Piezoelectric vibration device

Abstract

According to the present invention, a sufficient bonding region is ensured between a substrate on which a piezoelectric vibration element is mounted and a package, thereby making it possible to suppress displacement of the free end of the piezoelectric vibration element due to external impacts.　Piezoelectric vibration element connection terminals 21 and 23 are formed on an outer bottom surface 2a of a substrate 2, the piezoelectric vibration element connection terminals 21 and 23 being arranged in parallel along one short side (the right side in fig. 3) of the rectangular shape of the substrate 2. One piezoelectric vibration element connection terminal 21 is formed with a length that is slightly shorter than the length in the long-side direction of the substrate 2, and the other piezoelectric vibration element connection terminal 23 is formed with a length that slightly exceeds a line L representing the center of the long side of the substrate 2. Thus, when the piezoelectric vibration element connection terminals 21 and 23 of the substrate 2 are respectively bonded to piezoelectric vibration element mounting pads of the package, a sufficient bonding area is ensured as a bonding region between the package and the left end of the substrate 2, which is cantilevered on a stepped portion of the package.

Description

Piezoelectric vibration device

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

[0002] Conventionally, there is a piezoelectric vibration device described in Patent Document 1 in which a piezoelectric vibration element is hermetically sealed inside a package. This type of piezoelectric vibration device includes, for example, a ceramic package having a rectangular parallelepiped outer shape, a recess inside, and an open upper surface, a piezoelectric vibration element having one end joined and fixed to the inner bottom surface of the recess of the package in a cantilever state, and a lid member that closes the upper surface opening of the package and hermetically seals the inside of the package. At this time, the other end of the piezoelectric vibration element opposite to the one end on the cantilever support side is a free end that can be displaced.

[0003] Japanese Patent Application Laid-Open No. 2018-142866

[0004] In the case of a piezoelectric vibration device having a configuration in which a piezoelectric vibration element is supported in a cantilever state inside a conventional package, when an external shock is applied to the device, the free end side opposite to the cantilever support side of the substrate on which the piezoelectric vibration element is mounted is greatly displaced in the direction of the inner bottom surface of the package by the external shock and contacts the inner bottom surface, which may have an adverse effect on the characteristics of the piezoelectric vibration device.

[0005] Further, in a configuration in which a step portion is formed at a position higher than the inner bottom surface of the package near the upper surface opening, one end of the piezoelectric vibration element is supported in a cantilever manner on the step portion, and an integrated circuit element having an oscillation amplification circuit is arranged on the inner bottom surface of the package, when the free end of the substrate on which the piezoelectric vibration element is mounted is greatly displaced by an external shock, the piezoelectric vibration element may contact the integrated circuit element.

[0006] Therefore, in order to suppress the displacement of the free end side of the piezoelectric vibration element due to an external shock, it is conceivable to increase the bonding strength by widening the bonding region between the cantilever support side of one end of the substrate and the package. However, in the face of strong demands for miniaturization and thinning (low-profile) of recent piezoelectric vibration devices, it is difficult to secure a sufficient bonding region between the substrate on which the piezoelectric vibration element is mounted and the package due to space constraints, and an effective countermeasure is desired.

[0007] This invention has been made in view of the above problems, and aims to ensure a sufficient bonding area between the substrate on which the piezoelectric vibration element is mounted and the package, thereby suppressing displacement of the free end of the piezoelectric vibration element due to external impact.

[0008] To achieve the above objective, the piezoelectric vibration device according to the present invention comprises a substrate that is substantially rectangular in plan view and has at least two connection terminals on its outer bottom surface, a piezoelectric vibration element mounted on the side of the substrate opposite to the outer bottom surface, an electronic component, and a package that hermetically seals the substrate, the piezoelectric vibration element mounted on the substrate, and the electronic component, wherein the piezoelectric vibration element has a pair of excitation electrodes, the two connection terminals on the substrate are connection terminals for the piezoelectric vibration element that are respectively connected to the pair of excitation electrodes, and the package has a rectangular parallelepiped outer shape with an open top surface, a recess formed off-center to one side, and a stepped portion formed above the inner bottom surface of the recess. The electronic component is positioned on the inner bottom surface of the recess, and the substrate is cantilevered at one end and positioned above the electronic component, with the other end being a free end, as the two piezoelectric vibration element connection terminals are joined to the pair of mounting pads via a bonding material. The two piezoelectric vibration element connection terminals are arranged in parallel on the outer bottom surface along the short side of one end of the substrate, and are formed to extend more than half the length of the long side from the short side of one end of the substrate, so as to overlap with the pair of mounting pads in a plan view.

[0009] According to this configuration, the two connection terminals for the piezoelectric vibration element are arranged in parallel on the outer bottom surface along the short side of one end of the substrate, and are formed to extend more than half the length of the long side from the short side of one end of the substrate in the direction of the long side, so that they overlap with the pair of mounting pads in a plan view. Therefore, when the substrate is joined to the mounting pad of the package, a sufficient bonding area can be secured between the one end of the substrate, which is cantilevered at the stepped portion of the package, and the package, thereby increasing the bonding strength with the substrate and suppressing displacement of the free end of the piezoelectric vibration element due to external impact.

[0010] Therefore, when the free end of the substrate opposite the cantilever support side is positioned above the electronic component, it is possible to suppress the free end of the substrate opposite the cantilever support side from being displaced significantly in the direction of the inner bottom surface of the package due to external impact, thereby preventing contact with the electronic component and providing a highly reliable piezoelectric vibration device.

[0011] Furthermore, it is preferable that one of the two connection terminals for the piezoelectric vibration element be formed to have a length that substantially extends from the short side on one end of the substrate to the short side on the other end of the substrate opposite to that short side.

[0012] With this configuration, even if, for example, two connection terminals for piezoelectric vibration elements are positioned diagonally opposite each other on the outer bottom surface of the substrate, by using connection terminals for piezoelectric vibration elements that have a length that substantially reaches from one short side of the substrate to the other short side opposite to that short side, both excitation electrodes can be connected to the outside without changing the internal wiring or internal structure of the package, thereby suppressing the cost increase associated with changing the internal wiring or internal structure.

[0013] Furthermore, the bonding material is preferably a conductive adhesive. With this configuration, the shrinkage force of the conductive adhesive during curing acts to lift the free end of the substrate, making it easier to maintain the substrate in a more horizontal position. In addition, when solder is used as the bonding material, there is a risk that the solder will wet and spread to unintended areas of the metal piezoelectric vibration element connection terminals, whereas conductive adhesive does not wet and spread to metal, making it easy to control the bonding area.

