JP2017200065A - Piezoelectric vibrator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric vibrator which is compatible with miniaturization and thinning and which can stably support a tuning fork type piezoelectric vibrating piece.SOLUTION: The other end side 202 of a base portion 20 of a tuning-fork type quartz-crystal vibrating piece 2 is cantilevered and joined to the two mounting pads 3a, 3b provided inside the container 1 via bonding materials 8, 9. Junctions J1, J2 between the tuning-fork type crystal vibrating piece 2 and the two mounting pads 3a, 3b are separated from each other. The imaginary straight line VL1 passing through the junctions J1, J2 is inclined with respect to the width direction of the base portion 20 in plan view.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a piezoelectric vibrator using a tuning fork type piezoelectric vibrating piece.

  Piezoelectric vibrators using tuning-fork type crystal vibrating pieces have long been used as reference signal sources for watches and the like. As such a piezoelectric vibrator, a surface-mounted type whose appearance is a substantially rectangular parallelepiped is widely used (see Patent Document 1). In recent years, piezoelectric vibrators have been reduced in size and thickness. For example, piezoelectric vibrators mounted inside wearable devices, IC cards, and the like have been required to be particularly thin (for example, The total height of the piezoelectric vibrator is 0.45 mm or less).

  Taking a tuning fork crystal resonator as an example of the piezoelectric resonator, a tuning fork crystal resonator (hereinafter abbreviated as a crystal resonator) is a tuning fork crystal resonator element (hereinafter referred to as a crystal resonator) as shown in FIGS. 14, a rectangular parallelepiped insulating container (hereinafter abbreviated as container) 13 having a concave portion 17 that accommodates the quartz crystal vibrating piece, and an upper surface of a bank portion that surrounds the concave portion 17. A flat lid 15 (not shown in FIG. 7) for hermetically sealing the quartz crystal vibrating piece 14 is a main component. On the inner bottom surface 170 of the concave portion 17 of the container 13, mounting pads 16 a and 16 b that are electromechanically connected to the crystal vibrating piece 14 are provided.

  The container described above is generally integrally formed by firing in a state where a plurality of ceramic sheets are laminated, but in order to cope with the reduction in thickness, it is necessary to reduce the number of laminated ceramic sheets as much as possible. For example, in the example shown in FIG. 8, the container 13 is configured by two layers of a plate-like bottom plate portion 13 a and a frame portion 13 b that is stacked on the outer peripheral portion of the upper surface of the bottom plate portion 13 a. In the case of such a layer configuration, the container can be configured with a minimum number of layers. However, in the case of a container having a two-layer structure, a step portion for securing a gap with the crystal vibrating piece 14 on the inner bottom surface 170 (the upper surface of the bottom plate portion 13a) of the concave portion 17 formed by the bottom plate portion 13a and the frame portion 13b. Cannot be formed. For this reason, in the case of a container having a two-layer structure, it is necessary to form a thickness of the mounting pad thicker than a thickness of the mounting pad in the case where a stepped portion exists as in Patent Document 1 by a metallization process such as tungsten. is there. In FIG. 8, the mounting pads 16a and 16b have a two-stage structure by two metallization processes for thickening.

  The quartz crystal vibrating piece 14 protrudes from the side end portion of the base portion 140 toward one side in the width direction of the base portion, a pair of vibrating arms 141 and 141 extending in the same direction from one end side 1401 of the base portion. This is a tuning-fork-shaped piezoelectric vibrating piece provided with a protrusion 142. The other end side 1402 of the base of the crystal vibrating piece 14 is cantilevered and supported on the mounting pads 16a and 16b of the container by a bonding material (18, 19) such as a conductive adhesive or a metal bump. When the crystal resonator element is ultrasonically bonded onto the mounting pad using metal bumps as the bonding material, it is suitable for miniaturization of the crystal resonator because it can perform reliable conductive bonding in a minute region (for example, substantially rectangular parallelepiped shape) The external dimensions of the quartz crystal resonator in plan view are 1.6 mm in length and 1.0 mm in width).

