JP2015162700A - Piezoelectric vibration element and piezoelectric device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric vibration element that suppresses a mass change caused by a chemical reaction of an excitation electrode.SOLUTION: A vibration element 5 includes: a crystal piece 15; and a pair of excitation electrodes 17 formed in a layer shape on a surface of the crystal piece 15. The excitation electrodes 17 have a silver palladium alloy layer 25 composed of a silver palladium alloy formed by adding only palladium to silver, which is a main component.

Description

  The present invention relates to a piezoelectric vibration element and a piezoelectric device.

  A piezoelectric vibrating element (piezoelectric vibrating piece) used for a piezoelectric vibrator or a piezoelectric oscillator has a piezoelectric body (for example, quartz crystal) and at least one pair of excitation electrodes provided on the surface of the piezoelectric body.

  Patent Document 1 discloses an excitation electrode including a chromium (Cr) layer as a base layer superimposed on a surface of a piezoelectric body and a silver (Ag) layer superimposed on the chromium layer. This configuration is a commonly used configuration. Silver is used because of its high conductivity. Chromium is used to improve the adhesion strength between silver and quartz. Note that nickel (Ni) or nichrome (NiCr) may be used for the underlayer instead of chromium.

  In Patent Document 2, in view of the fact that the excitation electrode has a two-layer structure as described above, the manufacturing process becomes complicated and the manufacturing cost increases, so that an excitation electrode consisting of only one layer can be realized. We propose electrode materials with high strength. Specifically, Patent Document 2 proposes an alloy in which palladium (Pd) and copper (Cu) are added to silver as a main component, or an alloy in which palladium and titanium (Ti) are added to silver as a main component. doing. Further, in Patent Document 2, these alloys are less susceptible to oxidation than conventional electrode materials, and do not evaporate and scatter like silver even when exposed to high temperatures. It is also disclosed that an effect of suppressing a change in the resonance frequency is achieved.

Patent Document 3 proposes an electrode material with high adhesion strength to quartz that realizes an excitation electrode consisting of only one layer, as in Patent Document 2. Patent Document 3 considers that palladium is expensive in the technology of Patent Document 2, and proposes an alloy in which molybdenum (Mo) is added to silver as a main component as an electrode material. Patent Document 3 discloses that this alloy is advantageous also in corrosion resistance, oxygen plasma ashing resistance, UV / O ₃ resistance, etching ease, and heat resistance.

JP 07-154188 A JP 2001-44785 A JP 2005-236360 A

  When the excitation electrode reacts with the substance contained in the surrounding atmosphere after the manufacturing process and / or manufacturing, the mass of the excitation electrode changes, and consequently the frequency characteristics change. In the above-described patent documents, mention is made of mass change due to evaporation / scattering of silver, and also mentions corrosion resistance. However, in the above-described patent documents, a suitable electrode material is not selected by paying particular attention to a mass change due to a chemical reaction. Moreover, in the patent document mentioned above, there is no description which considers the property peculiar to silver that it is easy to react with sulfur (S).

  In view of the above, it is desired to provide a piezoelectric vibration element and a piezoelectric device in which mass change due to a chemical reaction of the excitation electrode is suppressed.

  A piezoelectric oscillator according to one embodiment of the present invention includes a piezoelectric body and at least one pair of excitation electrodes formed in a layered manner on the surface of the piezoelectric body, and the excitation electrode is composed of palladium on silver as a main component. The silver palladium alloy layer which consists of a silver palladium alloy to which only was added.

  Preferably, the excitation electrode is overlaid on the surface of the piezoelectric body, and an underlayer made of a material having higher adhesion strength to the piezoelectric body than the silver palladium alloy, and the silver palladium alloy layer overlaid on the underlayer. And consist of

  Preferably, the base layer is made of chromium.

  Preferably, the piezoelectric body is made of quartz, and the excitation electrode is made of the silver-palladium alloy layer superimposed on the surface of the piezoelectric body.

  Preferably, the palladium content of the silver-palladium alloy layer is 1.0% to 7.0% by weight.

  A piezoelectric device according to an aspect of the present invention includes the above-described piezoelectric vibration element and an element mounting member on which the piezoelectric vibration element is mounted via a conductive bump.

  According to said structure, the mass change by the chemical reaction of an excitation electrode is suppressed.