[0014] Furthermore, the piezoelectric vibration element has a vibrating section including the pair of excitation electrodes, and the vibrating section is preferably hermetically sealed inside the package by a sealing member.

[0015] This configuration makes it possible to provide a piezoelectric vibration device with a double-sealed structure. The double sealing makes it less susceptible to changes in the external environment, resulting in a piezoelectric vibration device with stable characteristics.

[0016] Furthermore, the piezoelectric vibration element may further include a piezoelectric diaphragm having a vibrating portion including the pair of excitation electrodes and the substrate being superimposed and joined to it, and a sealing member superimposed on the side of the piezoelectric diaphragm opposite to the mounting surface on the substrate, which hermetically seals the vibrating portion of the piezoelectric diaphragm together with the substrate.

[0017] This configuration provides a three-layer laminated structure consisting of a sealing member, a piezoelectric diaphragm, and a substrate, making it possible to provide a smaller piezoelectric vibrator with more stable characteristics.

[0018] Furthermore, at least on the other end of the substrate, a through-hole is formed in which a conductor is fitted inside a through-hole that penetrates in the thickness direction of the substrate, or a via is formed in which a conductor is filled inside the through-hole, one of the pair of excitation electrodes is led out to the other end of the substrate through the through-hole or the via, and one of the two piezoelectric vibration element connection terminals extends from one end of the substrate in the direction of the long side of the substrate and overlaps the through-hole or the via.

[0019] With this configuration, even when the two piezoelectric vibration element connection terminals are positioned approximately diagonally opposite each other on the outer bottom surface of the substrate, one of the pair of excitation electrodes can be led to the other end of the substrate, for example, through a through-hole or via formed in the thickness direction of the substrate, and electrically connected to the piezoelectric vibration element connection terminal that overlaps the through-hole or via. This allows the pair of excitation electrodes to be connected to the outside without changing the internal wiring or internal structure of the package, thereby suppressing the cost increase associated with changes to the internal wiring or internal structure.

[0020] Furthermore, the electronic component may be an integrated circuit element that forms an oscillation circuit together with the piezoelectric vibration element, or a temperature sensor.

[0021] This configuration makes it possible to provide a piezoelectric vibration device in which integrated circuit elements that constitute an oscillation circuit together with the piezoelectric vibration element, as well as electronic components such as a temperature sensor, are sealed within a package.

[0022] According to the present invention, it is possible to secure a sufficient bonding area between the substrate on which the piezoelectric vibration element is mounted and the package, thereby increasing the bonding strength between the substrate and the package, suppressing displacement of the free end of the piezoelectric vibration element due to external impact, and providing a piezoelectric vibration device with stable characteristics.

[0023] This is a cross-sectional view of a piezoelectric vibration device according to the first embodiment of the present invention. This is a plan view of the piezoelectric vibration device of Figure 1 with the lid member, piezoelectric vibration element, and IC removed. This is a bottom view of the substrate on which the piezoelectric vibration element of the piezoelectric vibration device of Figure 1 is mounted. This is a bottom view of the IC of the piezoelectric vibration device of Figure 1. This is a cross-sectional view of a piezoelectric vibration device according to the second embodiment of the present invention. This is a cross-sectional view of a piezoelectric vibration device according to the third embodiment of the present invention. This is a plan view of the sealing member of the piezoelectric vibration device of Figure 6. This is a bottom view of the sealing member of the piezoelectric vibration device of Figure 6. This is a plan view of the piezoelectric diaphragm of the piezoelectric vibration device of Figure 6. This is a bottom view of the piezoelectric diaphragm of the piezoelectric vibration device of Figure 6. This is a plan view of the substrate of the piezoelectric vibration device of Figure 6. This is a bottom view of the substrate of the piezoelectric vibration device of Figure 6. This is a bottom view of the substrate of the piezoelectric vibration device in the third embodiment.

[0024] <First Embodiment> A piezoelectric vibration device according to the first embodiment of the present invention will be described with reference to Figures 1 to 4.

[0025] (Configuration) As shown in Figure 1, the piezoelectric vibration device 1 in the first embodiment comprises a substrate 2 that is substantially rectangular in plan view and has at least two connection terminals on its outer bottom surface (bottom surface), a piezoelectric vibration element Pv, an integrated circuit element (hereinafter referred to as IC) 5 which is an electronic component, and a ceramic package 6 that hermetically seals the substrate 2, the piezoelectric vibration element Pv mounted on the substrate 2, and the IC 5. Here, the piezoelectric vibration element Pv has a piezoelectric diaphragm 3 mounted on the top surface, which is the surface opposite to the outer bottom surface (bottom surface) of the substrate 2, and a sealing member 4 joined to the top surface of the piezoelectric diaphragm 3. A metal lid member 7 is seam-welded to the top surface of the package 6 by a substantially rectangular metal member 8, thereby sealing the package 6.

[0026] As shown in Figure 1, the package 6 has a rectangular parallelepiped shape with an open top surface. Inside, a recess 61 is formed, offset to one side (the right side in Figure 1), and a stepped portion 62 is formed above the inner bottom surface 61a of the recess 61, protruding to approximately the center in a plan view. The stepped portion 62 is provided with a pair of mounting pads that are electrically connected to the two piezoelectric vibration element connection terminals of the substrate 2, which will be described later, and the IC 5 is positioned on the inner bottom surface 61a of the recess 61.

[0027] The piezoelectric vibration element Pv comprises a piezoelectric diaphragm 3 having a vibrating portion (not shown) including a pair of excitation electrodes, to which a substrate 2 is superimposed and joined, and a sealing member 4 superimposed on the side of the piezoelectric diaphragm 3 opposite to the mounting surface (upper surface) on the substrate 2, and hermetically sealing the vibrating portion of the piezoelectric diaphragm 3 together with the substrate 2. In the piezoelectric vibration element Pv, a sandwich structure is formed by joining the piezoelectric diaphragm 3, the sealing member 4 and the substrate 2, creating a space inside, and the vibrating portion of the piezoelectric diaphragm 3 is hermetically sealed in this internal space.

[0028] Here, the piezoelectric diaphragm 3 is made of an AT-cut quartz plate that has a roughly rectangular parallelepiped shape formed from a single quartz plate and performs thickness-sliding vibration, and has a roughly rectangular vibrating section in which one and the other excitation electrodes are formed at opposing positions on the upper main surface and the lower main surface. Furthermore, an AT-cut quartz plate is used as the sealing member 4 and the substrate 2, on which the surface joined to the piezoelectric diaphragm 3 is formed as a flat, smooth surface (mirror finish). Here, one and the other excitation electrodes correspond to the "pair of excitation electrodes" in the present invention.