JP 2014-82538 A

  In the case of the crystal resonator using the two-layer container described above, the vertical gap between the lower surface of the lid and the upper surface of the crystal vibrating piece, and the vertical distance between the lower surface of the crystal vibrating piece and the inner bottom surface of the recess The gaps in the directional gaps are very narrow compared to the gaps in a container composed of three or more layers. Therefore, depending on the variation in the level of the crystal resonator element after the crystal resonator element is mounted on the mounting pad, as shown in FIG. 8, the free end side of the crystal resonator element 14 is downward (the inner bottom surface 170 side of the recess). May be cantilevered on the mounting pads 16a and 16b in a tilted state. In this case, when the crystal resonator receives an external impact, the free end side of the crystal vibrating piece 14 bends downward (in the direction indicated by the arrow), and the tip portion (free end) of the crystal vibrating piece 14 is the inner bottom surface of the recess. There is a risk of contact with 170. If the tip of the crystal vibrating piece comes into contact with the inner bottom surface of the recess, the tip will be damaged and non-oscillation may occur, or the oscillation frequency may deviate from a predetermined standard.

  The present invention has been made in view of such points, and an object of the present invention is to provide a piezoelectric vibrator that can support a reduction in size and thickness and can stably support a tuning-fork type piezoelectric vibrating piece. Is.

  In order to achieve the above object, the invention according to claim 1 is characterized in that the other end side of the base portion of the tuning fork-type piezoelectric vibrating piece having a base portion and a pair of vibrating arms extending in the same direction from one end side of the base portion is A piezoelectric vibrator, which is cantilevered and supported on two mounting pads provided inside via a bonding material, wherein each joint between the tuning fork type piezoelectric vibrating piece and the two mounting pads is separated from each other. The virtual straight line passing through each joint is inclined with respect to the width direction of the base in plan view.

  According to the invention, the joints between the tuning fork type piezoelectric vibrating piece and the two mounting pads are separated from each other, and the virtual straight line passing through the joints is inclined with respect to the width direction of the base in a plan view. Yes. By arranging the two joints in such a positional relationship, compared to the case where the two joints are arranged parallel to the width direction of the base, the tuning fork-type piezoelectric vibrating piece after being mounted on the mounting pad is reduced. The level can be improved. Thereby, the impact resistance performance of the piezoelectric vibrator can be improved.

  In order to achieve the above object, according to a second aspect of the present invention, each of the joints is in the region of the base in a plan view, and the other end of the base with respect to the vibration node of the vibration arm of the base Located on the side.

  According to the above invention, since each joint is located in the region avoiding the vibration node of the base vibrating arm and on the other end side of the base, the vibrating arm does not hinder the vibration of the pair of vibrating arms. The vibration leakage of the vibration can be suppressed. As a result, the tuning fork type piezoelectric vibrating piece can be stably cantilevered and the equivalent resistance value of the piezoelectric vibrator can be reduced.

  In order to achieve the above object, the invention according to claim 3 is characterized in that the base portion includes a protruding portion that protrudes from the other end surface or the side surface of the base portion, and one of the connecting portions is in a plan view. Located in the protrusion, the other joint is located in the region of the base.

  According to the above invention, since one of the joint portions is located at the protruding portion that is further away from the vibrating arm, vibration leakage of vibration of the vibrating arm can be suppressed. Since the other joint is located within the base region, the tuning fork type piezoelectric vibrating piece can be stably supported in a cantilever manner while suppressing the vibration leakage and reducing the equivalent resistance value of the piezoelectric vibrator. Can do.

  As described above, according to the present invention, it is possible to provide a piezoelectric vibrator that can support a reduction in size and thickness and can stably support a tuning-fork type piezoelectric vibrating piece.

