JP2018037896A - Tuning fork type piezoelectric vibrating piece and tuning fork type piezoelectric vibrator using tuning fork type piezoelectric vibrating piece - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a turning fork type piezoelectric vibrating piece having excellent characteristics by inhibiting the influence of an unnecessary vibration mode even if the tuning fork type piezoelectric vibrating piece becomes ultra-small, and also to provide a tuning fork type piezoelectric vibrator using the turning fork type piezoelectric vibrating piece.SOLUTION: A tuning fork type crystal vibrating piece 20 includes: a base 2; and a pair of vibrating arms 21, 22 extending from one end side of the base 20 in the same direction. An insulation film 29 is formed on a base material of a rear surface 2b of the base 20, and on the insulation film 29, junction electrodes 271, 281 are formed which are pulled out from excitation electrodes 25, 26 of the pair of vibrating arms and conductively joined to the outside.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a piezoelectric vibrating piece having a tuning fork shape and a tuning fork type piezoelectric vibrator using the piezoelectric vibrating piece.

  Piezoelectric vibrators such as tuning fork type crystal vibrators are used in various electronic devices as reference clock sources. For example, a surface-mounted tuning fork crystal resonator (hereinafter abbreviated as a crystal resonator) has a base and a tuning fork crystal resonator piece having a pair of vibrating arms extending in the same direction from one end of the base. It is accommodated in the recess of the container, and a flat lid is joined to the opening end of the recess (see Patent Documents 1 and 2). Excitation electrodes for driving the vibrating arms are formed on the pair of vibrating arms.

  In the crystal resonator, the other end side of the base portion of the tuning-fork type crystal vibrating piece is conductively bonded to the electrode pad formed on the inner bottom surface of the concave portion of the container via a conductive bonding material. Here, the vibration mode is different between the vibration in the vibrating arm and the vibration in the base. Specifically, the presence of an unnecessary vibration mode (unnecessary vibration mode) such as a longitudinal vibration mode at the base may cause the oscillation frequency of the crystal resonator to become unstable or cause the equivalent series resistance value to decrease.

JP 2002-261575 A Japanese Patent No. 3896585

  Due to the recent miniaturization of the crystal unit (for example, the external dimensions of a crystal unit having a rectangular shape in a plan view are 1.6 mm × 1.0 mm or less), the tuning fork type crystal resonator element used for the crystal unit is also becoming smaller. ing. Therefore, as the tuning fork type crystal vibrating piece is miniaturized, the influence of the above-described unnecessary vibration mode becomes relatively large. This causes a problem that the characteristics of the crystal resonator are deteriorated.

  The present invention has been made in view of such a point, and even if the tuning fork type piezoelectric vibrating piece becomes ultra-small, the influence of the unnecessary vibration mode is suppressed, and the tuning fork type piezoelectric vibrating piece having good characteristics and the tuning fork type piezoelectric piece are provided. An object of the present invention is to provide a tuning fork type piezoelectric vibrator using a vibrating piece.

  In order to achieve the above object, the invention according to claim 1 is a tuning fork type piezoelectric vibrating piece including a base and a pair of vibrating arms extending in the same direction from one end of the base, and at least one of the bases. An insulating film is formed on the base surface of the main surface, and a bonding electrode is formed on the insulating film. The bonding electrode is drawn from the excitation electrodes of the pair of vibrating arms and conductively bonded to the outside.

  According to the said invention, since the insulating film is formed in the base material of the base material of the at least 1 main surface of the said base, it can suppress that the bending vibration of a pair of vibrating arm propagates to a joining electrode. This is because an insulating film (a film made of an insulating material having no piezoelectric effect) is formed on the base substrate, and a bonding electrode is formed on the insulating film, so that piezoelectric vibration occurs in the insulating film portion. Therefore, the influence of the unnecessary vibration mode at the base can be suppressed. Thereby, a tuning fork type piezoelectric vibrator having good characteristics can be obtained. In addition, since the insulating film is formed on the base material of the base material of at least one main surface of the base portion, it is possible to secure a longer path length from the pair of vibrating arms to the bonding electrode. Can be suppressed. Note that an insulating film may also be formed on the base substrate where the bonding electrode is not formed.