[0029] Incidentally, as shown in Figure 3, the substrate 2 is provided with three connection terminals on its outer bottom surface (lower surface) 2a side. Two of these are connection terminals 21 and 23 for piezoelectric vibration elements, which are connected to a pair of excitation electrodes of the piezoelectric diaphragm 3, respectively, and the remaining one is a ground connection terminal 22.

[0030] The two piezoelectric vibration element connection terminals 21 and 23 are arranged in parallel along the short side of one side (the right side in Figure 3) of the rectangle of the substrate 2. The dashed line in Figure 3 is a straight line L connecting the centers of the opposing long sides of the rectangle of the substrate 2. One piezoelectric vibration element connection terminal 21 is formed to be slightly shorter than the length of the long side of the substrate 2, and the other piezoelectric vibration element connection terminal 23 is formed to be slightly longer than the line L representing the center of the long side of the substrate 2. The ground connection terminal 22 is formed to be slightly to the left of the left end of the piezoelectric vibration element connection terminal 23 and extends to near the short side of the other side (the left side in Figure 3) of the rectangle of the substrate 2. The length of the ground connection terminal 22 in the direction of the long side of the substrate 2 is shorter than that of the piezoelectric vibration element connection terminal 23.

[0031] Figure 2 is a plan view showing the state of the package 6 before the lid member 7 is removed and the substrate 2, piezoelectric vibration element Pv, and IC 5 are housed inside the package 6. The dotted rectangle R1 represents the plan view outline of the substrate 2 and piezoelectric vibration element Pv, and the double dotted rectangle R2 represents the plan view outline of IC 5. As shown in Figure 2, the stepped portion 62 inside the package 6 is provided with a pair of piezoelectric vibration element mounting pads 63a and 63b, which are electrically connected to the two piezoelectric vibration element connection terminals 23 and 21 on the substrate 2, respectively. Furthermore, the recess 61 is provided with first to sixth IC mounting pads 64a, 64b, 4c, 64d, 64e, and 64f. Here, the piezoelectric vibration element mounting pads 63a and 63b correspond to the "mounting pads" in the present invention.

[0032] These piezoelectric vibration element-mounted pads 63a and 63b are electrically connected to the piezoelectric vibration element connection terminals 23 and 21, respectively, by a bonding material 65, such as a conductive adhesive. The bonding material 65 is not limited to a conductive adhesive; it may also be a metal bump.

[0033] Incidentally, as shown in Figure 4, the outer bottom surface (lower surface) of IC 5 is provided with first to sixth connection terminals 5a, 5b, 5c, 5d, 5e, and 5f. The first connection terminal 5a is, for example, a power terminal, the second connection terminal 5b is an output terminal, the third and fourth connection terminals 5c and 5d are two piezoelectric vibrator connection terminals, and the fifth and sixth connection terminals 5e and 5f are ground connection terminals. The first to sixth IC mounting pads 64a to 64f on the package 6 side are electrically connected to the first to sixth connection terminals 5a to 5f of IC 5, respectively, by metal bumps 66.

[0034] Then, when the piezoelectric vibration element Pv and IC 5 mounted on the substrate 2 are placed in predetermined positions within the package 6 and electrically bonded, the piezoelectric vibration element connection terminals 23 and 21 on the outer bottom surface of the substrate 2 overlap the piezoelectric vibration element mounting pads 63a and 63b, respectively. At this time, since the piezoelectric vibration element connection terminals 23 and 21 are formed to a length exceeding a straight line L representing half the length of the long side from the short side to the long side of one side of the substrate 2, when electrically bonding the piezoelectric vibration element connection terminals 23 and 21 of the substrate 2 to the piezoelectric vibration element mounting pads 63a and 63b of the package 6, a sufficient bonding area can be secured as the bonding region between the one end of the substrate 2 (the left end in Figure 1) which is cantilevered at the stepped portion 62 of the package 6 and the package 6, thereby increasing the bonding strength with the substrate 2 and suppressing displacement of the free end of the substrate 2 on which the piezoelectric vibration element Pv is mounted due to external impact.

[0035] Therefore, according to the first embodiment, when the free end (left side of Figure 3) opposite the cantilevered support side (right side of Figure 3) of the substrate 2 is positioned above the IC 5, it is possible to suppress the free end side of the substrate 2 mounted on the piezoelectric vibration element Pv from being displaced significantly in the direction of the inner bottom surface of the package 6 due to external impact, thereby preventing contact between the substrate 2 mounted on the piezoelectric vibration element Pv and the IC 5, and providing a highly reliable piezoelectric vibration device 1.

[0036] Furthermore, by joining the piezoelectric vibration element connection terminals 23 and 21 of the substrate 2 to the piezoelectric vibration element mounting pads 63a and 63b using a conductive adhesive as a bonding material 65, the shrinkage force of the conductive adhesive during curing acts to lift the free end side of the substrate 2, making it easier to maintain the substrate 2 in a horizontal position. In addition, while solder used as the bonding material 65 may spread to unintended areas of the metal piezoelectric vibration element connection terminals, conductive adhesive does not spread to metal, making it easy to control the bonding area.

[0037] Furthermore, the piezoelectric vibration element Pv has a three-layer laminated structure in which a piezoelectric diaphragm 3 having a vibrating section including a pair of excitation electrodes is bonded to the lower and upper surfaces of the piezoelectric diaphragm 3, respectively, and the vibrating section is further hermetically sealed inside the package 6, making it possible to provide a piezoelectric vibration device 1 with a double-sealed structure. Such double sealing makes it possible to provide a piezoelectric vibration device 1 that is less susceptible to changes in the external environment, is smaller, and has more stable characteristics.

[0038] <Second Embodiment> A piezoelectric vibration device according to the second embodiment of the present invention will be described with reference to Figure 5. Below, the differences between the piezoelectric vibration device 1A according to the second embodiment and the first embodiment will be described. In the following description, Figures 1 to 4 will also be referenced, and in Figure 5, the same reference numerals as in Figures 1 to 4 indicate the same or equivalent components.

