JP2018026723A - Tuning fork type piezoelectric vibrating piece and tuning fork type piezoelectric vibrator using the tuning fork type piezoelectric vibrating piece - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tuning fork type piezoelectric vibration piece which reduces vibration leakage even when the tuning fork type piezoelectric vibration piece becomes ultra-small and has good characteristics, and a tuning fork type piezoelectric vibrator using the tuning fork type piezoelectric vibration piece. With the goal. SOLUTION: On the other end side of one main surface of a base 20 of a tuning fork type crystal vibrating piece 2, bonding electrodes 271,281 are conductively bonded to electrode pads 6 and 7 provided in a container 3. .. Grooves M in which the base material of the base is thinned are formed around these bonding electrodes. Then, the connection electrodes 272 and 282 drawn out from the excitation electrodes 25 and 26 provided on the pair of vibrating arms 21 and 22 are arranged on the outside with respect to the junction electrodes 271,281 with the groove M interposed therebetween. The bonding electrodes 271,281 and the connecting electrodes 272 and 282 are electrically connected via the connecting portions 273 and 283. [Selection diagram] Fig. 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 insulating container via a conductive bonding material. Here, the vibration of the vibrating arm leaks and propagates to the joint between the base and the bonding material, so that the oscillation frequency of the crystal resonator may become unstable or the equivalent series resistance value may be reduced (so-called Vibration leak). In order to prevent this vibration leakage, the length in the length direction of the base (the total length in the extension direction of the vibration arm of the base) is sufficient with respect to the width of the vibration arm (the dimension in the direction orthogonal to the extension direction of the vibration arm). It is known to ensure a long length (for example, 4 times or more).

JP 2002-261575 A Japanese Patent No. 3896585

  However, when the crystal resonator becomes ultra-compact (for example, the external dimensions of a crystal resonator having a rectangular shape in plan view are 1.6 mm × 1.0 mm or less), the tuning-fork type crystal resonator element used for the crystal resonator is also smaller. become. In order to reduce the equivalent series resistance value in an ultra-small crystal resonator, it is necessary to ensure a long dimension in the extending direction of the vibrating arm. Therefore, it becomes difficult to ensure a sufficient dimension in the length direction of the base. In other words, in an ultra-small crystal unit, it is difficult to ensure that the dimension in the length direction of the base is sufficiently long with respect to the width of the vibrating arm. The problem of deterioration arises.

  The present invention has been made in view of such a point, and even if the tuning fork type piezoelectric vibrating piece is miniaturized, vibration leakage is reduced, and a tuning fork type piezoelectric vibrating piece having good characteristics and the tuning fork type piezoelectric vibrating piece are provided. An object of the present invention is to provide a tuning fork type piezoelectric vibrator used.

  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 side of the base, wherein the tuning fork type piezoelectric vibration is provided. On the other end side of one main surface of the base portion of the piece, there is provided a bonding electrode that is conductively bonded to an electrode pad provided on a container in which the tuning fork type piezoelectric vibrating piece is accommodated. A groove in which the base material is thinned is formed, and a connection electrode led out from an excitation electrode provided on the pair of vibrating arms is arranged outside the bonding electrode across the groove, and the bonding electrode And the connection electrode are electrically connected.

  According to the above invention, the joining electrode that is conductively joined to the electrode pad provided on the container in which the tuning fork type piezoelectric vibrating piece is housed is provided on the other end side of the one main surface of the base portion of the tuning fork type piezoelectric vibrating piece, A groove in which the base material of the base portion is thinned is formed around the bonding electrode, and the connection electrode drawn from the excitation electrode provided on the pair of vibrating arms is spaced from the bonding electrode with respect to the bonding electrode. The junction electrode and the connection electrode are electrically connected. As described above, since the connection electrode is formed around the bonding electrode with the groove interposed therebetween, it is possible to suppress the vibration propagated from the vibrating arm from propagating to the bonding electrode. Thereby, a tuning fork type piezoelectric vibrator having good characteristics can be obtained.