  In order to achieve the above object, the invention according to claim 2 is characterized in that the insulating film is formed in a region avoiding a region serving as a vibration node of the pair of vibrating arms in the base portion. To do.

  According to the above invention, since the insulating film is formed in a region that avoids the region of vibration of the pair of vibrating arms in the base, bending vibration is suppressed while suppressing the influence of unnecessary vibration mode in the base. It is possible to suppress the vibration of the pair of vibrating arms from propagating to the bonding electrode without hindering.

  In order to achieve the above object, the invention according to claim 3 is characterized in that the insulating film is made of silicon dioxide.

  According to the above invention, it is possible to easily form an insulating film that does not have a piezoelectric effect and has good adhesion to the base of the piezoelectric vibrating piece. This is because, for example, when artificial quartz is used as the substrate of the piezoelectric vibrating piece, silicon dioxide (silica: SiO 2) having no piezoelectric effect is used as the insulating film, so that the adhesion to the quartz substrate is good. In addition, adhesion to various electrodes (excitation electrode, extraction electrode, etc.) made of gold (Au) or the like formed on the tuning-fork type quartz vibrating piece is good. Further, the insulating film made of silicon dioxide can be easily formed on the base of the quartz crystal vibrating piece by EB vapor deposition (electron beam vapor deposition).

  In order to achieve the above object, according to a fourth aspect of the present invention, there is provided a tuning fork type piezoelectric vibrating piece joining electrode according to any one of the first to third aspects, provided inside a container having an opening. The tuning fork-type piezoelectric vibrator is hermetically sealed with the tuning fork-type piezoelectric vibrating piece being conductively bonded via the electrode pad and a bonding material, and a lid is bonded to the opening.

  According to the above-described invention, by using the tuning fork-type piezoelectric vibrating piece having the above-described effects, the tuning fork having good characteristics in which the influence of vibration leakage on the bonding electrode is reduced while the influence of the unnecessary vibration mode at the base is suppressed. Type piezoelectric vibrator can be obtained.

  As described above, according to the present invention, even if the tuning fork type piezoelectric vibrating piece becomes ultra-small, the influence of the unnecessary vibration mode is suppressed, and the tuning fork type piezoelectric vibrating piece having good characteristics and the tuning fork type piezoelectric vibrating piece are used. A tuning fork type piezoelectric vibrator can be provided.

Schematic top view of a tuning fork type crystal resonator according to an embodiment of the present invention before sealing Schematic sectional view taken along line AA in FIG. 1 is a schematic plan view of one main surface side of a tuning-fork type crystal vibrating piece according to an embodiment of the present invention. Plane schematic diagram of the other main surface side of the tuning-fork type crystal vibrating piece according to the embodiment of the present invention Schematic cross-sectional view along line BB in FIG. FIG. 5 is a schematic cross-sectional view of a base portion in a short direction of a tuning-fork type crystal vibrating piece according to a modification of the embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings, taking a tuning fork type crystal resonator as an example. The tuning fork type crystal resonator (hereinafter abbreviated as “crystal resonator”) in the present embodiment is a surface-mount type crystal resonator having a substantially rectangular parallelepiped package structure. In this embodiment, the external dimensions in plan view are 1.6 mm in length and 1.0 mm in width. The external dimensions of the crystal resonator in plan view are not limited to those dimensions. The present invention is suitable for a quartz resonator having an ultra-small external dimension (1.6 mm × 1.0 mm or less) in which it is difficult to ensure a sufficiently long dimension in the length direction of the base.

