Tuning-fork-type piezoelectric vibrating reed, tuning-fork-type piezoelectric vibrator, and tuning-fork-type piezoelectric oscillator

Abstract

Provided is a tuning-fork-type piezoelectric vibrating reed capable of improving frequency measurement reproducibility. A tuning fork type piezoelectric vibrating piece (10) is provided with: a crystal vibrating piece (20) having a base part (21), first and second vibrating arms (22, 23), and an external joining part (24); a pair of first and second excitation electrodes (31, 32) 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 excitation electrodes (31, 32) to the base section (21) and the external joining section (24); and first and second conductive bonding sections (41, 42) provided on the first and second extraction electrodes (33, 34), the first and second conductive bonding sections (41, 42) being provided so as to be inclined only toward the first region and present in the first region. The first region is a region of the outer joining portion (24), the region being located on the side of the first vibrating arm (22) with an imaginary center line (L1) passing through the center between the first and second vibrating arms (22, 23) and extending in the extension direction of the first and second vibrating arms (22, 23) as a reference line.

Description

Technical Field

[0001] The present invention relates to a tuning-fork type piezoelectric vibration piece in which a pair of vibration arms vibrate, a tuning-fork type piezoelectric vibrator having the tuning-fork type piezoelectric vibration piece, and a tuning-fork type piezoelectric oscillator. Background Art

[0002] A tuning-fork-type piezoelectric vibrating reed includes a component comprising a crystal vibrating reed having a base, a pair of vibrating arms (a first vibrating arm and a second vibrating arm) extending in one direction from one end of the base, and an external bonding portion provided at the other end of the base. The tuning-fork-type piezoelectric vibrating reed includes a pair of first and second excitation electrodes formed on the first and second vibrating arms, a first lead electrode extending from the first excitation electrode to the base and the external bonding portion, and a second lead electrode extending from the second excitation electrode to the base and the external bonding portion. Furthermore, the tuning-fork-type piezoelectric vibrating reed includes a first metal bump for electrically and mechanically bonding the first lead electrode to the first external electrode, and a second metal bump for electrically and mechanically bonding the second lead electrode to the second external electrode.

[0003] There is a tuning fork-type piezoelectric vibrating piece, in which, in the above-mentioned tuning fork-type piezoelectric vibrating piece, a line passing through the center between the first vibrating arm and the second vibrating arm and extending along the extension direction of the first vibrating arm and the second vibrating arm is set as an imaginary center line, and an area on the side of the external joint portion where the first vibrating arm exists with the imaginary center line as a reference line is set as a first area, and an area on the side of the external joint portion where the second vibrating arm exists with the imaginary center line as a reference line is set as a second area, the entire first metal bump is configured to exist in the first area, and the entire second metal bump is configured to exist in the second area (for example, see Patent Document 1).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2021-68955 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] However, the outer shape of the crystal vibrating plate that constitutes a tuning-fork-type piezoelectric vibrating piece is generally formed using photolithography and wet etching. When the outer shape of the crystal vibrating plate is processed using wet etching, asymmetric regions may sometimes form on the crystal vibrating plate. In particular, when wet etching is performed on anisotropic materials such as crystal, the tendency to develop such an asymmetric shape is more pronounced. The fork portion formed by the first vibrating arm, the second vibrating arm, and the base (hereinafter sometimes referred to as the "tuning-fork fork portion") becomes asymmetric, disrupting the balance between the first and second vibrating arms. When a tuning-fork-type piezoelectric vibrator having such a tuning-fork-type piezoelectric vibrating plate is vibrated, a vibration mode different from the main vibration occurs. Specifically, unwanted vibrations (spurious) occur at a lower frequency than the main vibration frequency, which degrades the reproducibility of the main vibration frequency measurement.

[0009] In view of the above problems, an object of the present invention is to provide a tuning-fork type piezoelectric vibrating piece capable of suppressing the influence of unnecessary vibration and improving the reproducibility of frequency measurement, a tuning-fork type piezoelectric vibrator and a tuning-fork type piezoelectric oscillator having the same.

[0010] Solutions to Problems

[0011] In order to achieve the above-mentioned purpose, the tuning fork-type piezoelectric vibrating piece involved in the present invention comprises: a base; a first vibrating arm and a second vibrating arm, which extend in one direction from one end of the base; an external bonding portion, which is provided at the other end of the base; a pair of first excitation electrodes and a second excitation electrode, which are formed on the first vibrating arm and the second vibrating arm; a first extraction electrode, which is extracted from the first excitation electrode to the base and the external bonding portion; a second extraction electrode, which is extracted from the second excitation electrode to the base and the external bonding portion; a first conductive bonding portion, which is used when electrically and mechanically bonding the first extraction electrode to the first external electrode; and a second conductive bonding portion, which is used when electrically and mechanically bonding the second extraction electrode to the first external electrode. When used when bonded to a second external electrode, the tuning fork-type piezoelectric vibration piece is characterized in that a line passing through the center between the first vibration arm and the second vibration arm and extending along the elongation direction of the first vibration arm and the second vibration arm when viewed from above is set as an imaginary center line, and when an area on the side of the first vibration arm with the imaginary center line as a reference line in the area of the external joint when viewed from above is set as a first area, and an area on the side of the second vibration arm with the imaginary center line as a reference line in the area of the external joint when viewed from above is set as a second area, the entire first conductive joint and the entire second conductive joint are set to exist in the first area only toward the first area.

[0012] According to this structure, by providing the entire first conductive bonding portion and the entire second conductive bonding portion only in the first region within the region of the external bonding portion, vibration modes different from the main vibration (unwanted vibration, spurious vibration) can be distanced from the main vibration or attenuated, thereby suppressing the influence of the unwanted vibration on the main vibration and improving the reproducibility of the frequency measurement of the main vibration. In addition, by providing the entire first conductive bonding portion and the entire second conductive bonding portion only in the first region within the region of the external bonding portion, the first conductive bonding portion and the second conductive bonding portion can be positioned away from the center of the base (away from the imaginary center line). The first conductive bonding portion and / or the second conductive bonding portion positioned away from the center of the base (away from the imaginary center line) are less susceptible to the influence of the unwanted vibration. As a result, the influence of vibration leakage and unwanted vibration transmitted to the base and the external bonding portion due to excitation of the first and second vibration arms of the tuning fork-type piezoelectric vibrating reed can be reduced, thereby improving the reproducibility of the frequency measurement.

[0013] Furthermore, 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 asymmetrical in the plan view.

[0014] In this structure, the entire first conductive bonding portion and the entire second conductive bonding portion are provided in the first region only in the region of the external bonding portion, and this configuration is particularly effective in reducing the influence of vibration leakage.

[0015] Furthermore, the area of the first region may be larger than the area of the second region in the plan view.

[0016] According to this structure, by making the area of the second region on the side where the unwanted vibration is released smaller than the area of the first region in the first and second regions of the external joint, it is possible to eliminate the residual unwanted vibration and make the first conductive joint and the second conductive joint more reliably less susceptible to the influence of the unwanted vibration. In addition, by making the area of the first region on the side where the entire first conductive joint and the entire second conductive joint are provided larger than the area of the second region in the first and second regions of the external joint, it is possible to set the first conductive joint and the second conductive joint further away from the center of the base (away from the imaginary center line), and the first conductive joint and / or the second conductive joint that are further away from the center of the base (away from the imaginary center line) can be less susceptible to the influence of the unwanted vibration. Furthermore, by making the area of the first region on the side where the entire first and second conductive bonding portions are provided larger than the area of the second region in the first and second regions of the external bonding portion, the areas of the first and second conductive bonding portions can be increased. The increased areas of the first and second conductive bonding portions can stabilize the mounting of the component provided with the first and second external electrodes. As a result, the effects of vibration leakage can be further reduced, further improving the reproducibility of frequency measurement.