Schematic top view of a crystal resonator before sealing according to an embodiment of the present invention. Schematic sectional view taken along line AA in FIG. Surface schematic diagram of quartz crystal resonator element according to an embodiment of the present invention The back surface schematic diagram of the crystal vibrating piece which concerns on embodiment of this invention The upper surface schematic diagram before sealing of the crystal resonator which concerns on the modification of embodiment of this invention Schematic top view of a quartz crystal resonator element according to another modification of the embodiment of the present invention Schematic diagram of the top surface of a conventional crystal unit before sealing Schematic cross-sectional view along line BB in FIG.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 4, taking a tuning fork type crystal resonator as an example of a piezoelectric resonator. The crystal resonator in the embodiment of the present invention is a surface mount type tuning fork type crystal resonator (hereinafter, abbreviated as a crystal resonator) formed of a substantially rectangular parallelepiped package. In this embodiment, the external dimensions of the crystal resonator in plan view are 1.2 mm in length and 1.0 mm in width.

  As shown in FIG. 1, the crystal resonator according to this embodiment includes a container 1 made of an insulating material as a base material, a tuning fork type crystal vibrating piece 2, and a tuning fork type crystal vibrating piece 2 bonded to the container 1. A flat lid (not shown) that hermetically seals is a main component. 1 and 2 are shown with the lid removed for convenience of explanation. 1 and 2, the description of various electrodes provided on the tuning-fork type quartz vibrating piece is omitted.

  The tuning-fork type crystal vibrating piece 2 is hermetically sealed by being accommodated in the recess (5) of the container 1 and then being joined to the opening end of the container 1 so as to cover the recess. The container 1 and the lid are joined via a sealing material (not shown). For example, a fusion method in which an alloy such as gold tin (AuSn) is melted in a heating atmosphere as a sealing material to join the lid and the container, or a glass resin is melted in a heating atmosphere as a sealing material and the lid and the container are melted And the like are used.

  The container 1 is a box-shaped body made of an insulating material based on a ceramic such as alumina, and is formed by laminating two ceramic green sheets 1a and 1b and firing them integrally (see FIG. 2). . The container 1 has a concave portion 5 having a rectangular shape in plan view inside a bank portion 6 having a frame shape in plan view.

  On one short side of the inner bottom surface 101 of the recess 5, two mounting pads 3 a and 3 b that are conductively bonded to the tuning fork type crystal vibrating piece 2 are arranged with a gap therebetween. These two mounting pads 3a and 3b are electrode pads on which the tuning-fork type crystal vibrating piece 2 is mounted via a bonding material, and are the four external connection terminals 4 provided at the four corners of the outer bottom surface 102 of the container 1. It is electrically connected to two of them. These two mounting pads 3a and 3b have different polarities.

  The mounting pads 3a and 3b have a structure in which a nickel plating layer is formed on the upper surface of the molybdenum metallized layer and a gold plating layer is further stacked thereon. These plating layers are formed by an electrolytic plating method.

  The mounting pad 3a is connected to four external connections on the outer bottom surface 102 of the container via an internal wiring (not shown) and a side conductor (castellation) provided at a corner of the first layer sheet (1a) of the container 1. It is electrically connected to one of the terminals 4. The mounting pad 3b is connected to the other one of the four external connection terminals 4 via a side conductor provided at a corner located diagonally to the corner of the first layer sheet. It is electrically connected to the external connection terminal.

  The mounting pads 3a and 3b are substantially rectangular in plan view, and the mounting pad 3a has a relatively larger area in plan view than the mounting pad 3b. This takes into account the shape of the tuning-fork type crystal vibrating piece and the position of the joint. Specifically, the long side direction (the direction indicated by the symbol “X” in FIG. 1) of the mounting pad 3a having a substantially rectangular shape in plan view is arranged so as to be substantially parallel to the short side of the concave portion 5 having a rectangular shape in plan view. Has been. The short side direction of the mounting pad 3 b having a substantially rectangular shape in plan view (the direction indicated by the symbol “X” in FIG. 1) is arranged so as to be substantially parallel to the short side of the recess 5. In the present embodiment, the two mounting pads have different areas in plan view, but the two mounting pads may have the same area in plan view.