  In order to achieve the above object, the invention according to claim 2 is characterized in that the bonding electrode and the connection electrode are electrically connected via a connection portion that crosses the groove.

  According to the said invention, the electrical connection with the said joining electrode and the said connection electrode can be performed reliably. When the electrical connection between the bonding electrode and the connection electrode is performed by forming a via (having a metal material filled in the through hole) in the base material in the region where the bonding electrode is formed, the bonding electrode is formed. Since it is difficult to drill a small-diameter through-hole in a substrate in a minute region, there is a risk that poor conduction will occur. Furthermore, stress due to the difference in thermal expansion coefficient between the piezoelectric material and the metal material by forming a via in the region where the bonding electrode is formed, which is inside the groove where the base material is thinned. Due to the influence of the above, there is a possibility that the region including the groove of the base portion becomes brittle and breakage or loss may occur.

  On the other hand, in the present invention, since the via is not formed in the base material in the region where the minute joining electrode is formed, the joining electrode and the connecting electrode are connected via the connecting portion, and therefore, the electrical Connection can be made reliably. In addition, since the via is not drilled in a minute region where the bonding electrode is formed, the influence of the stress due to the difference in the thermal expansion coefficient between the piezoelectric material and the metal material can be eliminated. Further, when the bonding electrode and the connection electrode are connected by a connection portion in which the base material of the base portion is not thinned, the thinned region can be reinforced by the groove around the connection portion. .

  In order to achieve the above object, the invention according to claim 3 is characterized in that the connection portion is formed on the other end side of the base portion with respect to the bonding electrode.

  According to the said invention, it can suppress more that the vibration propagated from the vibrating arm propagates to the bonding electrode. This is because the connecting portion is formed on the other end side of the base portion which is far from the vibrating arm. In other words, since the connection portion is not formed in the groove located on the one end side of the base portion that is close to the vibrating arm, the vibration propagated from the vibrating arm is attenuated by the groove so that it is difficult to propagate to the bonding electrode. Because it can.

  In addition, the width | variety in the one end side of a base with respect to the said junction electrode of the said groove | channel may be larger than the width | variety in the other end side of a base part with respect to the said junction electrode of the said groove | channel. According to the said structure, it can suppress more that the vibration propagated from the vibrating arm propagates to the bonding electrode. This is because the width of the groove on the side closer to the vibrating arm is larger than the width of the groove far from the vibrating arm, thereby further attenuating the vibration propagated from the vibrating arm. Because it can.

  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 according to any one of the first to third aspects, wherein the tuning fork type piezoelectric vibrating piece is accommodated in the container having an opening. The tuning fork type piezoelectric vibrating piece is hermetically sealed by bonding a lid to the tuning fork type piezoelectric vibrator.

  According to the above invention, a tuning fork type piezoelectric vibrator having good characteristics in which the influence of vibration leakage on the joint portion between the base portion and the joining material is reduced is obtained by using the tuning fork type piezoelectric vibrating piece having the above-described effects. be able to.

  As described above, according to the present invention, even if the tuning fork type piezoelectric vibrating piece becomes ultra-small, vibration leakage is reduced, and a tuning fork type piezoelectric vibrating piece having good characteristics and a tuning fork type using the tuning fork type piezoelectric vibrating piece. A piezoelectric vibrator can be provided.