[0039] The piezoelectric vibration device 1A according to the second embodiment differs from the piezoelectric vibration device 1 of the first embodiment in that, as shown in Figure 5, the piezoelectric vibration element 30 comprises a piezoelectric substrate made of quartz, a substantially rectangular vibrating portion in plan view with a pair of excitation electrodes formed on one main surface of the piezoelectric substrate and the other main surface on the opposite side, an outer frame portion having a rectangular inner wall in plan view surrounding the outer circumferential wall of the vibrating portion, a holding portion that holds the vibrating portion by connecting the outer circumferential wall of the vibrating portion and the inner wall of the outer frame portion, and a cutout portion formed between the vibrating portion and the outer frame portion by cutting out the piezoelectric substrate in the thickness direction. The piezoelectric vibration element 30 with this configuration is bonded to the upper surface of the substrate 2 by, for example, Au-Au diffusion bonding, and the piezoelectric vibration element 30 is mounted on the upper surface of the substrate 2, which is different from the three-layer stacked structure in which the piezoelectric vibration element Pv is mounted on the substrate 2 as in the first embodiment. In Figure 5, 67 is a bonding material such as a conductive adhesive that conductively bonds the piezoelectric vibration element connection terminals 23 and 21 on the outer bottom surface (bottom surface) of the substrate 2 on which the piezoelectric vibration element 30 is mounted to the piezoelectric vibration element mounting pads 63a and 63b of the package 6, respectively.

[0040] In the second embodiment, the piezoelectric vibration device 1A, similar to the piezoelectric vibration device 1 of the first embodiment, has connection terminals 23 and 21 for the piezoelectric vibration element on the outer bottom surface of the substrate 2, formed to extend beyond a straight line representing half the length of the long side from the short side to the long side on one side of the substrate 2 (the left side in Figure 5), and superimposed on the piezoelectric vibration element mounting pads 63a and 63b of the package 6. Therefore, when the piezoelectric vibration element 30 and IC 5 mounted on the substrate 2 are placed in predetermined positions within the package 6 and joined, a sufficient bonding area can be secured between the one end of the substrate 2 (the left end in Figure 1), which is cantilevered at the stepped portion 62 of the package 6, and the package 6.

[0041] Therefore, according to the second embodiment, the piezoelectric vibration element connection terminals 23 and 21 on the outer bottom surface of the substrate 2 are formed to a length exceeding a straight line representing half the length of the long side in the direction from the short side to the long side on one side of the substrate 2 (the left side in Figure 5), and are superimposed on the piezoelectric vibration element mounting pads 63a and 63b of the package 6, respectively, so that the same effects as the first embodiment can be obtained.

[0042] <Third Embodiment>A piezoelectric vibration device according to the third embodiment of the present invention will be described with reference to FIGS. 6 to 12. Hereinafter, differences between the piezoelectric vibration device 1B according to the third embodiment and the piezoelectric vibration device 1 of the first embodiment will be described. In the following description, FIGS. 1 to 4 will also be referred to, and in FIGS. 6 to 12, the same reference numerals as those in FIGS. 1 to 4 denote the same or corresponding components.

[0043] As shown in FIG. 6, the piezoelectric vibration device 1B according to the third embodiment has the same cross-sectional configuration as the piezoelectric vibration device 1 (see FIG. 1) according to the first embodiment, and is different from the first embodiment in the following points.

[0044] The piezoelectric vibration element PvB constituting the piezoelectric vibration device 1B shown in FIG. 6 includes a piezoelectric vibration plate 3B to which a substrate 2B as a lower sealing member is joined on the lower surface, and an upper sealing member 4B joined to the upper surface of the piezoelectric vibration plate 3B. As will be described later, vias 272B and 273B formed by filling conductors of through-holes penetrating in the thickness direction of the substrate 2B are formed in the substrate 2B, and the second excitation electrode 32Bb of the first and second excitation electrodes 32Ba and 32Bb of the piezoelectric vibration plate 3B to be described later is connected to the right end of the connection terminal 21B for piezoelectric vibration element of the substrate 2B through a connection bonding pattern 26B and a via 273B shown in FIGS. 11 and 12. Further, one of the connection terminals 21B and 23B for piezoelectric vibration element and the ground connection terminal 22B provided on the outer bottom surface (lower surface) 2Bb of the substrate 2B, the connection terminal 21B for piezoelectric vibration element extends in the long side direction of the substrate 2B from one end side (left end side in FIG. 6) of the substrate 2B as will be described later, which is different from the above-described first embodiment.

[0045] The sealing member 4B of the piezoelectric vibration element PvB is configured as shown in FIGS. 7 and 8, the piezoelectric vibration plate 3B is configured as shown in FIGS. 9 and 10, and the substrate 2B is configured as shown in FIGS. 11 and 12. The sealing member 4B, the piezoelectric vibration plate 3B, and the substrate 2B will be described below.

[0046] Specifically, as shown in FIGS. 9 and 10, the piezoelectric diaphragm 3B is a substantially rectangular parallelepiped quartz substrate 31B, and the first main surface 3Ba and the second main surface 3Bb are formed as flat and smooth surfaces (mirror-finished surfaces). As the piezoelectric diaphragm 3B, an AT-cut quartz plate that performs thickness-shear vibration is used. In the piezoelectric diaphragm 3B shown in FIGS. 9 and 10, the first and second main surfaces 3Ba and 3Bb of the piezoelectric diaphragm 3B are the XZ' planes.

[0047] In this XZ' plane, the direction parallel to the short side direction of the rectangle of the piezoelectric diaphragm 3B is defined as the X-axis direction, and the direction parallel to the long side direction of the rectangle of the piezoelectric diaphragm 3B is defined as the Z'-axis direction. Note that the AT-cut is a processing method in which, among the three crystal axes of synthetic quartz, the electrical axis (X-axis), the mechanical axis (Y-axis), and the optical axis (Z-axis), it is cut out at an angle inclined 35°15' around the X-axis with respect to the Z-axis. In the AT-cut quartz plate, the X-axis coincides with the crystal axis of the quartz. The Y'-axis and the Z'-axis coincide with the axes inclined 35°15' respectively from the Y-axis and the Z-axis of the crystal axis of the quartz. The Y'-axis direction and the Z'-axis direction correspond to the cutting directions when cutting out the AT-cut quartz plate. Note that the piezoelectric diaphragm 3B is not limited to the above-described AT-cut quartz plate, and an SC-cut quartz plate may be used, or a tuning fork type vibrator may be used.

