JP7543899B2 - Piezoelectric Vibration Device - Google Patents

Description

The present invention relates to piezoelectric vibration devices such as piezoelectric vibrators.

In recent years, the operating frequencies of various electronic devices have become higher and their packages have become smaller (especially lower profile). As a result, there is a demand for piezoelectric vibration devices (e.g., quartz crystal resonators, quartz crystal oscillators, etc.) to accommodate the higher frequencies and smaller packages.

In this type of piezoelectric vibration device, the housing is configured as a roughly rectangular parallelepiped package. This package is composed of a first sealing member and a second sealing member made of, for example, glass or quartz, and a piezoelectric vibration plate made of, for example, quartz with excitation electrodes formed on both main surfaces, and the first sealing member and the second sealing member are laminated and bonded via the piezoelectric vibration plate. The vibration part (excitation electrode) of the piezoelectric vibration plate arranged inside the package (internal space) is hermetically sealed (for example, Patent Document 1). Hereinafter, this type of laminated form of a piezoelectric vibration device is referred to as a sandwich structure.

JP 2010-252051 A

In the piezoelectric vibration device described above, the excitation electrode of the vibration part of the piezoelectric vibration plate is electrically connected to an external electrode terminal formed on the main surface of the second sealing member that does not face the internal space. When the piezoelectric vibration device is mounted on an external circuit board (mounting board), the external electrode terminal is electrically connected to the external circuit board via solder. However, since solder contains Sn (tin), if the electrical conduction path from the excitation electrode to the external electrode terminal contains Au (gold), there is a concern that the erosion action of the solder may cause an increase in conduction resistance or problems such as disconnection. Similar problems are also a concern when, for example, Au (gold) is contained in the electrical conduction path from the earth connection electrode formed on the main surface of the first sealing member that does not face the internal space to the external electrode terminal.

The present invention was made in consideration of the above-mentioned circumstances, and aims to provide a piezoelectric vibration device that can suppress the erosion caused by solder.

The present invention provides a means for solving the above-mentioned problems as follows: That is, the present invention provides a piezoelectric vibration device including a piezoelectric diaphragm having a first excitation electrode formed on one main surface of a substrate and a second excitation electrode formed on the other main surface of the substrate to be paired with the first excitation electrode, a first sealing member covering the first excitation electrode of the piezoelectric diaphragm, and a second sealing member covering the second excitation electrode of the piezoelectric diaphragm, the first sealing member and the piezoelectric diaphragm being bonded together, and the second sealing member being bonded together, thereby providing an internal space in which a vibration part of the piezoelectric diaphragm including the first excitation electrode and the second excitation electrode is hermetically sealed, wherein an external electrode terminal is formed on a main surface of the second sealing member that does not face the internal space, and the external electrode terminal is formed on a side surface of a package of the piezoelectric vibration device. the side wiring is electrically connected to a side wiring formed on a side surface of the second sealing member , a part or all of the side wiring is provided with an erosion-resistant structure against solder , the side wiring has at least one metal film made of a conductive metal other than Au formed on the side surface of the second sealing member and an Au film formed on the metal film, a part or all of the Au film of the side wiring is removed, and the side wiring is configured to be conductive via the conductive metal, the side wiring having the erosion-resistant structure is provided at least on the side surface of the second sealing member, and among the side wiring formed on the side surface of the package, the side wiring formed on the piezoelectric diaphragm is arranged to be shifted in a planar view with respect to the side wiring formed on the second sealing member .

According to the above configuration, the corrosion-resistant structure provided on some or all of the side wiring on the side of the package can block the corrosion path of the solder in the side wiring, so that it is possible to suppress the spread of solder in the conductive path via the side wiring to, for example, the first and second excitation electrodes and the earth connection electrode, and to suppress the erosion of the first and second excitation electrodes and the earth connection electrode by solder. It is also possible to suppress the increase in conductive resistance and the occurrence of breaks due to solder erosion of the side wiring.

In the above configuration, the side wiring having the erosion-resistant structure preferably has a metal film on the surface formed of a metal having a lower solder wettability than Au . According to this configuration, since the metal film on the surface of the side wiring is formed of a metal having a lower solder wettability than Au , the erosion path of the solder in the side wiring can be blocked, so that, for example, the spread of solder in the conduction path to the first and second excitation electrodes and the earth connection electrode can be suppressed, and the erosion of the first and second excitation electrodes and the earth connection electrode by solder can be suppressed. In addition, the increase in the conduction resistance due to the solder erosion of the side wiring and the occurrence of disconnection can be suppressed.

The present invention also relates to a piezoelectric vibration device including a piezoelectric diaphragm having a first excitation electrode formed on one main surface of a substrate and a second excitation electrode formed on the other main surface of the substrate to be paired with the first excitation electrode, a first sealing member covering the first excitation electrode of the piezoelectric diaphragm, and a second sealing member covering the second excitation electrode of the piezoelectric diaphragm, the first sealing member and the piezoelectric diaphragm being bonded together, and the second sealing member being bonded together, thereby providing an internal space in which a vibration part of the piezoelectric diaphragm including the first excitation electrode and the second excitation electrode is hermetically sealed. In this piezoelectric vibration device, an external electrode terminal is formed on a main surface of the second sealing member that does not face the internal space, and the external electrode terminal is formed on a side surface of a package of the piezoelectric vibration device. The side wiring is electrically connected to the second sealing member, and a part or all of the side wiring is provided with a solder erosion-resistant structure, and the side wiring has at least one metal film made of a conductive metal other than Au formed on the side of the second sealing member and an Au film formed on the metal film, and a part or all of the Au film of the side wiring is removed, and the side wiring is configured to be conductive by the conductive metal, and the side wiring having the erosion-resistant structure is provided at least on the side of the second sealing member , and among the side wirings formed on the package side, the side wiring formed on the piezoelectric diaphragm is arranged at a position that does not overlap the external electrode terminal in the vertical direction in a side view. With this configuration, at least on the side of the second sealing member among the package side, the erosion path of the solder can be blocked, and for example, erosion by solder of the first and second excitation electrodes and the earth connection electrode can be suppressed.

In the above configuration, it is preferable that the metal film is a film containing at least Ti. According to this configuration, a film containing at least Ti is formed on the surface of the metal film formed on the side surface of the package, so that the film containing Ti, which has low solder wettability, is exposed. This makes it possible to block the erosion path of the solder on the side surface of the package, and to suppress erosion by solder of, for example, the first and second excitation electrodes and the earth connection electrode.

In the above configuration, it is preferable that the piezoelectric diaphragm and the first and second sealing members are AT-cut quartz crystal plates, and the side wiring is formed along the Z'-axis direction of the AT-cut quartz crystal plate. With this configuration, it is possible to easily form stable side wiring that is less likely to break.

According to the piezoelectric vibration device of the present invention, the corrosion-resistant structure provided on some or all of the side wiring on the side of the package can block the corrosion path of the solder in the side wiring, so that, for example, it is possible to suppress the spread of solder in the conductive path to the first and second excitation electrodes and the earth connection electrode, and to suppress the erosion of the first and second excitation electrodes and the earth connection electrode by solder. In addition, it is possible to suppress the increase in conductive resistance and the occurrence of breakage due to solder erosion of the side wiring.

FIG. 1 is a schematic diagram showing the configuration of a crystal resonator according to this embodiment. FIG. 2 is a schematic plan view of the first main surface side of the first sealing member of the quartz crystal unit. FIG. 3 is a schematic plan view of the second main surface side of the first sealing member of the quartz crystal resonator. FIG. 4 is a schematic plan view of the first main surface side of the quartz crystal plate of the quartz crystal unit. FIG. 5 is a schematic plan view of the second main surface side of the quartz crystal plate of the quartz crystal unit. FIG. 6 is a schematic plan view of the first main surface side of the second sealing member of the quartz crystal unit. FIG. 7 is a schematic plan view of the second main surface side of the second sealing member of the quartz crystal resonator. FIG. 8 is a schematic side view of the crystal unit in the −X direction. FIG. 9 is a schematic side view of the +X direction side of the crystal unit. FIG. 10 is a schematic cross-sectional view of the second sealing member of the quartz crystal unit. FIG. 11 is a schematic side view of the crystal resonator according to the first modification, taken along the −X direction. FIG. 12 is a schematic side view of the +X direction side of the crystal unit according to the first modification.

Embodiments of the present invention will be described in detail below with reference to the drawings. Note that in the following embodiments, the piezoelectric vibration device to which the present invention is applied is a quartz crystal vibrator.

First, the basic structure of the quartz crystal unit 100 according to this embodiment will be described. As shown in FIG. 1, the quartz crystal unit 100 is configured to include a quartz crystal vibration plate (piezoelectric vibration plate) 10, a first sealing member 20, and a second sealing member 30. In this quartz crystal unit 100, the quartz crystal vibration plate 10 and the first sealing member 20 are bonded together, and the quartz crystal vibration plate 10 and the second sealing member 30 are bonded together to form a package having a substantially rectangular sandwich structure. That is, in the quartz crystal unit 100, the first sealing member 20 and the second sealing member 30 are bonded to each of the two main surfaces of the quartz crystal vibration plate 10 to form an internal space (cavity) of the package, and the vibration part 11 (see FIG. 4 and FIG. 5) is hermetically sealed in this internal space.