FIG. 2 is a schematic top view of the tuning fork type crystal resonator according to the first embodiment of the present invention before sealing. Schematic sectional view taken along line AA in FIG. FIG. 2 is a schematic plan view of one main surface side of the tuning-fork type crystal vibrating piece according to the first embodiment of the present invention. FIG. 2 is a schematic plan view of the other main surface side of the tuning-fork type crystal vibrating piece according to the first embodiment of the present invention. Partial enlarged schematic view of the base of FIG. Schematic cross-sectional view taken along line BB in FIG. Partial enlarged schematic view of a tuning-fork type crystal vibrating piece representing the second embodiment of the present invention Partial enlarged schematic view of a tuning-fork type crystal vibrating piece representing a third embodiment of the present invention Partial enlarged schematic view of a tuning-fork type crystal vibrating piece representing the fourth embodiment of the present invention Partial enlarged schematic view of a tuning-fork type crystal vibrating piece representing a fifth embodiment of the present invention Partial enlarged schematic view of a tuning-fork type crystal vibrating piece representing the sixth embodiment of the present invention Partial enlarged schematic view of a tuning-fork type crystal vibrating piece representing the seventh embodiment of the present invention

-First embodiment of the present invention-
Hereinafter, a first embodiment 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.

  A crystal resonator 1 according to a first embodiment of the present invention includes a container 3 made of an insulating material having a recess 5 and a tuning fork type crystal vibrating piece 2 (hereinafter referred to as a crystal vibrating piece 2) as shown in FIGS. And the flat lid 4 that seals the recess 5 is a main component. In FIG. 1, for convenience of explanation, the cover is removed. 1 and 2, the description of various electrodes formed on the 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 the present embodiment, the electrode pads 6 and 7 have a rectangular shape in plan view, and have different areas in plan view. That is, 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, a gold-tin alloy (AuSn) 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.

  As shown in FIG. 3, in the first embodiment of the present invention, the frequency adjustment metal film W (frequency adjustment weight) is formed on only one main surface (surface 2a) of the surfaces constituting the wide portion 23. Yes. By reducing the mass of the frequency adjusting metal film W by irradiation with a beam such as a laser beam or an ion beam, the frequency of the quartz crystal vibrating piece 2 is finely adjusted. Note that the frequency adjusting metal film W is formed so that the area in plan view is slightly smaller than the routing electrodes on the main surfaces of the wide portions 23 and 23.

  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. The protruding portion 24 described above is formed on one side surface of the reduced width portion 203. The projecting portion 24 and the base portion 20 form an alphabet “L” -shaped portion bent at a right angle in a 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.

  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).

  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 drawn from each of the lead wires via lead electrodes (described later) are formed.

  The first and second excitation electrodes 25 and 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 on the outer side surface and inner side surface of the other vibrating arm 22 via a lead electrode (reference numeral omitted). 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 inner side surface of one vibrating arm 21 via a routing electrode (not shown).

  The extraction electrodes 27 and 28 are formed on the base 20 and the protrusion 24 (only the back surface 2b). With the 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 vibrating arm 22 and the routing electrode (reference numeral omitted) A first excitation electrode 25 formed on the front and back main surfaces of the vibrating arm 21 is connected. Similarly, the extraction electrode 28 formed on the base 20 passes through the second excitation electrode 26 formed on each of the outer side surface and the inner side surface of one vibrating arm 21 and the routing electrode (not shown). The second vibrating electrode 22 is connected to a second excitation electrode 26 formed on the front and back main surfaces of the other vibrating arm 22.

  The extraction electrodes 27 and 28 are extracted from one end side 201 of the base portion 20 to the reduced width portion 203 on the surface 2 a of the crystal vibrating piece 2. On the other hand, the back surface 2 b of the crystal vibrating piece 2 is drawn to the other end side 202 and the tip end side of the protruding portion 24.

  As shown in FIGS. 4 to 5, the electrode pads 6, 7 of the container 3 and the bonding material are provided in the region on the other end side 202 of the base 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. Bonding electrodes 271 and 281 that are electromechanically bonded to each other are formed.

  In the first embodiment of the present invention, a groove M in which the base material of the crystal vibrating piece 2 (base portion 20) is thinned is formed around the bonding electrodes 271 and 281. As shown in FIG. 5, the groove M is formed in a trench shape so as to surround the outside of the substantially elliptical joining electrodes 271 and 281 in plan view. The connection electrodes 272 and 282 are arranged outside the bonding electrodes 271 and 281 with the groove M interposed therebetween. In the present embodiment, the opening width of the groove M is a substantially constant bottomed groove.