  As shown in FIG. 1, the two mounting pads 3 a and 3 b are not positioned on the same straight line on the side facing the short side of the concave portion 5 having a rectangular shape in plan view. That is, the mounting pad 3a is arranged at a position shifted from the mounting pad 3b by a distance d in the long side direction of the container 1 (the direction indicated by the symbol “X” in FIG. 1). In the present embodiment, the dimensions of the two mounting pads 3a and 3b in the long side direction of the container are the same.

  As shown in FIG. 1, the mounting pad 3a is formed so as to be shifted in the long side direction of the container 1 with respect to the mounting pad 3b, so that the area of the mounting pad located below the tuning-fork type crystal vibrating piece 2 is enlarged. can do. As a result, even when the crystal resonator is subjected to external impact and the free end side of the tuning-fork type crystal vibrating piece 2 is bent vertically downward, the mounting pad 3a made of metal serves as a buffer material and the vibrating piece. By making contact with the base portion (details will be described later), it is possible to prevent the free end side from coming into contact with the inner bottom surface 101 of the recess.

  In the present embodiment, the mounting pads 3a and 3b are thicker than the mounting pads formed in a container having three or more ceramic green sheets stacked. This is because, in this embodiment, the container 1 has a two-layer structure in order to reduce the thickness of the crystal unit, so that a step portion is not formed on the inner bottom surface 101 and a flat surface is formed. That is, since the stepped portion does not exist in the container according to the present embodiment, the bottom surface of the tuning fork type crystal vibrating piece 2 (the surface facing the inner bottom surface 101) with the tuning fork type crystal vibrating piece 2 mounted on the inner bottom surface 101 of the recess. In order to ensure a certain gap between the inner bottom surface 101 of the recess and the mounting pad, the mounting pad is formed thick.

  In this embodiment, the molybdenum portions of the mounting pads 3a and 3b are overlaid in two steps from the point of minimum unit thickness of metallization, and the total thickness including two plating layers formed on the surface of the molybdenum portion is as follows. It is 0.02 mm (0.005 to 0.035 mm). Note that tungsten may be used instead of molybdenum.

  The molybdenum portion of the mounting pad 3a is composed of two layers of a first pad 3a1 on the inner bottom surface 101 of the recess and a second pad 3a2 stacked on the first pad 3a1. Similarly, the molybdenum portion of the mounting pad 3b is composed of two layers of a first pad 3b1 on the inner bottom surface 101 of the recess and a second pad 3b2 stacked on the first pad 3b1. The second pads 3a2 and 3b2 are formed so as to have a slightly smaller area in plan view than the first pads 3a1 and 3b1.

  In FIG. 1, a sealing material (not shown) is formed on the upper surface 100 of the bank portion 6 in a circumferential shape in plan view. This sealing material corresponds to the peripheral edge portion of the joint surface of the lid with the container.

  The lid described above is a metallic flat plate having a rectangular shape in a plan view using Kovar as a base, and a plating layer is laminated on the front and back surfaces of the lid in the order of a nickel plating layer and a gold plating layer (not shown). A gold tin alloy (AuSn) is formed in a circumferential shape on the gold plating layer at the peripheral edge of the joint surface with the lid container.

  Next, the tuning fork type crystal vibrating piece 2 will be described with reference to FIGS. For convenience of explanation, of the two main surfaces facing each other of the tuning-fork type crystal vibrating piece, the main surface on the side facing the mounting pad when mounted on the container is called the back surface, and the main surface on the opposite side of the back surface Is called the surface. 3 is a schematic diagram viewed from the front surface side of the tuning fork type crystal vibrating piece 2, and FIG. 4 is a schematic diagram viewed from the back side of the tuning fork type crystal vibrating piece 2.

  In the present embodiment, the tuning fork type crystal vibrating piece (hereinafter abbreviated as “crystal vibrating piece”) 2 is a piezoelectric vibrating piece in which various electrodes are added to a tuning fork shaped quartz vibrating piece. As shown in FIG. 3, the quartz crystal vibrating piece 2 includes a base 20, a pair of vibrating arms 21 and 22 extending in the same direction from one end 201 of the base, and a width direction of the base from the other end 202 of the base (FIG. 3). In the direction indicated by the reference sign “X”). The distal ends of the pair of vibrating arms 21 and 22 (side away from the one end side 201 of the base) are wider than the arm widths of the pair of vibrating arms 21 and 22 (dimensions in the direction perpendicular to the extending direction of the vibrating arms). Wide portions 23 and 23 are provided.