The crystal unit 100 according to this embodiment has a package size of, for example, 1.0 x 0.8 mm, and is designed to be compact and low-profile. In addition, in order to achieve the miniaturization, the package does not form castellations, but instead uses side wiring, etc., to provide electrical continuity between the electrodes, as described below. The crystal unit 100 is also designed to be electrically connected to an external circuit board (not shown) provided externally via solder.

Next, the quartz crystal plate 10, the first sealing member 20, and the second sealing member 30 in the above-mentioned quartz crystal unit 100 will be described with reference to Figs. 1 to 7. Note that the following describes each component that is configured as a single unit without being joined. Figs. 2 to 7 merely show an example configuration of the quartz crystal plate 10, the first sealing member 20, and the second sealing member 30, and are not intended to limit the present invention.

As shown in Figs. 4 and 5, the quartz crystal vibration plate 10 is a piezoelectric substrate made of quartz crystal, and both main surfaces (first main surface 101, second main surface 102) are formed as flat and smooth surfaces (mirror finish). In this embodiment, an AT-cut quartz crystal plate that performs thickness-shear vibration is used as the quartz crystal vibration plate 10. In the quartz crystal vibration plate 10 shown in Figs. 4 and 5, both main surfaces 101 and 102 of the quartz crystal vibration plate 10 are XZ' planes. In this XZ' plane, the direction parallel to the short side direction (short side direction) of the quartz crystal vibration plate 10 is the X-axis direction, and the direction parallel to the long side direction (long side direction) of the quartz crystal vibration plate 10 is the Z'-axis direction. The AT cut is a processing technique in which the three crystal axes of artificial quartz crystal, the electrical axis (X-axis), the mechanical axis (Y-axis), and the optical axis (Z-axis), are cut at an angle of 35°15' around the X-axis with respect to the Z-axis. In an AT-cut quartz plate, the X-axis coincides with the crystal axis of the quartz. The Y'-axis and Z'-axis coincide with axes that are inclined at approximately 35°15' from the Y-axis and Z-axis of the quartz crystal, respectively (this cutting angle may be changed somewhat within the range that adjusts the frequency-temperature characteristics of the AT-cut quartz plate). The Y'-axis and Z'-axis directions correspond to the cutting direction when cutting out the AT-cut quartz plate.

A pair of excitation electrodes (first excitation electrode 111, second excitation electrode 112) are formed on both main surfaces 101, 102 of the quartz crystal vibration plate 10. The quartz crystal vibration plate 10 has a vibration part 11 formed in a substantially rectangular shape, an outer frame part 12 surrounding the outer periphery of the vibration part 11, and a holding part 13 that holds the vibration part 11 by connecting the vibration part 11 and the outer frame part 12. In other words, the quartz crystal vibration plate 10 is configured such that the vibration part 11, the outer frame part 12, and the holding part 13 are integrally provided. The holding part 13 extends (protrudes) from only one corner of the vibration part 11 located in the +X direction and the -Z' direction to the outer frame part 12 in the -Z' direction. And, a cutout part 10a formed by cutting out the quartz crystal vibration plate 10 is provided between the vibration part 11 and the outer frame part 12. In this embodiment, the quartz crystal vibration plate 10 has only one holding portion 13 that connects the vibration portion 11 and the outer frame portion 12, and the cutout portion 10a is formed continuously so as to surround the outer periphery of the vibration portion 11.

The first excitation electrode 111 is provided on the first main surface 101 side of the vibration part 11, and the second excitation electrode 112 is provided on the second main surface 102 side of the vibration part 11. The first excitation electrode 111 and the second excitation electrode 112 are connected to lead-out wiring (first lead-out wiring 113, second lead-out wiring 114) for connecting these excitation electrodes to external electrode terminals. The first lead-out wiring 113 is led out from the first excitation electrode 111 and connected to the connection bonding pattern 14 formed on the outer frame part 12 via the holding part 13. The second lead-out wiring 114 is led out from the second excitation electrode 112 and connected to the connection bonding pattern 15 formed on the outer frame part 12 via the holding part 13.

On both main surfaces (first main surface 101, second main surface 102) of the quartz crystal vibration plate 10, a vibration plate-side sealing portion for bonding the quartz crystal vibration plate 10 to the first sealing member 20 and the second sealing member 30 is provided. A vibration plate-side first bonding pattern 121 is formed as the vibration plate-side sealing portion of the first main surface 101, and a vibration plate-side second bonding pattern 122 is formed as the vibration plate-side sealing portion of the second main surface 102. The vibration plate-side first bonding pattern 121 and the vibration plate-side second bonding pattern 122 are provided on the outer frame portion 12 and are formed in a ring shape in a plan view. The outer peripheral edge of the vibration plate-side first bonding pattern 121 is provided close to the outer peripheral edge of the first main surface 101 of the quartz crystal vibration plate 10 (outer frame portion 12). The outer peripheral edge of the vibration plate-side second bonding pattern 122 is provided close to the outer peripheral edge of the second main surface 102 of the quartz crystal vibration plate 10 (outer frame portion 12).

Interlaminar wiring bonding patterns 181, 182 are formed on the outer periphery of the vibration plate-side first bonding pattern 121 on the first main surface 101 of the quartz crystal vibration plate 10. The interlaminar wiring bonding patterns 181, 182 are not connected to the vibration plate-side first bonding pattern 121, and are provided at a predetermined distance from the vibration plate-side first bonding pattern 121. The interlaminar wiring bonding pattern 181 is provided on the -X direction side and +Z' direction side of the first main surface 101 of the quartz crystal vibration plate 10, and is connected to the first side wiring 171 described later. The interlaminar wiring bonding pattern 182 is provided on the +X direction side and -Z' direction side of the first main surface 101 of the quartz crystal vibration plate 10, and is connected to the second side wiring 172 described later.

In addition, interlaminar wiring bonding patterns 183 and 184 are formed on the outer periphery of the vibration plate side second bonding pattern 122 on the second main surface 102 of the quartz crystal vibration plate 10. The interlaminar wiring bonding patterns 183 and 184 are not connected to the vibration plate side second bonding pattern 122, and are provided at a predetermined interval from the vibration plate side second bonding pattern 122. The interlaminar wiring bonding pattern 183 is provided on the -X direction side and +Z' direction side of the second main surface 102 of the quartz crystal vibration plate 10, and is connected to the first side wiring 171 described later. The interlaminar wiring bonding pattern 184 is provided on the +X direction side and -Z' direction side of the second main surface 102 of the quartz crystal vibration plate 10, and is connected to the second side wiring 172 described later.

As shown in Figs. 4 and 5, the quartz crystal vibration plate 10 has one through hole formed between the first main surface 101 and the second main surface 102. Specifically, the first through hole 162 is provided in the outer frame portion 12, on the inner periphery side of the vibration plate side first bonding pattern 121 and the vibration plate side second bonding pattern 122. The first through hole 162 is also provided on one side in the Z' axis direction of the vibration portion 11 (the -Z' direction side in Figs. 4 and 5). Around the first through hole 162, a connection bonding pattern 124 is formed on the first main surface 101 side, and a connection bonding pattern 15 is formed on the second main surface 102 side.

In the first through-hole 162, a through electrode for establishing electrical continuity between the electrodes formed on the first main surface 101 and the second main surface 102 is formed along the inner wall surface of the first through-hole 162. The central portion of the first through-hole 162 is a hollow through portion that penetrates between the first main surface 101 and the second main surface 102. Note that electrical continuity between the electrodes on the first main surface 101 and the second main surface 102 may be achieved by means other than the through-hole through-electrode (for example, wiring formed on the inner wall surface of the outer frame portion 12, etc.).

As shown in Figures 4 and 5, two side wirings are formed on the side of the quartz crystal plate 10. Specifically, a first side wiring 171 is formed on the side 103 on the -X direction side of the quartz crystal plate 10. A second side wiring 172 is formed on the side 104 on the +X direction side of the quartz crystal plate 10.

The first side wiring 171 is formed on the +Z' direction side of the side surface 103 on the -X direction side of the quartz crystal plate 10. The first side wiring 171 is connected to an interlayer wiring bonding pattern 181 provided on the first main surface 101 of the quartz crystal plate 10. The first side wiring 171 is connected to an interlayer wiring bonding pattern 183 provided on the second main surface 202 of the quartz crystal plate 10.

The second side wiring 172 is formed on the -Z' direction side of the side 104 on the +X direction side of the quartz crystal plate 10. The second side wiring 172 is connected to an interlayer wiring bonding pattern 182 provided on the first main surface 101 of the quartz crystal plate 10. The second side wiring 172 is connected to an interlayer wiring bonding pattern 184 provided on the second main surface 202 of the quartz crystal plate 10.

In addition, as shown in Figures 4 and 5, two internal wirings are formed on the inner wall surface of the outer frame portion 12 of the quartz vibration plate 10. Specifically, a first internal wiring 173 is formed on the inner wall surface 105 on the -X direction side of the outer frame portion 12 of the quartz vibration plate 10. A second internal wiring 174 is formed on the inner wall surface 106 on the +X direction side of the outer frame portion 12 of the quartz vibration plate 10.

The first internal wiring 173 is provided with a predetermined width in the center of the inner wall surface 105 on the -X direction side of the outer frame portion 12. The first internal wiring 173 is connected to the vibration plate side first bonding pattern 121 provided on the first main surface 101 of the quartz vibration plate 10. The first internal wiring 173 is connected to the vibration plate side second bonding pattern 122 provided on the second main surface 102 of the quartz vibration plate 10.

