Tuning fork type piezoelectric vibrating piece, tuning fork type piezoelectric vibrator, and tuning fork type piezoelectric oscillator

Abstract

Provided is a tuning-fork-type piezoelectric vibrating piece that can improve the reproducibility of frequency measurement.　This tuning-fork-type piezoelectric vibrating piece (10) comprises: a crystal vibration piece (20) that has a base (21), first and second vibrating arms (22, 23), and an external junction (24); a pair of first and second vibration electrodes (31, 32) that are formed on the first and second vibrating arms (22, 23); first and second extraction electrodes (33, 34) that are extracted from the first and second vibration electrodes (31, 32) to the base (21) and the external junction (24); and first and second electroconductive junctions (41, 42) that are provided to the first and second extraction electrodes (33, 34). The entirety of the first and second electroconductive junctions (41, 42) is provided so as to be present biased only in a first region on the side where the first vibrating arm (22) is located, with a virtual center line (L1) that passes through the center between the first and second vibrating arms (22, 23) and extends in the elongation direction of the first and second vibrating arms (22, 23) being used as a reference line, from among regions of the external junction (24).

Description

[Technical Field]

[0001] The present invention relates to a tuning-fork type piezoelectric vibrating piece having a pair of vibrating arms, a tuning-fork type piezoelectric vibrator having the tuning-fork type piezoelectric vibrating piece, and a tuning-fork type piezoelectric oscillator. [Background technology]

[0002] Some tuning-fork-type piezoelectric vibrating reeds include a quartz crystal vibrating reed having a base, a pair of vibrating arms (first vibrating arm, second vibrating arm) extending in one direction from one end of the base, and an external joint provided at the other end of the base. This tuning-fork-type piezoelectric vibrating reed is provided with a pair of first and second excitation electrodes formed on the first and second vibrating arms, a first extraction electrode extending from the first excitation electrode to the base and the external joint, and a second extraction electrode extending from the second excitation electrode to the base and the external joint. Furthermore, the tuning-fork-type piezoelectric vibrating reed is provided with a first metal bump used to electrically and mechanically join the first extraction electrode to the first external electrode and a second metal bump used to electrically and mechanically join the second extraction electrode to the second external electrode.

[0003] In the above tuning fork-type piezoelectric vibrating piece, if a line passing through the center between the first vibrating arm and the second vibrating arm and extending in the extension direction of the first vibrating arm and the second vibrating arm is defined as a virtual center line, and the region of the external joint on the side where the first vibrating arm is located is defined as a first region using the virtual center line as a reference line, and the region on the side where the second vibrating arm is located is defined as a second region using the virtual center line as a reference line, then there is a tuning fork-type piezoelectric vibrating piece in which the entire first metal bump is positioned to be present in the first region and the entire second metal bump is positioned to be present in the second region (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-68955 Summary of the Invention [Problem to be solved by the invention]

[0005] The outer shape of a quartz crystal vibrating piece that constitutes a tuning-fork-type piezoelectric vibrating piece is generally formed using photolithography and wet etching. Wet etching a quartz crystal vibrating piece to form an outer shape can result in asymmetric regions on the vibrating piece. This tendency to form asymmetric shapes is particularly pronounced when anisotropic materials such as quartz are wet-etched. This causes the fork portion (hereinafter sometimes referred to as the "tuning-fork fork portion") formed by the first and second vibrating arms and the base to become asymmetric, resulting in an imbalance between the first and second vibrating arms. When a tuning-fork-type piezoelectric vibrating piece is vibrated in a tuning-fork-type piezoelectric resonator having such a tuning-fork-type piezoelectric vibrating piece, a vibration mode different from the main vibration appears. Specifically, unwanted vibrations (spurious) appear at frequencies lower than the main vibration frequency, which degrades the reproducibility of measurements of the main vibration frequency.

[0006] In view of the above problems, the present invention aims to provide a tuning-fork-type piezoelectric vibrating piece that can suppress the effects of unwanted vibrations and improve the reproducibility of frequency measurements, a tuning-fork-type piezoelectric vibrator that includes the tuning-fork-type piezoelectric vibrating piece, and a tuning-fork-type piezoelectric oscillator. [Means for solving the problem]

[0007] In order to achieve the above object, a tuning fork type piezoelectric vibrating piece according to the present invention comprises a base, first and second vibrating arms extending in one direction from one end of the base, an external joint provided at the other end of the base, a pair of first and second excitation electrodes formed on the first and second vibrating arms, a first extraction electrode extending from the first excitation electrode to the base and the external joint, a second extraction electrode extending from the second excitation electrode to the base and the external joint, a first conductive joint used when electrically and mechanically joining the first extraction electrode to a first external electrode, and a second conductive joint used when electrically joining the second extraction electrode to a second external electrode. and a second conductive joint portion used when electrically and mechanically joining the first and second vibrating arms, wherein a line passing through the center between the first and second vibrating arms in a plan view and extending in the extension direction of the first and second vibrating arms is defined as a virtual center line, and within a region of the external joint portion in the plan view, a region on a side where the first vibrating arm is located with the virtual center line as a reference line is defined as a first region, and a region on a side where the second vibrating arm is located with the virtual center line as a reference line is defined as a second region, the entire first conductive joint portion and the entire second conductive joint portion are provided so as to be biased only in the first region. The base, the first vibrating arm, the second vibrating arm, and the external joint are made of quartz, and in the plan view, the negative direction of the X axis of the quartz is the direction in which the first vibrating arm and the second vibrating arm are arranged side by side, and is the direction from the second vibrating arm to the first vibrating arm. It is characterized by the following.

[0008] According to this configuration, by distributing the entire first conductive junction and the entire second conductive junction only in the first region of the external junction area, vibration modes (unwanted vibrations, spurious) different from the main vibration can be distanced from the main vibration and attenuated, thereby suppressing the influence of the unwanted vibrations on the main vibration and improving the reproducibility of the main vibration frequency measurement. Furthermore, by distributing the entire first conductive junction and the entire second conductive junction only in the first region of the external junction area, the first conductive junction and the second conductive junction can be positioned away from the center of the base (away from the virtual center line), making the first conductive junction and / or the second conductive junction positioned away from the center of the base (away from the virtual center line) less susceptible to unwanted vibrations. As a result, the excitation of the first vibrating arm and the second vibrating arm of the tuning-fork-type piezoelectric vibrating piece reduces the influence of unwanted vibrations and vibration leakage transmitted to the base and the external junction, improving the reproducibility of the frequency measurement. In addition, a slope is created due to the difference in etching rate in the area from the edge of the base on the negative X-axis side to the edge of the external joint, which increases the strength of that area and reduces the occurrence of defects in the tuning fork-type piezoelectric vibrating piece.

[0009] Further, a configuration may be adopted in which a fork portion formed by the first vibrating arm, the second vibrating arm and the base portion is asymmetric in the plan view.

[0010] In this configuration, arranging the entire first conductive joint and the entire second conductive joint so that they are biased to only the first region of the external joint region is particularly effective in reducing the effects of vibration leakage.

[0011] The area of ​​the first region may be larger than the area of ​​the second region in the plan view.