  A large number of quartz crystal vibrating pieces 2 are formed simultaneously from an artificial quartz wafer made of one Z plate. In the present embodiment, the external shape of the crystal vibrating piece 2 is formed by using a photolithography technique and wet etching. As shown in FIGS. 3 to 4, the crystal resonator element has the Y axis of the crystal axis of the crystal in the extending direction of the vibrating arm, the X axis in the width direction of the vibrating arm, and the Z axis in the thickness direction of the vibrating arm. Has been.

  The tip corners of each of the wide portions 23, 23 are processed into a chamfered shape (C surface shape). In addition, a rectangular groove G in plan view is formed on the front and back main surfaces of each of the pair of vibrating arms 21 and 22 in order to reduce an equivalent series resistance value (hereinafter referred to as a CI value). Note that the base portion 20 has a reduced width portion 203 whose width in a plan view is locally narrowed in a region between the one end side 201 and the other end side 202 thereof.

  The quartz crystal resonator element 2 includes a first excitation electrode 25 and a second excitation electrode 26 configured with different potentials, and extraction electrodes 27 and 28 drawn from the first and second excitation electrodes 25 and 26, respectively. Is formed.

  Part of the first and second excitation electrodes 25, 26 is formed so as to extend inside the grooves G of the pair of vibrating arms 21, 22. Thereby, even if the quartz crystal vibrating piece 2 is downsized, vibration leakage of the pair of vibrating arms 21 and 22 is suppressed, and a good CI value can be obtained.

  The first excitation electrode 25 is formed on the front and back main surfaces of one vibration arm 21 and the inner and outer surfaces of the other vibration arm 22 via the front and back main surfaces of the tip 221. Similarly, the second excitation electrode 26 is formed on the front and back main surfaces of the other vibrating arm 22 and the inner and outer surfaces of one vibrating arm 21 via the front and back main surfaces of the tip portion 211.

  As shown in FIG. 3, the extraction electrodes 27 and 28 are formed in a part of the base portion 20 (region excluding the reduced width portion and the protruding portion) on the surface of the quartz crystal vibrating piece. On the other hand, as shown in FIG. 4, the back surface of the quartz crystal vibrating piece is formed on the base 20 and the protrusions 24 and 24. The first excitation electrode 25 formed on the front and back main surfaces of one vibrating arm 21 is formed on the inner and outer surfaces of the other vibrating arm 22 and the front and back main surfaces of the tip 221 by the extraction electrode 27 formed on the base portion 20. The first excitation electrode 25 is connected. Similarly, the second excitation electrode 26 formed on the front and back main surfaces of the other vibrating arm 22 by the extraction electrode 28 formed on the base portion 20 causes the inner and outer surfaces of the one vibrating arm 21 and the front and back main surfaces of the tip portion 211. The second excitation electrode 26 is connected to the second excitation electrode 26.

  In the present embodiment, the electrical connection between the front and back surfaces of the quartz crystal vibrating piece is led out to the side surfaces of the one end side 201 and the outer side surfaces of the base portion 20 between the connection portions of the pair of vibrating arms 21 and 22 and the base portion 20. This is done via the electrodes 27 and 28. However, the electrical connection means between the front and back surfaces of the crystal vibrating piece is not limited to this configuration, and two through holes penetrating between the front and back main surfaces of the base 20 are drilled, and a conductive substance is applied to the inner wall surface of the through hole. You may carry out through the deposited through-hole electrode.

  As shown in FIG. 4, the extraction electrodes 27 and 28 are led out to the other end side 202 of the base portion and the tip ends of the projecting portions 24 and 24 on the back surface of the crystal vibrating piece. And each area | region of the front end side of the protrusion parts 24 and 24 is the connection electrodes 271,281. These two connection electrodes 271 and 281 have different polarities.