  As shown in FIGS. 1 to 2, the crystal resonator 1 according to the present embodiment includes a container 3 made of an insulating material having a recess 5, a tuning-fork type crystal vibrating piece 2 (hereinafter abbreviated as the crystal vibrating piece 2, and a recess). A flat lid 4 for sealing 5 is a main constituent member. In FIG. 1, for convenience of explanation, the cover is removed. In FIG. 1, illustration of various electrodes formed on the quartz crystal vibrating piece is omitted. After the quartz crystal vibrating piece 2 is accommodated in the recess 5 of the container 3, the lid 4 is joined to the opening end of the container 3 so as to cover the recess 5, and is hermetically sealed. Here, the container 3 and the lid 4 are joined via a sealing material (not shown).

  The container 3 is a box-shaped body made of an insulating material mainly composed of ceramic such as alumina, and is formed by laminating two ceramic green sheets and integrally firing them (see FIG. 2). The container 3 has a concave portion 5 having a rectangular shape in plan view inside the frame-shaped bank portion 30. A sealing material (not shown) is formed in a frame shape in plan view on the upper surface 300 of the bank portion 30, and the bonding material corresponds to the outer peripheral portion of the lid 4.

  On one short side of the inner bottom surface 301 of the concave portion 5 that is rectangular in plan view, two electrode pads 6 and 7 that are conductively bonded to the crystal vibrating piece 2 are formed in parallel with a gap therebetween. Yes. The two electrode pads 6 and 7 are two of the four external connection terminals 8 (only two are shown in FIG. 2) provided at the four corners of the outer bottom surface 302 of the container 3 through internal wiring and vias (not shown). Is electrically connected to two terminals. These two electrode pads 6 and 7 have different polarities.

  In the present embodiment, the two electrode pads 6 and 7 are formed by laminating gold on the upper surface of the tungsten metallized layer using a technique such as plating. As the metallized layer, molybdenum may be used instead of tungsten.

  The tungsten portions of the electrode pads 6 and 7 are overlaid in two steps in terms of the minimum unit thickness of metallization. In this embodiment, since the container 3 has a two-layer structure in order to reduce the thickness of the crystal resonator, a step portion cannot be formed on the inner bottom surface 301 of the recess 5. This is to ensure a certain gap between the lower surface (the surface facing the inner bottom surface 301) of the quartz crystal vibrating piece and the inner bottom surface 301 in the later state.

  In this embodiment, the electrode pads 6 and 7 have a rectangular shape in plan view, and the electrode pad 7 has a relatively larger area in plan view than the electrode pad 6. This is configured to correspond to the shape of the quartz crystal vibrating piece 2. The application of the present invention is not limited to electrode pads having different areas in plan view, and the two electrode pads may have the same area in plan view.

  The lid 4 is a metallic lid body having a rectangular shape in a plan view using Kovar as a base, and nickel plating layers are formed on the front and back surfaces of the lid. Further, on the joint surface side of the lid 4 with the container, a brazing material made of metal is formed on the nickel plating layer along the outer periphery of the joint surface. In this embodiment, silver brazing is used as the brazing material.

  Next, the quartz crystal resonator element according to this embodiment will be described with reference to FIGS. For convenience of explanation, of the two opposing main surfaces (2a, 2b) of the quartz crystal vibrating piece 2, the main surface on the side facing the electrode pads 6, 7 when mounted on the container is defined as the back surface 2b. The main surface on the opposite side opposite to the surface 2a will be described as the surface 2a. 3 is a schematic plan view seen from the front surface side (2a) of the quartz crystal vibrating piece, and FIG. 4 is a schematic plan view seen from the back surface side (2b) of the quartz crystal vibrating piece.

  As shown in FIGS. 3 to 4, the quartz crystal vibrating piece 2 has a tuning fork shape, and includes a base portion 20, a pair of vibrating arms 21 and 22 extending in the same direction from one end side 201 of the base portion 20, and the other end side 202 of the base portion. And a projecting portion 24 projecting from one side surface toward one side in the width direction of the base portion 20 (the dimension of the base portion in the axial direction indicated by the symbol X in FIGS. 3 to 4). The pair of vibrating arms 21 and 22 are formed symmetrically with respect to an imaginary straight line CL that passes through the approximate center in the width direction of the base 20.