The second internal wiring 174 is provided with a predetermined width in the center of the inner wall surface 106 on the +X direction side of the outer frame portion 12. The second internal wiring 174 is connected to the vibration plate side first bonding pattern 121 provided on the first main surface 101 of the quartz vibration plate 10. The second internal wiring 174 is connected to the vibration plate side second bonding pattern 122 provided on the second main surface 102 of the quartz vibration plate 10. The first internal wiring 173 and the second internal wiring 174 are arranged to face each other with the vibration part 11 in between.

As shown in Figures 2 and 3, the first sealing member 20 is a rectangular parallelepiped substrate formed from a single AT-cut quartz plate, and the second main surface 202 (the surface that is bonded to the quartz vibration plate 10) of this first sealing member 20 is formed as a flat and smooth surface (mirror finish). Although the first sealing member 20 does not have a vibrating part, by using an AT-cut quartz plate like the quartz vibration plate 10, the thermal expansion coefficients of the quartz vibration plate 10 and the first sealing member 20 can be made the same, and thermal deformation in the quartz vibration unit 100 can be suppressed. In addition, the orientations of the X-axis, Y-axis, and Z'-axis in the first sealing member 20 are also the same as those of the quartz vibration plate 10.

2, the first main surface 201 (the outer main surface not facing the quartz crystal plate 10) of the first sealing member 20 has first and second terminals 22, 23 for wiring and a metal film 28 for shielding (earth connection). The first and second terminals 22, 23 for wiring are provided as wiring for electrically connecting the first and second excitation electrodes 111, 112 of the quartz crystal plate 10 to the external electrode terminal 32 of the second sealing member 30. The first and second terminals 22, 23 are provided at both ends in the Z'-axis direction, with the first terminal 22 provided on the +Z'-direction side and the second terminal 23 provided on the -Z'-direction side. The first and second terminals 22, 23 are formed to extend in the X-axis direction. The first terminal 22 and the second terminal 23 are formed in a substantially rectangular shape. The first terminal 22 extends to the end of the first main surface 201 on the -X direction side and is connected to a third side wiring 271, which will be described later. The second terminal 23 extends to the end of the first main surface 201 on the +X direction side and is connected to a fourth side wiring 272, which will be described later.

The metal film 28 is provided between the first and second terminals 22, 23 and is disposed at a predetermined interval from the first and second terminals 22, 23. The metal film 28 is provided in almost all areas of the first main surface 201 of the first sealing member 20 where the first and second terminals 22, 23 are not formed. The metal film 28 is provided from the end in the +X direction to the end in the -X direction of the first main surface 201 of the first sealing member 20. The metal film 28 extends to the end in the -X direction of the first main surface 201 and is connected to the fifth side wiring 273 described later. The metal film 28 also extends to the end in the +X direction of the first main surface 201 and is connected to the sixth side wiring 274 described later.

As shown in Figures 2 and 3, the first sealing member 20 has two through holes formed between the first main surface 201 and the second main surface 202. Specifically, second and third through holes 212 and 213 are provided in the +Z' and -Z' directions in Figures 2 and 3, respectively.

In the second and third through holes 212 and 213, a through electrode for establishing electrical continuity between the electrodes formed on the first main surface 201 and the second main surface 202 is formed along the inner wall surface of each of the second and third through holes 212 and 213. In addition, the central portion of each of the second and third through holes 212 and 213 is a hollow through portion that penetrates between the first main surface 201 and the second main surface 202. The through electrode of the second through hole 212 is electrically connected to the first terminal 22. The through electrode of the third through hole 213 is electrically connected to the second terminal 23.

On the second main surface 202 of the first sealing member 20, a sealing member side first bonding pattern 24 is formed as a sealing member side first sealing part for bonding to the quartz crystal vibration plate 10. The sealing member side first bonding pattern 24 is formed in a ring shape in a plan view. The outer periphery of the sealing member side first bonding pattern 24 is provided close to the outer periphery of the second main surface 202 of the first sealing member 20. In addition, on the second main surface 202 of the first sealing member 20, a connection bonding pattern 261 is formed around the second through hole 212, and a connection bonding pattern 262 is formed around the third through hole 213. Furthermore, a connection bonding pattern 263 is formed on the opposite side (-Z' direction side) of the long axis direction of the first sealing member 20 from the connection bonding pattern 261, and the connection bonding pattern 261 and the connection bonding pattern 263 are connected by a wiring pattern 27.

In addition, on the second main surface 202 of the first sealing member 20, interlaminar wiring bonding patterns 281 and 282 are formed on the outer periphery of the sealing member side first bonding pattern 24. The interlaminar wiring bonding patterns 281 and 282 are not connected to the sealing member side first bonding pattern 24 and are provided at a predetermined interval from the sealing member side first bonding pattern 24. The interlaminar wiring bonding pattern 281 is provided on the -X direction side and +Z' direction side of the second main surface 202 of the first sealing member 20 and is connected to the third side wiring 271 described later. The interlaminar wiring bonding pattern 282 is provided on the +X direction side and -Z' direction side of the second main surface 202 of the first sealing member 20 and is connected to the fourth side wiring 272 described later.

As shown in Figures 2 and 3, four side wirings are formed on the side of the first sealing member 20. Specifically, a third side wiring 271 and a fifth side wiring 273 are formed on the side 203 on the -X direction side of the first sealing member 20. A fourth side wiring 272 and a sixth side wiring 274 are formed on the side 204 on the +X direction side of the first sealing member 20.

The third side wiring 271 is formed on the +Z' direction side of the side surface 203 on the -X direction side of the first sealing member 20. The third side wiring 271 is connected to the first terminal 22 provided on the first main surface 201 of the first sealing member 20. The third side wiring 271 is connected to the interlayer wiring bonding pattern 281 provided on the second main surface 202 of the first sealing member 20.

The fourth side wiring 272 is formed on the -Z' direction side of the side 204 on the +X direction side of the first sealing member 20. The fourth side wiring 272 is connected to the second terminal 23 provided on the first main surface 201 of the first sealing member 20. The fourth side wiring 272 is connected to the interlayer wiring bonding pattern 282 provided on the second main surface 202 of the first sealing member 20.

The fifth side wiring 273 is formed on the -Z' direction side of the side 203 on the -X direction side of the first sealing member 20. The fifth side wiring 273 is connected to the metal film 28 provided on the first main surface 201 of the first sealing member 20. The fifth side wiring 273 is connected to the sealing member side first bonding pattern 24 provided on the second main surface 202 of the first sealing member 20.

The sixth side wiring 274 is formed on the +Z' direction side of the side 204 on the +X direction side of the first sealing member 20. The sixth side wiring 274 is connected to the metal film 28 provided on the first main surface 201 of the first sealing member 20. The sixth side wiring 274 is connected to the sealing member side first bonding pattern 24 provided on the second main surface 202 of the first sealing member 20.

As shown in Figures 6 and 7, the second sealing member 30 is a rectangular parallelepiped substrate formed from a single AT-cut quartz plate, and the first main surface 301 (the surface that is bonded to the quartz vibration plate 10) of this second sealing member 30 is formed as a flat and smooth surface (mirror-finished). Note that it is preferable that the second sealing member 30 also uses an AT-cut quartz plate like the quartz vibration plate 10, and that the orientation of the X-axis, Y-axis, and Z'-axis is also the same as that of the quartz vibration plate 10.

A sealing member-side second bonding pattern 31 is formed on the first main surface 301 of the second sealing member 30 as a sealing member-side second sealing portion for bonding to the quartz crystal vibration plate 10. The sealing member-side second bonding pattern 31 is formed in a ring shape in a plan view. The outer peripheral edge of the sealing member-side second bonding pattern 31 is provided close to the outer peripheral edge of the first main surface 301 of the second sealing member 30.

In addition, on the first main surface 301 of the second sealing member 30, interlaminar wiring bonding patterns 381 and 382 are formed on the outer periphery of the sealing member side second bonding pattern 31. The interlaminar wiring bonding patterns 381 and 382 are not connected to the sealing member side second bonding pattern 31 and are provided at a predetermined interval from the sealing member side second bonding pattern 31. The interlaminar wiring bonding pattern 381 is provided on the -X direction side and +Z' direction side of the first main surface 301 of the second sealing member 30 and is connected to the seventh side wiring 371 described later. The interlaminar wiring bonding pattern 382 is provided on the +X direction side and -Z' direction side of the first main surface 301 of the second sealing member 30 and is connected to the eighth side wiring 372 described later.

Four external electrode terminals 32 are provided on the second main surface 302 (the outer main surface not facing the quartz crystal vibration plate 10) of the second sealing member 30, which are electrically connected to an external circuit board provided outside the quartz crystal vibration plate 100. The external electrode terminals 32 are located at the four corners (corner portions) of the second main surface 302 of the second sealing member 30. In a plan view, the external electrode terminals 32 are each provided along the internal space of the package of the quartz crystal vibration plate 100, and are formed in a substantially L-shape. In a plan view, the external electrode terminals 32 are provided at positions that overlap the outer frame portion 12 of the quartz crystal vibration plate 10 described above.