[0048] The piezoelectric diaphragm 3B has a vibration portion 33B having a substantially rectangular planar shape in which a pair of excitation electrodes, the first excitation electrode 32Ba and the second excitation electrode 32Bb, are formed on the first main surface 3Ba and the second main surface 3Bb, an outer frame portion 34B having an inner peripheral wall having a rectangular shape in plan view surrounding the outer peripheral wall of the vibration portion 33B, a holding portion 35B that holds the vibration portion 33B by connecting the outer peripheral wall of the vibration portion 33B and the inner peripheral wall of the outer frame portion 34B, and a cutout portion 36B formed by cutting out the piezoelectric diaphragm 3B in the plate thickness direction between the vibration portion 33B and the outer frame portion 34B. That is, the piezoelectric diaphragm 3B has a configuration in which the vibration portion 33B, the outer frame portion 34B, and the holding portion 35B are integrally provided.

[0049] The holding portion 35B is provided at only one location between the vibrating portion 33B and the outer frame portion 34B. Furthermore, the vibrating portion 33B and the holding portion 35B are formed thinner than the outer frame portion 34B. Due to this difference in thickness between the outer frame portion 34B and the holding portion 35B, the natural frequencies of the piezoelectric vibrations of the outer frame portion 34B and the holding portion 35B are different, and the propagation of vibrations excited in the vibrating portion 33B is suppressed. In addition, when the sealing member 4B and the substrate 2B are joined to the piezoelectric diaphragm 3B, a gap is formed between the vibrating portion 33B and the sealing member 4B and substrate 2B on the inner side of the inner circumferential wall of the outer frame portion 34B, and this gap is sealed. Furthermore, the outer frame portion 34B of the piezoelectric diaphragm 3B may be formed thicker than the vibrating portion 33B and the holding portion 35B, and a gap may be formed by joining the flat sealing member 4B and the substrate 2B. Alternatively, the outer frame portion 34B may be made the same thickness as the vibrating portion 33B and the holding portion 35B, and a gap may be formed by creating recesses in the sealing member 4B and the substrate 2B and joining them together. In addition, the location of the holding portion 35B is not limited to one place, but may be provided in two or more places between the vibrating portion 33B and the outer frame portion 34B.

[0050] The holding portion 35B extends from only one corner of the vibrating portion 33B located in the +X and -Z' directions to the outer frame portion 34B in the -Z' direction. In this way, since the holding portion 35B is provided at the corner of the outer circumference of the vibrating portion 33B where the displacement of piezoelectric vibration is relatively small, it is possible to suppress leakage of piezoelectric vibration to the outer frame portion 34B through the holding portion 35B compared to when the holding portion 35B is provided at a part other than the corner (the center of the side), and the vibrating portion 33B can be vibrated piezoelectrically more efficiently. Furthermore, compared to when two or more holding portions 35B are provided, the stress acting on the vibrating portion 33B can be reduced, and the frequency shift of the piezoelectric vibration caused by such stress can be reduced, thereby improving the stability of the piezoelectric vibration.

[0051] The first excitation electrode 32Ba is provided on the first main surface 3Ba side of the vibrating section 33B, and the second excitation electrode 32Bb is provided on the second main surface 3Bb side of the vibrating section 33B. The first excitation electrode 32Ba and the second excitation electrode 32Bb are connected to the first and second excitation electrodes 32Ba and 32Bb, respectively, by first lead wiring 37Ba and second lead wiring 37Bb, which connect these first and second excitation electrodes 32Ba and 32Bb to external electrode terminals. The first lead wiring 37Ba is drawn out from the first excitation electrode 32Ba and connected via the holding section 35B to a roughly rectangular connecting joint pattern 381B that is elongated in the X-axis direction and formed at the -Z' side of the outer frame section 34B. The second lead wire 37Bb is led out from the second excitation electrode 32Bb and connected via the holding portion 35B to a substantially circular connecting joint pattern 382B formed in the +X direction and -Z' direction of the outer frame portion 34B. Thus, the first lead wire 37Ba is formed on the first main surface 3Ba side of the holding portion 35B, and the second lead wire 37Bb is formed on the second main surface 3Bb side of the holding portion 35B.

[0052] Furthermore, on the first main surface 3Ba side and the second main surface 3Bb side of the outer frame portion 34B of the piezoelectric diaphragm 3B, substantially rectangular connecting joint patterns 383B and 384B, respectively, are formed on the +Z' side, and a substantially crescent-shaped connecting joint pattern 385B is formed at a position in the +X direction and -Z' direction on the first main surface 3Ba side of the outer frame portion 34B of the piezoelectric diaphragm 3B. In addition, on the opposite side of the connecting joint pattern 381B on the second main surface 3Bb of the outer frame portion 34B of the piezoelectric diaphragm 3B, a substantially rectangular connecting joint pattern 386B, which is long in the X direction, is formed.

[0053] The first main surface 3Ba and the second main surface 3Bb of the piezoelectric diaphragm 3B are provided with vibration-side sealing portions for joining the piezoelectric diaphragm 3B to the sealing member 4B and the substrate 2B, respectively. The vibration-side sealing portion of the first main surface 3Ba has a vibration-side first bonding pattern 387Ba formed for joining to the sealing member 4B. The vibration-side sealing portion of the second main surface 3Bb has a vibration-side second bonding pattern 387Bb formed for joining to the substrate 2B. The vibration-side first bonding pattern 387Ba and the vibration-side second bonding pattern 387Bb are provided on the outer frame portion 34B and are formed in an annular shape in plan view. The first excitation electrode 32Ba and the second excitation electrode 32Bb are not electrically connected to the vibration-side first bonding pattern 387Ba and the vibration-side second bonding pattern 387Bb.

[0054] Furthermore, as shown in Figures 9 and 10, the piezoelectric diaphragm 3B has a connecting bonding pattern 381B that is connected to a connecting bonding pattern 386B formed on the second main surface 3Bb side of the outer frame 34B via internal wiring 39B formed on the inner wall surface of the outer frame 34B. The internal wiring 39B is provided on the inner wall surface of the outer frame 34B that is aligned with the X-axis direction and on the -Z' side. In this case, the internal wiring 39B is formed in a V-shaped recess in plan view provided on the inner wall surface of the outer frame 34B. The first excitation electrode 32Ba is then connected to the piezoelectric vibration element connection terminal 23B via the connecting bonding pattern 381B, the internal wiring 39B, the connecting bonding pattern 386B, and the connecting bonding pattern 25B and via 272B of the substrate 2B, which will be described later.

[0055] The sealing member 4B is, for example, a rectangular parallelepiped substrate formed from a single quartz substrate 41B. As shown in Figure 7, nothing is formed on the first main surface (upper surface) 4Ba of the sealing member 4B that does not face the piezoelectric diaphragm 3B, as shown in Figure 8. The second main surface (lower surface) 4Bb of the sealing member 4B that is joined to the piezoelectric diaphragm 3B is formed as a flat, smooth surface (mirror finish). It is preferable to use AT-cut quartz for the sealing member 4B, similar to the piezoelectric diaphragm 3B, in order to ensure that their thermal expansion coefficients are the same. However, other quartz cut plates, piezoelectric substrates, glass substrates, etc., may also be used.

