portion, the first sealing member side sealing portion, and the second sealing member side sealing portion are provided within the region of the projection in a plan view.

7. A piezoelectric vibration device according to claim 3, characterized in that the upper wiring portion, the lower wiring portion, the first sealing member side wiring portion, and the second sealing member side wiring portion are provided within the area of ​​the projection portion in a plan view.

8. A piezoelectric vibration device according to claim 1 or 2, characterized in that the plurality of external terminals are arranged in the corner region of the lower surface of the second sealing member, and the protrusions are provided so as to overlap substantially uniformly with each external terminal in a plan view.

9. A piezoelectric vibration device according to claim 1 or 2, wherein the piezoelectric diaphragm comprises a holding portion connecting the outer peripheral wall of the vibrating portion and the inner peripheral wall of the outer frame portion, and a cutout portion provided between the vibrating portion and the outer frame portion and formed by cutting out the piezoelectric diaphragm in the thickness direction.

10. A piezoelectric vibration device according to claim 1 or 2, characterized in that the projection is formed of a metal film.

11. A piezoelectric vibration device according to claim 10, characterized in that the projection is formed of the same metal material as the upper sealing portion, the lower sealing portion, the first sealing member side sealing portion, and the second sealing member side sealing portion.

12. A piezoelectric vibration device according to claim 1 or 2, characterized in that the width of the portion of the inner circumferential wall of the outer frame of the piezoelectric diaphragm that is parallel to the short side of the piezoelectric diaphragm is greater than the width of the portion parallel to the long side of the piezoelectric diaphragm.

Images