As shown in Figures 6 and 7, four side wirings are formed on the side of the second sealing member 30. Specifically, a seventh side wiring 371 and a ninth side wiring 373 are formed on the side 303 on the -X direction side of the second sealing member 30. An eighth side wiring 372 and a tenth side wiring 374 are formed on the side 304 on the +X direction side of the second sealing member 30.

The seventh side wiring 371 is formed on the +Z' direction side of the side surface 303 on the -X direction side of the second sealing member 30. The seventh side wiring 371 is connected to the interlayer wiring junction pattern 381 provided on the first main surface 301 of the second sealing member 30. The seventh side wiring 371 is connected to the external electrode terminal 32 provided on the second main surface 302 of the second sealing member 30.

The eighth side wiring 372 is formed on the -Z' direction side of the side 304 on the +X direction side of the second sealing member 30. The eighth side wiring 372 is connected to the interlayer wiring junction pattern 382 provided on the first main surface 301 of the second sealing member 30. The eighth side wiring 372 is connected to the external electrode terminal 32 provided on the second main surface 302 of the second sealing member 30.

The ninth side wiring 373 is formed on the -Z' direction side of the side surface 303 on the -X direction side of the second sealing member 30. The ninth side wiring 373 is connected to the sealing member side second bonding pattern 31 provided on the first main surface 301 of the second sealing member 30. The ninth side wiring 373 is connected to the external electrode terminal 32 provided on the second main surface 302 of the second sealing member 30.

The tenth side wiring 374 is formed on the +Z' direction side of the side 304 on the +X direction side of the second sealing member 30. The tenth side wiring 374 is connected to the sealing member side second bonding pattern 31 provided on the first main surface 301 of the second sealing member 30. The tenth side wiring 374 is connected to the external electrode terminal 32 provided on the second main surface 302 of the second sealing member 30.

In the quartz crystal vibrator 100 including the quartz crystal vibrating plate 10, the first sealing member 20, and the second sealing member 30 configured as above, the quartz crystal vibrating plate 10 and the first sealing member 20 are diffusion bonded in a state where the first bonding pattern 121 on the diaphragm side and the first bonding pattern 24 on the sealing member side are overlapped, and the quartz crystal vibrating plate 10 and the second sealing member 30 are diffusion bonded in a state where the second bonding pattern 122 on the diaphragm side and the second bonding pattern 31 on the sealing member side are overlapped, thereby manufacturing a sandwich-structured package as shown in Figures 1, 8, and 9. This hermetically seals the internal space of the package, i.e., the space housing the vibrating portion 11.

In the quartz crystal vibrator 100, the sealing portions (seal paths) 115, 116 that hermetically seal the vibration portion 11 of the quartz crystal vibrating plate 10 are formed in a ring shape in a plan view. The seal path 115 is formed by diffusion bonding (Au-Au bonding) of the above-mentioned vibration plate side first bonding pattern 121 and the sealing member side first bonding pattern 24, and the inner edge shape of the seal path 115 is formed in a substantially octagonal shape. The outer edge shape of the seal path 115 is formed in a substantially rectangular shape, and the outer periphery of the seal path 115 is disposed close to the outer periphery of the package. Similarly, the seal path 116 is formed by diffusion bonding (Au-Au bonding) of the above-mentioned vibration plate side second bonding pattern 122 and the sealing member side second bonding pattern 31, and the inner edge shape of the seal path 116 is formed in a substantially octagonal shape. The outer edge shape of the seal path 116 is formed in a substantially rectangular shape, and the outer periphery of the seal path 116 is disposed close to the outer periphery of the package.

In the quartz crystal unit 100 in which the seal paths 115, 116 are formed by diffusion bonding in this manner, the first sealing member 20 and the quartz crystal plate 10 have a gap of 1.00 μm or less, and the second sealing member 30 and the quartz crystal plate 10 have a gap of 1.00 μm or less. In other words, the thickness of the seal path 115 between the first sealing member 20 and the quartz crystal plate 10 is 1.00 μm or less, and the thickness of the seal path 116 between the second sealing member 30 and the quartz crystal plate 10 is 1.00 μm or less (specifically, 0.15 μm to 1.00 μm in the Au-Au bonding of this embodiment). As a comparative example, the thickness of a conventional metal paste sealing material using Sn is 5 μm to 20 μm.

The above-mentioned connection bonding patterns and interlaminar wiring bonding patterns are also diffusion bonded in a state of being superimposed. The connection bonding patterns and the interlaminar wiring bonding patterns are bonded to each other, and thus, in the quartz crystal resonator 100, electrical conduction is obtained between the first excitation electrode 111, the second excitation electrode 112, and the external electrode terminal 32. Specifically, the first excitation electrode 111 is connected to the external electrode terminal 32 via the first lead wiring 113, the wiring pattern 27, the second through hole 212, the first terminal 22, the third side wiring 271, the first interlaminar wiring 117, the first side wiring 171, the second interlaminar wiring 118, and the seventh side wiring 371 in this order. The first interlaminar wiring 117 is a wiring disposed between the first sealing member 20 and the quartz crystal plate 10. The first interlayer wiring 117 is formed by diffusion bonding between an interlayer wiring bonding pattern 281 formed on the second main surface 202 of the first sealing member 20 and an interlayer wiring bonding pattern 181 formed on the first main surface 101 of the quartz crystal vibration plate 10. As shown in FIG. 8, a third side surface wiring 271 is connected to an end of the first interlayer wiring 117 on the +Z' direction side, and a first side surface wiring 171 is connected to an end of the first interlayer wiring 117 on the -Z' direction side. The second interlayer wiring 118 is a wiring disposed between the layers of the quartz crystal vibration plate 10 and the second sealing member 30. The second interlayer wiring 118 is formed by diffusion bonding between an interlayer wiring bonding pattern 183 formed on the second main surface 102 of the quartz crystal vibration plate 10 and an interlayer wiring bonding pattern 381 formed on the first main surface 301 of the second sealing member 30.
As shown in FIG. 8, the first side wiring 171 is connected to the end of the second interlayer wiring 118 on the -Z' direction side, and the seventh side wiring 371 is connected to the end of the second interlayer wiring 118 on the +Z' direction side.

The second excitation electrode 112 is connected to the external electrode terminal 32 via the second lead-out wiring 114, the first through hole 162, the third through hole 213, the second terminal 23, the fourth side wiring 272, the third interlaminar wiring 119, the second side wiring 172, the fourth interlaminar wiring 120, and the eighth side wiring 372 in this order. The third interlaminar wiring 119 is a wiring disposed between the first sealing member 20 and the quartz crystal vibration plate 10. The third interlaminar wiring 119 is formed by diffusion bonding between the interlaminar wiring bonding pattern 282 formed on the second main surface 202 of the first sealing member 20 and the interlaminar wiring bonding pattern 182 formed on the first main surface 101 of the quartz crystal vibration plate 10. As shown in FIG. 9, the fourth side wiring 272 is connected to the end of the third interlayer wiring 119 on the -Z' direction side, and the second side wiring 172 is connected to the end of the third interlayer wiring 119 on the +Z' direction side. The fourth interlayer wiring 120 is a wiring arranged between the layers of the quartz crystal vibration plate 10 and the second sealing member 30. This fourth interlayer wiring 120 is formed by diffusion bonding between the interlayer wiring bonding pattern 184 formed on the second main surface 102 of the quartz crystal vibration plate 10 and the interlayer wiring bonding pattern 382 formed on the first main surface 301 of the second sealing member 30. As shown in FIG. 9, the second side wiring 172 is connected to the end of the fourth interlayer wiring 120 on the +Z' direction side, and the eighth side wiring 372 is connected to the end of the fourth interlayer wiring 120 on the -Z' direction side.

Furthermore, the metal film 28 is connected to earth (ground connection, using a part of the external electrode terminal 32) via the fifth side wiring 273, the seal path 115, the first internal wiring 173, the seal path 116, and the ninth side wiring 373 in that order. Similarly, the metal film 28 is connected to earth (ground connection, using a part of the external electrode terminal 32) via the sixth side wiring 274, the seal path 115, the second internal wiring 174, the seal path 116, and the tenth side wiring 374 in that order.

In this embodiment, the electrical conduction paths between the first and second excitation electrodes 111, 112 and the external electrode terminals 32, 32 are not electrically connected to the annular seal paths 115, 116.

Specifically, inside the annular seal paths 115 and 116 in plan view, the first excitation electrode 111 is electrically connected to the first terminal 22 on the first main surface 201 of the first sealing member 20 through the through electrode of the second through hole 212. The first terminal 22 is arranged across the inside and outside of the annular seal paths 115 and 116 in plan view. Then, outside the annular seal paths 115 and 116 in plan view, the first terminal 22 is electrically connected to the external electrode terminal 32 on the second main surface 302 of the second sealing member 30 via the side wiring 271, 171, and 371 formed on the package side of the quartz crystal unit 100. Such an electrical conduction path between the first excitation electrode 111 and the external electrode terminal 32 is not electrically connected to the annular seal paths 115 and 116.