[0012] According to this configuration, by making the area of ​​the second region, which is the side that releases unwanted vibrations, smaller than the area of ​​the first region, it is possible to eliminate residual unwanted vibrations and more reliably make the first conductive joints and the second conductive joints less susceptible to unwanted vibrations. Furthermore, by making the area of ​​the first region, which is the side where the entire first conductive joint and the entire second conductive joint are provided, larger than the area of ​​the second region, it is possible to position the first conductive joints and the second conductive joints farther from the center of the base (farther from the imaginary center line), and the first conductive joints and / or the second conductive joints located farther from the center of the base (farther from the imaginary center line) can be less susceptible to unwanted vibrations. Furthermore, by making the area of ​​the first region where the entire first conductive bonding portion and the entire second conductive bonding portion are provided larger than the area of ​​the second region, it is possible to increase the areas of the first conductive bonding portion and the second conductive bonding portion, and the increased areas of the first conductive bonding portion and / or the second conductive bonding portion can stably hold and mount the first external electrode and the second external electrode on the member on which they are provided. As a result, the effects of vibration leakage can be further reduced, and the frequency measurement reproducibility can be further improved.

[0013] The first conductive joint portion and the second conductive joint portion may each be formed of a metal bump.

[0014] According to this configuration, by forming the first conductive joint and the second conductive joint with metal bumps, the electrical conductivity between the first lead electrode and the first external electrode and between the second lead electrode and the second external electrode can be improved and the joint can be more firmly bonded. This allows the area of ​​the first conductive joint and the second conductive joint to be reduced, thereby enabling miniaturization of tuning-fork-type piezoelectric vibrators using tuning-fork-type piezoelectric vibrating pieces. Furthermore, metal bumps cannot absorb stress and vibration as well as conductive resin adhesives and are more susceptible to vibration leakage. However, by positioning the metal bumps away from the center of the base (away from the imaginary center line), the joint can be less susceptible to unwanted vibrations. Furthermore, even if the metal bumps are biased toward the first region of the external joint and bonded to the external electrodes (first external electrode, second external electrode), they can be bonded more firmly and stably to the external electrodes than conductive resin adhesives.

[0015] A constriction may be provided between the base and the outer joint.

[0016] This configuration can attenuate unwanted vibrations transmitted from the base portion to the external joint portion.

[0017] Furthermore, the width of the base in the direction in which the first vibrating arm and the second vibrating arm are arranged side by side in the planar view may become smaller from the side of the base where the first vibrating arm and the second vibrating arm are located toward the side of the base where the external joint is located.

[0018] This configuration can attenuate unwanted vibrations transmitted from the base portion to the external joint portion.

[0019] Furthermore, if the line connecting the ends of the other end of the base in the planar view is taken as a virtual placement line, the external joint may be present only in the area on the side where the base does not exist, with the virtual placement line as the reference line in the planar view.

[0020] According to this configuration, it is possible to realize a miniaturization of the tuning-fork type piezoelectric vibrating piece.

[0021] In addition, a through hole or a recess may be provided in the base, and the through hole or the recess may be provided between the first vibrating arm and the conductive joint of the first conductive joint and the second conductive joint that is closer to the virtual center line when viewed in the plane.

[0022] This configuration makes it difficult for unwanted vibrations to be transmitted from the base to the conductive joint between the first and second conductive joints, whichever is closer to the imaginary center line, making the conductive joint even less susceptible to the effects of unwanted vibrations.

[0025] Also, the tuning-fork type piezoelectric vibrator according to the present invention is characterized in that the tuning-fork type piezoelectric vibrating piece is mounted and housed inside a container and is hermetically sealed.

[0026] According to this configuration, it is possible to provide a tuning-fork type piezoelectric vibrator having a tuning-fork type piezoelectric vibrating piece that is excellent in frequency measurement reproducibility.

[0027] Furthermore, the tuning-fork type piezoelectric oscillator according to the present invention is characterized in that the tuning-fork type piezoelectric vibrating piece and an integrated circuit element having a temperature compensation circuit are mounted and housed inside a container and hermetically sealed.

[0028] This configuration provides a tuning-fork type piezoelectric oscillator having a tuning-fork type piezoelectric vibrating piece with excellent frequency measurement reproducibility. In particular, tuning-fork type piezoelectric oscillators with temperature compensation circuits have the added function of applying a compensation voltage corresponding to the ambient temperature to the tuning-fork type piezoelectric vibrator's inherent frequency characteristics, changing the capacitance and suppressing frequency variation, thereby improving frequency stability. However, if variation occurs in the frequency reproducibility of the tuning-fork type piezoelectric vibrating piece, further temperature compensation will be performed in the temperature compensation circuit in response to that variation, which could further increase the final frequency variation. In the present invention, by improving the frequency reproducibility of the tuning-fork type piezoelectric vibrating piece, further variation caused by the temperature compensation circuit is suppressed, thereby further improving frequency stability. [Effects of the Invention]

[0029] According to the present invention, by distributing the entire first conductive junction and the entire second conductive junction so that they are present only in the first region of the external junction area, vibration modes (unwanted vibrations, spurious) different from the main vibration can be distanced from the main vibration and attenuated, thereby suppressing the influence of the unwanted vibrations on the main vibration and improving the reproducibility of the measured frequency of the main vibration. Furthermore, by distributing the entire first conductive junction and the entire second conductive junction so that they are present only in the first region of the external junction area, the first conductive junction and the second conductive junction can be positioned away from the center of the base (away from the imaginary center line), making the first conductive junction and / or the second conductive junction positioned away from the center of the base (away from the imaginary center line) less susceptible to the unwanted vibrations. As a result, the excitation of the first vibrating arm and the second vibrating arm of the tuning-fork-type piezoelectric vibrating piece reduces the influence of the unwanted vibrations and vibration leakage transmitted to the base and the external junction, thereby improving the reproducibility of the measured frequency. [Brief explanation of the drawings]

[0030] [Figure 1]1 is a schematic plan view of one main surface side of a tuning-fork type piezoelectric vibrating piece according to a first embodiment of the present invention. [Figure 2] 2 is a schematic plan view of another main surface side of the tuning-fork type piezoelectric vibrating piece of FIG. 1. FIG. [Figure 3] 3 is a schematic plan view of the upper surface side of a tuning-fork type piezoelectric vibrator having the tuning-fork type piezoelectric vibrating piece of FIGS. 1 and 2 before being hermetically sealed. FIG. [Figure 4] 4 is a schematic diagram of a cross section taken along line AA in FIG. 3 as viewed from the side in the direction of the arrow. [Figure 5] FIG. 10 is a comparison diagram for comparing the repeatability of frequency measurement depending on the arrangement positions of the first conductive junction and the second conductive junction. [Figure 6] FIG. 10 is a schematic plan view of another main surface side of a tuning-fork type piezoelectric vibrating piece according to a second embodiment of the present invention. [Figure 7] FIG. 11 is a schematic plan view of the upper surface side of a tuning-fork type piezoelectric oscillator having the tuning-fork type piezoelectric vibrating piece of FIGS. 1 and 2 before being hermetically sealed, according to a third embodiment of the present invention. [Figure 8] 8 is a schematic diagram of a cross section taken along line BB in FIG. 7 as viewed from the side in the direction of the arrow. DETAILED DESCRIPTION OF THE INVENTION

[0031] First Embodiment A tuning-fork type piezoelectric vibrating piece 10 according to a first embodiment of the present invention and a tuning-fork type piezoelectric vibrator 1 having the tuning-fork type piezoelectric vibrating piece 10 will be described in detail below with reference to Figures 1 to 5. Note that Figures 1 to 4 and Figure 6, which will be used in the following description, are illustrated using the same X-axis, Y-axis, and Z-axis.