1 is an exploded perspective view showing a schematic configuration of a crystal resonator according to a first embodiment of the present invention. 2A is a cross-sectional view of the crystal resonator taken along line IIa-IIa in FIG. 1, and FIG. 2B is an enlarged view of region IIb in FIG. The flowchart which shows the procedure of the manufacturing method of the crystal oscillator of FIG. Sectional drawing corresponding to FIG.2 (b) explaining the vibration element which concerns on the 2nd Embodiment of this invention.

  Hereinafter, a piezoelectric vibrator according to an embodiment of the present invention will be described with reference to the drawings. Note that the drawings used in the following description are schematic, and the dimensional ratios and the like on the drawings do not necessarily match the actual ones.

  The piezoelectric vibrator may be either upward or downward, but in the following, for convenience, the orthogonal coordinate system xyz is defined and the positive side in the z direction is upward, and the upper surface, the lower surface, etc. The following terms shall be used.

<First Embodiment>

  FIG. 1 is an exploded perspective view showing a schematic configuration of a crystal resonator 1 according to an embodiment of the present invention. 2A is a cross-sectional view of the crystal unit 1 taken along the line IIa-IIa in FIG.

  For example, as shown in FIG. 1, the crystal resonator 1 is roughly composed of three members. That is, the crystal unit 1 includes the element mounting member 3 in which the recess 3a is formed, the vibration element 5 accommodated in the recess 3a, and the lid member 7 that closes the recess 3a.

  For example, the crystal unit 1 is substantially rectangular parallelepiped in a state where the recess 3 a is closed by the lid member 7, and the dimensions thereof may be set appropriately. For example, in a relatively small one, the length of one side in the x direction or the y direction is 1 to 2 mm, and the length of one side in the z direction is 0.2 to 0.4 mm. The recess 3a is sealed by the lid member 7, and the inside thereof is, for example, evacuated or sealed with nitrogen.

  The element mounting member 3 may be the same as a known one. The element mounting member 3 includes, for example, a base 9 that is a main body of the element mounting member 3, an element mounting pad 11 for mounting the vibration element 5, and a crystal resonator 1 for mounting on a circuit board (not shown). And an external terminal 13.

  The substrate 9 is made of an insulating material. The insulating material is, for example, ceramic or resin. The base 9 may be composed of a plurality of members, or may be integrally formed as a whole. The base body 9 may have an appropriate shape as long as the vibration element 5 can be mounted and sealed. For example, the base body 9 is formed in a substantially rectangular parallelepiped box shape whose upper surface side is open, and has the above-described recess 3a.

  The element mounting pad 11 is provided on the bottom surface of the recess 3a, for example. More specifically, for example, a pair of element mounting pads 11 is provided on one side of the bottom surface of the recess 3a in the longitudinal direction (positive side in the x direction). The pair of element mounting pads 11 are arranged in the short side direction (y direction) of the bottom surface of the recess 3a. The element mounting pad 11 is made of, for example, a conductive material (for example, metal) formed in a layer shape (including a plate shape, the same applies hereinafter). The planar shape may be set appropriately. The element mounting pad 11 may be configured by laminating two or more metal layers.

  The external terminals 13 are provided at the four corners of the lower surface of the element mounting member 3, for example. Each external terminal 13 is made of, for example, a conductive material (for example, metal) formed in a layer shape. The planar shape may be set appropriately. The external terminal 13 may be configured by laminating two or more metal layers. The crystal resonator 1 is mounted on a circuit board by, for example, joining the external terminals 13 and pads (not shown) of the circuit board with solder or the like.

  One external terminal 13 and one element mounting pad 11 are connected by a connection conductor (not shown), and the other one external terminal 13 and another one element mounting pad 11 are connected by a connection conductor (not shown). Yes. The connection conductor is constituted by, for example, a via conductor or an inner layer conductor provided inside the base body 9.

  The vibration element 5 includes, for example, a crystal piece 15, a pair of excitation electrodes 17 for applying a voltage to the crystal piece 15, and a pair of extraction electrodes 19 for mounting the vibration element 5 on the element mounting pad 11. have.

  The crystal piece 15 is formed in a substantially rectangular plate shape, for example. The pair of excitation electrodes 17 are provided in layers on the center side of both main surfaces of the crystal piece 15. The pair of extraction electrodes 19 are extracted from the excitation electrode 17 and provided at one end side portion in the longitudinal direction (x direction) of the crystal piece 15. For example, the pair of excitation electrodes 17 and the pair of extraction electrodes 19 extend in the longitudinal direction (x direction) of the crystal piece 15 so that either of the main surfaces of the vibration element 5 may be the upper surface or the lower surface. It is formed in a shape that is 180 ° rotationally symmetric with respect to the center line.