  A wide portion 23 having a width wider than the arm width of the vibrating arms 21 and 22 (the dimension of the arm in the direction orthogonal to the extending direction of the vibrating arms) is provided on the distal end side of each of the pair of vibrating arms 21 and 22. 23 is formed. The wide portions 23, 23 are formed integrally with the tip portions of the vibrating arms 21, 22 via widened portions (reference numerals omitted) that gradually widen in the extending direction of the vibrating arms. The vibrating arms 21 and 22, the widened portion, and the wide portions 23 and 23 have a pair of side surfaces (reference numerals omitted) facing the pair of opposed main surfaces 2 a and 2 b.

  Long grooves G are formed on the front and back main surfaces of the pair of vibrating arms 21 and 22 so as to face each other for the purpose of further reducing the equivalent series resistance value (hereinafter referred to as CI value). . The long groove G is formed on the front and back main surfaces of each of the pair of vibrating arms 21 and 22 with a predetermined depth, and one end side thereof extends to one end side 201 of the base portion 20. On the other hand, the other end side of the long groove G is located on the base side of the vibrating arm with respect to the boundary between the vibrating arm and the widened portion.

  In the present embodiment, the dimension in the width direction of the base 20 is larger than the distance between the outer edges of the pair of vibrating arms 21 and 22 (the dimension in the X-axis direction occupied by the pair of vibrating arms). That is, the left end portion and the right end portion of the base portion 20 are configured to protrude outward from the outer surfaces of the vibrating arms 21 and 22. By providing such a protruding region, the vibration propagated from the vibrating arm can be propagated outside in the width direction of the base. Thereby, the influence of the vibration leakage to the junction part of a base and a joining material can be reduced more.

  The base portion 20 is formed with a reduced width portion 203 where the other end side 202 is narrower than the one end side 201. By forming such a reduced width portion, it is possible to reduce the influence of vibration leakage on the joint portion between the base portion and the joining material.

  A projecting portion 24 is formed on one side surface of the reduced width portion 203. The protruding portion 24 and the base 20 form an “L” -shaped portion of the alphabet that is bent at a right angle in plan view. The tuning fork type crystal vibrating piece is not limited to the shape in the present embodiment. For example, the protruding portion may have a shape protruding not only from one side surface of the base portion but also from the other side surface of the base portion (side surface facing the one side surface), that is, a shape in which the protruding portions protrude from both outer sides of the base portion. Alternatively, the projecting portion may have a bilaterally symmetric shape that projects in parallel to each other by changing the direction in the extending direction of the vibrating arm after projecting outward from the base. Moreover, the shape in which the protrusion part is not formed in the base may be sufficient.

  As shown in FIGS. 4 to 5, an insulating film 29 is formed on the quartz substrate on the back surface side (2 b) of the base 20. In this embodiment, the insulating film 29 is made of silicon dioxide (SiO 2). In this embodiment, the thickness t of the insulating film 29 is 0.05 μm. In the present embodiment, the insulating film is formed thinner than the thickness (0.07 μm) of various electrodes (excitation electrode, extraction electrode, routing electrode, bonding electrode). As described above, the thickness of the insulating film 29 is thinner than the thickness of the extraction electrodes 27 and 28 at the base, so that the extraction electrode can overcome the step generated by the formation of the insulating film on the base material of the base. Even if it is formed, it is possible to prevent the extraction electrode from being disconnected at the edge portion of the step.

  In the present embodiment, silicon dioxide (SiO 2) is used as the insulating film. Silicon dioxide does not have a piezoelectric effect and has good adhesion to the base material of the quartz crystal vibrating piece. In addition, adhesion to various electrodes (described later) formed on the quartz crystal vibrating piece is good. This insulating film made of silicon dioxide can be easily formed on the base of the quartz crystal vibrating piece by EB vapor deposition. The insulating film according to the present invention is preferably made of a material that does not have a piezoelectric effect, has good adhesion to the substrate and various electrodes of the piezoelectric vibrating piece, and generates a small amount of gas due to heat.