[0032] First, the configuration of the tuning-fork-type piezoelectric vibrating piece 10 will be described with reference to Figures 1 and 2. Figure 1 is a schematic plan view of one main surface of the tuning-fork-type piezoelectric vibrating piece 10, and Figure 2 is a schematic plan view of the other main surface of the tuning-fork-type piezoelectric vibrating piece 10.

[0033] The tuning fork-type piezoelectric vibrating piece 10 is a piezoelectric vibrating piece in which various electrodes (first excitation electrode 31, second excitation electrode 32, first extraction electrode 33, second extraction electrode 34), conductive joints (first conductive joint 41, second conductive joint 42), etc. are added to a tuning fork-shaped quartz vibrating piece 20.

[0034] The tuning fork-type piezoelectric vibrating piece 10 includes the above-mentioned tuning fork-shaped quartz vibrating piece 20, which, as shown in Figures 1 and 2, includes a base 21, a pair of vibrating arms (a first vibrating arm 22 and a second vibrating arm 23) extending from one end 21a of the base 21 in one direction (in this embodiment, the positive direction of the Y-axis), and an external joint 24 provided at the other end 21b of the base 21.

[0035] A large number of quartz crystal vibrating pieces 20 are simultaneously formed from a single synthetic quartz crystal wafer made of a Z-plate. In this embodiment, the outer shape of the quartz crystal vibrating piece 20 is formed using photolithography and wet etching. In FIGS. 1 to 4 and FIG. 6, which will be used in the following description, the quartz crystal vibrating piece 20 has the positive Y-axis direction in the direction (extension direction) in which the first vibrating arm 22 and the second vibrating arm 23 extend from the base 21, the negative X-axis direction in the width direction of the first vibrating arm 22 and the second vibrating arm 23 (the direction in which the first vibrating arm 22 and the second vibrating arm 23 are arranged side by side) from the second vibrating arm 23 toward the first vibrating arm 22, and the positive Z-axis direction in the thickness direction of the first vibrating arm 22 and the second vibrating arm 23, from one principal surface 20a toward the other principal surface 20b of the quartz crystal vibrating piece 20.

[0036] In the quartz crystal vibrating piece 20, when viewed in a plan view (hereinafter sometimes simply referred to as "plan view") in which one main surface 20a or the other main surface 20b of the quartz crystal vibrating piece 20 is viewed from a perpendicular direction, a constriction 25 is provided between the base 21 and the external joint portion 24.

[0037] The width of the base 21 in the direction in which the first vibrating arm 22 and the second vibrating arm 23 are arranged side by side in plan view (positive and negative directions of the X axis) becomes smaller from one end 21a side of the base 21 (the side of the first vibrating arm 22 and the second vibrating arm 23 of the base 21) to the other end 21b side of the base 21 (the side of the external joint 24 of the base 21). Note that the shape of the base 21 is not limited to this shape, and for example, the width of the base 21 in plan view may be once larger and then smaller from one end 21a side of the base 21 (the side of the first vibrating arm 22 and the second vibrating arm 23 of the base 21) to the other end 21b side of the base 21 (the side of the external joint 24 of the base 21).

[0038] The external joint 24 has a shape having a first extension portion extending from the other end 21b of the base 21 in the opposite direction (negative y-axis direction) to the direction in which the first vibrating arm 22 and the second vibrating arm 23 extend from the base 21, and a second extension portion extending from the first extension portion in a direction in which the first vibrating arm 22 and the second vibrating arm 23 are arranged side by side, that is, in a direction from the second vibrating arm 23 toward the first vibrating arm 22 (negative x-axis direction), and is L-shaped when viewed in a plane.

[0039] A virtual center line L1 is a line that passes through the center of the first vibrating arm 22 and the second vibrating arm 23 in the width direction (positive and negative directions of the X axis) in a plan view (the center of the first vibrating arm 22 and the second vibrating arm 23 excluding the fork portion (tuning fork portion) formed by the first vibrating arm 22, the second vibrating arm 23 and the base 21) and extends in the extension direction of the first vibrating arm 22 and the second vibrating arm 23. Within the region of the external joint 24 in a plan view, the region on the side where the first vibrating arm 22 is located (the region on the negative side of the X axis from the virtual center line L1) is defined as a first region, and the region on the side where the second vibrating arm 23 is located (the region on the positive side of the X axis from the virtual center line L1) is defined as a second region. A line connecting the ends of the other end 21b of the base 21 in a plan view is defined as a virtual placement line L2.

[0040] In plan view, the external joints 24 are present only in the region on the side where the base 21 is not present (the region on the negative Y-axis side of the imaginary placement line L2), with the imaginary placement line L2 as the reference line. In other words, in plan view, the external joints 24 are not present in the region on the side where the base 21 is present (the region on the positive Y-axis side of the imaginary placement line L2), with the imaginary placement line L2 as the reference line. In addition, in plan view, the area of ​​the first region of the external joints 24 is larger than the area of ​​the second region thereof.

[0041] In the crystal vibrating piece 20, whose outer shape is formed by photolithography and wet etching, the fork portion (tuning fork portion) formed by the first vibrating arm 22, the second vibrating arm 23, and the base portion 21 is asymmetrical with respect to the imaginary center line L1 in plan view. In this embodiment, the deepest portion of the tuning fork portion is located closer to the first vibrating arm 22 than the imaginary center line L1 (on the negative side of the X-axis than the imaginary center line L1).

[0042] The first vibrating arm 22 has a first wide portion 26 on its tip side (the side away from one end 21a of the base 21), which is a region wider than the arm width of the first vibrating arm 22 (the dimension in the direction perpendicular to the extension direction of the first vibrating arm 22 (the positive and negative X-axis direction in this embodiment)). The second vibrating arm 23 has a second wide portion 27 on its tip side (the side away from one end 21a of the base 21), which is a region wider than the arm width of the second vibrating arm 23 (the dimension in the direction perpendicular to the extension direction of the second vibrating arm 23 (the positive and negative X-axis direction in this embodiment)).

[0043] Long grooves are formed on one main surface 20a side and the other main surface 20b side of each of the pair of first vibrating arms 22 and second vibrating arms 23 in order to further reduce the equivalent series resistance value (crystal impedance: hereinafter, sometimes referred to as "CI value"). More specifically, long grooves 22a and 22b are formed to a predetermined depth on one main surface 20a side and the other main surface 20b side of the first vibrating arm 22 so as to face each other (so as to overlap in a plan view), and long grooves 23a and 23b are formed to a predetermined depth on one main surface 20a side and the other main surface 20b side of the second vibrating arm 23 so as to face each other (so as to overlap in a plan view). The long grooves 22a and 22b are formed so that, in a plan view, one end of each long groove extends to a region on one end 21a side of the base 21, and the other end of each long groove is located closer to the base 21 than the first wide portion 26. The long grooves 23a and 23b are formed so that, in a plan view, one end of each long groove extends to a region on one end 21a side of the base 21, and the other end of each long groove is located closer to the base 21 than the second wide portion 27. The long grooves 22a, 22b, 23a, and 23b have a longitudinal direction along the direction in which the first vibrating arm 22 and the second vibrating arm 23 extend (positive and negative Y-axis direction), and a width direction along the direction in which the first vibrating arm 22 and the second vibrating arm 23 are arranged side by side (positive and negative X-axis direction).