Similarly, inside the annular seal paths 115 and 116 in plan view, the second excitation electrode 112 is electrically connected to the second terminal 23 on the first main surface 201 of the first sealing member 20 through the through electrode of the first through hole 162 and the through electrode of the third through hole 213. The second terminal 23 is arranged across the inside and outside of the annular seal paths 115 and 116 in plan view. Then, outside the annular seal paths 115 and 116 in plan view, the second terminal 23 is electrically connected to the external electrode terminal 32 on the second main surface 302 of the second sealing member 30 via the side wiring 272, 172, and 372 formed on the package side of the quartz crystal unit 100. Such an electrical conduction path between the second excitation electrode 112 and the external electrode terminal 32 is not electrically connected to the annular seal paths 115 and 116.

In the quartz crystal unit 100, the various bonding patterns described above are preferably formed by stacking multiple layers on the quartz crystal plate, with a Ti (titanium) layer and an Au (gold) layer formed from the bottom layer side by vapor deposition or sputtering. In addition, if the other wiring and electrodes formed on the quartz crystal unit 100 have the same configuration as the bonding pattern, the bonding pattern, wiring, and electrodes can be patterned simultaneously, which is preferable.

In this embodiment, in the quartz crystal unit 100 having the above configuration, a part or all of the Au film is removed from the seventh and eighth side wirings 371, 372 of the second sealing member 30, and the seventh and eighth side wirings 371, 372 of the second sealing member 30 are configured to be conductive by a conductive metal other than Au, so that the quartz crystal unit 100 has a structure that is resistant to erosion by solder. This point will be described in detail below.

On the second main surface 302 of the second sealing member 30 of the quartz crystal unit 100, which does not face the internal space, an external electrode terminal 32 is formed, which is electrically connected to an external circuit board via solder. The external electrode terminal 32 is electrically connected to the first excitation electrode 111 via side wirings 371, 171, and 271 formed on the package side of the quartz crystal unit 100. The external electrode terminal 32 is also electrically connected to the second excitation electrode 112 via side wirings 372, 172, and 272 formed on the package side of the quartz crystal unit 100. The seventh and eighth side wirings 371 and 372 of the second sealing member 30 are provided with a solder erosion-resistant structure.

The erosion-resistant structure of this embodiment will be described with reference to FIG. 10. Note that FIG. 10 only shows the erosion-resistant structure provided on the seventh side wiring 371 on the side 303 on the −X direction side of the second sealing member 30, but a similar erosion-resistant structure is also provided on the eighth side wiring 372 on the side 304 on the +X direction side of the second sealing member 30.

As shown in FIG. 10, a seventh side wiring 371 is formed on the side surface 303 on the -X direction side of the second sealing member 30. The seventh side wiring 371 electrically connects the external electrode terminal 32 formed on the second main surface 302 of the second sealing member 30 and the second interlayer wiring 118 formed on the first main surface 301 of the second sealing member 30.

The seventh side wiring 371 has a first metal film 371a made of a first conductive metal formed by vapor deposition or sputtering on the side 303 on the -X direction side of the second sealing member 30, and a second metal film 371b made of a second conductive metal formed by vapor deposition or sputtering on the first metal film 371a.

The external electrode terminal 32 has a first metal film 32a made of a first conductive metal formed by vapor deposition or sputtering on the second main surface 302 of the second sealing member 30, a second metal film 32b made of a second conductive metal formed by vapor deposition or sputtering on the first metal film 32a, and an Au film 32c made of Au (gold) formed by vapor deposition, for example, on the second metal film 32b.

The second interlayer wiring 118 is formed by bonding an interlayer wiring bonding pattern 381 provided on the first main surface 301 of the second sealing member 30 and an interlayer wiring bonding pattern 183 provided on the second main surface 202 of the quartz crystal vibration plate 10. Since the Au film is removed from the second sealing member 30 in the wafer state before the second interlayer wiring 118 is formed (before bonding), FIG. 10 shows only the interlayer wiring bonding pattern 381 before the second interlayer wiring 118 is formed (before bonding). The interlayer wiring bonding pattern 381 has a first metal film 381a made of a first conductive metal formed by vapor deposition or sputtering on the first main surface 301 of the second sealing member 30, and an Au film 381c made of Au (gold) formed by vapor deposition or sputtering on the first metal film 381a.

In this embodiment, Ti (titanium) is used as the first conductive metal, and NiTi (nickel-titanium) is used as the second conductive metal. The above-mentioned first and second conductive metals are only examples, and conductive metals other than those mentioned above may be used. The multi-layer structure of the seventh side wiring 371, the external electrode terminal 32, and the interlayer wiring bonding pattern 381 is only an example, and the number of layers of each electrode is not particularly limited. For example, the interlayer wiring bonding pattern 381 may have a three-layer structure having a second metal film, similar to the external electrode terminal 32, or the external electrode terminal 32 may have a two-layer structure without a second metal film, similar to the interlayer wiring bonding pattern 381.

The first metal film 381a of the interlayer wiring bonding pattern 381, the first metal film 371a of the seventh side wiring 371, and the first metal film 32a of the external electrode terminal 32 are integrally formed. In addition, the second metal film 371b of the seventh side wiring 371 and the second metal film 32b of the external electrode terminal 32 are integrally formed.

On the other hand, the Au film 381c of the interlaminar wiring bonding pattern 381 and the Au film 32c of the external electrode terminal 32 are not formed integrally, and are cut off at the side surface 303 on the -X direction side of the second sealing member 30. The seventh side wiring 371 is configured such that the interlaminar wiring bonding pattern 381 and the external electrode terminal 32 are electrically connected by a conductive metal other than Au. In this case, the seventh side wiring 371 can be formed by removing the Au film formed on the side surface 303 on the -X direction side of the second sealing member 30. In other words, an Au film is formed in advance on the side surface 303 on the -X direction side of the second sealing member 30, and this Au film is formed integrally with the Au film 381c of the interlaminar wiring bonding pattern 381 and the Au film 32c of the external electrode terminal 32. Then, the Au film on the side surface 303 on the -X direction side of the second sealing member 30 is removed by, for example, metal etching, to form the seventh side surface wiring 371 that does not include the Au film. In this way, the seventh side surface wiring 371 from which the Au film has been removed is formed on the side surface 303 on the -X direction side of the second sealing member 30. The removal of the Au film is performed on the second sealing member 30 in the form of a wafer, and is performed before the second sealing member 30 is bonded to the quartz crystal plate 10.

As shown in FIG. 10, the entire Au film on the side surface 303 of the second sealing member 30 on the -X direction side may be removed, or only a portion of the Au film on the side surface 303 of the second sealing member 30 on the -X direction side may be removed.

In this embodiment, part or all of the Au film is removed from the seventh side wiring 371, and the seventh side wiring 371 is configured to provide electrical continuity through a conductive metal other than Au, so that it has resistance to corrosion by solder.

In more detail, when mounting the quartz crystal unit 100 on an external circuit board, solder is generally used, and the solder is interposed between the external electrode terminal 32 of the second sealing member 30 and the external circuit board. However, since solder contains Sn (tin), if the seventh side wiring 371 has an Au film, there is a risk that the solder will wet and spread along the Au film into the seventh side wiring 371. For this reason, there is a concern that the Au constituting the Au film will diffuse into the solder due to the erosion of the solder, causing problems such as an increase in electrical resistance and disconnection. Thus, if the seventh side wiring 371 is configured to be conductive via an Au film, there is a possibility that the Au film will become an erosion path for the solder.

Therefore, in this embodiment, the Au film that can be a solder erosion path is blocked in the seventh side wiring 371, and the first metal film 371a formed of a conductive metal other than Au is used to electrically connect the interlayer wiring bonding pattern 381 on the first main surface 301 of the second sealing member 30 to the external electrode terminal 32 on the second main surface 302. In this way, the erosion-resistant structure provided in the seventh side wiring 371 can block the solder erosion path in the seventh side wiring 371, so that the wetting and spreading of solder in the conductive path to the first excitation electrode 111 can be suppressed, and the erosion of the first excitation electrode 111 by solder can be suppressed. In addition, the increase in conductive resistance due to solder erosion of the seventh side wiring 371 and the occurrence of disconnection can be suppressed.

Similarly, the corrosion-resistant structure provided in the eighth side wiring 372 can block the corrosion path of the solder in the eighth side wiring 372, thereby suppressing the spread of solder in the conductive path to the second excitation electrode 112 and suppressing the corrosion of the second excitation electrode 112 by solder. In addition, it is possible to suppress an increase in conductive resistance and the occurrence of breakage, etc., due to solder erosion of the eighth side wiring 372.

As described above, in this embodiment, the metal film on the surface of the seventh and eighth side wirings 371 and 372 is formed of a metal (in this case, NiTi) that has low solder wettability. The metal film on the surface of the seventh and eighth side wirings 371 and 372 is formed of a film containing at least Ti, and the film containing Ti that has low solder wettability is exposed. This makes it possible to block the solder erosion path in the seventh and eighth side wirings 371 and 372, thereby suppressing the spread of solder wettability in the conduction path to the first and second excitation electrodes 111 and 112, and suppressing the erosion of the first and second excitation electrodes 111 and 112 by solder. In addition, it is possible to suppress an increase in the conduction resistance due to solder erosion of the seventh and eighth side wirings 371 and 372, and the occurrence of disconnections, etc.

In this embodiment, the quartz crystal plate 10, the first and second sealing members 20 and 30 are each an AT-cut quartz crystal plate, and the side wiring 271, 171, 371 and the side wiring 272, 172, 372 are formed along the Z'-axis direction (on the X-axis end surface) of the AT-cut quartz crystal plate. This makes it possible to easily form stable side wiring 271, 171, 371 and side wiring 272, 172, 372 that are less likely to break. This point will be explained below.