[0017] In addition, the first conductive bonding portion and the second conductive bonding portion may be formed of metal bumps, respectively.

[0018] According to this structure, by forming the first and second conductive bonding portions 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 further improved, and the bonding can be more secure. This allows the area of the first and second conductive bonding portions to be reduced, enabling miniaturization of tuning fork-type piezoelectric resonators, etc., that utilize tuning fork-type piezoelectric resonators. Furthermore, compared to conductive resin adhesives, metal bumps are less able to absorb stress and vibration and are more susceptible to vibration leakage. However, by positioning the metal bumps away from the center of the base (away from the imaginary centerline), they are less susceptible to unwanted vibration. Furthermore, even when the metal bumps are offset to the first region of the external bonding portion and bonded to the external electrodes (the first and second external electrodes), they can still be more securely and stably bonded to the external electrodes than with conductive resin adhesives.

[0019] Furthermore, a constricted portion may be provided between the base portion and the external joining portion.

[0020] According to this structure, it is possible to attenuate unnecessary vibration transmitted from the base portion to the external joining portion.

[0021] Furthermore, the width of the base portion in the direction in which the first vibrating arm and the second vibrating arm are arranged side by side in the plan view may decrease from the side of the base portion where the first vibrating arm and the second vibrating arm are located toward the side of the base portion where the external joining portion is located.

[0022] According to this structure, it is possible to attenuate unnecessary vibration transmitted from the base portion to the external joining portion.

[0023] Alternatively, when a line connecting the ends of the other end portion of the base in the plan view is set as an imaginary configuration line, the external joining portion may exist only in an area on the side where the base does not exist with the imaginary configuration line as a reference line in the plan view.

[0024] According to this structure, the tuning-fork type piezoelectric vibrating piece can be miniaturized.

[0025] Furthermore, the base may be provided with a through hole or a recessed portion, and the through hole or the recessed portion may be provided between the first vibrating arm and the conductive bonding portion closer to the imaginary center line between the first conductive bonding portion and the second conductive bonding portion in the plan view.

[0026] According to this structure, unnecessary vibration can be less likely to be transmitted from the base to the conductive joining portion closer to the imaginary center line between the first conductive joining portion and the second conductive joining portion, and the conductive joining portion can be further less likely to be affected by the unnecessary vibration.

[0027] In addition, the base, the first vibration arm, the second vibration arm and the external joint may be made of crystal, and in the top view, the negative direction of the X-axis of the crystal is the direction in which the first vibration arm and the second vibration arm are arranged side by side and from the second vibration arm toward the first vibration arm.

[0028] According to this configuration, a slope due to the etching rate difference occurs in the portion from the edge of the base portion on the negative side in the X-axis direction to the edge of the external bonding portion. This increases the strength of this portion and prevents defects in the tuning-fork type piezoelectric vibrating reed.

[0029] Furthermore, the tuning fork type piezoelectric vibrator according to the present invention is characterized in that the tuning fork type piezoelectric vibrating reed is mounted and housed inside a container of the tuning fork type piezoelectric vibrator and is hermetically sealed.

[0030] According to this configuration, it is possible to provide a tuning-fork type piezoelectric vibrator including a tuning-fork type piezoelectric vibrating piece having excellent frequency measurement reproducibility.

[0031] Furthermore, the tuning-fork type piezoelectric oscillator according to the present invention is characterized in that the tuning-fork type piezoelectric vibrating reed and the integrated circuit element having the temperature compensation circuit are mounted and housed inside a container of the tuning-fork type piezoelectric oscillator and are hermetically sealed.

[0032] This structure enables a tuning-fork piezoelectric oscillator having a tuning-fork piezoelectric vibrating piece with excellent frequency measurement reproducibility. In particular, a tuning-fork piezoelectric oscillator with a temperature compensation circuit has an additional function that applies a compensation voltage corresponding to the ambient temperature to the inherent frequency characteristics of the tuning-fork piezoelectric vibrator, thereby varying the capacitance and suppressing frequency fluctuations, thereby improving frequency stability. In contrast, when the frequency reproducibility of the tuning-fork piezoelectric vibrating piece fluctuates, further temperature compensation is performed using the temperature compensation circuit based on this fluctuation, which may lead to further fluctuations in the final frequency. In the present invention, by improving frequency reproducibility using a tuning-fork piezoelectric vibrating piece, further fluctuations caused by the temperature compensation circuit are suppressed, further improving frequency stability.

[0033] Effects of the Invention

[0034] According to the present invention, by arranging the entire first conductive bonding portion and the entire second conductive bonding portion so that they are located only in the first region of the region of the external bonding portion, vibration modes different from the main vibration (unwanted vibrations, spurious signals) can be distanced from the main vibration or attenuated, thereby suppressing the influence of the unwanted vibrations on the main vibration and improving the reproducibility of the frequency measurement of the main vibration. Furthermore, by arranging the entire first conductive bonding portion and the entire second conductive bonding portion so that they are located only in the first region of the region of the external bonding portion, the first conductive bonding portion and the second conductive bonding portion can be located away from the center of the base (away from the imaginary center line). The first conductive bonding portion and / or the second conductive bonding portion located away from the center of the base (away from the imaginary center line) are less susceptible to the influence of the unwanted vibrations. As a result, the influence of vibration leakage and unwanted vibrations transmitted to the base and the external bonding portion due to excitation of the first and second vibration arms of the tuning-fork piezoelectric vibrating reed can be reduced, thereby improving the reproducibility of the frequency measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic plan view of one principal surface side of a tuning-fork type piezoelectric vibrating piece according to the first embodiment of the present invention.

[0036] Figure 2 yes Figure 1 A schematic plan view of the other principal surface side of a tuning-fork type piezoelectric vibrating piece.

[0037] Figure 3 Is a Figure 1 and Figure 2 Schematic plan view of the upper surface side of the tuning-fork-type piezoelectric vibrator before the tuning-fork-type piezoelectric vibrating piece is hermetically sealed.

[0038] Figure 4 It is from along Figure 3 This is a schematic diagram of a cross section taken along line AA as viewed sideways in the direction of the arrow.

[0039] Figure 5 This is a comparison chart for comparing the measurement reproducibility of the frequency obtained based on the arrangement positions of the first conductive bonding portion and the second conductive bonding portion.

[0040] Figure 6 It is a schematic plan view of the other principal surface side of a tuning-fork type piezoelectric vibrating piece according to the second embodiment of the present invention.

[0041] Figure 7 The third embodiment of the present invention is related to Figure 1 and Figure 2 A schematic plan view of the upper surface side of a tuning-fork-type piezoelectric vibrating piece before hermetically sealing the tuning-fork-type piezoelectric oscillator.

[0042] Figure 8 It is from along Figure 7 This is a schematic diagram of a cross section taken along line BB as viewed sideways in the direction of the arrow. DETAILED DESCRIPTION

[0043] First Implementation Method

[0044] Below, refer to Figures 1 to 5 The tuning-fork type piezoelectric vibrating piece 10 and the tuning-fork type piezoelectric vibrator 1 having the tuning-fork type piezoelectric vibrating piece 10 according to the first embodiment of the present invention will be described in detail. Figures 1 to 4 , and in the following descriptions Figure 6 Each figure is illustrated using the same X-axis, Y-axis, and Z-axis.