[0056] As shown in Figure 8, a first sealing-side bonding pattern 42B is formed on the second main surface 4Bb of the sealing member 4B, serving as a first sealing portion for bonding to the upper surface of the piezoelectric diaphragm 3B. This first sealing-side bonding pattern 42B is formed in an annular shape in plan view, similar to the first bonding pattern 387Ba on the vibration side of the piezoelectric diaphragm 3B.

[0057] Furthermore, connection bonding patterns 43B, 44B, and 45B are formed on the second main surface 4Bb of the sealing member 4B at positions facing the connection bonding patterns 381B, 383B, and 385B of the piezoelectric diaphragm 3B, respectively. The connection bonding patterns 43B, 44B, and 45B have substantially the same shape as the connection bonding patterns 381B, 383B, and 385B of the piezoelectric diaphragm 3B, respectively.

[0058] As shown in Figures 11 and 12, the substrate 2B is a rectangular parallelepiped substrate formed from, for example, a single quartz substrate 20B, and the first main surface 2Ba of this substrate 2B (the upper surface that is joined to the piezoelectric diaphragm 3B) is formed as a flat, smooth surface (mirror finish). It is preferable to use AT-cut quartz for the substrate 2B as well as the piezoelectric diaphragm 3B in order to ensure that their thermal expansion coefficients are the same, but other quartz cut plates, piezoelectric substrates, glass substrates, etc. may also be used.

[0059] As shown in Figure 11, a second sealing side bonding pattern 24B is formed on the first main surface 2Ba of the substrate 2B, serving as a second sealing side sealing portion for bonding to the piezoelectric diaphragm 3B. The second sealing side bonding pattern 24B is formed in an annular shape in plan view, similar to the first and second bonding patterns 387Ba and 387Bb on the vibration side of the piezoelectric diaphragm 3B and the first sealing side bonding pattern 42B of the sealing member 4B.

[0060] Furthermore, a connecting bonding pattern 25B is formed on the first main surface 2Ba of the substrate 2B at a position opposite to the connecting bonding pattern 386B for the piezoelectric diaphragm 3B. This connecting bonding pattern 25B extends along the long side on the B1 side from the A1 side towards the A2 side and has a U-shape in plan view. A connecting bonding pattern 26B is formed on the first main surface 2Ba of the substrate 2B at a position opposite to the connecting bonding pattern 384B for the piezoelectric diaphragm 3B. This connecting bonding pattern 26B has a shape that extends along the long side on the B2 side from the A2 side towards the A1 side.

[0061] Furthermore, as shown in Figure 12, the second main surface 2Bb, which is the outer bottom surface (lower surface) of the substrate 2B, is provided with three connection terminals 21B, 22B, and 23B, similar to the substrate 2 of the first embodiment. Two of these connection terminals, 23B and 21B, are connection terminals for piezoelectric vibration elements that are connected to the first and second excitation electrodes 32Ba and 32Bb of the piezoelectric diaphragm 3B, respectively, while the remaining connection terminal 22B is a ground connection terminal. Hereinafter, these will be referred to as the connection terminals 21B and 23B for piezoelectric vibration elements and the ground connection terminal 22B.

[0062] The two piezoelectric vibration element connection terminals 21B and 23B are arranged in parallel along the short side of one side (the right side in Figure 12) of the rectangle of the substrate 2B. The dashed line in Figure 3 is a straight line L connecting the centers of the opposing long sides of the rectangle of the substrate 2B. The piezoelectric vibration element connection terminal 21B is formed to be slightly shorter than the length of the long side of the substrate 2B, the piezoelectric vibration element connection terminal 23B is formed to be slightly longer than the line L representing the center of the long side of the substrate 2B, and the ground connection terminal 22B is formed to be extended from a position slightly to the left of the left end of the piezoelectric vibration element connection terminal 23B to near the short side of the other side (the left side in Figure 12) of the rectangle of the substrate 2B. The length of the ground connection terminal 22B in the direction of the long side of the substrate 2B is shorter than that of the piezoelectric vibration element connection terminal 23B. As shown in Figure 12, the corner portion 21Ba of the piezoelectric vibration element connection terminal 21B in the A1-B2 direction is cut at an angle.

[0063] Furthermore, as shown in Figure 12, vias 272B and 273B are formed by filling the through-holes in the substrate 2B with conductors. Via 273B passes through the connection bonding pattern 26B and the piezoelectric vibration element connection terminal 21B, while via 272B passes through the connection bonding pattern 25B on the A2 side and also passes through the piezoelectric vibration element connection terminal 23B, as shown in Figure 11.

[0064] Similar to the piezoelectric vibration device 1 of the first embodiment, the piezoelectric vibration element connection terminals 23B and 21B on the second main surface 2Bb, which is the outer bottom surface (lower surface) of the substrate 2B, are formed to a length exceeding a straight line L representing half the length of the long side, extending from the short side to the long side on one side of the substrate 2B (the right side in Figure 12), and are superimposed on the piezoelectric vibration element mounting pads 63a and 63b provided on the stepped portion 62 of the package 6, respectively. Here, the via 273B is formed at the A2 side end (right end in Figure 12) of the piezoelectric vibration element connection terminal 21B, and the length of the piezoelectric vibration element connection terminal 21B may be shortened to the position shown by the dashed line in Figure 12. This reduces the risk of contact with the IC 5 located below the free end (left end in Figure 12) of the substrate 2B even if it is displaced by an impact.

[0065] At this time, of the first and second excitation electrodes 32Ba and 32Bb of the piezoelectric diaphragm 3B, the first excitation electrode 32Ba is connected to the piezoelectric vibration element connection terminal 23B on the second main surface 2Bb of the substrate 2B via a connecting bonding pattern 381B, internal wiring 39B, connecting bonding pattern 386B, connecting bonding pattern 25B, and via 272B. The second excitation electrode 32Bb is led out to the other end of the substrate 2B (the right side in Figure 12) via a connecting bonding pattern 382B, connecting bonding pattern 26B, and via 273B, and is connected to the A2 side end of the piezoelectric vibration element connection terminal 21B on the second main surface 2Bb of the substrate 2B.