[0044] The quartz crystal vibrating piece 20 is formed with a pair of first excitation electrodes 31 and second excitation electrodes 32 formed on the first vibrating arm 22 and the second vibrating arm 23 which are configured with different potentials, a first extraction electrode 33 which is drawn from the first excitation electrode 31 to the base 21 and the external joint 24, and a second extraction electrode 34 which is drawn from the second excitation electrode 32 to the base 21 and the external joint 24.

[0045] The first excitation electrode 31 is formed on the outer side surface and inner side surface of the second vibrating arm 23, via the one main surface 20a side and the other main surface 20b side of the first vibrating arm 22, and the one main surface 20a side and the other main surface 20b side of the wide portion 27 of the second vibrating arm 23. A portion of the first excitation electrode 31 formed on the one main surface 20a side and the other main surface 20b side of the first vibrating arm 22 is formed to extend over the entire inside of the long grooves 22a, 22b of the first vibrating arm 22. The second excitation electrode 32 is formed on the one main surface 20a side and the other main surface 20b side of the second vibrating arm 23, and the one main surface 20a side and the other main surface 20b side of the wide portion 26 of the first vibrating arm 22, and the outer side surface and inner side surface of the first vibrating arm 22. A portion of the second excitation electrode 32 formed on the one principal surface 20a side and the other principal surface 20b side of the second vibrating arm 23 is formed to extend over the entire interior of the long grooves 23a, 23b of the second vibrating arm 23. By forming the long grooves 22a, 22b, 23a, 23b, the electric field efficiency between the pair of first vibrating arms 22 and second vibrating arms 23 is increased even when the tuning-fork-type piezoelectric vibrating piece 10 is miniaturized, and a good CI value can be obtained. Note that a portion of the first excitation electrode 31 may be formed only in a partial region of the long grooves 22a, 22b of the first vibrating arm 22, and a portion of the second excitation electrode 32 may be formed only in a partial region of the long grooves 23a, 23b of the second vibrating arm 23.

[0046] The first extraction electrode 33 is formed on the one main surface 20a side and the other main surface 20b side of the base 21, and on the other main surface 20b side of the external joint 24. The second extraction electrode 34 is formed on the one main surface 20a side and the other main surface 20b side of the base 21, and on the other main surface 20b side of the external joint 24. In the region surrounded by the dotted line in FIG. 2 on the other main surface 20b side of the external joint 24, the dividing groove dividing the first extraction electrode 33 and the second extraction electrode 34 is located closer to the first vibrating arm 22 than the imaginary center line L1, and the first extraction electrode 33 and the second extraction electrode 34 are provided so that the entire first conductive joint 41 can be disposed in the portion of the first extraction electrode 33 between the imaginary center line L1 and the dividing groove.

[0047] The base 21 has a through hole penetrating in the thickness direction (positive and negative Z-axis directions), and a first through-hole electrode 35 coated with a conductive material on the inner wall surface of the through hole, and the first through-hole electrode 35 electrically connects a portion of the first extraction electrode 33 formed on the one main surface 20 a side of the base 21 to a portion of the first extraction electrode 33 formed on the other main surface 20 b side of the base 21. The base 21 also has a through hole penetrating in the thickness direction (Z-axis direction), and a second through-hole electrode 36 coated with a conductive material on the inner wall surface of the through hole, and the second through-hole electrode 36 electrically connects a portion of the second extraction electrode 34 formed on the one main surface 20 a side of the base 21 to a portion of the second extraction electrode 34 formed on the other main surface 20 b side of the base 21. The through hole in which the first through-hole electrode 35 is formed on the inner wall surface is, in a planar view, located between the first vibrating arm 22 and the first conductive junction 41, whichever of the first conductive junction 41 and the second conductive junction 42 is closer to the virtual center line L1.

[0048] In addition, when viewed in a plane, a recess may be provided between the first vibrating arm 22 and the first conductive joint 41, whichever of the first and second conductive joints 41 is closer to the virtual center line L1.

[0049] The first excitation electrode 31, second excitation electrode 32, first extraction electrode 33, and second extraction electrode 34 described above have a layered structure in which a chromium (Cr) layer is formed on a quartz substrate, and a gold (Au) layer is laminated on this chromium layer. Note that the layered structure of each electrode 31-34 is not limited to a gold layer laminated on a chromium layer, but may be other layered structures, such as a gold (Au) layer laminated on a titanium (Ti) layer. Each electrode 31-34 is formed on the entire main surface (one main surface 20a, the other main surface 20b) of the quartz wafer by film formation means such as vacuum deposition or sputtering, and then simultaneously shaped into the desired pattern using photolithography and metal etching.

[0050] A first frequency adjustment metal film (first frequency adjustment weight) 26W is formed only on the one main surface 20a side of the first wide portion 26, and a second frequency adjustment metal film (second frequency adjustment weight) 27W is formed only on the one main surface 20a side of the second wide portion 27. The frequency of the tuning-fork-type piezoelectric vibrating piece 10 is finely adjusted by reducing the mass of each frequency adjustment metal film 26W, 27W by irradiating it with a beam such as a laser beam or an ion beam. The first frequency adjustment metal film 26W is formed to have an area in a plan view that is slightly smaller than the portion of the second excitation electrode 32 that is formed on the one main surface 20a side of the first wide portion 26, and the second frequency adjustment metal film 27W is formed to have an area in a plan view that is slightly smaller than the portion of the first excitation electrode 31 that is formed on the one main surface 20a side of the second wide portion 27.

[0051] A first conductive joint 41 is provided on a portion of the first extraction electrode 33 that is formed on the other surface 20b of the external joint 24, and a second conductive joint 42 is provided on a portion of the second extraction electrode 34 that is formed on the other surface 20b of the external joint 24. In this embodiment, the first conductive joint 41 and the second conductive joint 42 are formed of metal bumps such as gold bumps or gold-plated bumps. Note that the conductive joints 41, 42 are not limited to metal bumps and may be, for example, a conductive resin adhesive.

[0052] In a plan view, the entire first conductive joint 41 and the entire second conductive joint 42 are arranged to be biased only in a first region (a region on the side where the first vibrating arm 22 is located, with the imaginary center line L1 as the reference line (a region on the negative X-axis side of the imaginary center line L1)) of the region of the external joint 24. In a plan view, the first conductive joint 41 that is closer to the imaginary center line L1 out of the first conductive joint 41 and the second conductive joint 42 is arranged in the vicinity of the imaginary center line L1.

[0053] In a planar view, the area of ​​the first conductive joint 41, which is closer to the imaginary center line L1, is larger than the area of ​​the second conductive joint 42, which is farther from the imaginary center line L1.

[0054] In a planar view, the first conductive joint 41 and the second conductive joint 42 each have an elliptical shape, and the first conductive joint 41 and the second conductive joint 42 are arranged so that, in a planar view, the direction of the long axis of the first conductive joint 41 and the direction of the long axis of the second conductive joint 42 are respectively in the direction in which the first conductive joint 41 and the second conductive joint 42 are arranged side by side (positive and negative directions of the X-axis).

[0055] Next, a tuning fork-type piezoelectric vibrator 1 including the tuning fork-type piezoelectric vibrating piece 10 of Figures 1 and 2 will be described with reference to Figures 3 and 4. Figure 3 is a schematic plan view of the upper surface side of the tuning fork-type piezoelectric vibrator 1 including the tuning fork-type piezoelectric vibrating piece of Figures 1 and 2 before hermetically sealing, and Figure 4 is a schematic cross-sectional view taken along line AA in Figure 3. Note that Figures 1 and 2 omit illustration of the electrodes (first excitation electrode 31, second excitation electrode 32, first extraction electrode 33, second extraction electrode 34) and the like provided on the tuning fork-type piezoelectric vibrating piece 10.