  The first and second excitation electrodes 25, 26, the extraction electrodes 27, 28, and the connection electrodes 271, 281 described above have a chromium (Cr) layer formed on a quartz base material, and gold ( A film structure in which an Au) layer is formed. These electrodes are formed simultaneously in a desired pattern by a photolithographic technique and metal etching after the metal film having the above-mentioned layer structure is formed on the entire main surface of the quartz wafer by a film forming means such as vacuum evaporation or sputtering. ing. The layer structure of the various electrodes is not limited to the film structure in which the gold layer is formed on the chromium layer, and may be another film structure.

  Lead electrodes 27 and 28 are respectively routed on the front and back main surfaces of the wide portions 23 and 23 of the pair of vibrating arms 21 and 22. A frequency adjusting metal film W (frequency adjusting weight) is formed on the upper surface of the extraction electrode on the surface side of the crystal vibrating piece (the side not facing the inner bottom surface of the container). By reducing the mass of the metal film W by beam irradiation such as a laser beam or ion etching, the frequency of the crystal vibrating piece 2 is finely adjusted.

  As shown in FIG. 4, bonding materials 8 and 9 (in this embodiment, plating bumps) made of conductive bumps are formed in advance on the upper surfaces of the two connection electrodes 271 and 281, respectively. Both of these two bonding materials 8 and 9 are members that contribute to conductive bonding with the mounting pads 3a and 3b of the container, whereas the bonding material 8 is a member that contributes to the main bonding, whereas the bonding material 9 Is a member that contributes to secondary joining. In the present embodiment, these two bonding materials 8 and 9 have the same size in plan view. The two bonding materials 8 and 9 may have a magnitude relationship in plan view.

  The two bonding materials 8 and 9 are substantially elliptical in plan view, and these bumps have substantially the same thickness (height). The bonding materials 8 and 9 that are substantially elliptical in plan view are formed on the connection electrodes 271 and 281 so that the long axes of the bonding materials are shifted in the long-side direction of the container 1. In the present embodiment, the degree of displacement of the bonding materials 8 and 9 in the long side direction of the container 1 is about the size of one bonding material (the minor axis having a substantially elliptical shape in plan view). Note that the amount (size) of the deviation is an example, and is not necessarily limited to about one bonding material.

  The major axis of the bonding material 8 that is substantially elliptical in plan view is substantially orthogonal to the virtual center line CL that extends in the extending direction of the vibrating arm through the center in the width direction of the base portion 20 (the center between the pair of vibrating arms). It has become a direction. The bonding material 8 is formed at a position close to the virtual center line CL. The position is a position on the other end side of the base portion with respect to the vibration node of the vibrating arm of the base portion 20. Thus, by arranging one of the two bonding materials as a fulcrum at a position close to the virtual center line or on the virtual center line, it is possible to reduce the influence of vibration of the vibrating arm on the bonded portion. As a result, a good CI value can be obtained. In addition, the formation position of the bonding material serving as a fulcrum (the bonding material 8 in the present embodiment) is not limited to the position close to the virtual center line or the virtual center line.

  On the other hand, the bonding material 9 is formed in a region near the tip of one protrusion 24. The position where the bonding material 9 is formed is also on the other end side of the base portion with respect to the vibration node of the vibrating arm of the base portion 20.

  The two bonding materials 8 and 9 formed in advance on the crystal vibrating piece 2 and the two mounting pads 3a and 3b of the container 1 are conductively bonded on a one-to-one basis. In FIG. 3, the joint portions of the tuning fork type piezoelectric vibrating piece 2 and the two mounting pads 3a and 3b are indicated as joint portions J1 and J2.

  As shown in FIG. 3, the joint portion J <b> 1 is located in the region of the base portion 20 and the joint portion J <b> 2 is located in the region of the protruding portion 24 in plan view. The virtual straight line VL1 passing through each of the joints J1 and J2 is inclined with respect to the width direction of the base (a direction indicated by “X” in FIG. 3) in plan view. In FIG. 3, for convenience of explanation, it is illustrated as a virtual straight line passing through the approximate centers (O 1, O 2) of the respective joining materials 8, 9 that are elliptical in plan view. There is no need to pass through O1, O2). That is, any virtual straight line that passes through a part of each region of each joint J1, J2 may be used.