  The insulating film 29 is formed in a region avoiding a region serving as a vibration node of the pair of vibrating arms 21 and 22 in the main surface on the back surface side of the base (see FIG. 4). Here, the vibration node of the pair of vibrating arms 21 and 22 is a position separated from the base portion of the base of the pair of vibrating arms in the Y-axis direction of the crystal axis of the crystal vibrating piece to the other end side 202 of the base. it is conceivable that. Then, as a result of forming the insulating film while avoiding the region serving as the vibration node, the length of the insulating film in the longitudinal direction of the crystal vibrating piece 2 (the Y-axis direction of the crystal axis) is the length indicated by the symbol L in FIG. It has become. On the insulating film 29, lead electrodes (27, 28) to be described later are laminated.

  According to the above configuration, since the insulating film 29 is formed in a region that avoids the region serving as the vibration node of the pair of vibrating arms 21 and 22 in the base portion 20, while suppressing the influence of the unnecessary vibration mode in the base portion, Propagation of the vibration of the pair of vibrating arms 21 and 22 to the bonding electrodes 271 and 281 can be suppressed without hindering bending vibration.

  A large number of the quartz crystal vibrating pieces 2 described above are formed simultaneously from a single quartz wafer (Z plate) using a photolithographic technique and wet etching (wet etching using an etching solution). The insulating film 29 described above is formed in advance in a region corresponding to the base portion of the crystal wafer at the stage before forming the external shape of each crystal resonator element into a tuning fork shape in the manufacturing process of the crystal resonator element 2. Is possible. Alternatively, an insulating film is formed in a predetermined region of the base of each tuning-fork-shaped quartz vibrating piece with the quartz base exposed before the vapor deposition process for forming various electrodes, which is performed after the outer shape of each quartz-crystal vibrating piece is formed. You may make it do. In this embodiment, the insulating film 29 is formed by EB vapor deposition.

  As shown in FIGS. 3 to 4, the quartz crystal resonator element 2 includes a first excitation electrode 25 and a second excitation electrode 26 configured with different potentials, and a first excitation electrode 25 and a second excitation electrode 26. Lead electrodes 27 and 28 are formed from each via a lead electrode (reference numeral omitted).

  The first excitation electrode 25 and the second excitation electrode 26 are formed over the entire inside of the long grooves G and G of the pair of vibrating arms 21 and 22. By forming the long groove, vibration leakage of the pair of vibrating arms 21 and 22 is suppressed even when the crystal vibrating piece is downsized, and a good CI value can be obtained. Note that only the first and second excitation electrodes may be formed only in a partial region inside the long grooves G and G of the pair of vibrating arms.

  The first excitation electrode 25 is formed on the front and back main surfaces of one vibrating arm 21 and the outer surface and inner surface of the other vibrating arm 22 via a routing electrode. Similarly, the second excitation electrode 26 is formed on the front and back main surfaces of the other vibrating arm 22 and on the outer side surface and the inner side surface of the one vibrating arm 21 via the routing electrode.

  The above-described routing electrodes are formed on all of the pair of main surfaces and the pair of side surfaces constituting the wide portions 23, 23, respectively. In the present embodiment, the routing electrode is formed on the entire circumference of the wide portion 23 and the entire circumference (a pair of main surfaces and a pair of side surfaces) of the portion near the widened portion of the vibrating arms 21 and 22.

  Of the routing electrodes provided on the entire circumference of the wide portion, the frequency adjusting metal film W (for frequency adjustment) is further provided above the routing electrode formed on one main surface (surface 2a) of the wide portion 23. A weight) is formed. The frequency of the crystal vibrating piece 2 is finely adjusted by reducing the mass of the frequency adjusting metal film W by beam irradiation such as laser beam or ion beam.