In the manufacturing process of the quartz crystal unit 100, the quartz crystal plate 10 and the first and second sealing members 20 and 30 are manufactured in the form of a wafer, but the outer shapes of the quartz crystal plate 10 and the first and second sealing members 20 and 30 are each formed by wet etching. Here, due to the anisotropy of the AT-cut quartz crystal plate, protrusions protruding in the Z'-axis direction may be formed on the Z'-axis end faces of the quartz crystal plate 10, etc., and when forming side wiring on the Z'-axis end face, problems arise such as the film thickness of the side wiring becoming smaller at the protrusions, or shadows of the protrusions being cast during exposure, making it difficult to pattern the side wiring.

On the other hand, such protrusions are not formed on the X-axis end face of the quartz crystal plate 10, etc., and the X-axis end face has a shape in which multiple inclined surfaces are connected at obtuse angles. Therefore, when forming side wiring on the X-axis end face of the quartz crystal plate 10, etc., the film thickness of the side wiring can be easily ensured, shadows are less likely to occur during exposure, and the side wiring can be easily patterned. As a result, side wiring can be easily formed on the X-axis end face of the quartz crystal plate 10, etc., compared to the Z'-axis end face, and the conductive resistance can also be reduced.

Therefore, in this embodiment, by forming the side wirings 271, 171, 371 and the side wirings 272, 172, 372 (on the X-axis end faces) along the Z'-axis direction of the quartz vibration plate 10 and the first and second sealing members 20, 30 formed from an AT-cut quartz plate, it is possible to easily form stable side wirings 271, 171, 371 and side wirings 272, 172, 372 that are less likely to break.

In addition to the side wiring 271, 171, 371 and the side wiring 272, 172, 372, the side wiring 273, 373 and the side wiring 274, 374 are also formed along the Z'-axis direction of the first and second sealing members 20 and 30, so that stable side wiring 273, 373 and side wiring 274, 374 that are less likely to break can be easily formed.

In addition, in the wafer of the quartz crystal vibration plate 10, the electrode configuration of the first side wiring 171 and the second side wiring 172 is common to the electrode configuration of the first and second excitation electrodes 111, 112 of the vibration part 11. Therefore, the base electrode film (e.g., Ti film) of the first side wiring 171 and the second side wiring 172 is formed thinner than the electrode configuration of the first and second sealing members 20, 30. For example, the electrode configuration of the quartz crystal vibration plate 10 is configured to include a Ti film and an Au film, and the electrode configuration of the first and second sealing members 20, 30 is configured to include a Ti film, a NiTi film, and an Au film. In addition, the Ti film of the electrode configuration of the quartz crystal vibration plate 10 is thinner than the Ti film of the electrode configuration of the first and second sealing members 20, 30.

In this embodiment, the first excitation electrode 111 is electrically connected to the first terminal 22 formed on the first main surface 201 on the side not facing the internal space of the first sealing member 20 via the through electrode of the second through hole 212 provided in the first sealing member 20. The second excitation electrode 112 is electrically connected to the second terminal 23 formed on the first sealing member 20 via the through electrode of the first through hole 162 provided in the quartz crystal plate 10 and the through electrode of the third through hole 213 provided in the first sealing member 20. The first terminal 22 is electrically connected to the external electrode terminal (first external electrode terminal) 32 formed on the second main surface 302 on the side not facing the internal space of the second sealing member 30 via the side wiring 271, 171, 371 formed on the package side of the quartz crystal vibrator 100. The second terminal 23 is electrically connected to an external electrode terminal (second external electrode terminal) 32 formed on the second main surface 302 of the second sealing member 30 via side wiring 272, 172, 372 formed on the package side of the quartz crystal unit 100.

According to this embodiment, the first and second excitation electrodes 111, 112 are electrically connected to the external electrode terminals 32, 32 via the first and second terminals 22, 23 formed on the first main surface 201 on the side not facing the internal space of the first sealing member 20, so that the electrical conduction path from the first and second excitation electrodes 111, 112 to the external electrode terminals 32, 32 can be lengthened, and erosion of the first and second excitation electrodes 111, 112 by solder can be suppressed. In addition, an increase in the conduction resistance due to solder erosion of the side wirings 271, 171, 371 and the side wirings 272, 172, 372, and the occurrence of breakage, etc. can be suppressed. Furthermore, since the first and second terminals 22, 23 and the external electrode terminals 32, 32 are electrically connected without using through holes, there is no need to form through holes in the outer peripheral edges of the quartz crystal plate 10 and the first and second sealing members 20, 30, respectively, and the quartz crystal unit 100 can be easily miniaturized.

In this case, the side wiring 271, 171, 371 and the side wiring 272, 172, 372 are formed without forming a recess (castellation) on the side of the package. This eliminates the need to form a recess on the side of each of the quartz crystal plate 10 and the first and second sealing members 20, 30, making it easy to miniaturize the quartz crystal unit 100.

In this embodiment, among the side wirings 271, 171, and 371 formed on the package side of the quartz crystal vibrator 100, the first side wiring 171 formed on the quartz crystal vibrating plate 10 is arranged to be shifted in a planar view with respect to at least the seventh side wiring 371 formed on the second sealing member 30. As shown in FIG. 8, the first side wiring 171 of the quartz crystal vibrating plate 10 is arranged to be shifted in a planar view with respect to both the third side wiring 271 of the first sealing member 20 and the seventh side wiring 371 of the second sealing member 30. The first side wiring 171 of the quartz crystal vibrating plate 10 is connected to the third side wiring 271 of the first sealing member 20 via the first interlayer wiring 117, and the first side wiring 171 is connected to the seventh side wiring 371 of the second sealing member 30 via the second interlayer wiring 118. In this way, by offsetting the first side wiring 171 formed on the quartz crystal plate 10 with respect to the third and seventh side wirings 271, 371 formed on the first and second sealing members 20, 30, it is possible to suppress the erosion of the solder on the package side of the quartz crystal vibrator 100, and it is possible to suppress the erosion of the first excitation electrode 111 by the solder.

In addition, among the side wirings 272, 172, and 372 formed on the package side of the quartz crystal vibrator 100, the second side wiring 172 formed on the quartz crystal vibrating plate 10 is arranged to be shifted in a planar view with respect to at least the eighth side wiring 372 formed on the second sealing member 30. As shown in FIG. 9, the second side wiring 172 of the quartz crystal vibrating plate 10 is arranged to be shifted in a planar view with respect to both the fourth side wiring 272 of the first sealing member 20 and the eighth side wiring 372 of the second sealing member 30. The second side wiring 172 of the quartz crystal vibrating plate 10 is connected to the fourth side wiring 272 of the first sealing member 20 via the third interlayer wiring 119, and the second side wiring 172 is connected to the eighth side wiring 372 of the second sealing member 30 via the fourth interlayer wiring 120. In this way, by offsetting the second side wiring 172 formed on the quartz crystal plate 10 with respect to the fourth and eighth side wirings 272, 372 formed on the first and second sealing members 20, 30, it is possible to suppress the erosion of the solder on the package side of the quartz crystal vibrator 100, and it is possible to suppress the erosion of the second excitation electrode 112 by the solder.

The amount of shift (length in the Z'-axis direction) is not particularly limited as long as the side wirings 171, 172 of the quartz vibration plate 10 and the side wirings 271, 272, 371, 372 of the first and second sealing members 20, 30 do not overlap in side view. In the example shown in Figures 8 and 9, between the side wirings 171, 172 of the quartz vibration plate 10 and the side wirings 371, 372 of the second sealing member 30, there is a gap of approximately the same length as the width of the side wirings 171, 172 of the quartz vibration plate 10 in the Z'-axis direction. In addition, between the side wirings 171, 172 of the quartz vibration plate 10 and the side wirings 271, 272 of the first sealing member 20, there is a gap of approximately the same length as the width of the side wirings 171, 172 of the quartz vibration plate 10 in the Z'-axis direction.

In this embodiment, a metal film 28 is provided on the first main surface 201 of the first sealing member 20 as an earth electrode. The metal film 28 is electrically connected to the external electrode terminal 32 formed on the second main surface 302 of the second sealing member 30 via the first internal wiring 173 formed on the inner wall surface 105 of the outer frame portion 12 of the quartz vibration plate 10. The metal film 28 is also electrically connected to the external electrode terminal 32 formed on the second main surface 302 of the second sealing member 30 via the second internal wiring 174 formed on the inner wall surface 106 of the outer frame portion 12 of the quartz vibration plate 10. In this way, the internal wiring 173, 174 for earth connection is provided on the inner wall surfaces 105, 106 of the outer frame portion 12 of the quartz vibration plate 10, so that it is less susceptible to the influence of the external environment and the earth connection can be stably performed.