  The vibration element 5 is accommodated in the recess 3a with the main surface facing the bottom surface of the recess 3a. The extraction electrode 19 is joined to the element mounting pad 11 by a conductive bump 21 (FIG. 2A). Thus, the vibration element 5 is supported like a cantilever on the element mounting member 3 and is electrically connected to the element mounting pad 11.

  The bump 21 may be a known one used for mounting a vibration element or a known one used for mounting an electronic element. For example, the bump 21 is made of a conductive adhesive (for example, an Ag paste in which a silver filler is mixed with a resin).

  The configuration of the lid member 7 may be the same as a known one. For example, the lid member 7 is made of metal. The lid member 7 is formed, for example, in a substantially rectangular flat plate shape and is overlaid on the upper surface of the frame portion of the element mounting member 3. The lid member 7 and the element mounting member 3 are fixed to each other, for example, by welding metal layers provided on both.

  FIG. 2B is an enlarged view of the region IIb in FIG.

  The excitation electrode 17 includes a chromium layer 23 superimposed on the surface of the crystal piece 15 and a silver palladium alloy layer 25 superimposed on the chromium layer 23. Although not shown in the drawing, the same applies to the extraction electrode 19.

  The chromium layer 23 is made of chromium (pure metal). The silver palladium alloy layer 25 is made of a silver palladium alloy (binary alloy) in which only palladium is added to silver as a main component. The palladium content of the silver-palladium alloy may be appropriately set within a range where at least one of the effects of the present embodiment described later is exhibited. For example, the palladium content is 0.5% to 40%, preferably 1.0% to 7.0% by weight.

  Note that the pure metal and the binary alloy may contain a small amount of unintended impurities remaining or mixed in the process of manufacturing (refining, etc.) and film formation of these metal materials. For example, an unintended impurity of less than 0.1% by weight, more preferably less than 0.05% may be included. For reference, according to the Japanese Industrial Standard (JIS), for silver bullion, one silver bullion contains 99.99% or more of silver, and two kinds of silver bullion contains 99.95% or more of silver. (JIS 2141).

  The silver palladium alloy layer 25 is a layer mainly constituting the excitation electrode 17, and the chromium layer 23 is a base layer for improving the adhesion strength of the silver palladium alloy layer 25 to the crystal piece 15. Therefore, the silver palladium alloy layer 25 is relatively thick, and the chromium layer 23 is relatively thin. For example, the thickness of the chromium layer 23 is 100 to 200 mm, and the thickness of the silver palladium alloy layer 25 is 2000 to 3000 mm.

  FIG. 3 is a flowchart showing the procedure of the method for manufacturing the crystal unit 1.

  First, the crystal piece 15 is washed (step S1). Washing may be performed by a known method. For example, the crystal piece 15 is cleaned using an appropriate cleaning solution, then the cleaning solution is removed with pure water, and then dried.

  Next, the excitation electrode 17 and the extraction electrode 19 are formed on the crystal piece 15 (step S2). Specifically, first, the chromium layer 23 is formed, and then the silver palladium alloy layer 25 is formed. These metal layers may be formed by a known method. For example, a mask made of a resist is formed on the crystal piece 15 by photolithography, and a metal material (chromium or silver palladium alloy) is formed by vapor deposition through the mask. The vapor deposition may be vacuum vapor deposition or sputtering.

  In addition, the silver palladium alloy itself is well-known, and the manufacturing method of a silver palladium alloy may be made into a well-known thing. For example, the silver palladium alloy may be manufactured by melting and mixing pure silver and pure palladium, or may be manufactured by a sintering method or a plating method.

  Next, the vibration element 5 is mounted on the element mounting member 3 (step S3). The mounting may be performed by a known method. For example, first, bumps 21 made of a conductive adhesive are formed on the element mounting pad 11 by a screen printing method, a dispenser method, or the like. Next, the vibration element 5 is disposed in the recess 3 a of the element mounting member 3 so that the extraction electrode 19 contacts the bump 21. Thereafter, the bumps 21 are heated and cured by, for example, transporting the element mounting member 3 and the vibration element 5 to a curing furnace (heating furnace).