  As described above, since the connection electrodes 272 and 282 are formed around the bonding electrodes 271 and 281 with the groove M interposed therebetween, vibrations propagated from the vibrating arms 21 and 22 are prevented from propagating to the bonding electrodes 271 and 281. be able to. Thereby, the tuning fork type crystal resonator 1 having good characteristics can be obtained.

  Electrical connection between the bonding electrodes 271 and 281 and the connection electrodes 272 and 282 is performed through the connection portion 283. Specifically, as shown in FIG. 6, the connection portion 283 includes a bridge portion 283 </ b> B that remains without being thinned in the base material of the base portion 20, and a metal film 283 </ b> M formed on the upper surface of the bridge portion 283 </ b> B. Yes. The base portion of the base portion 20 is not thinned, and the bridge portion 283B is formed so as to cross the groove M in the width direction. That is, the bridge portion 283B is formed with base-like island-shaped substrate regions where the bonding electrodes 271 and 281 are formed, and connection electrodes 272 and 282 that are disposed outside the bonding electrodes 271 and 281 with the groove M therebetween. It is the site | part which connects the base-material area | region of the base part made. The presence of the bridge portion 283B makes the groove M discontinuous. That is, the groove M has a substantially horseshoe shape in plan view as shown in FIG.

  According to the above configuration, the electrical connection between the bonding electrodes 271 and 281 and the connection electrodes 272 and 282 can be reliably performed. When electrical connection between the bonding electrodes 271 and 281 and the connection electrodes 272 and 282 is performed by forming a via in a base material in a region where the bonding electrodes are formed, the base material in a minute region where the bonding electrodes are formed Furthermore, since it is difficult to drill a small-diameter through hole, there is a risk that poor conduction will occur. Furthermore, stress due to the difference in thermal expansion coefficient between the crystal and the metal material is formed by forming a via in a region where the bonding electrode is formed, which is inside the groove M where the base material of the base 20 is thinned. Due to the influence of the above, there is a possibility that the region including the groove of the base portion becomes brittle and breakage or loss may occur.

  On the other hand, in the present embodiment, vias are not formed in the base material in the region where the minute bonding electrodes are formed, and the bonding electrodes 271 and 281 and the connection electrodes 272 and 822 are connected via the connection portion 283. The electrical connection between both electrodes can be reliably performed. Further, since the via is not drilled in a minute region where the bonding electrodes 271 and 281 are formed, it is possible to eliminate the influence of stress caused by the difference in thermal expansion coefficient between the crystal and the metal material. Furthermore, since the base electrode of the base portion is not thinned and is connected by the connecting portion 283 that crosses the groove M, the bonding electrode and the connection electrode can reinforce the thinned region by forming the groove M.

  A groove is formed in the entire outer periphery of the region where the bonding electrode of the base is formed, a connection electrode is formed in a region outside the groove of the base, and the metal film is crossed along the inner wall surface of the groove. In the configuration in which both electrodes are electrically connected to each other, it is difficult to reliably form a metal film on the inner wall surface of the groove, which is a minute region, and the risk of occurrence of poor conduction increases. On the other hand, the presence of the connecting portions as shown in FIGS. 5 to 6 can prevent the conduction failure.

  FIG. 5 is a partially enlarged view of the base portion on the back surface 2b of the crystal vibrating piece 2 shown in FIG. As shown in FIG. 5, in the first embodiment of the present invention, connecting portions 273 and 283 are formed on the other end side (202) of the base portion with respect to the bonding electrodes 271 and 281.

  According to the above configuration, the vibration propagated from the vibrating arms 21 and 22 can be further suppressed from propagating to the bonding electrodes 271 and 281. This is because the connecting portion 283 is formed on the other end side 202 of the base portion that is far from the vibrating arms 21 and 22. That is, since no connection portion is formed in the groove located on the one end side 201 of the base portion close to the vibrating arms 21 and 22, the vibration propagated from the vibrating arms 21 and 22 is attenuated by the groove M. This is because it can be made difficult to propagate to the bonding electrodes 271 and 281.