[0045] First, refer to Figure 1 and Figure 2 The structure of the tuning-fork type piezoelectric vibrating piece 10 will be described. Figure 1 is a schematic top view of one principal surface side of the tuning fork type piezoelectric vibrating piece 10. Figure 2 1 is a schematic plan view of the other principal surface side of the tuning-fork type piezoelectric vibrating piece 10 .

[0046] The tuning-fork type piezoelectric vibrating piece 10 is a piezoelectric vibrating piece obtained by adding various electrodes (first excitation electrode 31 , second excitation electrode 32 , first extraction electrode 33 , second extraction electrode 34 ), conductive bonding portions (first conductive bonding portion 41 , second conductive bonding portion 42 ), and the like to a tuning-fork-shaped crystal vibrating piece 20 .

[0047] The tuning fork type piezoelectric vibrating piece 10 includes the above-mentioned tuning fork-shaped crystal vibrating piece 20. The crystal vibrating piece 20 is as shown in FIG. Figure 1 and Figure 2 As shown, the base 21 includes a pair of vibration arms (a first vibration arm 22 and a second vibration arm 23 ) extending from one end 21 a of the base 21 in one direction (in the positive direction of the Y axis in this embodiment), and an external joint 24 provided at the other end 21 b of the base 21 .

[0048] Regarding the crystal vibrating plate 20, a plurality of crystal vibrating plates 20 are formed simultaneously by collectively forming a plurality of crystal vibrating plates 20 from an artificial crystal wafer composed of a single Z plate. In this embodiment, the outer shape of the crystal vibrating plate 20 is formed by using photolithography and wet etching. Figures 1 to 4 , and the following descriptions Figure 6 In the crystal vibrating plate 20, the positive direction of the Y axis of the crystal is set for the direction in which the first vibrating arm 22 and the second vibrating arm 23 extend from the base 21 (the extension direction), the negative direction of the X axis of the crystal is set for 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) and the direction from the second vibrating arm 23 toward the first vibrating arm 22, and the positive direction of the Z axis of the crystal is set for the thickness direction of the first vibrating arm 22 and the second vibrating arm 23 and the direction from one main surface 20a toward the other main surface 20b of the crystal vibrating plate 20.

[0049] The crystal resonator plate 20 has a constricted portion 25 between the base portion 21 and the external bonding portion 24 in a plan view (hereinafter sometimes simply referred to as “plan view”) when viewing one principal surface 20 a or the other principal surface 20 b of the crystal resonator plate 20 from a vertical direction.

[0050] The width of the base portion 21 in the direction in which the first vibrating arm 22 and the second vibrating arm 23 are arranged side by side (the positive and negative directions of the X-axis) decreases as it moves from one end 21a of the base portion 21 (the side of the base portion 21 where the first vibrating arm 22 and the second vibrating arm 23 are located) toward the other end 21b of the base portion 21 (the side of the external bonding portion 24 of the base portion 21). It should be noted that the shape of the base portion 21 is not limited to this shape. For example, the base portion 21 may have a shape in which the width of the base portion 21 increases and then decreases as it moves from one end 21a of the base portion 21 (the side of the base portion 21 where the first vibrating arm 22 and the second vibrating arm 23 are located) toward the other end 21b of the base portion 21 (the side of the external bonding portion 24 of the base portion 21) when viewed from above.

[0051] The external joint 24 has a shape including a first extension portion and a second extension portion. The first extension portion extends from the other end portion 21 b of the base 21 to the side opposite to the direction in which the first vibrating arm 22 and the second vibrating arm 23 extend from the base 21 (the negative side of the y-axis). The second extension portion extends from the first extension portion to the direction in which the first vibrating arm 22 and the second vibrating arm 23 are arranged side by side and from the second vibrating arm 23 toward the first vibrating arm 22 (the negative direction of the x-axis). The external joint 24 has an L-shape when viewed from above.

[0052] A line passing through the centers of the first and second vibrating arms 22 and 23 in the width direction (positive and negative directions of the X-axis) when viewed from above (the centers of the first and second vibrating arms 22 and 23 excluding the fork portion (tuning fork fork portion) formed by the first and second vibrating arms 22 and 23 and the base 21 and extending in the extension direction of the first and second vibrating arms 22 and 23 when viewed from above is defined as the imaginary center line L1. Within the region of the external junction 24 when viewed from above, the region on the side of the first vibrating arm 22 with respect to the imaginary center line L1 as a reference line (the region on the negative side of the X-axis with respect to the imaginary center line L1) is defined as the first region, and within the region of the external junction 24 when viewed from above, the region on the side of the second vibrating arm 23 with respect to the imaginary center line L1 as a reference line (the region on the positive side of the X-axis with respect to the imaginary center line L1) is defined as the second region. A line connecting the ends of the other end portion 21 b of the base 21 when viewed from above is defined as the imaginary configuration line L2.

[0053] In a plan view, the external bonding portion 24 exists only in the region on the side of the imaginary arrangement line L2 where the base portion 21 is not present (the region on the negative side of the Y-axis relative to the imaginary arrangement line L2). That is, in a plan view, the external bonding portion 24 does not exist in the region on the side of the imaginary arrangement line L2 where the base portion 21 is present (the region on the positive side of the Y-axis relative to the imaginary arrangement line L2). Furthermore, in a plan view, the area of the first region of the external bonding portion 24 is larger than the area of the second region of the external bonding portion 24.

[0054] In the crystal resonator plate 20, whose outer shape is fabricated using photolithography and wet etching, the fork portion (tuning fork tines) formed by the first and second resonating arms 22, 23, and the base 21 is asymmetrical relative to the imaginary centerline L1 when viewed from above. In this embodiment, the deepest portion of the tuning fork tines is located closer to the first resonating arm 22 than the imaginary centerline L1 (on the negative side of the x-axis relative to the imaginary centerline L1).

[0055] The first vibrating arm 22 has a first width portion 26 at its front end (the side away from the one end portion 21a of the base 21). The first width portion 26 is a portion wider than the arm width of the first vibrating arm 22 (the dimension in a direction perpendicular to the extension direction of the first vibrating arm 22 (in the present embodiment, the positive and negative directions of the X-axis)). Furthermore, the second vibrating arm 23 has a second width portion 27 at its front end (the side away from the one end portion 21a of the base 21). The second width portion 27 is a portion wider than the arm width of the second vibrating arm 23 (the dimension in a direction perpendicular to the extension direction of the second vibrating arm 23 (in the present embodiment, the positive and negative directions of the X-axis)).

[0056] To further reduce the equivalent series resistance (Crystal Impedance; sometimes referred to as "CI value"), long grooves are formed on one principal surface 20a and the other principal surface 20b of each of the first and second vibrating arms 22 and 23. More specifically, the long grooves 22a and 22b are formed on the one principal surface 20a and the other principal surface 20b of the first vibrating arm 22, with the long grooves 22a and 22b facing each other (overlapping in plan view) at a predetermined depth. The long grooves 23a and 23b are formed on the one principal surface 20a and the other principal surface 20b of the second vibrating arm 23, with the long grooves 23a and 23b facing each other (overlapping in plan view) at a predetermined depth. The long grooves 22a and 22b are formed so that, when viewed from above, one end of each long groove extends to a region on the one end portion 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. Furthermore, the long grooves 23a and 23b are formed such that, in a plan view, one end of the long groove extends to a region on the side of one end portion 21a of the base portion 21, and the other end of the long groove is located closer to the base portion 21 than the second width portion 27. The long grooves 22a, 22b, 23a, and 23b have a length direction along the direction in which the first vibrating arm 22 and the second vibrating arm 23 extend (positive and negative directions of the Y axis), 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 directions of the X axis).