  The quartz crystal resonator element in the present embodiment has a tuning fork shape in which protrusions that protrude toward both outer sides in the width direction of the base portion are formed. However, the quartz crystal resonator element to which the present invention is applicable is limited to the shape. It is not something. For example, the present invention can be applied even to a tuning-fork type crystal vibrating piece in which a protrusion is not formed on the base. Further, a pair of left and right symmetric support arms that extend in parallel with each other by changing the direction in the extending direction of the vibrating arm after protruding from the other end side of the base portion in the width direction of the base portion may be provided.

  In the case of the tuning-fork type crystal vibrating piece having the pair of support arms, for example, one bump is provided in the tip region of one support arm and another bump is provided in a position separated from the tip region of the other support arm. May be. The two mounting pads on the container side may be formed at positions corresponding to these two bumps, and the two mounting pads and the two bumps may be conductively bonded on a one-to-one basis. At this time, it is only necessary that the two bumps be arranged so that a virtual straight line passing through each joint portion between the crystal vibrating piece and the two mounting pads is inclined with respect to the width direction of the base portion in plan view.

  In the present embodiment, conductive bonding between the tuning fork type crystal vibrating piece and the mounting pad is performed using an FCB method (Flip Chip Bonding). Specifically, the main surface (surface) opposite to the surface on which the bonding materials 8 and 9 of the tuning-fork type crystal vibrating piece are formed is adsorbed and held by a horn for applying ultrasonic waves. The horn is provided with a suction hole for sucking and holding the tuning fork type crystal vibrating piece. The held tuning-fork type crystal vibrating piece is positioned and mounted on the upper surface of the mounting pad using image recognition means. Then, an ultrasonic wave is applied from a horn while applying temperature and pressure. Thereby, the bump and the mounting pad are ultrasonically bonded. In the present embodiment, as described above, the extraction electrodes 27 and 28 are formed on the surface of the crystal vibrating piece in the region excluding the reduced width portion and the protruding portion of the base portion 20 (see FIG. 3). That is, the extraction electrode is not formed in a region corresponding to the joints J1 and J2 on the surface of the crystal vibrating piece. As a result, the metal (extraction electrode) on the surface of the quartz crystal vibrating piece to be adsorbed and held is damaged by rubbing against the horn during ultrasonic bonding, or the metal peels off and adheres to and falls out of the horn. It is possible to avoid problems caused by this.

  According to the above configuration, the joints J1 and J2 between the crystal vibrating piece 2 and the two mounting pads 3a and 3b are separated from each other, and the virtual straight line VL1 passing through the joints J1 and J2 is the width of the base 20 in plan view. Inclined with respect to direction. That is, the joint portion J1 is located closer to the one end side 201 of the base portion than the joint portion J2. By arranging the two joints J1 and J2 in this positional relationship, the crystal vibrating piece is supported more stably than when the two joints are arranged in parallel with the width direction of the base. be able to. As a result, it is possible to improve the levelness after the crystal vibrating piece is mounted on the mounting pad.

  Further, since the joint portion J1 is located closer to the one end side 201 of the base portion with respect to the joint portion J2, the fulcrum shifts to the free end side, so that the free end of the crystal vibrating piece when subjected to an external impact The amount of displacement on the side can be reduced. Thereby, the contact between the free end of the crystal resonator element and the inner bottom surface of the recess can be prevented, and the impact resistance performance of the crystal resonator can be improved.

  Further, according to the above configuration, each joint portion J1, J2 is located in a region avoiding the vibration node of the vibrating arm of the base portion 20 and on the other end side of the base portion. The vibration leakage of the vibration of the vibrating arm can be suppressed without inhibiting the vibration. As a result, the tuning fork type crystal vibrating piece can be cantilevered stably, and the CI value of the crystal resonator can be reduced.