[0066] Therefore, as shown in Figure 11, the position where the first excitation electrode 32Ba of the piezoelectric diaphragm 3B is led out onto the first main surface 2Ba of the substrate 2B is via 272B, and similarly, the position where the second excitation electrode 32Bb is led out is the A2 side end of the connecting bonding pattern 26B. Furthermore, the position where the second excitation electrode 32Bb is led out onto the first main surface 2Ba extends through the connecting bonding pattern 26B and to via 273B. The positions where the first and second excitation electrodes 32Ba and 32Bb are led out onto the second main surface 2Bb of the substrate 2B become vias 272B and via 273B of the substrate 2B, and are electrically connected to the piezoelectric vibration element connection terminals 23B and 21B, respectively.

[0067] Therefore, according to the third embodiment, the piezoelectric vibration element connection terminals 23B and 21B on the outer bottom surface of the substrate 2B are formed to a length exceeding a straight line L representing half of the long side, in the direction from the short side to the long side on one side of the substrate 2B (the right side in Figure 12), and are superimposed on the piezoelectric vibration element mounting pads 63a and 63b of the package 6, respectively, thus obtaining the same effects as the first embodiment.

[0068] Furthermore, as described above, the positions from which the first and second excitation electrodes 32Ba and 32Bb are derived on the substrate 2B are vias 272B and 273B on the substrate 2B, respectively. By forming the piezoelectric vibration element connection terminal 21B to be approximately the same length as the long side of the substrate 2B, it becomes possible to connect the first and second excitation electrodes 32Ba and 32Bb to the outside via piezoelectric vibration element mounting pads 63a and 63b provided on the stepped portion 62 of the package 6 without changing the internal wiring or internal structure of the package 6, thereby suppressing the cost increase associated with changing the internal wiring or internal structure of the piezoelectric vibration device 1B.

[0069] Furthermore, as shown in Figure 12, by cutting the corner portion 21Ba in the A1-B2 direction of the piezoelectric vibration element connection terminal 21B at an angle, the probability of contact with the IC 5 located below it can be reduced even if the free end on the left side of the substrate 2B in Figure 12 is displaced by an impact, thereby further improving reliability.

[0070] <Modification of the Third Embodiment> Modifications of the substrate of the piezoelectric vibration device according to the third embodiment described above will be explained with reference to Figure 13. The differences between the substrate of the modification and the substrate 2B of the third embodiment will be explained below. In the following explanation, Figures 6 to 12 will also be referenced, and in Figure 13, the same reference numerals as in Figures 6 to 12 indicate the same or equivalent components.

[0071] This modified example relates to a piezoelectric vibration device having a structure in which the piezoelectric diaphragm 3B and the upper sealing member 4B of the piezoelectric vibration device 1B shown in Figure 6 are laminated on the first main surface (upper surface) of a substrate 2C having a structure similar to that of substrate 2B (see Figures 11 and 12), as shown in Figure 13. Specifically, the shapes of the piezoelectric vibration element connection terminals 21C, 23C and the ground connection terminal 22C formed on the second main surface 2Cb, which is the outer bottom surface (lower surface) of substrate 2C, differ from the piezoelectric vibration element connection terminals 21B, 23B and the ground connection terminal 22B of substrate 2B in the third embodiment. In Figure 13, the positions of the outer frame portion 34B, cutout portion 36B, vibrating portion 33B and the second excitation electrode 32Bb of the piezoelectric diaphragm 3B (see Figures 9 and 10), which is joined to the first main surface of substrate 2C in an overlapping state, are shown by dashed lines, and 34B1 represents the inner peripheral wall of the outer frame portion 34B. Furthermore, Figure 13 omits the illustration of vias 272B and 273B shown in Figure 12.

[0072] The configuration of the second main surface 2Cb of substrate 2C will now be described. Similar to the piezoelectric vibration element connection terminals 21B, 23B and ground connection terminal 22B on the second main surface 2Bb of substrate 2B (see Figure 12), the second main surface 2Cb of substrate 2C is provided with piezoelectric vibration element connection terminals 21C, 23C and ground connection terminal 22C, as shown in Figure 13. At this time, as can be seen by comparing it with substrate 2B shown in Figure 12, the shapes of the regions M1, M2, and M3 enclosed by dashed lines in Figure 13 are different.

[0073] First, in the region M1 enclosed by the dashed line in Figure 13, a portion of the piezoelectric vibration element connection terminals 21C and 23C is cut diagonally. By cutting a portion of the piezoelectric vibration element connection terminals 21C and 23C in this way, there is a first advantage in that the area in which the first and second excitation electrodes 32Ba and 32Bb of the piezoelectric diaphragm 3B (see Figures 9 and 10) and the piezoelectric vibration element connection terminals 21C and 23C overlap can be reduced, thereby reducing parasitic capacitance. At this time, the piezoelectric vibration element connection terminals 23C and 21C and the piezoelectric vibration element mounting pads 63a and 63b of the package 6 (see Figure 2) can be joined by the bonding material 65 at a position close to the line L connecting the centers of the pair of long sides of the substrate 2C shown in Figure 13, and sufficient bonding strength can be secured without reducing the bonding area, thus achieving the same effects as in the third embodiment.

[0074] Next, the piezoelectric vibration element connection terminal 21C in region M2, enclosed by a dashed line in Figure 13, is cut out so that the edge of the piezoelectric vibration element connection terminal 21C near the free end in that region M2 forms an arc shape. By cutting out the edge in region M2 in this arc shape, the width of the piezoelectric vibration element connection terminal 21C in the B direction on the free end side of that edge becomes W1, which can be made larger than the width W2 (<W1) of the piezoelectric vibration element connection terminal 21C in the B direction on the free end side of that edge when the edge of the piezoelectric vibration element connection terminal 21C in region M2 is cut out at a right angle, as shown by the L-shaped dotted line in Figure 13.

[0075] Therefore, while maintaining the effect of the notches in the piezoelectric vibration element connection terminals 21C and 23C in region M1 in Figure 13, the overall area of ​​the piezoelectric vibration element connection terminal 21C can be made larger, and even with a configuration in which the width of the piezoelectric vibration element connection terminal 21C in direction B is partially narrowed, there is a second advantage in that the conductivity resistance of the piezoelectric vibration element connection terminal 21C can be kept low.

[0076] In Figure 13, the entire edge of the piezoelectric vibration element connection terminal 21C in region M2 is cut out in an arc shape, but the cutout portion does not need to be arc-shaped; it just needs to be curved. Also, at least a part of the cutout portion of the edge of the piezoelectric vibration element connection terminal 21C in region M2 needs to be curved.