[0057] The crystal vibrating plate 20 includes 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 with different potentials, a first lead-out electrode 33 extending from the first excitation electrode 31 to the base 21 and the external bonding portion 24, and a second lead-out electrode 34 extending from the second excitation electrode 32 to the base 21 and the external bonding portion 24.

[0058] The first excitation electrode 31 is formed on the one principal surface 20a side and the other principal surface 20b side of the first vibrating arm 22, and on the outer side and inner side of the second vibrating arm 23 via the one principal surface 20a side and the other principal 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 principal surface 20a side and the other principal surface 20b side of the first vibrating arm 22 is formed covering the entire interior of the long grooves 22a and 22b of the first vibrating arm 22. The second excitation electrode 32 is formed on the one principal surface 20a side and the other principal surface 20b side of the second vibrating arm 23, and on the outer side and inner side of the first vibrating arm 22 via the one principal surface 20a side and the other principal surface 20b side of the wide portion 26 of the first vibrating arm 22. A portion of the second excitation electrode 32 formed on one principal surface 20a and the other principal surface 20b of the second vibrating arm 23 extends throughout the interior of the long grooves 23a and 23b of the second vibrating arm 23. By forming the long grooves 22a, 22b, 23a, and 23b, even when the tuning-fork piezoelectric vibrating piece 10 is miniaturized, the electric field efficiency between the pair of first and second vibrating arms 22 and 23 is high, and a good CI value can be obtained. It should be noted that a portion of the first excitation electrode 31 may be formed only in a portion of the long grooves 22a and 22b of the first vibrating arm 22, and a portion of the second excitation electrode 32 may be formed only in a portion of the long grooves 23a and 23b of the second vibrating arm 23.

[0059] The first extraction electrode 33 is formed on the one principal surface 20a side and the other principal surface 20b side of the base 21, and on the other principal surface 20b side of the external bonding portion 24. The second extraction electrode 34 is formed on the one principal surface 20a side and the other principal surface 20b side of the base 21, and on the other principal surface 20b side of the external bonding portion 24. Figure 2 In the area surrounded by the dotted line, the first lead electrode 33 and the second lead electrode 34 are provided in such a manner that the dividing groove for dividing the first lead electrode 33 and the second lead electrode 34 is located on the side of the first vibration arm 22 relative to the imaginary center line L1, and the first conductive bonding portion 41 can be configured as a whole in the portion between the imaginary center line L1 in the first lead electrode 33 and the dividing groove.

[0060] A through-hole extending through the base portion 21 in the thickness direction (positive and negative directions of the Z axis) is provided, and a first through-hole electrode 35 coated with a conductive material is formed on the inner wall surface of the through-hole. The first through-hole electrode 35 electrically connects the portion of the first extraction electrode 33 formed on the one principal surface 20 a side of the base portion 21 with the portion of the first extraction electrode 33 formed on the other principal surface 20 b side of the base portion 21. Furthermore, a through-hole extending through the base portion 21 in the thickness direction (Z axis direction) is provided, and a second through-hole electrode 36 coated with a conductive material is formed on the inner wall surface of the through-hole. The second through-hole electrode 36 electrically connects the portion of the second extraction electrode 34 formed on the one principal surface 20 a side of the base portion 21 with the portion of the second extraction electrode 34 formed on the other principal surface 20 b side of the base portion 21. The through hole having the first through-hole electrode 35 formed on the inner wall surface is provided between the first vibrating arm 22 and the first conductive bonding portion 41 , whichever of the first and second conductive bonding portions 41 , 42 is closer to the imaginary center line L1 , in a plan view.

[0061] Note that a recess may be provided between the first vibrating arm 22 and the first conductive bonding portion 41 , whichever of the first and second conductive bonding portions 41 , 42 is closer to the imaginary center line L1 , in a plan view.

[0062] The first excitation electrode 31, second excitation electrode 32, first extraction electrode 33, and second extraction electrode 34 have a layered structure consisting of a chromium (Cr) layer formed on a quartz crystal substrate, and a gold (Au) layer stacked on top of the chromium layer. The layered structure of each electrode 31-34 is not limited to a layered structure consisting of a gold layer stacked on top of a chromium layer; for example, a layered structure consisting of a gold (Au) layer stacked on top of a titanium (Titanium) layer may also be employed. Each electrode 31-34 is formed onto the entire principal surface (one principal surface 20a and the other principal surface 20b) of the quartz crystal wafer using a film-forming method such as vacuum deposition or sputtering, and then simultaneously formed into the desired pattern using photolithography and metal etching.

[0063] A first frequency-adjusting metal film (first frequency-adjusting weight) 26W is formed only on the one principal surface 20a side of the first wide portion 26, and a second frequency-adjusting metal film (second frequency-adjusting weight) 27W is formed only on the one principal surface 20a side of the second wide portion 27. By irradiating the frequency-adjusting metal films 26W and 27W with a beam such as a laser beam or an ion beam, the frequency of the tuning-fork piezoelectric vibrating reed 10 is finely adjusted. The first frequency-adjusting metal film 26W is formed to be slightly smaller in area, as seen in plan view, than the portion of the second excitation electrode 32 formed on the one principal surface 20a side of the first wide portion 26, and the second frequency-adjusting metal film 27W is formed to be slightly smaller in area, as seen in plan view, than the portion of the first excitation electrode 31 formed on the one principal surface 20a side of the second wide portion 27.

[0064] A first conductive bonding portion 41 is provided on a portion of the first extraction electrode 33 that is formed on the other side 20b of the external bonding portion 24, and a second conductive bonding portion 42 is provided on a portion of the second extraction electrode 34 that is formed on the other side 20b of the external bonding portion 24. In this embodiment, the first conductive bonding portion 41 and the second conductive bonding portion 42 are formed of metal bumps such as gold bumps or gold-plated bumps. It should be noted that the conductive bonding portions 41 and 42 are not limited to metal bumps and may also be, for example, a conductive resin adhesive.

[0065] In a plan view, the entire first conductive bonding portion 41 and the entire second conductive bonding portion 42 are located only in the first region of the region of the external bonding portion 24 (the region on the side of the first vibrating arm 22 relative to the imaginary center line L1 (the region on the negative side of the x-axis relative to the imaginary center line L1)). In a plan view, the first conductive bonding portion 41, which is closer to the imaginary center line L1, is located near the imaginary center line L1.

[0066] In a plan view, the area of the first conductive bonding portion 41 closer to the imaginary center line L1 is larger than the area of the second conductive bonding portion 42 farther from the imaginary center line L1.

[0067] The first conductive bonding portion 41 and the second conductive bonding portion 42 are respectively elliptical in shape when viewed from above, and are arranged in such a manner that the direction of the long axis of the first conductive bonding portion 41 and the direction of the long axis of the second conductive bonding portion 42 when viewed from above become the directions in which the first conductive bonding portion 41 and the second conductive bonding portion 42 are arranged side by side (positive and negative directions of the X-axis).