[0056] The tuning-fork-type piezoelectric vibrator 1 is mainly composed of a container 50 made of an insulating material as a base material, the tuning-fork-type piezoelectric vibrating piece 10 described with reference to FIGS. 1 and 2, and a flat lid (not shown) that is joined to the container 50 to airtightly seal the tuning-fork-type piezoelectric vibrating piece 20. The tuning-fork-type piezoelectric vibrating piece 10 is accommodated in a recess 51 of the container 50, and then the lid is joined to the open end of the container 50 so as to cover the recess, thereby airtightly sealing it. The container 50 and the lid are joined together via a sealant (not shown). Here, the container 50 and the lid are joined together via a sealant (not shown).

[0057] The container 50 is box-shaped and made of an insulating material with a ceramic base such as alumina, and is formed, for example, by stacking two ceramic green sheets 50a and 50b and firing them together. The container 50 has a recess 51 that is rectangular in plan view inside a bank portion 52 that is frame-shaped in plan view. A sealing material (not shown) that is frame-shaped in plan view is formed on the upper surface of the bank portion 52, and the sealing material corresponds to the outer periphery of the lid.

[0058] On one short side of the inner bottom surface 53 of the recess 51, a first mounting pad (first external electrode) 61 and a second mounting pad (second external electrode) 62 are arranged with a gap between them. The first mounting pad 61 and the second mounting pad 62 are mechanically and electrically joined to the first extraction electrode 33 and the second extraction electrode 34 of the tuning-fork-type piezoelectric vibrating piece 10 by the first conductive joint 41 and the second conductive joint 42. In addition, an external connection terminal 63 is provided at each of the four corners of the outer bottom surface 54 of the container 50, and the first mounting pad 61 is connected to one external connection terminal 63, and the second mounting pad 62 is connected to the other external connection terminal 63. The first mounting pad 61 and the second mounting pad 62 have opposite polarities.

[0059] The first mounting pad 61 and the second mounting pad 62 are formed by depositing gold on the upper surface of a tungsten metallization layer using a method such as plating. Note that molybdenum, for example, may be used as the metallization layer instead of tungsten. Note that a metal film of the same layer as the mounting pads is also formed on the open end of the container 50, which is connected to a lid described later.

[0060] The first mounting pad 61 is electrically connected to one of the four external connection terminals 63 on the outer bottom surface 54 of the container 50 via internal wiring (not shown) and side conductors (castellations) (not shown) provided at the corners of the first ceramic green sheet 50a of the container 50. The second mounting pad 62 is electrically connected to another of the four external connection terminals 63 on the outer bottom surface 54 of the container 50 via internal wiring (not shown) and side conductors (castellations) (not shown) provided at the corners of the first ceramic green sheet 50a of the container 50.

[0061] The lid is a metal lid body that is rectangular in plan view and has a base material of Kovar, and a nickel-plated layer is formed on the front and back surfaces of the lid. Furthermore, a metallic brazing material is formed over the entire surface of the bonding surface of the lid that is to be joined to the container 50 on the nickel-plated layer. Examples of the brazing material include a gold-tin alloy layer. In this case, the lid has a nickel-plated layer on the top surface of the Kovar, a gold-plated layer on top of that, and a gold-tin alloy layer on top of that.

[0062] According to the tuning-fork-type piezoelectric vibrating piece 10 of the first embodiment, by distributing the entire first conductive joint 41 and the entire second conductive joint 42 only in the first region of the external joint 24, vibration modes different from the main vibration (unwanted vibrations, spurious) can be distanced from the main vibration and attenuated, thereby suppressing the influence of the unwanted vibrations on the main vibration and improving the measurement reproducibility of the main vibration frequency. Furthermore, by distributing the entire first conductive joint 41 and the entire second conductive joint 42 only in the first region of the external joint 24, the first conductive joint 41 and the second conductive joint 42 can be positioned away from the center of the base (away from the imaginary center line L1). This makes the first conductive joint 41 and / or the second conductive joint 42 (the second conductive joint 42 in this embodiment) located away from the center of the base 21 (away from the imaginary center line L1) less susceptible to the influence of the unwanted vibrations. As a result, the excitation of the first vibrating arm 22 and the second vibrating arm 23 of the tuning fork-type piezoelectric vibrating piece 10 reduces the effects of vibration leakage and unwanted vibrations transmitted to the base 21 and the external joint 24, thereby improving the reproducibility of frequency measurements.

[0063] The tuning-fork-type piezoelectric vibrating piece 10 of the first embodiment described above is particularly suitable for use in a tuning-fork-type piezoelectric oscillator incorporating a temperature compensation circuit such as a TCXO or RTC. A temperature compensation circuit typically applies a compensation voltage corresponding to the ambient temperature to the inherent frequency characteristics of the tuning-fork-type piezoelectric vibrator, changing the capacitance to suppress frequency variation and improving frequency stability. However, if variation occurs in the frequency reproducibility of the tuning-fork-type piezoelectric vibrating piece 10, the temperature compensation circuit will further compensate for the variation, potentially resulting in further variation in the final frequency. By improving the frequency reproducibility of the tuning-fork-type piezoelectric vibrating piece 10 of the first embodiment described above, further variation due to the temperature compensation circuit is suppressed, thereby improving frequency stability.

[0064] Here, the arrangement of the first conductive bonding portion 41 and the second conductive bonding portion 42 of the tuning-fork-type piezoelectric vibrating piece 10 of the first embodiment described above will be compared with the frequency measurement reproducibility of different arrangements. Figure 5(a) shows a tuning-fork-type piezoelectric vibrating piece 10a in which the entire first conductive bonding portion 41 is located in the second region and the entire second conductive bonding portion 42 is located in the first region. Figure 5(b) shows a tuning-fork-type piezoelectric vibrating piece 10b in which the first conductive bonding portion 41 is located in the first region and the second conductive bonding portion 42 is located in the first region so as to straddle the imaginary center line L1. Figure 5(c) shows a tuning-fork-type piezoelectric vibrating piece 10 (this embodiment) in which the entire first conductive bonding portion 41 and the entire second conductive bonding portion 42 are located in the first region. A mounting test was conducted five times using multiple tuning-fork-type piezoelectric vibrating pieces 10a, 10b, and 10. The tuning-fork-type piezoelectric vibrating pieces 10a, 10b, and 10c each have a size of L (in the Y-axis positive / negative direction) = 1.2 mm and W = 0.4 mm (in the X-axis positive / negative direction), and an external joint 24 that is approximately L-shaped in plan view is provided below the base 21. A first conductive joint 41 and a second conductive joint 42 (gold-plated bumps) are formed on the extraction electrodes 33 and 34 of the external joint 24. The base (container 50) that houses the tuning-fork-type piezoelectric vibrating pieces 10a, 10b, and 10c is an alumina ceramic base measuring 1.6 mm x 1.0 mm, and the first conductive joint 41 and the second conductive joint 42 (gold-plated bumps) of the tuning-fork-type piezoelectric vibrating pieces 10a, 10b, and 10c are ultrasonically bonded to mounting electrode pads on the inner bottom surface of the base. The first conductive joint 41 and the second conductive joint 42 (gold-plated bumps) are ellipsoids measuring 0.03 μm in length and 0.045 μm in width, and the distance between the first conductive joint 41 and the second conductive joint 42 is 0.17 μm in Figure 5(a), 0.14 μm in Figure 5(b), and 0.10 μm in Figure 5(c). The hermetically sealed surface-mount tuning fork resonator was placed in a frequency measurement jig, and the frequency was measured. This was repeated five times, and the frequency was measured each time. This variation was judged as the frequency measurement reproducibility.From Figures 5(a) to (c), it can be seen that the tuning-fork-type piezoelectric vibrating piece 10 (this embodiment), in which the entire first conductive bonding portion 41 and the entire second conductive bonding portion 42 are located in the first region, has higher frequency measurement reproducibility than the other two tuning-fork-type piezoelectric vibrating pieces 10a and 10b.