  In the present embodiment, as shown in FIG. 6, the formation depth of the groove M is about half of the base material thickness t of the base portion 20. The formation depth of the groove M is an example, and is not limited to about half the thickness of the base material of the base portion 20. In the present embodiment, the groove M is formed by a photolithography technique and wet etching. Note that the formation depth of the groove can be controlled by adjusting the opening size of the photomask.

  In the schematic diagram shown in FIG. 6, the cross-sectional shape of the groove M is a shape dug vertically, but the inner wall surface of the groove is relative to the main surface of the crystal due to the crystal anisotropy of the Z-plate crystal. The inclined surface may be inclined at an angle unique to the crystal. The groove M may be formed by a method other than photolithography and wet etching, for example, dry etching.

  As shown in FIGS. 4 to 6, conductive bonding materials S and S are formed on the upper surfaces of the two bonding electrodes 271 and 281, respectively. In the present embodiment, the bonding material S is a plating bump formed by an electrolytic plating method. In the present embodiment, the bonding material S made of a plating bump is formed to be slightly smaller than the formation region of the bonding electrodes 271 and 281 in plan view. 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). In all the embodiments of the present invention, metal bumps (plating bumps) are used as bonding materials, but conductive adhesives may be used. When a conductive adhesive is used, even if the adhesive flows out of the bonding electrode formation region, the adhesive can be caused to flow into the groove M around the bonding electrode. As a result, it is possible to prevent deterioration of characteristics (for example, increase in equivalent series resistance value) due to enlargement of the adhesive application region more than expected.

  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.

  In the first and second excitation electrodes 25 and 26, the extraction electrodes 27 and 28, and the routing electrodes (not shown) described above, a chromium (Cr) layer is formed on a quartz base material, and a gold layer is formed on the chromium layer. It has a layer structure in which (Au) layers are stacked. 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, the extraction electrode, and the drawing electrode are formed on the entire main surface of the quartz wafer by vacuum deposition or sputtering, and then simultaneously formed into a desired pattern by photolithography and metal etching. Molded.

-Second embodiment of the present invention-
Next, a second embodiment of the present invention will be described with reference to FIG. The description of the same configuration as that of the above-described first embodiment of the present invention is omitted. Note that in FIG. 7 and all other embodiments of the present invention to be described later, the protruding portion extends from one side surface of the other end side of the base portion to one side in the width direction of the base portion, as in the first embodiment of the present invention. And has a protruding shape.

In the second embodiment of the present invention shown in FIG. 7, the groove M <b> 1 is formed around the bonding electrode 291 with respect to the connection electrode 292 among the two connection electrodes 292 and 300 having different polarities.
On the other hand, no groove is formed in the connection electrode 300, and the connection electrode 300 itself serves as a bonding electrode.

  In the present embodiment, the two bonding materials S1 and S2 made of metal bumps have different sizes in plan view. Here, the bonding material S1 located on the side close to the center in the width direction of the base 90 is a main bonding portion. On the other hand, the bonding material S2 located on the side far from the center in the width direction of the base portion 90 is a secondary bonding portion.

  As shown in FIG. 7, in the present embodiment, the bonding material S1 that is the main bonding portion is larger in size in plan view than the bonding material S2 that is the sub-bonding portion. Thus, by making the bonding material S1 relatively larger than the bonding material S2, the mechanical connection between the crystal vibrating piece 9 and the container (3) can be more reliably performed.