[0068] Next, refer to Figure 3 and Figure 4 To illustrate the Figure 1 and Figure 2 The tuning-fork type piezoelectric vibrator 1 is a tuning-fork type piezoelectric vibrating piece 10 . Figure 3 Is a Figure 1 and Figure 2 A schematic plan view of the upper surface side of the tuning fork type piezoelectric vibrator 1 before the tuning fork type piezoelectric vibrating piece is hermetically sealed, Figure 4 yes Figure 3 It should be noted that the schematic cross-sectional view at line AA of FIG. Figure 1 and Figure 2 , which is a diagram of the electrodes (the first excitation electrode 31 , the second excitation electrode 32 , the first extraction electrode 33 , the second extraction electrode 34 ) and the like provided on the tuning-fork type piezoelectric vibrating piece 10 .

[0069] The tuning fork type piezoelectric vibrator 1 is formed by using a container 50 made of an insulating material as a base material. Figure 1 and Figure 2 The tuning-fork-type piezoelectric vibrating piece 10 described above and a flat-plate-shaped lid (not shown) that hermetically seals the tuning-fork-type piezoelectric vibrating piece 20 by bonding it to the container 50 are the main components. After the tuning-fork-type piezoelectric vibrating piece 10 is housed in the recess 51 of the container 50, the lid is connected to the open end of the container 50 so as to cover the recess, thereby hermetically sealing the container 50. The container 50 and the lid are bonded together via a sealing member (not shown).

[0070] The container 50 is a box-shaped structure made of an insulating material based on ceramics such as alumina. It is formed, for example, by stacking two ceramic green sheets 50a and 50b and firing them together. The container 50 has a rectangular recess 51 within a frame-shaped bank 52 in plan view. A seal (not shown) is formed on the upper surface of the bank 52 in a frame-shaped pattern in plan view, corresponding to the outer periphery of the lid.

[0071] On one short side of the inner bottom surface 53 of the recessed portion 51, a first mounting pad (first external electrode) 61 and a second mounting pad (second external electrode) 62 are mechanically and electrically bonded to the first extraction electrode 33 and the second extraction electrode 34 of the tuning-fork piezoelectric vibrating piece 10 via the first conductive bonding portion 41 and the second conductive bonding portion 42, with a gap therebetween. Furthermore, external connection terminals 63 are provided at each of the four corners of the outer bottom surface 54 of the container 50. 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.

[0072] The first mounting pad 61 and the second mounting pad 62 are formed by laminating the upper surface of the tungsten metallization layer using methods such as gold plating. It should be noted that molybdenum, for example, can be used as the metallization layer instead of tungsten. The same metal film as the mounting pads is also formed on the open end of the container 50, which is connected to the lid (described later).

[0073] 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 corners of the ceramic green sheet 50a in the first layer of the container 50. The second mounting pad 62 is electrically connected to the other 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 corners of the ceramic green sheet 50a in the first layer of the container 50.

[0074] The lid is a metal cover body with a rectangular shape when viewed from above, based on Kovar alloy. Nickel plating is formed on the front and back of the lid. Furthermore, a brazing filler metal is formed entirely on the nickel plating on the side of the lid that joins with the container 50. Examples of the brazing filler metal include a gold-tin alloy layer. In this case, the nickel plating is formed on the upper surface of the Kovar alloy, a gold plating is formed on top of the nickel plating, and a gold-tin alloy layer is formed on top of the nickel plating.

[0075] According to the tuning-fork piezoelectric vibrating piece 10 of the first embodiment described above, the entire first conductive bonding portion 41 and the entire second conductive bonding portion 42 are arranged so as to be located only in the first region within the region of the external bonding portion 24. This allows vibration modes different from the main vibration (unwanted vibrations, spurious vibrations) to be separated from the main vibration or attenuated. This suppresses the influence of the unwanted vibrations on the main vibration and improves the reproducibility of the frequency measurement of the main vibration. Furthermore, by arranging the entire first conductive bonding portion 41 and the entire second conductive bonding portion 42 so as to be located only in the first region within the region of the external bonding portion 24, the first conductive bonding portion 41 and the second conductive bonding portion 42 can be located away from the center of the base portion (away from the imaginary center line L1). The first conductive bonding portion 41 and / or the second conductive bonding portion 42 (in this embodiment, the second conductive bonding portion 42) located away from the center of the base portion 21 (away from the imaginary center line L1) are less susceptible to the influence of the unwanted vibrations. As a result, the vibration leakage and the influence of unnecessary vibration transmitted to the base 21 and the external bonding portion 24 due to the excitation of the first and second vibration arms 22 and 23 of the tuning-fork type piezoelectric vibration piece 10 can be reduced, thereby improving the reproducibility of frequency measurement.

[0076] The tuning-fork-type piezoelectric vibrating piece 10 of the first embodiment described above is particularly suitable for use in tuning-fork-type piezoelectric oscillators such as TCXOs and RTCs that incorporate a temperature compensation circuit. Generally, a temperature compensation circuit applies a compensation voltage corresponding to the ambient temperature to the inherent frequency characteristics of the tuning-fork-type piezoelectric vibrator, thereby varying the capacitance and suppressing frequency fluctuations, thereby improving frequency stability. In contrast, when the frequency reproducibility of the tuning-fork-type piezoelectric vibrating piece 10 fluctuates, further temperature compensation is performed using the temperature compensation circuit based on this fluctuation, which can lead to further fluctuations 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 fluctuations caused by the temperature compensation circuit are suppressed, thereby improving frequency stability.

[0077] Here, the frequency measurement reproducibility of 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 according to the first embodiment described above is compared with that of an arrangement different therefrom. Figure 5 In (a), the object is a tuning-fork type piezoelectric vibrating piece 10 a 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 The object of (b) is a tuning-fork type piezoelectric vibrating piece 10 b in which the first conductive bonding portion 41 is located in the first region and the second region so as to straddle the imaginary center line L1 and the entire second conductive bonding portion 42 is located in the first region. Figure 5The test subject for (c) was a tuning-fork piezoelectric vibrating piece 10 (this embodiment) in which the entire first conductive bonding portion 41 and the entire second conductive bonding portion 42 were located in the first region. Five cycles were performed on multiple tuning-fork piezoelectric vibrating pieces 10a, 10b, and 10c. The tuning-fork piezoelectric vibrating pieces 10a, 10b, and 10c had dimensions of L (positive and negative directions of the Y axis) = 1.2 mm and W = 0.4 mm (positive and negative directions of the X axis). An external bonding portion 24, which was generally L-shaped when viewed from above, was provided below the base 21. The first conductive bonding portion 41 and the second conductive bonding portion 42 (gold-plated bumps) were formed on the lead electrodes 33 and 34 of the external bonding portion 24. The base (container 50) housing the tuning-fork piezoelectric vibrating reeds 10a, 10b, and 10c is a 1.6 mm x 1.0 mm alumina ceramic base. The first conductive bonding portion 41 and the second conductive bonding portion 42 (gold-plated bumps) of the tuning-fork piezoelectric vibrating reeds 10a, 10b, and 10c are ultrasonically bonded to the mounting electrode pads on the base's inner bottom surface. The first conductive bonding portion 41 and the second conductive bonding portion 42 (gold-plated bumps) are elliptical in size, 0.03 μm long by 0.045 μm wide. The distance between the first conductive bonding portion 41 and the second conductive bonding portion 42 is 1.6 mm x 1.0 mm. Figure 5 (a) is 0.17 μm, in Figure 5 (b) is 0.14μm, in Figure 5 (c) is 0.10μm. Repeat the operation of placing the above-mentioned hermetically sealed surface-mounted tuning fork vibrator in a frequency measuring fixture to measure the frequency, taking it out of the measuring fixture and placing it again 5 times, and measure the frequency at each measurement. The fluctuation is judged as the measurement reproducibility of the frequency. Figure 5 As shown in (a) to (c), the tuning-fork 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 piezoelectric vibrating pieces 10 a and 10 b.