  Thereafter, the lid member 7 is joined to the element mounting member 3, and the recess 3a is sealed (step S5). The joining method of the lid member 7 to the element mounting member 3 may be a known method. For example, seam welding is performed in a vacuum atmosphere.

  As described above, in the present embodiment, the resonator element 5 includes the crystal piece 15 and the pair of excitation electrodes 17 formed in a layer on the surface of the crystal piece 15, and the excitation electrode 17 is a main component. The silver-palladium alloy layer 25 is made of a silver-palladium alloy obtained by adding only palladium to silver.

By adding palladium to the silver constituting the excitation electrode 17, the silver constituting the excitation electrode 17 may react with sulfur existing in the surroundings during and / or after the manufacturing process of the crystal unit 1. It is suppressed. That is, the production of silver sulfide (Ag ₂ S) is suppressed. As a result, the change in the mass of the vibration element 5 is suppressed, and as a result, the frequency characteristics of the vibration element 5 are stabilized. Moreover, since it consists only of silver and palladium with high corrosion resistance, compared with the case where copper etc. are added to silver in addition to palladium, it is anticipated that it will suppress that a mass changes by reacting with oxygen.

Examples of sulfur existing around the excitation electrode 17 include sulfur contained in sulfur dioxide (SO ₂ ) or hydrogen sulfide (H ₂ S) in the atmosphere, and a mask (resist for forming the excitation electrode 17. ).

  In the present embodiment, the excitation electrode 17 is superimposed on the surface of the crystal piece 15, and an underlayer (chrome layer 23) made of a material having higher adhesion strength to the piezoelectric body (crystal) than the silver-palladium alloy, and the chromium A silver palladium alloy layer 25 superimposed on the layer 23.

  Therefore, the adhesion strength between the silver palladium alloy layer 25 and the crystal piece 15 is improved. As described above, in the silver-palladium alloy layer 25, only palladium is added to silver in order to suppress not only sulfidation but also oxidation, and copper or the like is not added to increase adhesion strength. Absent. However, by increasing the adhesion strength by the chromium layer 23, the mass of the excitation electrode 17 as a whole is suppressed from mass change due to sulfidation and oxidation, and the adhesion strength to the crystal piece 15 is improved.

  Furthermore, in the prototype (palladium content 1.0%) according to the present embodiment of the present inventor, compared to the conventional technique in which the silver layer as the main layer is stacked on the chromium layer 23 as the underlayer, It has been confirmed that the phenomenon in which the main layer (in this embodiment, the silver-palladium alloy layer 25) locally peels from the chromium layer 23 and expands is suppressed. Therefore, in this embodiment, by using a silver palladium alloy instead of silver, not only the effect of suppressing the mass change of the main layer by suppressing the reaction with sulfur, but also the local peeling of the main layer from the underlayer is achieved. There is also an effect of suppressing the above.

  By suppressing local peeling of the main layer, for example, variation in charge distribution on the surface of the crystal piece 15 when a voltage is applied to the crystal piece 15 by the excitation electrode 17 is suppressed. Variation in frequency characteristics is suppressed.

  In addition, the above-mentioned local peeling has occurred after the curing (heating) in step S4, and the presence / absence of the occurrence depends on the amount of oxygen in the curing furnace and the residence time from after curing to sealing. Has an effect. The reason why local exfoliation is suppressed by adding palladium to silver is, for example, that aggregation is less likely to occur compared to pure silver, silver sulfidation is suppressed, and / or adhesion. The strength is increased.

  Therefore, the present inventor has confirmed the presence or absence of local peeling when the silver layer or the silver palladium alloy layer 25 as the main layer is formed on the chromium layer 23, but the underlayer is other than chromium. Even in the case of a material or when the silver-palladium alloy layer 25 is directly stacked on the crystal piece 15 (second embodiment), the main layer is obtained by using a silver-palladium alloy instead of silver as the material of the main layer. It is considered that the effect of suppressing the occurrence of local peeling is exhibited.

  In the present embodiment, the base layer is made of chromium. Chromium is superior in corrosion resistance to nickel and nichrome because it forms an oxide on the surface and suppresses further oxidation. Therefore, it is suppressed that the oxidation of the underlayer proceeds and the mass of the excitation electrode 17 changes from when the underlayer (chrome layer 23) is formed to when the silver palladium alloy layer 25 is formed, The frequency characteristic of the vibration element 5 is stabilized. In another aspect, regarding the stabilization of the frequency characteristics, the time from the formation of the underlayer to the formation of the silver-palladium alloy layer 25 and the manufacturing conditions of the atmosphere are relaxed.