  Further, according to the above configuration, the groove M1 in which the base material of the base is thinned is formed around the bonding electrode 291, and the connection electrode 292 is disposed outside the bonding electrode 291 with the groove M1 interposed therebetween. The bonding electrode 291 and the connection electrode 292 are electrically connected through the connection portion 293. As described above, since the connection electrode 292 is formed around the bonding electrode 291 with the groove M1 therebetween, the vibration propagated from the vibrating arms 91 and 92 can be prevented from propagating to the bonding electrode 291. Thereby, a tuning fork type crystal resonator having good characteristics can be obtained.

-Third embodiment of the present invention-
Next, a third embodiment of the present invention will be described with reference to FIG. In the present embodiment, only the configuration of the connection portion is different from that in the second embodiment of the present invention described above.

  As shown in FIG. 8, the width of the connecting portion 313 of the crystal vibrating piece 10 is not constant. That is, the width W1 on the connection portion side between the connection portion 313 and the connection electrode 312 is smaller than the width W2 on the connection portion side between the connection portion 313 and the bonding electrode 311 (W1 <W2). According to such a configuration, it is possible to further suppress propagation of vibration from the vibrating arm to the bonding electrode. This is because the vibration propagating from the vibrating arm to the base becomes difficult to propagate to the bonding electrode side because the entrance side to the connection portion is relatively narrower than the exit side. Further, since the shape of the connecting portion in plan view is tapered, the vibration wave that reaches the inlet side of the connecting portion (the connecting portion side of the connecting portion 313 and the bonding electrode 311) It can be attenuated as it advances to the connection portion 313 and the connection electrode 312 side. Thus, propagation of vibration from the vibrating arm to the bonding electrode can be effectively suppressed.

-Fourth embodiment of the present invention-
Next, a fourth embodiment of the present invention will be described with reference to FIG. This embodiment is different from the above-described first embodiment of the present invention only in the configuration of the groove surrounding the connecting portion.

  Specifically, the groove M3 shown in FIG. 9 of the crystal resonator element 11 has a width d1 on one end side of the base (the side indicated as “arm tip side” in FIG. 9) with respect to the bonding electrode 321. It is larger than the width d2 on the other end side of the base portion (the direction opposite to the direction described as “arm tip side” in FIG. 9) with respect to the bonding electrode 321 of the groove (d1> d2).

  According to the above configuration, it is possible to further suppress the vibration propagated from the vibrating arm from propagating to the bonding electrode 321. This is because the width d1 of the groove on the side closer to the vibrating arm is larger than the width d2 of the groove far from the vibrating arm, thereby further attenuating the vibration propagated from the vibrating arm. Because it can.

-Fifth embodiment of the present invention-
Next, a fifth embodiment of the present invention will be described with reference to FIG. This embodiment differs from the first to fourth embodiments of the present invention described above in the shape of the bonding electrode and the groove and the number of connection portions formed.

  As shown in FIG. 10, the bonding electrode 331 of the crystal vibrating piece 12 has a substantially elliptical shape in plan view. The groove M4 is formed with a substantially constant gap with respect to the bonding electrode 331 so as to be concentric with the elliptical bonding electrode 331.

  In the present embodiment, two connection portions are provided (333a, 333b). The junction electrode 331 and the connection electrode 332 are electromechanically connected by the two connection portions 333a and 333b. Here, the two connection portions 333 a and 333 b are formed on the other end side of the base portion with respect to the bonding electrode 331. By forming two connection portions in such a place, no connection portion is formed in the groove located on one end side of the base portion that is close to the vibration arm, so that the vibration propagated from the vibration arm can be reduced. It can be made difficult to propagate to the bonding electrode by being attenuated by the groove M4. Furthermore, even when a continuity failure occurs in either one of the two connection portions, continuity can be ensured with the remaining one connection portion.

-Sixth embodiment of the present invention-
Next, a sixth embodiment of the present invention will be described with reference to FIG. In this embodiment, the shape of the bonding electrode and the groove is different from the first embodiment of the present invention described above.