[0078] When the fork portion (tuning fork fork portion) formed by the first vibrating arm 22, the second vibrating arm 23 and the base 21 is asymmetrical, it is particularly effective to reduce the influence of vibration leakage by arranging the first conductive bonding portion 41 as a whole and the second conductive bonding portion 42 as a whole so as to be present only in the first region within the region of the external bonding portion 24.

[0079] Furthermore, by making the area of the second region of the first and second regions of the external bonding portion 24 smaller than the area of the first region of the first and second regions of the external bonding portion 24, which is on the side where the unwanted vibration is released, the residual unwanted vibration can be eliminated, and the first conductive bonding portion 41 and the second conductive bonding portion 42 can be more reliably less susceptible to the influence of the unwanted vibration. Furthermore, by making the area of the first region of the first and second regions of the external bonding portion 24 larger than the area of the second region, the first conductive bonding portion 41 and the second conductive bonding portion 42 can be positioned further away from the center of the base 21 (further away from the imaginary center line L1). The first conductive bonding portion 41 and / or the second conductive bonding portion 42 (in this embodiment, the second conductive bonding portion 42) positioned further away from the center of the base 21 (further away from the imaginary center line L1) can be less susceptible to the influence of the unwanted vibration. Furthermore, by making the area of the first region on the side 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 first and second regions of the external bonding portion 24, the areas of the first and second conductive bonding portions 41, 42 can be increased. The increased areas of the first and second conductive bonding portions 41, 42 (in this embodiment, the first conductive bonding portion 41) can stabilize the mounting and holding of the component provided with the first and second external electrodes that mechanically and electrically bond the first and second extraction electrodes 33, 34. As a result, the effects of vibration leakage can be further reduced, further improving the reproducibility of frequency measurement.

[0080] Furthermore, by forming the first conductive bonding portion 41 and the second conductive bonding portion 42 from metal bumps, the electrical conductivity between the first extraction electrode 33 and the first external electrode to which the first extraction electrode 33 is mechanically and electrically bonded, and between the second extraction electrode 34 and the second external electrode to which the second extraction electrode 34 is mechanically and electrically bonded, can be further improved, and the bonding can be more secure. This allows the area of the first conductive bonding portion 41 and the second conductive bonding portion 42 to be reduced, thereby contributing to miniaturization of the tuning fork-type piezoelectric vibrator 1 and the like using the tuning fork-type piezoelectric vibrating reed 10. Furthermore, compared to conductive resin adhesives and the like, metal bumps are less able to absorb stress and vibration and are more susceptible to vibration leakage. However, by positioning the metal bumps away from the center of the base 21 (away from the imaginary center line L1), the metal bumps are less susceptible to unwanted vibration. Furthermore, even if the metal bump is provided in a biased manner in the first region of the external bonding portion 24 and bonded to the external electrodes (first external electrode, second external electrode), it can be bonded to the external electrodes more firmly and stably than with a conductive resin adhesive or the like.

[0081] Furthermore, by providing the constricted portion 25 between the base portion 21 and the external joining portion 24 , it is possible to attenuate unnecessary vibration transmitted from the base portion 21 to the external joining portion 24 .

[0082] Furthermore, 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 (in the positive and negative directions of the X-axis) as it moves from one end 21 a of the base 21 (the side of the base 21 where the first vibrating arm 22 and the second vibrating arm 23 are located) toward the other end 21 b of the base 21 (the side of the base 21 where the external joining portion 24 is located), it is possible to attenuate unwanted vibrations transmitted from the base 21 to the external joining portion 24.

[0083] Furthermore, the external bonding portion 24 exists only in the region on the side where the base portion 21 does not exist with respect to the imaginary arrangement line L2 , thereby enabling miniaturization of the tuning-fork type piezoelectric vibrating piece 10 .

[0084] Furthermore, in the base 21, a through-hole having a first through-hole electrode 35 formed therein is provided on the inner wall surface between the first vibrating arm 22 and the first conductive bonding portion 41 (whichever is closer to the imaginary center line L1) of the first and second conductive bonding portions 41, 42. This prevents unwanted vibrations from being transmitted from the base 21 to the first conductive bonding portion 41, further minimizing the effects of unwanted vibrations on the first conductive bonding portion 41. It should be noted that, instead of forming the through-hole having the first through-hole electrode 35 on the inner wall surface, a recessed portion may be provided in the base 21 between the first vibrating arm 22 and the first conductive bonding portion 41 (whichever is closer to the imaginary center line L1) of the first and second conductive bonding portions 41, 42.

[0085] Furthermore, the negative direction of the X-axis of the crystal of the crystal resonator plate 20 is set so that the first resonator arm 22 and the second resonator arm 23 are arranged side by side, and the direction is from the second resonator arm 23 toward the first resonator arm 22. As a result, an inclination due to the difference in etching rate occurs in the portion from the edge of the base portion 21 on the negative side of the X-axis to the edge of the external joint portion 24. As a result, the strength of this portion is increased, and defects in the tuning fork-type piezoelectric resonator plate 10 can be suppressed.

[0086] In addition, by making the area of the first conductive bonding portion 41 on the side closer to the imaginary center line L1 larger than the area of the second conductive bonding portion 42 on the side farther from the imaginary center line L1, it is possible to prevent the first conductive bonding portion 41 from being crushed and the tuning fork type piezoelectric vibration piece 10 from tilting when the tuning fork type piezoelectric vibration piece 10 is mounted on a component provided with a first external electrode and a second external electrode that mechanically and electrically join the first lead electrode 33 and the second lead electrode 34, and thus the tuning fork type piezoelectric vibration piece 10 can be stably mounted on the component.

[0087] In addition, by arranging the first conductive bonding portion 41 and the second conductive bonding portion 42 in such a manner that the first conductive bonding portion 41 and the second conductive bonding portion 42 are respectively formed into an elliptical shape and the direction of the long axis of the first conductive bonding portion 41 and the direction of the long axis of the second conductive bonding portion 42 are respectively set as the direction in which the first conductive bonding portion 41 and the second conductive bonding portion 42 are arranged side by side (positive and negative directions of the X-axis), it is possible to suppress the situation in which the tuning fork type piezoelectric vibration piece 10 is tilted when it is mounted on a component provided with the first external electrode and the second external electrode that mechanically and electrically bond the first lead electrode 33 and the second lead electrode 34, and the tuning fork type piezoelectric vibration piece 10 can be stably mounted on the component without increasing the size of the first conductive bonding portion 41 and the second conductive bonding portion 42 more than necessary.

[0088] In addition, by setting the external joint portion 24 to be L-shaped when viewed from above, the area of the first region and the area of the second region of the external joint portion 24 do not need to be increased more than necessary when viewed from above, so that the area of the first region can be larger than the area of the second region, thereby enabling the miniaturization of the tuning fork-type piezoelectric vibration piece 10 having the external joint portion 24.