[0065] When the fork portion (tuning fork portion) formed by the first vibrating arm 22, the second vibrating arm 23 and the base 21 is asymmetric, arranging the entire first conductive joint 41 and the entire second conductive joint 42 so that they are biased only to the first region of the region of the external joint 24 is particularly effective in reducing the effects of vibration leakage.

[0066] Furthermore, by making the area of ​​the second region, which is the side that releases unwanted vibrations, smaller than the area of ​​the first region, of the first and second regions of the external joint 24, it is possible to eliminate residual unwanted vibrations and more reliably make the first conductive joints 41 and the second conductive joints 42 less susceptible to unwanted vibrations. Furthermore, by making the area of ​​the first region, which is the side where the entire first conductive joints and the entire second conductive joints are provided, larger than the area of ​​the second region of the first and second regions of the external joint 24, it is possible to position the first conductive joints 41 and the second conductive joints 42 farther from the center of the base 21 (farther from the imaginary center line L1), and the first conductive joints 41 and / or the second conductive joints 42 (the second conductive joints 42 in this embodiment) positioned farther from the center of the base 21 (farther from the imaginary center line L1) can be made less susceptible to unwanted vibrations. Furthermore, by making the area of ​​the first region, where the entire first conductive bonding portion 41 and the entire second conductive bonding portion 42 are provided, larger than the area of ​​the second region of the external bonding portion 24, it is possible to increase the areas of the first conductive bonding portion 41 and the second conductive bonding portion 42. The increased area of ​​the first conductive bonding portion 41 and / or the second conductive bonding portion 42 (first conductive bonding portion 41 in this embodiment) stabilizes the mounting of the first external electrode and the second external electrode, which mechanically and electrically connect the first extraction electrode 33 and the second extraction electrode 34, on a member provided with the first external electrode and the second external electrode. As a result, the effects of vibration leakage can be further reduced, further improving the reproducibility of frequency measurements.

[0067] Furthermore, by forming the first conductive joint 41 and the second conductive joint 42 with metal bumps, it is possible to further improve the electrical conductivity between the first lead electrode 33 and the first external electrode that mechanically and electrically joins the first lead electrode 33, and between the second lead electrode 34 and the second external electrode that mechanically and electrically joins the second lead electrode 34, and to achieve a stronger bond, which makes it possible to reduce the area of ​​the first conductive joint 41 and the second conductive joint 42 and achieve miniaturization of the tuning fork type piezoelectric vibrator 1 that uses the tuning fork type piezoelectric vibrating piece 10. Furthermore, metal bumps cannot absorb stress and vibration as well as conductive resin adhesives and are more susceptible to vibration leakage, but by positioning the metal bumps away from the center of the base 21 (away from the imaginary center line L1), it is possible to reduce the influence of unwanted vibrations. Furthermore, even if the metal bumps are biased toward the first region of the external bonding portion 24 and bonded to the external electrodes (first external electrode, second external electrode), they can be bonded to the external electrodes more firmly and stably than conductive resin adhesives, etc.

[0068] Furthermore, by providing a constriction 25 between the base 21 and the outer joint 24, unwanted vibrations transmitted from the base 21 to the outer joint 24 can be attenuated.

[0069] In addition, by decreasing the width of the base 21 in the direction in which the first vibrating arm 22 and the second vibrating arm 23 are arranged side by side (positive and negative directions of the X axis) from one end 21a side of the base 21 (the side of the first vibrating arm 22 and the second vibrating arm 23 of the base 21) to the other end 21b side of the base 21 (the side of the external joint 24 of the base 21), unwanted vibrations transmitted from the base 21 to the external joint 24 can be attenuated.

[0070] Furthermore, by making the external joints 24 exist only in the area on the side where the base portion 21 does not exist, with the imaginary placement line L2 as the reference line, the tuning-fork type piezoelectric vibrating piece 10 can be made smaller.

[0071] Furthermore, by providing a through hole in the base 21, between the first vibrating arm 22 and the first conductive joint 41, of the first conductive joint 41 and the second conductive joint 42, which is closer to the virtual center line L1, and having the first through-hole electrode 35 formed on the inner wall surface, it is possible to make it difficult for unwanted vibrations to be transmitted from the base 21 to the first conductive joint 41, and to make the first conductive joint 41 even less susceptible to the effects of unwanted vibrations. Note that, instead of a through hole in which the first through-hole electrode 35 is formed on the inner wall surface, a recess may be provided in the base 21 between the first vibrating arm 22 and the first conductive joint 41, of the first conductive joint 41 and the second conductive joint 42, which is closer to the virtual center line L1, to obtain the same effect.

[0072] Furthermore, by aligning the negative direction of the X-axis of the quartz crystal of the quartz crystal vibrating piece 20 with the direction in which the first vibrating arm 22 and the second vibrating arm 23 are arranged side by side, and the direction from the second vibrating arm 23 to the first vibrating arm 22, a slope due to the difference in etching rate is created in the portion from the edge on the negative X-axis side of the base 21 to the edge of the external joint 24, thereby increasing the strength of that portion and suppressing the occurrence of defects in the tuning fork-type piezoelectric vibrating piece 10.

[0073] Furthermore, by making the area of ​​the first conductive joint 41, which is closer to the imaginary center line L1, larger than the area of ​​the second conductive joint 42, which is farther from the imaginary center line L1, it is possible to prevent the first conductive joint 41 from being crushed and the tuning-fork-type piezoelectric vibrating piece 10 from tilting when the tuning-fork-type piezoelectric vibrating piece 10 is mounted on a member provided with first and second external electrodes that mechanically and electrically join the first and second extraction electrodes 33 and 34, and it is possible to stably mount the tuning-fork-type piezoelectric vibrating piece 10 on the member.

[0074] Furthermore, by making the first conductive joint 41 and the second conductive joint 42 each elliptical in shape and arranging the first conductive joint 41 and the second conductive joint 42 so that the direction of the long axis of the first conductive joint 41 and the direction of the long axis of the second conductive joint 42 are each in the direction in which the first conductive joint 41 and the second conductive joint 42 are arranged side by side (positive and negative directions of the X-axis), it is possible to prevent the tuning-fork-type piezoelectric vibrating piece 10 from tilting when mounted on a member provided with first and second external electrodes that mechanically and electrically join the first and second extraction electrodes 33 and 34, without making the first conductive joint 41 and the second conductive joint 42 each larger than necessary, and the tuning-fork-type piezoelectric vibrating piece 10 can be stably mounted on the member.

[0075] Furthermore, by making the external joint 24 L-shaped in a planar view, the area of ​​the first region can be made larger than the area of ​​the second region in a planar view without making the areas of the first region and the second region of the external joint 24 larger than necessary, thereby making it possible to miniaturize the tuning fork-type piezoelectric vibrating piece 10 having the external joint 24.