  As shown in FIG. 11, the bonding electrode 341 of the quartz crystal vibrating piece 13 has a circular shape in plan view. The groove M5 is formed with a substantially constant gap with respect to the bonding electrode 341 so as to be concentric with the circular bonding electrode 341. When the grooves are concentric as described above, the area that is thinned by the formation of the grooves can be minimized, which is suitable for an ultra-small crystal vibrating piece in which the groove forming area is narrowed. In addition, the planar view shape of the groove | channel in this invention is not limited to the shape in embodiment mentioned above, If it is a groove | channel of the form which surrounds a joining electrode, it belongs to the technical scope of this invention.

-Seventh embodiment of the present invention-
Next, a seventh embodiment of the present invention will be described with reference to FIG. In the present embodiment, the shape of the groove is different from the first to sixth embodiments described above. That is, in the present embodiment, the grooves are doubled in plan view.

  In the present embodiment, the crystal vibrating piece 14 includes an annular portion 15 surrounding the groove M6, a groove M7 outside the annular portion 15, and a groove M6 formed so as to surround the periphery of the bonding electrode 351. Is formed.

  The joining electrode 351 and the annular portion 15 are electromechanically connected via the first connecting portion 353, and the annular portion 15 and the connecting electrode 355 are separated from each other by two connecting portions (second connecting portion 354a, 354b) is connected electromechanically.

  In the case of the above configuration, since the grooves are formed in multiples, it is possible to further suppress the propagation of the vibration propagated from the vibrating arm to the bonding electrode 351. Further, between the two grooves, the annular portion 15, the first connection portion 353, and the second connection portions 354 a and 354 b function as an elastic body, so that the vibration propagated from the vibrating arm can be attenuated.

  Also, as shown in FIG. 12, in the present embodiment, all of the three connecting portions are not located on a single straight line. By arranging a plurality of connections in such a positional relationship, it is possible to attenuate the vibration propagated from the vibrating arm until it reaches the bonding electrode.

  In all the embodiments of the present invention described above, the crystal resonator element is exemplified by the configuration in which the grooves (M to M7) are formed on the main surface (the back surface 2b) facing the electrode pad of the container. In addition, the groove may be formed on the main surface (surface 2a) opposite to the main surface facing the electrode pad of the container of the crystal vibrating piece. For example, a long groove extending in the width direction of the base may be formed on the surface (2a) side of the base. Thus, by forming a groove | channel on both the main surfaces of a base, it can suppress more that the vibration which propagated from the vibrating arm propagates to a joining electrode.

  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, 9, 10, 11, 12, 13, 14 Tuning fork type crystal vibrating piece 20, 90 Base 21, 22 Vibrating arm 271, 281, 291, 311, 321, 331, 341, 351 Bonding electrode 272, 282, 292, 312, 332, 355 Connection electrode 273, 283, 293, 313, 333a, 333b, 353, 354a, 354b Connection 3 Container M, M2-M7 Groove

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,
On the other end side of one main surface of the base of the tuning fork type piezoelectric vibrating piece, a bonding electrode is provided which is conductively bonded to an electrode pad provided on a container in which the tuning fork type piezoelectric vibrating piece is accommodated.
A groove in which the base material of the base is thinned is formed around the bonding electrode,
A connection electrode drawn from an excitation electrode provided on the pair of vibrating arms is disposed outside the bonding electrode with the groove interposed therebetween,
A tuning-fork type piezoelectric vibrating piece, wherein the bonding electrode and the connection electrode are electrically connected.   2. The tuning fork type piezoelectric vibrating piece according to claim 1, wherein the bonding electrode and the connection electrode are electrically connected to each other through a connection portion that crosses the groove.   The tuning fork type piezoelectric vibrating piece according to claim 2, wherein the connection portion is formed on the other end side of the base portion with respect to the bonding electrode.   The tuning fork type piezoelectric vibrating piece according to any one of claims 1 to 3 is accommodated in the container having an opening, and the tuning fork type piezoelectric vibrating piece is hermetically sealed by joining a lid to the opening. Sealed tuning fork type piezoelectric vibrator.

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