Here, in the manufacturing process of the quartz crystal vibrator 100, the quartz crystal vibrating plate 10 is manufactured in the state of a wafer, but in the wafer of the quartz crystal vibrating plate 10, the electrode configuration of the first internal wiring 173, the second internal wiring 174, etc. is common to the electrode configuration of the first and second excitation electrodes 111, 112 of the vibrating part 11. Therefore, compared to the electrode configuration of the first and second sealing members 20, 30, the base electrode film (e.g., Ti film) of the first internal wiring 173, the second internal wiring 174, etc. is formed thinly. Therefore, by mounting the package of the quartz crystal vibrator 100 with solder, the electrodes provided on the side of the package have a high risk of disconnection due to solder erosion, and there is a possibility that the earth connection cannot be stably performed. However, in this embodiment, by providing a first internal wiring 173 (second internal wiring 174) for earth connection on the inner wall surface 105 (106) of the outer frame portion 12 of the quartz crystal vibration plate 10, such disconnection due to solder erosion can be prevented in advance, and an earth connection can be stably made via the first internal wiring 173 (second internal wiring 174).

In this embodiment, as described above, the annular seal paths 115, 116 are electrically connected to the first internal wiring 173 (second internal wiring 174). This allows the vibration part 11 of the quartz crystal vibration plate 10 to be surrounded by the earth-connected annular seal paths 115, 116, thereby improving the electromagnetic wave shielding effect.

In addition, in this embodiment, the first internal wiring 173 (second internal wiring 174) is formed in a planar shape so as to extend along the inner wall surface 105 (106) of the outer frame portion 12 of the quartz vibration plate 10. In this way, the first internal wiring 173 (second internal wiring 174) formed in a planar shape on the inner wall surface 105 (106) of the outer frame portion 12 can enhance the electromagnetic wave shielding effect. In this case, the first and second internal wirings 173 and 174 are provided on a pair of inner wall surfaces 105 and 106 that face each other in a planar view of the outer frame portion 12 of the quartz vibration plate 10. As a result, the vibration portion 11 is sandwiched between the pair of first and second internal wirings 173 and 174 formed in a planar shape, so that electromagnetic waves from the side of the vibration portion 11 can be effectively shielded. Furthermore, in the direction in which the first and second internal wirings 173, 174 extend (Z'-axis direction), the width of the first and second internal wirings 173, 174 is greater than the width of the first and second excitation electrodes 111, 112, which further enhances the electromagnetic wave shielding effect.

In this embodiment, as described above, the metal film 28 formed on the first main surface 201 of the first sealing member 20 that does not face the internal space is electrically connected to the fifth side wiring 273 formed on the side 203 on the -X direction side of the first sealing member 20, and the external electrode terminal 32 of the second sealing member 30 is electrically connected to the ninth side wiring 373 formed on the side 303 on the -X direction side of the second sealing member 30. In addition, the metal film 28 of the first sealing member 20 is electrically connected to the sixth side wiring 274 formed on the side 204 on the +X direction side of the first sealing member 20, and the external electrode terminal 32 of the second sealing member 30 is electrically connected to the tenth side wiring 374 formed on the side 304 on the +X direction side of the second sealing member 30. According to this configuration, it is not necessary to provide through holes for electrical connection in the outer peripheral portion of the seal paths 115, 116 of the first and second sealing members 20, 30, so that the crystal unit 100 can be easily miniaturized. In addition, since the metal film 28 is formed on the first main surface 201 on the side not facing the internal space of the first sealing member 20, it does not interfere with the formation of wiring formed in the internal space, and there is no risk of short circuiting with the first and second excitation electrodes 111, 112, etc. Furthermore, since the metal film 28 is formed on the package surface that is relatively far from the first and second excitation electrodes 111, 112, the electromagnetic wave shielding effect can be further improved.

In this embodiment, as shown in FIG. 4, a first side wiring 171 electrically connected to the first excitation electrode 111 is provided on the side surface 103 on the -X direction side of the quartz crystal vibration plate 10, and a first internal wiring 173 is arranged between this first side wiring 171 and the first excitation electrode 111. The first side wiring 171 and the first excitation electrode 111 overlap in a side view, but by arranging the first internal wiring 173 connected to earth between the first side wiring 171 and the first excitation electrode 111, the parasitic capacitance generated due to the overlap between the first side wiring 171 and the first excitation electrode 111 can be suppressed.

As shown in FIG. 5, a second side wiring 172 electrically connected to the second excitation electrode 112 is provided on the side 104 on the +X direction side of the quartz crystal plate 10, and a second internal wiring 174 is arranged between the second side wiring 172 and the second excitation electrode 112. The second side wiring 172 and the second excitation electrode 112 overlap in a side view, but by arranging the second internal wiring 174 connected to earth between the second side wiring 172 and the second excitation electrode 112, the parasitic capacitance generated due to the overlap between the second side wiring 172 and the second excitation electrode 112 can be suppressed.

The embodiments disclosed herein are illustrative in all respects and are not intended to be a basis for a restrictive interpretation. Therefore, the technical scope of the present invention is not to be interpreted solely by the above-described embodiments, but is defined based on the claims. Furthermore, all modifications within the meaning and scope of the claims are included.

The above-mentioned corrosion-resistant structure is an example, and can be modified in various ways. For example, in addition to removing part or all of the Au film from the seventh and eighth side wirings 371, 372 of the second sealing member 30, a part of the Au film 32c at the end of the external electrode terminal 32 of the second sealing member 30 may be removed, or a part of the Au film 381c at the end of the interlayer wiring bonding pattern 381 of the second sealing member 30 may be removed.

In the above embodiment, a case where a part or all of the Au film is removed from the seventh and eighth side wirings 371 and 372 of the second sealing member 30 has been described. However, this is not limited to this, and an erosion-resistant structure may be configured by leaving the Au film of the seventh and eighth side wirings 371 and 372 of the second sealing member 30 and forming a metal film made of a metal (e.g., Ti) having low solder wettability on the Au film. The surface of the Au film of the seventh and eighth side wirings 371 and 372 of the second sealing member 30 is covered with a metal film made of a metal other than Au. In this case, it is possible to suppress the solder from spreading along the Au film of the seventh and eighth side wirings 371 and 372 of the second sealing member 30, and to suppress the occurrence of defects such as an increase in conductive resistance and disconnection. In order to more reliably suppress the spreading of the solder, it is preferable to block the corrosion path of the solder by removing the Au film of the seventh and eighth side wirings 371 and 372 of the second sealing member 30, as in the above embodiment.

In the above embodiment, in addition to removing part or all of the Au film from the seventh and eighth side wirings 371, 372 of the second sealing member 30, a part of the Au film 32c of the external electrode terminal 32 of the second sealing member 30 may be removed, or a part of the Au film 381c of the interlayer wiring bonding pattern 381 of the second sealing member 30 may be removed.

The above-mentioned erosion-resistant structure is preferably provided at least in the seventh and eighth side wirings 371, 372 of the second sealing member 30, but it is also possible to provide a similar erosion-resistant structure in the third and fourth side wirings 271, 272 of the first sealing member 20 in addition to the seventh and eighth side wirings 371, 372 of the second sealing member 30. In this case, it is preferable that the erosion path of the solder can be blocked not only in the seventh and eighth side wirings 371, 372 of the second sealing member 30 but also in the third and fourth side wirings 271, 272 of the first sealing member 20.

In the above embodiment, the side wiring 371, 171, 271 and side wiring 372, 172, 272 electrically connected to the first and second excitation electrodes 111, 112 are provided with a solder erosion-resistant structure. However, the side wiring 373, 273 and side wiring 374, 274 electrically connected to the metal film 28 as the earth electrode formed on the first main surface 201 of the first sealing member 20 may be provided with a solder erosion-resistant structure. Alternatively, the side wiring 371, 171, 271 and side wiring 372, 172, 272 electrically connected to the first and second excitation electrodes 111, 112, as well as the side wiring 373, 273 and side wiring 374, 274 electrically connected to the metal film 28 as the earth electrode may be provided with a solder erosion-resistant structure. In these cases, it is preferable that the above-mentioned erosion-resistant structure is provided at least in the ninth and tenth side wirings 373, 374 of the second sealing member 30, but in addition to the ninth and tenth side wirings 373, 374 of the second sealing member 30, it is also possible to provide a similar erosion-resistant structure in the fifth and sixth side wirings 273, 274 of the first sealing member 20.

In the above embodiment, the side wirings 171, 172 of the quartz vibration plate 10 are arranged offset in the Z'-axis direction relative to both the side wirings 271, 272 of the first sealing member 20 and the side wirings 371, 372 of the second sealing member 30. However, the side wirings 171, 172 of the quartz vibration plate 10 may be arranged offset in the Z'-axis direction only relative to the side wirings 371, 372 of the second sealing member 30 without being offset in the Z'-axis direction relative to the side wirings 271, 272 of the first sealing member 20.

In addition, in the above embodiment, the side wirings 271, 272 of the first sealing member 20 and the side wirings 371, 372 of the second sealing member 30 are arranged at approximately the same position in a side view, but the side wirings 271, 272 of the first sealing member 20 and the side wirings 371, 372 of the second sealing member 30 may be arranged with a shift in a side view.

In the above embodiment, the side wirings 171, 172 of the quartz vibration plate 10, the side wirings 271, 272 of the first sealing member 20, and the side wirings 371, 372 of the second sealing member 30 were formed on the side surface in the X-axis direction (X-axis end surface) of the package of the quartz vibration element 100, but the side wirings 171, 172 of the quartz vibration plate 10, the side wirings 271, 272 of the first sealing member 20, and the side wirings 371, 372 of the second sealing member 30 may also be formed on the side surface in the Z'-axis direction (Z'-axis end surface) of the package of the quartz vibration element 100. However, as described above, by forming the side wirings 171, 172 of the quartz crystal plate 10, the side wirings 271, 272 of the first sealing member 20, and the side wirings 371, 372 of the second sealing member 30 on the side surface (X-axis end surface) in the X-axis direction of the package of the quartz crystal unit 100, it is possible to easily form stable side wiring that is less likely to break.