[0089] In addition, by arranging the first conductive bonding portion 41, which is closer to the imaginary center line L1, near the imaginary center line L1, the tuning fork-type piezoelectric vibration piece 10 can be stably mounted on a component provided with a first external electrode and a second external electrode that mechanically and electrically bond the first lead electrode 33 and the second lead electrode 34, the routing of the first external electrode that is mechanically and electrically bonded to the first lead electrode 33 provided with the first conductive bonding portion 41 can be reduced, and the component provided with a first external electrode and a second external electrode that mechanically and electrically bonded the first lead electrode 33 and the second lead electrode 34 can be miniaturized.

[0090] Furthermore, according to the tuning-fork type piezoelectric vibrator 1 of the first embodiment described above, it is possible to provide the tuning-fork type piezoelectric vibrator 1 including the tuning-fork type piezoelectric vibrating piece 10 having the above-described effects such as excellent frequency measurement reproducibility.

[0091] Second Implementation Method

[0092] Below, refer to Figure 6 A tuning-fork type piezoelectric vibrating piece 10A according to a second embodiment of the present invention will be described in detail. Figure 6 10A is a schematic plan view of the other principal surface side of the tuning-fork type piezoelectric vibrating piece 10A.

[0093] The difference between the first embodiment and the second embodiment is that the portion of the first extraction electrode 33 formed on the other principal surface 20b side of the external joint 24 and the portion of the second extraction electrode 34 formed on the other principal surface 20b side of the external joint 24 in the first embodiment have different shapes from the portion of the first extraction electrode 33A formed on the other principal surface 20b side of the external joint 24 and the portion of the second extraction electrode 34A formed on the other principal surface 20b side of the external joint 24 in the second embodiment. Other structures are the same in the first and second embodiments, and the same reference numerals as in the first embodiment are given in the second embodiment and their description is omitted.

[0094] The first extraction electrode 33A is formed on the one principal surface 20a side and the other principal surface 20b side of the base 21, and on the other principal surface 20b side of the external bonding portion 24. The second extraction electrode 34A is formed on the one principal surface 20a side and the other principal surface 20b side of the base 21, and on the other principal surface 20b side of the external bonding portion 24. Figure 6 In the area surrounded by the dotted line, the first lead electrode 33A and the second lead electrode 34A are provided with a dividing groove that divides the first lead electrode 33A and the second lead electrode 34A, which is located on the side of the first vibration arm 22 relative to the imaginary center line L1, and the first conductive bonding portion 41 as a whole can be arranged in the portion between the imaginary center line L1 in the first lead electrode 33A and the dividing groove.

[0095] In the first embodiment, the other main surface 20b side of the external bonding portion 24 is formed by Figure 2 The portion surrounded by the dotted line and the portion on the other main surface 20b side of the external bonding portion 24 of the second embodiment are Figure 6When compared with the portion surrounded by the dotted line, the first extraction electrode 33A is formed farther from the imaginary center line L1 in the direction from the second vibrating arm 23 toward the first vibrating arm 22 (the negative direction of the X-axis) than the first extraction electrode 33 in a plan view. In this embodiment, the first extraction electrode 33A protrudes toward the second extraction electrode 34A in a plan view.

[0096] The tuning-fork-type piezoelectric vibrating piece 10A of the second embodiment described above achieves 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 improve the protrusion of the first conductive bonding portion 41 from the first extraction electrode 33A, and the position of the wiring pattern of the package mounting portion visible through the tuning-fork-type piezoelectric vibrating piece 10A can be easily identified, thereby suppressing deviation in the mounting position.

[0097] Third Implementation Method

[0098] Below, refer to Figure 7 、 Figure 8 A tuning-fork-type piezoelectric vibrating piece 10 and a tuning-fork-type piezoelectric oscillator 7 including the tuning-fork-type piezoelectric vibrating piece 10 according to a third embodiment of the present invention will be described in detail. It should be noted that the third embodiment utilizes the same tuning-fork-type piezoelectric vibrating piece 10 as disclosed in the first embodiment. In the third embodiment, identical portions to those in the first embodiment are denoted by the same reference numerals, and descriptions thereof are partially omitted. Only the differences will be described.

[0099] The tuning fork type piezoelectric oscillator 7 is made of a container 70 made of an insulating material as a base material, Figure 1 and Figure 2 The main components of the device are the tuning-fork piezoelectric resonator piece 10 described above, the integrated circuit device 8 for a TCXO (Temperature Compensated Crystal Oscillator) that includes a temperature compensation circuit and an oscillator circuit, and a flat-plate lid (not shown) that hermetically seals the tuning-fork piezoelectric resonator piece 10 by bonding it to a container 70. After the tuning-fork piezoelectric resonator piece 10 and the integrated circuit device 8 are housed in a recess 71 of the container 70, the lid is connected to the open end of the container 70 to cover the recess 71, thereby hermetically sealing the container 70. The container 70 and lid are bonded together via a sealing member (not shown).

[0100] Container 70 is a box-shaped structure made of an insulating material based on ceramics such as alumina. It is formed, for example, by stacking three ceramic green sheets 70a, 70b, and 70c and firing them together. Container 70 has a rectangular recess 71 within a frame-shaped bank 72 in plan view. A seal (not shown) is formed on the upper surface of bank 72 in a frame-shaped pattern in plan view, corresponding to the outer periphery of the lid.

[0101] Multiple mounting pads 730 for mechanically and electrically bonding the integrated circuit element 8 are arranged with gaps between them on the inner bottom surface 73 of the recess 71. External terminals (not shown) of the integrated circuit element 8 are bonded to the mounting pads 730 via conductive bonding materials such as gold bumps.

[0102] A middle portion 74 is formed above the inner bottom surface 73 of the recess 71. A first mounting pad (first external electrode) 731 and a second mounting pad (second external electrode) 732 are arranged on the upper surface of the middle portion 74, mechanically and electrically bonded to the first extraction electrode 33 and the second extraction electrode 34 of the tuning-fork piezoelectric vibrating piece 10 via the first conductive bonding portion 41 and the second conductive bonding portion 42, with a gap therebetween. Furthermore, external connection terminals 76 are provided at the four corners of the outer bottom surface 75 of the container 70, each of which makes the necessary connections 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.

[0103] The lid is a metal cover body with a rectangular shape when viewed from above, based on a Kovar alloy. Nickel plating is formed on the front and back surfaces of the lid. Furthermore, a brazing filler metal is formed entirely on the nickel plating on the side of the lid that joins with the container 70. It should be noted that a gold-tin alloy layer is formed as the brazing filler metal, for example. In this case, the nickel plating is formed on the upper surface of the Kovar alloy, a gold plating layer is formed on top of this, and a gold-tin alloy layer is formed on top of this.

[0104] In the third embodiment described above, an example of an integrated circuit element for a TCXO having a temperature compensation circuit and an oscillator circuit was described as the integrated circuit element 8. However, the integrated circuit element 8 can also be applied to an integrated circuit element for an RTC (Real Time Clock) having a circuit having a date and time calendar function in addition to the temperature compensation circuit and the oscillator circuit.