  The extraction electrodes 27 and 28 are formed on the base 20 and the protrusion 24 (only the back surface 2b). Here, a part of the extraction electrodes 27 and 28 is formed so as to cover the insulating film 29 formed on one main surface (2b) of the base 20 as shown in FIG.

  According to the above configuration, since the insulating film 29 is formed on the base material of the base surface of the base 20, the bending vibrations of the pair of vibrating arms 21 and 22 are propagated to the bonding electrodes 271 and 281. Can be suppressed. This is because an insulating film made of an insulating material having no piezoelectric effect is formed on the base material substrate, and a bonding electrode is formed on the insulating film, so that piezoelectric vibration is generated in the insulating film portion. Since it does not occur, the influence of the unnecessary vibration mode in the base 20 can be suppressed. Thereby, a tuning fork type crystal resonator having good characteristics can be obtained. In addition, since the insulating film 29 is formed on the base material of the main surface of the base portion 20, a longer path length from the pair of vibrating arms 21 and 22 to the bonding electrodes 271 and 281 can be secured. Therefore, the influence of vibration leakage can be suppressed.

  By means of an extraction electrode 27 formed on the base portion 20, the first excitation electrode 25 formed on each of the outer surface and the inner surface of the other vibration arm 22 and one vibration arm 21 via the routing electrode. Are connected to the first excitation electrodes 25 formed on the front and back main surfaces. Similarly, the extraction electrode 28 formed on the base 20 causes the second excitation electrode 26 formed on each of the outer surface and the inner surface of one vibrating arm 21 and the other electrode via the routing electrode. It is connected to a second excitation electrode 26 formed on the front and back main surfaces of the vibrating arm 22.

  In the Y-axis direction of the crystal axis of the crystal vibrating piece, the extraction electrodes 27 and 28 are drawn from the one end side 201 of the base portion 20 to the boundary portion with the reduced width portion 203 on the surface 2 a of the crystal vibrating piece 2. On the other hand, on the back surface 2 b of the quartz crystal vibrating piece 2, the base 20 is drawn from one end side 201 to the other end side 202 (including the tip end side of the protruding portion 24).

  As shown in FIGS. 4 to 5, the region on the other end side 202 of the base portion 20 and the region on the distal end side of the projecting portion 24 on the back surface 2 b of the crystal vibrating piece 2 are bonded to the electrode pads 6 and 7 of the container 3 and the bonding material. It becomes the joining electrodes 271 and 281 that are electrically joined via each other.

  The first excitation electrode 25 and the second excitation electrode 26, the extraction electrodes 27 and 28, the routing electrodes (reference numerals omitted), and the bonding electrodes 271 and 281 described above have a chromium (Cr) layer formed on a quartz base material. In addition, a gold (Au) layer is laminated on the chromium layer. The layer configuration of the various electrodes is not limited to a layer configuration in which a gold layer is formed on a chromium layer, but may be other layer configurations.

  The first and second excitation electrodes, extraction electrodes, routing electrodes, and bonding electrodes are formed on the entire main surface of the quartz wafer by a film forming method such as vacuum deposition or sputtering, and then photolithography technology and metal The desired pattern is simultaneously formed by etching.

  Conductive bonding materials S and S are respectively formed on the upper surfaces of the two bonding electrodes 271 and 281 (see FIG. 4). In the present embodiment, the bonding material S is a plating bump formed by an electrolytic plating method. In the embodiment of the present invention, metal bumps (plating bumps) are used as the bonding material, but a conductive adhesive may be used.