  In the present embodiment, the palladium content of the silver-palladium alloy layer 25 is 1.0% to 7.0% by weight.

  If the palladium content is within the above range, the frequency characteristics of the vibration element 5 are preferably stabilized. Specifically, it is as follows.

  As described above, in the prototype (Example) of the present inventor, it has been confirmed that the local peeling of the excitation electrode 17 is sufficiently suppressed when the palladium content is at least 1.0%. Therefore, if the palladium content is at least 1.0%, the frequency characteristics of the vibration element 5 are stable. Since it is considered that silver sulfidation influences local peeling, from another viewpoint, if the palladium content is at least 1.0%, the effect of suppressing sulfidation can be obtained.

  It is known that the effect of suppressing sulfidation is increased by increasing the palladium content. Therefore, from the viewpoint of suppressing sulfurization, the palladium content may be sufficiently increased. In addition, it is considered that an electrically unique property does not appear when the palladium content is sufficiently increased. For example, Japanese Patent Laid-Open No. 7-233696 discloses that there is a track record of using a silver palladium alloy having a palladium content of 10%, 30%, 40%, and 60% as an electrical contact material.

  However, when the palladium content is increased, the volume resistivity of the silver-palladium alloy increases, and as a result, the excitation electrode 17 tends to generate heat. Since the frequency at which the crystal piece 15 vibrates changes depending on the temperature, if the excitation electrode 17 easily generates heat, the frequency at which the crystal piece 15 vibrates easily changes. Therefore, the palladium content is preferably suppressed to a certain value or less. And if palladium content is 7.0% or less, it is thought that the instability of the frequency by such heat_generation | fever is fully suppressed.

  For example, as described above, as the underlayer, in addition to chromium (volume resistivity at room temperature: about 13 μΩcm), nickel (volume resistivity at room temperature: about 7 μΩcm), nichrome (volume resistivity at room temperature) : About 108 μΩcm) is used. Empirically, the thickness of these underlayers is considered to be about 1/10 of the thickness of the silver layer (volume resistivity at room temperature: about 1.6 μΩcm), which is the main layer, and these layers are 1 It is considered that the pair of excitation electrodes 17 are connected in series with respect to the voltage application direction. In this case, the resistance value of the excitation electrode 17 changes in the range of 1.4 to 7.8 times the resistance value in the case of only the silver layer, depending on which material is used as the base layer. Therefore, it can be said that this change in the resistance value of the excitation electrode 17 is allowed.

  On the other hand, referring to known literature, if the palladium content is 7.0% or less, the volume resistivity of the silver-palladium alloy is expected to be well within several times the volume resistivity of pure silver. For example, Japanese Patent Laid-Open No. 2001-192752 discloses about 3.0 μΩcm (about twice the volume resistivity of pure silver) as the volume resistivity at room temperature of a silver palladium alloy having a palladium content of 3%.

  From the above, the palladium content is preferably 1.0% or more and 7.0% or less, 1.0% or more and 3.0% or less, or 1.0%. In these numerical values, the first decimal place is a significant digit. For example, 1.0% includes 0.95% and 7.0% includes 7.04%.

  In the above embodiment, the crystal resonator 1 is an example of a piezoelectric device, the vibration element 5 is an example of a piezoelectric vibration element, the crystal piece 15 is an example of a piezoelectric body, and the chromium layer 23 is an example of a base layer. is there.

<Second Embodiment>
FIG. 4 is a cross-sectional view corresponding to FIG. 2B for explaining the vibration element 205 according to the second embodiment.

  The vibration element 205 is different from the vibration element 5 of the first embodiment only in the material of the excitation electrode. That is, the excitation electrode 17 of the first embodiment is composed of the chromium layer 23 and the silver palladium alloy layer 25, whereas the excitation electrode 217 of the second embodiment is composed only of the silver palladium alloy layer 25. It is configured.

  Also in the second embodiment, the vibration element 205 includes the crystal piece 15 and a pair of excitation electrodes 217 formed in layers on the surface of the crystal piece 15, and the excitation electrode 217 is used as a main component. Since it has the silver palladium alloy layer 25 which consists of a silver palladium alloy which added only palladium to silver, the effect similar to 1st Embodiment is show | played. For example, sulfidation and oxidation of the excitation electrode 217 are suppressed, and consequently, a change in mass of the excitation electrode 217 is suppressed, and the frequency characteristics of the vibration element 205 are stabilized.