[0105] Thus, the tuning-fork-type piezoelectric vibrating piece 10 of the third embodiment described above is more suitable for use in tuning-fork-type piezoelectric oscillators 7 that incorporate a temperature compensation circuit, such as a TCXO or RTC. Generally, a temperature compensation circuit applies a compensation voltage corresponding to the ambient temperature to the inherent frequency characteristics of a tuning-fork-type piezoelectric vibrator, thereby varying the capacitance and suppressing frequency fluctuations, thereby improving frequency stability. In contrast, when the frequency reproducibility of the tuning-fork-type piezoelectric vibrating piece 10 fluctuates, further temperature compensation is performed using a temperature compensation circuit based on this fluctuation, which can lead to further fluctuations in the final frequency. The tuning-fork-type piezoelectric vibrating piece 10 of the first embodiment described above improves frequency reproducibility, thereby suppressing further fluctuations caused by the temperature compensation circuit and improving frequency stability.

[0106] It should be noted that the tuning-fork piezoelectric vibrating piece, the tuning-fork piezoelectric vibrator, and the tuning-fork piezoelectric oscillator are not limited to the above-described tuning-fork piezoelectric vibrating piece 10 , 10A, the tuning-fork piezoelectric vibrator 1 , and the tuning-fork piezoelectric oscillator 7 , and various modifications can be made.

[0107] For example, in the first embodiment and other embodiments described above, the area of the first conductive bonding portion 41, which is closer to the imaginary center line L1, is larger than the area of the second conductive bonding portion 42, which is farther from the imaginary center line L1, when viewed from above. However, the present invention is not limited to this. For example, the area of the first conductive bonding portion 41, which is closer to the imaginary center line L1, is smaller than the area of the second conductive bonding portion 42, which is farther from the imaginary center line L1, when viewed from above. In this way, the first conductive bonding portion 41 can be less susceptible to the influence of unwanted vibrations.

[0108] In addition, in the third embodiment described above, a package structure made of an insulating material with a ceramic base (ceramic package) is used as the container, but this is not limited to this. A package structure made of an insulating material covered with a molded resin (molded package) may also be used. The general structure of the molded package is described below. In the molded package, a glass epoxy substrate or the like is used as a flat base substrate for mounting components. The necessary wiring for electrical connection to the components is provided on the upper surface of the glass epoxy substrate, and the necessary external terminals for leading from the wiring to an external circuit substrate are formed on the bottom surface. The sheet-type tuning fork-type piezoelectric vibrator disclosed in the above embodiment is mounted on a portion of the wiring on the upper portion of the glass epoxy substrate by being electrically and mechanically bonded using a conductive bonding material such as solder. An IC chip is mounted in parallel with the tuning fork-type piezoelectric vibrator by being mechanically bonded using a resin adhesive, and a metal wire such as gold is bonded to a portion of the wiring to achieve the necessary electrical connection. A mold resin is formed on the upper portion of the glass epoxy substrate on which the tuning fork type piezoelectric vibrator and the IC chip are mounted so as to cover the components.

[0109] Furthermore, the contents of the above-described embodiment and the contents of the modified examples may be appropriately combined.

[0110] Industrial applicability

[0111] The present invention is widely applicable to a tuning-fork type piezoelectric vibration piece in which a pair of vibration arms vibrate, a tuning-fork type piezoelectric vibrator including the tuning-fork type piezoelectric vibration piece, and a tuning-fork type piezoelectric oscillator.

[0112] Description of Reference Numerals

[0113] 1: Tuning fork type piezoelectric vibrator

[0114] 10, 10A: Tuning fork type piezoelectric vibration piece

[0115] 20: Crystal vibrator

[0116] 21: Base

[0117] 22: First vibration arm

[0118] 23: Second vibration arm

[0119] 24: External joint

[0120] 25: Neck shrinkage

[0121] 31: First excitation electrode

[0122] 32: Second excitation electrode

[0123] 33, 33A: First lead electrode

[0124] 34, 34A: Second lead electrode

[0125] 35: First through-hole electrode

[0126] 36: Second through-hole electrode

[0127] 41: First conductive bonding portion

[0128] 42: Second conductive joint

[0129] L1: Imaginary center line

[0130] L2: Imaginary configuration line.

Claims

1. A tuning fork type piezoelectric vibrating piece comprising: base; a first vibrating arm and a second vibrating arm extending in one direction from one end of the base; an external joint portion provided at the other end portion of the base portion; a pair of first excitation electrodes and second excitation electrodes, which are formed on the first vibrating arm and the second vibrating arm; a first lead-out electrode led out from the first excitation electrode to the base portion and the external bonding portion; a second lead-out electrode led out from the second excitation electrode to the base portion and the external bonding portion; a first conductive bonding portion used to electrically and mechanically bond the first lead electrode to the first external electrode; and a second conductive bonding portion used to electrically and mechanically bond the second lead electrode to the second external electrode; The tuning fork type piezoelectric vibrating piece is characterized in that A line passing through the center between the first vibrating arm and the second vibrating arm in a plan view and extending in the extension direction of the first vibrating arm and the second vibrating arm is set as an imaginary center line, and In the case where a region of the external junction portion in the plan view on the side where the first vibrating arm exists with the imaginary center line as a reference line is defined as a first region, and a region of the external junction portion in the plan view on the side where the second vibrating arm exists with the imaginary center line as a reference line is defined as a second region, The entire first conductive bonding portion and the entire second conductive bonding portion are provided so as to be biased toward and present in the first region.

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

3. The tuning-fork type piezoelectric vibrating piece according to claim 1 or 2, wherein: In the plan view, the area of the first region is larger than the area of the second region.

4. The tuning-fork type piezoelectric vibrating piece according to claim 1 or 2, wherein: The first conductive bonding portion and the second conductive bonding portion are respectively formed of metal bumps.

5. The tuning-fork type piezoelectric vibrating piece according to claim 1 or 2, wherein: A constricted portion is provided between the base portion and the external engaging portion.

6. The tuning-fork type piezoelectric vibrating piece according to claim 1 or 2, wherein: The width of the base portion in the direction in which the first vibrating arm and the second vibrating arm are arranged side by side in the plan view decreases from the side of the base portion where the first vibrating arm and the second vibrating arm are located toward the side of the base portion where the external joint is located.

7. The tuning-fork type piezoelectric vibrating piece according to claim 1 or 2, wherein: When a line connecting the ends of the other end portion of the base in the plan view is defined as an imaginary arrangement line, the external junction portion exists only in a region on the side where the base does not exist with the imaginary arrangement line as a reference line in the plan view.

8. The tuning-fork type piezoelectric vibrating piece according to claim 1 or 2, wherein: A through hole or a recess is provided in the base. The through hole or the recessed portion is provided between the first vibrating arm and the conductive bonding portion closer to the imaginary center line between the first conductive bonding portion and the second conductive bonding portion in the plan view.

9. The tuning-fork type piezoelectric vibrating piece according to claim 1 or 2, wherein: The base, the first vibration arm, the second vibration arm and the external joint are made of crystal. In the plan view, the negative direction of the X-axis of the crystal is a direction from the second vibrating arm toward the first vibrating arm, where the first vibrating arm and the second vibrating arm are arranged side by side.

10. A tuning fork type piezoelectric vibrator, characterized in that ， The tuning-fork type piezoelectric vibrating piece according to claim 1 or 2 is mounted and housed inside the container of the tuning-fork type piezoelectric vibrator and is hermetically sealed.

11. A tuning fork type piezoelectric oscillator, characterized in that ， The tuning-fork type piezoelectric vibrating piece according to claim 1 or 2 and the integrated circuit element having a temperature compensation circuit are mounted and housed inside a container of the tuning-fork type piezoelectric oscillator and are hermetically sealed.

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