  In the present embodiment, the conductive bonding between the crystal vibrating piece 2 and the electrode pads 6 and 7 is performed by the FCB method (Flip Chip Bonding). Specifically, the main surface (2a) opposite to the surface on which the bonding materials S, S of the crystal vibrating piece 2 are formed is sucked and held by a horn for applying ultrasonic waves. The horn is provided with a suction hole for sucking and holding the quartz crystal vibrating piece. The held crystal vibrating piece is positioned and mounted on the upper surfaces of the electrode pads 6 and 7 by using image recognition means. Then, an ultrasonic wave is applied from a horn while applying temperature and pressure. Thereby, the bonding materials S and S and the electrode pads 6 and 7 are ultrasonically bonded.

  In the present embodiment, as described above, on the surface (2a) of the quartz crystal vibrating piece, the extraction electrodes 27 and 28 are formed in a region from one end side 201 of the base 20 to the boundary portion with the reduced width portion 203 ( (See FIG. 3 or FIG. 5). That is, the extraction electrode is not formed in the region of the surface (2a) corresponding to the region where the bonding materials S and S of the bonding electrodes 271 and 281 on the back surface (2b) of the crystal vibrating piece are disposed. With such a configuration, the metal (extraction electrode) on the surface side of the quartz crystal vibrating piece 2 to be sucked and held is damaged by rubbing against the horn during ultrasonic bonding, or the metal peels off and adheres to the horn. Problems caused by dropping off can be avoided.

-Variation of the embodiment of the present invention-
A modification of the embodiment of the present invention will be described with reference to FIG. The description of the same configuration as that of the above-described embodiment of the present invention is omitted. FIG. 6 is a schematic cross-sectional view of the base portion in the short direction of the tuning fork type crystal vibrating piece, and is a cross-sectional view of the base portion at a position closer to the vibrating arm with respect to the reduced width portion. Also in the modification of the present embodiment, the outer shape of the tuning fork type crystal vibrating piece is the same as that of the above-described embodiment of the present invention.

  In the modification of the embodiment of the present invention shown in FIG. 6, an insulating film 40 is formed on each of four surfaces (a set of opposing main surfaces and an opposing set of side surfaces) constituting the base. Yes. That is, the insulating film 40 is formed over the entire circumference in the base 20 cross-sectional direction.

  Even when the insulating film is formed as shown in FIG. 6, an electric field is not generated in the region where the bonding electrode of the insulating film is not formed, and the insulating film has no piezoelectric effect. Since it is formed of a material, the influence of unnecessary vibration modes at the base can be suppressed.

  The present invention can be implemented in various other forms without departing from the spirit or main features thereof. Therefore, the above-described embodiment is merely an example in all respects and should not be interpreted in a limited manner. The scope of the present invention is indicated by the claims, and is not restricted by the text of the specification. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

  It can be applied to mass production of tuning fork type piezoelectric vibrating pieces and tuning fork type piezoelectric vibrators.

DESCRIPTION OF SYMBOLS 1 Tuning fork type crystal resonator 2 Tuning fork type crystal vibrating piece 20 Base 21, 22 Vibrating arm 271, 281 Bonding electrode 29, 40 Insulating film 3 Container

Claims (4)

A tuning fork-type piezoelectric vibrating piece having a base and a pair of vibrating arms extending in the same direction from one end of the base,
An insulating film is formed on a base material of at least one principal surface of the base,
A tuning fork-type piezoelectric vibrating piece, wherein a bonding electrode is formed on the insulating film so as to be drawn out from the excitation electrodes of the pair of vibrating arms and conductively bonded to the outside.   2. The tuning fork type piezoelectric vibrating piece according to claim 1, wherein the insulating film is formed in a region avoiding a region serving as a vibration node of the pair of vibrating arms in the base portion.   The tuning fork type piezoelectric vibrating piece according to claim 1 or 2, wherein the insulating film is made of silicon dioxide.   The bonding electrode of the tuning-fork type piezoelectric vibrating piece according to any one of claims 1 to 3, is conductively bonded via an electrode pad and a bonding material provided inside a container having an opening, and is bonded to the opening. A tuning fork type piezoelectric vibrator in which the tuning fork type piezoelectric vibrating piece is hermetically sealed by bonding a lid.

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