[0076] Furthermore, by arranging the first conductive joint 41, which is closer to the imaginary center line L1, of the first conductive joint 41 and the second conductive joint 42, in the vicinity of the imaginary center line L1, the tuning fork-type piezoelectric vibrating piece 10 can be stably mounted on a member provided with first external electrodes and second external electrodes that mechanically and electrically join the first extraction electrode 33 and the second extraction electrode 34, and the routing of the first external electrode that is mechanically and electrically joined to the first extraction electrode 33 on which the first conductive joint 41 is provided can be reduced, thereby realizing the miniaturization of the member provided with the first external electrodes and second external electrodes that mechanically and electrically join the first extraction electrode 33 and the second extraction electrode 34.

[0077] Furthermore, according to the tuning-fork type piezoelectric vibrator 1 of the first embodiment described above, it is possible to provide a tuning-fork type piezoelectric vibrator 1 having a tuning-fork type piezoelectric vibrating piece 10 that has the above-mentioned effects, such as excellent frequency measurement reproducibility.

[0078] Second Embodiment A tuning-fork type piezoelectric vibrating piece 10A according to a second embodiment of the present invention will be described in detail below with reference to Fig. 6. Fig. 6 is a schematic plan view of the other main surface side of the tuning-fork type piezoelectric vibrating piece 10A.

[0079] The first embodiment differs from the second embodiment in that the portions of the first extraction electrode 33 formed on the other main surface 20b of the external joint 24 and the portions of the second extraction electrode 34 formed on the other main surface 20b of the external joint 24 in the first embodiment have different shapes from the portions of the first extraction electrode 33A formed on the other main surface 20b of the external joint 24 and the portions of the second extraction electrode 34A formed on the other main surface 20b of the external joint 24 in the second embodiment. The other configurations are similar between the first and second embodiments, and therefore the same reference numerals as in the first embodiment are used in the second embodiment, and description thereof will be omitted.

[0080] The first extraction electrode 33A is formed on the one main surface 20a side and the other main surface 20b side of the base 21, and on the other main surface 20b side of the external joint 24. The second extraction electrode 34A is formed on the one main surface 20a side and the other main surface 20b side of the base 21, and on the other main surface 20b side of the external joint 24. In the region surrounded by the dotted line in FIG. 6 on the other main surface 20b side of the external joint 24, the separating groove separating the first extraction electrode 33A and the second extraction electrode 34A is located closer to the first vibrating arm 22 than the imaginary center line L1, and the first extraction electrode 33A and the second extraction electrode 34A are provided so that the entire first conductive joint 41 can be disposed in the portion of the first extraction electrode 33A between the imaginary center line L1 and the separating groove.

[0081] When comparing the portion surrounded by the dotted line in FIG. 2 on the other main surface 20b side of the external joint 24 of the first embodiment with the portion surrounded by the dotted line in FIG. 6 on the other main surface 20b side of the external joint 24 of the second embodiment, the first extraction electrode 33A is closer to the virtual center than the first extraction electrode 33 in the direction from the second vibrating arm 23 to the first vibrating arm 22 (X-axis negative direction) in plan view. The first extraction electrode 33A is formed so as to extend to a position away from the line L1. In this embodiment, the first extraction electrode 33A protrudes toward the second extraction electrode 34A in plan view.

[0082] The tuning-fork-type piezoelectric vibrating piece 10A of the second embodiment described above has the same effects as the tuning-fork-type piezoelectric vibrating piece 10 of the first embodiment described above. Furthermore, the tuning-fork-type piezoelectric vibrating piece 10A can reduce the protrusion of the first conductive bonding portion 41 from the first extraction electrode 33A, and also makes it easier to recognize the position of the wiring pattern of the package mounting portion that is visible through the tuning-fork-type piezoelectric vibrating piece 10A, thereby suppressing misalignment of the mounting position.

[0083] Third Embodiment A tuning-fork-type piezoelectric vibrating piece 10 according to a third embodiment of the present invention and a tuning-fork-type piezoelectric oscillator 7 having the tuning-fork-type piezoelectric vibrating piece 10 will be described in detail below with reference to Figures 7 and 8. Note that the third embodiment uses the same tuning-fork-type piezoelectric vibrating piece 10 as disclosed in the first embodiment. In addition, in the third embodiment, the same parts as in the first embodiment are given the same reference numerals, and some of the description will be omitted, with only the differences being described.

[0084] The tuning-fork type piezoelectric oscillator 7 is mainly composed of a container 70 made of an insulating material as a base material, the tuning-fork type piezoelectric vibrating piece 10 described with reference to Figures 1 and 2, an integrated circuit element 8 for a TCXO (Temperature Compensated Crystal Oscillator) having a temperature compensation circuit, an oscillator circuit, etc., and a flat lid (not shown) that is bonded to the container 70 to hermetically seal the tuning-fork type piezoelectric vibrating piece 10. The tuning-fork type piezoelectric vibrating piece 10 and the integrated circuit element 8 are housed in a recess 71 of the container 70, and then the lid is connected to the open end of the container 70 so as to cover the recess 71, thereby hermetically sealing the tuning-fork type piezoelectric vibrating piece 10. Here, the container 70 and the lid are bonded together via a sealant (not shown).

[0085] The container 70 is box-shaped and made of an insulating material with a ceramic base such as alumina, and is formed, for example, by stacking three ceramic green sheets 70a, 70b, and 70c and firing them together. The container 70 has a recess 71 that is rectangular in plan view inside a bank portion 72 that is frame-shaped in plan view. A sealing material (not shown) is formed in a frame shape in plan view on the upper surface of the bank portion 72, and the sealing material corresponds to the outer periphery of the lid.

[0086] A plurality of mounting pads 730, which are mechanically and electrically bonded to the integrated circuit element 8, are arranged with gaps between them on the inner bottom surface 73 of the recess 71. The external terminals (not shown) of the integrated circuit element 8 and the mounting pads 730 are bonded by a conductive bonding material such as gold bumps.

[0087] A middle stage 74 is formed at the top of the inner bottom surface 73 of the recess 71. On the upper surface of the middle stage 74, a first mounting pad (first external electrode) 731 and a second mounting pad (second external electrode) 732 are arranged with a gap between them. The first mounting pad (first external electrode) 731 and the second mounting pad (second external electrode) 732 are mechanically and electrically joined to the first extraction electrode 33 and the second extraction electrode 34 of the tuning-fork-type piezoelectric vibrating piece 10 by the first conductive joint 41 and the second conductive joint 42. In addition, external connection terminals 76 are provided at each of the four corners of the outer bottom surface 75 of the container 70, and are respectively connected as required to the mounting pads 730 connected to the integrated circuit element 8. These four external connection terminals 76 include, for example, a power supply terminal, a ground terminal, and an output terminal.

[0088] The lid is a metal lid body that is rectangular in plan view and has a base material of Kovar, and a nickel plating layer is formed on the front and back surfaces of the lid. Furthermore, a metallic brazing material is formed over the entire surface of the bonding surface of the lid that is to be joined to the container 70 on the nickel plating layer. The brazing material may be, for example, a gold-tin alloy layer. In this case, the configuration is such that a nickel plating layer is formed on the top surface of the Kovar, a gold plating layer is formed on top of that, and a gold-tin alloy layer is formed on top of that.