  In the second embodiment, the silver palladium alloy layer 25 is directly superimposed on the surface of the crystal piece 15. Therefore, the configuration of the excitation electrode 217 is simple, and the manufacturing process can be simplified and the cost can be reduced. In addition, compared with 1st Embodiment, the adhesive strength with respect to the crystal piece 15 of the silver palladium alloy layer 25 falls. However, as already described, since peeling due to sulfuration is suppressed, the adhesion strength is higher than when a silver layer made of pure silver is directly stacked on the surface of the crystal piece 15.

  The present invention is not limited to the above embodiment, and may be implemented in various aspects.

  The piezoelectric device is not limited to a piezoelectric vibrator such as a crystal vibrator, and may be, for example, a piezoelectric oscillator having an oscillation circuit. In addition, piezoelectric devices such as piezoelectric vibrators and piezoelectric oscillators may include electronic elements other than vibration elements, such as ICs (for example, including an oscillation circuit) and thermistors.

  The entire structure including the package (element mounting member or lid) of the piezoelectric device can be changed as appropriate. For example, a piezoelectric vibration element may be mounted on a single layer substrate, and the piezoelectric vibration element may be covered with a metal cap. A recess may be formed on both the upper and lower surfaces of the element mounting member, a vibration element may be disposed in one recess, and a thermistor or IC may be disposed in the other recess.

  The vibration element is not limited to a plate-like one (AT cut type), and may be a tuning fork type, for example. As is well known, a tuning fork type vibration element has a pair of arms and two pairs of excitation electrodes on each arm. In each arm, excitation electrodes having different potentials are provided on the surface of the arm so as to be orthogonal to each other. That is, two or more pairs of excitation electrodes may be provided in the vibration element, and the pair of excitation electrodes does not need to be opposed to each other with the plate-shaped piezoelectric body interposed therebetween. Further, the piezoelectric body is not limited to one made of quartz, and may be made of ceramic, for example.

  The excitation electrode is not limited to a one-layer structure composed of a silver-palladium alloy layer or a two-layer structure composed of an underlayer and a silver-palladium alloy layer. For example, another layer may be formed on the silver palladium alloy layer. Further, when the excitation electrode is composed of two or more layers, the thickness of the silver palladium alloy layer in the thickness of the excitation electrode may be set as appropriate. However, considering conductivity, the thickness of the silver-palladium alloy layer is preferably half or more than the thickness of the excitation electrode, more preferably 90% or more.

  When an underlayer is provided between the piezoelectric body and the silver-palladium alloy layer, the material of the underlayer is not limited to chromium, and is appropriately selected from metal materials having higher adhesion strength to the piezoelectric body than the silver-palladium alloy. Good. For example, the material of the underlayer may be nickel or nichrome.

  DESCRIPTION OF SYMBOLS 1 ... Crystal oscillator (piezoelectric device), 5 ... Vibration element (piezoelectric vibration element), 15 ... Crystal piece (piezoelectric body), 17 ... Excitation electrode, 25 ... Silver palladium alloy layer.

Claims (6)

A piezoelectric body;
At least one pair of excitation electrodes formed in a layer on the surface of the piezoelectric body;
Have
The excitation electrode has a silver-palladium alloy layer made of a silver-palladium alloy in which only palladium is added to silver as a main component. The excitation electrode is
An underlying layer made of a material that is superimposed on the surface of the piezoelectric body and has a higher adhesion strength to the piezoelectric body than a silver-palladium alloy;
The piezoelectric vibration element according to claim 1, comprising: the silver-palladium alloy layer superimposed on the base layer. The piezoelectric vibration element according to claim 2, wherein the base layer is made of chromium. The piezoelectric body is made of quartz,
The piezoelectric vibration element according to claim 1, wherein the excitation electrode includes the silver-palladium alloy layer superimposed on a surface of the piezoelectric body. The piezoelectric vibration element according to claim 1, wherein a palladium content of the silver-palladium alloy layer is 1.0% to 7.0% by weight. The piezoelectric vibration element according to any one of claims 1 to 5,
An element mounting member on which the piezoelectric vibration element is mounted via a conductive bump;
A piezoelectric device having:

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