In the above embodiment, the first and second side wirings 171, 172 formed on the quartz crystal plate 10 are arranged in a position where they overlap in the vertical direction in a side view with the external electrode terminals 32, 32 formed on the second main surface 302 on the side that does not face the internal space of the second sealing member 30 (see Figures 8 and 9). However, as in Modification Example 1 shown in Figures 11 and 12, for example, the first and second side wirings 171a, 172a may be arranged in a position where they do not overlap in the vertical direction with the external electrode terminals 32, 32 in a side view.

In this modified example 1, as shown in FIG. 11, the first side wiring 171a formed on the side surface 103 on the -X direction side of the quartz crystal plate 10 is shifted toward the -Z' direction side from the first side wiring 171 in FIG. 8. In addition, in a side view, the first side wiring 171a is disposed in the space between the two external electrode terminals 32, 32. In a side view, the first side wiring 171a is disposed at a position where it does not overlap the external electrode terminals 32, 32 in the up-down direction.

As shown in FIG. 12, the second side wiring 172a formed on the side 104 on the +X direction side of the quartz crystal plate 10 is shifted toward the +Z' direction side from the second side wiring 172 in FIG. 9. In addition, in a side view, the second side wiring 172a is arranged in the space between the two external electrode terminals 32, 32. In a side view, the second side wiring 172a is arranged at a position where it does not overlap with the external electrode terminals 32, 32 in the vertical direction.

According to this modification 1, the first and second side wirings 171a, 172a formed on the quartz crystal plate 10 are not overlapped in the vertical direction in a side view with the external electrode terminals 32, 32 formed on the second sealing member 30, so that the solder protruding from the external electrode terminals 32, 32 is prevented from contacting and adhering to the first and second side wirings 171a, 172a. This makes it possible to suppress an increase in the conduction resistance and the occurrence of breaks, etc., due to the adhesion of solder to the first and second side wirings 171a, 172a.

In the above embodiment, two of the four external electrode terminals 32 are used as electrode terminals for earth connection, but only one external electrode terminal 32 may be used as an electrode terminal for earth connection. For example, the tenth side wiring 374 may be directly connected to the external electrode terminal 32, and the ninth side wiring 373 may be electrically connected to this external electrode terminal 32 via the metal film 28. In this case, the ninth side wiring 373 is electrically connected to the metal film 28 via the seal path 116, the first internal wiring 173, the seal path 115, and the fifth side wiring 273 in this order, and is further electrically connected to the external electrode terminal 32 via the sixth side wiring 274, the seal path 115, the second internal wiring 174, the seal path 116, and the tenth side wiring 374 in this order. Note that only one of the first and second internal wirings 173 and 174 may be provided.

In the above embodiment, the first and second internal wirings 173, 174 connected to earth are formed on the inner wall surfaces 105, 106 of the outer frame portion 12 of the quartz crystal plate 10, but the configuration may also be such that the outer surface (e.g., the side surfaces 103, 104) of the quartz crystal plate 10 is provided with side wiring connected to earth. In this case, the side wiring of the quartz crystal plate 10 connected to earth may be arranged offset in plan view with respect to the ninth and tenth side wirings 373, 374 formed in the second sealing member 30. Alternatively, the side wiring of the quartz crystal plate 10 connected to earth may be arranged offset in plan view with respect to the ninth and tenth side wirings 373, 374 formed in the second sealing member 30 and the fifth and sixth side wirings 273, 274 formed in the first sealing member 20. These configurations make it possible to lengthen the electrical conduction path from the seal paths 115, 116 to the external electrode terminals 32, 32, and suppress the solder erosion of the seal paths 115, 116. In addition, it is possible to suppress the occurrence of breaks and the like due to solder erosion of the side wiring of the ground-connected quartz crystal plate 10, the side wirings 373, 374, and the side wirings 273, 274.

In the above embodiment, the first and second internal wirings 173, 174 are formed on the inner wall surface 105 on the -X direction side and the inner wall surface 106 on the +X direction side of the outer frame portion 12 of the quartz vibration plate 10, but the internal wirings may be formed on the inner wall surface on the -Z' direction side and the inner wall surface on the +Z' direction side of the outer frame portion 12 of the quartz vibration plate 10. Also, the internal wirings may be formed on all four inner wall surfaces (the inner wall surface 105 on the -X direction side, the inner wall surface 106 on the +X direction side, the inner wall surface on the -Z' direction side, and the inner wall surface on the +Z' direction side) of the outer frame portion 12 of the quartz vibration plate 10.

In the above embodiment, an earth electrode is provided on the first main surface 201 of the first sealing member 20, which does not face the internal space, but this is not limited thereto, and an earth electrode may be formed on the second main surface 202 of the first sealing member 20, which faces the internal space.

In the above embodiment, the number of external electrode terminals 32 on the second main surface 302 of the second sealing member 30 is four, but this is not limited thereto, and the number of external electrode terminals 32 may be, for example, two, six, or eight. In addition, the present invention has been described as being applied to a quartz crystal resonator 100, but this is not limited thereto, and the present invention may also be applied to, for example, a quartz crystal oscillator.

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

10 Quartz crystal vibration plate (piezoelectric vibration plate)
20 First sealing member 30 Second sealing member 32 External electrode terminal 100 Quartz crystal resonator (piezoelectric resonator device)
111 First excitation electrode 112 Second excitation electrode 171 First side wiring 172 Second side wiring 271 Third side wiring 272 Fourth side wiring 302 Second principal surface (principal surface not facing the internal space)
371 7th side wiring 372 8th side wiring

Claims (5)

a piezoelectric diaphragm having a first excitation electrode formed on one main surface of a substrate and a second excitation electrode formed on the other main surface of the substrate to be paired with the first excitation electrode;
a first sealing member that covers the first excitation electrode of the piezoelectric diaphragm;
a second sealing member that covers the second excitation electrode of the piezoelectric diaphragm;
a piezoelectric vibration device in which the first sealing member and the piezoelectric vibration plate are joined together, and the second sealing member and the piezoelectric vibration plate are joined together to provide an internal space in which a vibration portion of the piezoelectric vibration plate including the first excitation electrode and the second excitation electrode is hermetically sealed;
an external electrode terminal is formed on a main surface of the second sealing member that does not face the internal space;
the external electrode terminal is electrically connected to a side wiring formed on a side surface of a package of the piezoelectric vibration device, and a part or all of the side wiring is provided with an erosion-resistant structure against solder ;
the side wiring has at least one metal film made of a conductive metal other than Au formed on a side surface of the second sealing member, and an Au film formed on the metal film, a part or all of the Au film of the side wiring is removed, and the side wiring is configured to be conductive via the conductive metal,
the side wiring having the erosion-resistant structure is provided on at least a side surface of the second sealing member,
A piezoelectric vibration device characterized in that, among the side wirings formed on the side of the package, the side wiring formed on the piezoelectric vibration plate is shifted in a planar view with respect to the side wiring formed on the second sealing member . a piezoelectric diaphragm having a first excitation electrode formed on one main surface of a substrate and a second excitation electrode formed on the other main surface of the substrate to be paired with the first excitation electrode;
a first sealing member that covers the first excitation electrode of the piezoelectric diaphragm;
a second sealing member that covers the second excitation electrode of the piezoelectric diaphragm;
a piezoelectric vibration device in which the first sealing member and the piezoelectric vibration plate are joined together, and the second sealing member and the piezoelectric vibration plate are joined together to provide an internal space in which a vibration portion of the piezoelectric vibration plate including the first excitation electrode and the second excitation electrode is hermetically sealed;
an external electrode terminal is formed on a main surface of the second sealing member that does not face the internal space;
the external electrode terminal is electrically connected to a side wiring formed on a side surface of a package of the piezoelectric vibration device, and a part or all of the side wiring is provided with an erosion-resistant structure against solder ;
the side wiring has at least one metal film made of a conductive metal other than Au formed on a side surface of the second sealing member, and an Au film formed on the metal film, a part or all of the Au film of the side wiring is removed, and the side wiring is configured to be conductive via the conductive metal,
the side wiring having the erosion-resistant structure is provided on at least a side surface of the second sealing member,
A piezoelectric vibration device characterized in that, among the side wirings formed on the side of the package, the side wirings formed on the piezoelectric vibration plate are positioned in a position that does not overlap in the vertical direction with the external electrode terminals when viewed from the side . 3. The piezoelectric vibration device according to claim 1 ,
The side wiring having the erosion-resistant structure is a piezoelectric vibration device, characterized in that the metal film on the surface is formed from a metal that has lower solder wettability than Au . 4. The piezoelectric vibration device according to claim 3 ,
The piezoelectric vibration device is characterized in that the metal film is a film containing at least Ti. The piezoelectric vibration device according to any one of claims 1 to 4,
the piezoelectric diaphragm and the first and second sealing members are AT-cut quartz crystal plates,
A piezoelectric vibration device, characterized in that the side wiring is formed along the Z' axis direction of the AT-cut quartz crystal plate.

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