[0089] In the above-described third embodiment, the integrated circuit element 8 is described as an integrated circuit element for a TCXO having a temperature compensation circuit, an oscillator circuit, etc. However, the integrated circuit element 8 can also be used as an integrated circuit element for an RTC (Real Time Clock) consisting of a circuit having a calendar function for date and time in addition to a temperature compensation circuit and an oscillator circuit.

[0090] As such, the tuning-fork-type piezoelectric vibrating piece 10 of the third embodiment described above is particularly suitable for use in a tuning-fork-type piezoelectric oscillator 7 incorporating a temperature compensation circuit such as a TCXO or RTC. A temperature compensation circuit typically applies a compensation voltage corresponding to the ambient temperature to the inherent frequency characteristics of the tuning-fork-type piezoelectric vibrator, changing the capacitance to suppress frequency variation and improving frequency stability. However, if variation occurs in the frequency reproducibility of the tuning-fork-type piezoelectric vibrating piece 10, the temperature compensation circuit will further compensate for the variation, potentially resulting in even greater variation in the final frequency. By improving the frequency reproducibility of the tuning-fork-type piezoelectric vibrating piece 10 of the first embodiment described above, further variation due to the temperature compensation circuit is suppressed, thereby improving frequency stability.

[0091] The tuning fork type piezoelectric vibrating piece, tuning fork type piezoelectric vibrator, and tuning fork type piezoelectric oscillator are not limited to the tuning fork type piezoelectric vibrating piece 10, 10A, tuning fork type piezoelectric vibrator 1, and tuning fork type piezoelectric oscillator 7 described above, and various modifications can be made.

[0092] For example, in the first embodiment and the like described above, the area of ​​the first conductive joint 41, which is closer to the imaginary center line L1 in plan view, of the first conductive joint 41 and the second conductive joint 42, is larger than the area of ​​the second conductive joint 42, which is farther from the imaginary center line L1. However, this is not limited to this. For example, the area of ​​the first conductive joint 41, which is closer to the imaginary center line L1 in plan view, of the first conductive joint 41 and the second conductive joint 42, may be smaller than the area of ​​the second conductive joint 42, which is farther from the imaginary center line L1. This makes the first conductive joint 41 less susceptible to unwanted vibrations.

[0093] Furthermore, in the third embodiment, a ceramic-based insulating package structure (ceramic package) is used as the container. However, this is not limiting, and a molded package structure (molded package) of an insulating material coated with molded resin may also be used. Therefore, the general structure of a molded package will be described below. In a molded package, a glass epoxy substrate or the like is used as a flat base substrate on which components are mounted. The top surface of this glass epoxy substrate is provided with necessary wiring for electrical connection to the components, and the bottom surface is provided with necessary external terminals for leading the wiring to an external circuit board. A chip-type tuning fork piezoelectric vibrator disclosed in the above embodiment is mounted on some of the wiring on the top of the glass epoxy substrate, electrically and mechanically bonded with a conductive bonding material such as solder. An IC chip is mounted in parallel to the tuning fork piezoelectric vibrator, mechanically bonded with a resin adhesive, and the necessary electrical connection is made by bonding a metal wire such as gold to some of the wiring. A molded resin is formed on the glass epoxy substrate on which the tuning fork piezoelectric vibrator and the IC chip are mounted, covering each component.

[0094] Furthermore, the contents of the above-described embodiment and the contents of the modified examples may be combined as appropriate. [Industrial Applicability]

[0095] The present invention can be widely applied to tuning-fork type piezoelectric vibrating pieces in which a pair of vibrating arms vibrate, tuning-fork type piezoelectric vibrators having the tuning-fork type piezoelectric vibrating pieces, and tuning-fork type piezoelectric oscillators. [Explanation of symbols]

[0096] 1: Tuning fork type piezoelectric vibrator 10, 10A: tuning fork type piezoelectric vibrating piece 20: Crystal vibrating piece 21: Base 22: First vibrating arm 23: Second vibrating arm 24: External joint 25: Waistline 31: First excitation electrode 32: Second excitation electrode 33, 33A: First extraction electrode 34, 34A: Second extraction electrode 35: First through-hole electrode 36: Second through-hole electrode 41: First conductive joint 42: Second conductive joint L1: Virtual center line L2: Virtual placement line

Claims

1. A base and a first vibrating arm and a second vibrating arm extending in one direction from one end of the base; an external joint provided at another end of the base; a pair of first and second excitation electrodes formed on the first and second vibrating arms; a first extraction electrode that is extracted from the first excitation electrode to the base portion and the external joint portion; a second extraction electrode that is extracted from the second excitation electrode to the base portion and the external joint portion; a first conductive joint portion used to electrically and mechanically join the first lead electrode to a first external electrode; a second conductive joint used to electrically and mechanically join the second lead electrode to a second external electrode; A tuning fork type piezoelectric vibrating piece comprising: a line that passes through the center between the first vibrating arm and the second vibrating arm in a plan view and extends in an extension direction of the first vibrating arm and the second vibrating arm is defined as a virtual center line; In the plan view, in the region of the external joint, when the virtual center line is used as a reference line and the region on the side where the first vibrating arm is located is defined as a first region, and when the virtual center line is used as a reference line and the region on the side where the second vibrating arm is located is defined as a second region, the first conductive junction and the second conductive junction are provided so as to be entirely present only in the first region, the base, the first vibrating arm, the second vibrating arm, and the external joint are made of quartz crystal; In the plan view, the negative direction of the X axis of the quartz crystal is the direction in which the first vibrating arm and the second vibrating arm are arranged side by side, and is the direction from the second vibrating arm to the first vibrating arm. A tuning fork type piezoelectric vibrating piece characterized by:

2. 2. The tuning-fork type piezoelectric vibrating piece according to claim 1, wherein a fork portion formed by the first vibrating arm, the second vibrating arm and the base portion is asymmetric in the plan view.

3. 3. The tuning-fork type piezoelectric vibrating piece according to claim 1, wherein an area of ​​the first region is larger than an area of ​​the second region in the plan view.

4. 3. The tuning-fork type piezoelectric vibrating piece according to claim 1, wherein the first conductive bonding portion and the second conductive bonding portion are each formed of a metal bump.

5. 3. The tuning-fork type piezoelectric vibrating piece according to claim 1, wherein a constriction is provided between the base and the outer joint.

6. 3. The tuning-fork-type piezoelectric vibrating piece according to claim 1, wherein the width of the base in the direction in which the first vibrating arm and the second vibrating arm are arranged side by side in the planar view becomes smaller as it moves from the side of the base where the first vibrating arm and the second vibrating arm are located to the side of the base where the external joint is located.

7. When a line connecting the ends of the other end of the base portion in the plan view is defined as a virtual arrangement line, The external joint portion exists only in an area on the side where the base portion does not exist, with the virtual placement line as a reference line in the plan view.

3. The tuning-fork type piezoelectric vibrating piece according to claim 1 or 2.

8. The base portion has a through hole or a recess, The through hole or the recess is provided between the first vibrating arm and one of the first conductive joint and the second conductive joint that is closer to the imaginary center line in the plan view.

3. The tuning-fork type piezoelectric vibrating piece according to claim 1 or 2.

9. 3. A tuning-fork type piezoelectric vibrator, wherein the tuning-fork type piezoelectric vibrating piece according to claim 1 or 2 is mounted and housed inside a container and hermetically sealed.

10. 3. A tuning-fork type piezoelectric oscillator, comprising: the tuning-fork type piezoelectric vibrating piece according to claim 1 or 2; and an integrated circuit element having a temperature compensation circuit, which are mounted and housed inside a container and hermetically sealed.

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