[0077] Furthermore, in the region M3 enclosed by the dashed line in Figure 13, the corner of the ground connection terminal 22C in the A2-B2 direction is cut out in an L-shape. At this time, the edge of the L-shaped cutout is cut out so as to follow the inner peripheral wall 34B1 of the outer frame portion 34B of the piezoelectric diaphragm 3B (see Figures 9 and 10). By cutting it out in an L-shape in this way, the ground connection terminal 22C does not overlap with the cutout portion 36B between the outer frame portion 34B and the vibrating portion 33B of the piezoelectric diaphragm 3B (see Figures 9 and 10). This has a third advantage: when laminating the piezoelectric diaphragm 3B and the upper sealing member 4B onto the substrate 2C and pressurizing them together, the pressure during pressurizing between the substrate 2C and the piezoelectric diaphragm 3B can be effectively transmitted to the piezoelectric diaphragm 3B in the middle.

[0078] Therefore, according to the above modification, in addition to being able to achieve the same effects as the first embodiment, just like the third embodiment, it becomes possible to provide a piezoelectric vibration device that has the first, second, and third advantages described above.

[0079] It should be noted that the present invention is not limited to the above-described configuration, and various design modifications can be made within the scope of the matters described in the claims.

[0080] For example, in the embodiment described above, the shape of the vibrating part of the piezoelectric vibration element is rectangular (AT cut), but it is not limited to this, and for example it may be rectangular (SC cut, etc.) or tuning fork shaped (BT cut).

[0081] Furthermore, in the above-described embodiment, the piezoelectric vibration element mounting pads 63a and 63b were described as being electrically connected to the piezoelectric vibration element connection terminals 23, 21, 23B, 21B, 23C, and 21C of the substrates 2 and 2B, respectively, by a bonding material 65 such as a conductive adhesive. However, the bonding material is not limited to a conductive adhesive; it may also be a metal bump.

[0082] Alternatively, instead of the vias 272B and 273B described above, through-holes with conductors attached to their interiors may be formed.

[0083] Furthermore, in piezoelectric vibration devices 1, 1A, and 1B, the materials used for the piezoelectric vibration elements Pv, 30, and PvB are not limited to quartz, as long as they perform piezoelectric vibration.

[0084] Furthermore, the electronic component housed in package 6 is not limited to the IC 5 described above, but may also be a temperature sensor.

[0085] Furthermore, the above-described embodiment is applicable to both temperature sensor-integrated oscillators, SPXOs (Simple Packaged Crystal Oscillators), and TCXOs (Temperature Compensated Crystal Oscillators).

[0086] The present invention is widely applicable to piezoelectric vibration devices comprising a substrate that is substantially rectangular in plan view and has at least two connection terminals on its outer bottom surface, a piezoelectric vibration element mounted on the side of the substrate opposite to the outer bottom surface, an electronic component, and a package that hermetically seals the substrate, the piezoelectric vibration element mounted on the substrate, and the electronic component.

[0087] 1, 1A, 1B... Piezoelectric vibration device 2, 2B, 2C... Substrate 2a, 2Bb, 2Cb... Outer bottom surface 21, 23, 21B, 23B, 21C, 23C... Connection terminals for piezoelectric vibration element 3, 3B... Piezoelectric diaphragm 32Ba, 32Bb... First and second excitation electrodes 33B... Vibrating part 272B, 273B... Via 4, 4B... Sealing material Pv, PvB, 30... Piezoelectric vibration element 5... IC (Electronic component / integrated circuit element) 6... Package 61... Recess 62... Step 63a, 63b... Piezoelectric vibration element mounting pad (mounting pad) 65... Bonding material

Claims

1. A piezoelectric vibration device comprising: a substrate that is substantially rectangular in plan view and has at least two connection terminals on its outer bottom surface; a piezoelectric vibration element mounted on the side of the substrate opposite to the outer bottom surface; an electronic component; and a package that hermetically seals the substrate, the piezoelectric vibration element mounted on the substrate, and the electronic component, wherein the piezoelectric vibration element has a pair of excitation electrodes; the two connection terminals on the substrate are connection terminals for the piezoelectric vibration element, each connected to the pair of excitation electrodes; the package has a rectangular parallelepiped outer shape with an open top surface, and includes a recess formed off-center to one side, a stepped portion formed above the inner bottom surface of the recess, and a pair of mounting pads provided on the stepped portion that are electrically bonded to each of the two connection terminals for the piezoelectric vibration element; the electronic component is arranged on the inner bottom surface of the recess; and the substrate is cantilevered at one end and positioned above the electronic component with the other end as a free end, by which the two connection terminals for the piezoelectric vibration element are bonded to the pair of mounting pads via a bonding material. The piezoelectric vibration device is characterized in that the two connection terminals for piezoelectric vibration elements are arranged in parallel on the outer bottom surface along the short side of one end of the substrate, and are formed to a length exceeding half the length of the long side in the direction from the short side of one end of the substrate, so as to overlap with the pair of mounting pads in a plan view.

2. The piezoelectric vibration device according to claim 1, characterized in that one of the two connection terminals for the piezoelectric vibration element is formed to a length that substantially extends from the short side on one end of the substrate to the short side on the other end of the substrate opposite to the short side.

3. The piezoelectric vibration device according to claim 1 or 2, characterized in that the bonding material is a conductive adhesive.

4. The piezoelectric vibration device according to claim 1 or 2, wherein the piezoelectric vibration element has a vibrating portion including the pair of excitation electrodes, and the vibrating portion is hermetically sealed inside the package by a sealing member.

5. The piezoelectric vibration device according to claim 1 or 2, further comprising: a piezoelectric diaphragm having a vibrating portion including the pair of excitation electrodes and the substrate being superimposed and joined; and a sealing member superimposed on the side of the piezoelectric diaphragm opposite to the mounting surface on the substrate, which hermetically seals the vibrating portion of the piezoelectric diaphragm together with the substrate.

6. A piezoelectric vibration device according to claim 2, characterized in that at least on the other end of the substrate, a through-hole is formed in which a conductor is fitted inside a through-hole that penetrates in the thickness direction of the substrate, or a via is formed in which a conductor is filled inside a through-hole, one of the pair of excitation electrodes is led out to the other end of the substrate through the through-hole or the via, and one of the two connection terminals for the piezoelectric vibration element extends from one end of the substrate in the direction of the long side of the substrate and overlaps the through-hole or the via.

7. The piezoelectric vibration device according to claim 1, characterized in that the electronic component is an integrated circuit element that constitutes an oscillation circuit together with the piezoelectric vibration element, or a temperature sensor.

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