  Furthermore, according to the above configuration, since one of the two joints (J2) is located at the protrusion 24 that is further away from the vibrating arm, vibration leakage of vibration of the vibrating arm can be suppressed. Since the other joint (J1) is located in the base region, the tuning fork type quartz vibrating piece is stably supported in a cantilever manner while suppressing vibration leakage and reducing the CI value of the quartz resonator. be able to.

  In the case of a configuration in which two joint portions are arranged in parallel with the extending direction of the vibrating arm (a configuration in which a virtual straight line passing through the two joint portions is orthogonal to the width direction of the base portion in plan view) The tilt in the width direction of the base portion after mounting the quartz crystal vibrating piece is likely to occur. However, with the configuration shown in FIGS. 3 to 4, the quartz crystal vibrating piece can be stably supported and the quartz vibrating piece can be mounted. Inclination in the width direction of the base portion can also be suppressed.

-Variation of the embodiment of the present invention-
Next, a modification of the embodiment of the present invention is shown in FIG. In addition, about the structure same as embodiment of this invention mentioned above, the same number is attached | subjected and the description is omitted. Hereinafter, the difference from the above-described embodiment of the present invention will be mainly described.

  The two mounting pads 3b and 3c shown in FIG. 5 are different from the mounting pads in FIG. 1 on the inner bottom surface 120 of the recess 12 while being aligned in the short side direction of the container 10 without being displaced in the long side direction of the container 10. Has been placed. That is, the peripheral edges of the two mounting pads 3b and 3c on the side facing the short side of the concave portion 12 having a rectangular shape in plan view are positioned on the same straight line. In the modification of the embodiment of the present invention, each molybdenum portion of the two mounting pads has a two-stage configuration.

  In a modification of the embodiment of the present invention, the shape of the tuning fork type crystal vibrating piece 11 is different from the above-described embodiment of the present invention. Specifically, a protruding portion 111 protruding only on one side in the width direction of the base portion 110 is formed. As described above, each configuration of the mounting pad and the crystal vibrating piece is different from that of the embodiment of the present invention described above, but passes through the joints J3 and J4 between the tuning fork type crystal vibrating piece 11 and the two mounting pads 3b and 3c. The virtual straight line VL2 is provided with two bumps so as to be inclined with respect to the width direction of the base portion in plan view.

  According to the configuration shown in FIG. 5, the tuning fork type piezoelectric vibrating piece can be stably cantilevered without relatively shifting the positions of the two mounting pads.

-Other Modifications of Embodiments of the Present Invention-
As another modification of the embodiment of the present invention, the configuration shown in FIG. 6 may be used. In FIG. 6, the long axis of the bonding material 80 having an elliptical shape in plan view is arranged closer to one end side of the base so as to be parallel to the extending direction of the vibrating arm. In FIG. 6, for simplification, the container including the mounting pad is not shown, and only the outer shape of the tuning-fork type crystal vibrating piece and the bonding material (bump) are shown.

  Also in FIG. 6, the bonding material 80 is formed at a position close to the virtual center line CL. The position is a position on the other end side of the base with respect to the vibration node of the vibration arm of the base. The bonding material 9 is the same as the formation position in the above-described embodiment of the present invention, and is on the other end side of the base with respect to the vibration node of the vibration arm of the base. Also in another modification of the present embodiment, the two bonding materials 80 and 9 are configured such that the virtual straight line VL3 passing through the bonding portions J5 and J6 between the tuning fork type crystal vibrating piece 11 and the two mounting pads (not shown) is flat. It arrange | positions so that it may incline with respect to the width direction of a base part in view.

  According to the configuration shown in FIG. 6, since the major axes of the two bumps having an elliptical shape in plan view are orthogonal to each other, the level of the tuning fork type crystal vibrating piece after being mounted on the mounting pad is further improved. Can be improved. Compared to the configuration in which the two major-axis directions of the two elliptical bumps in plan view are arranged identically by arranging the two bumps in the elliptical shape in plan view so that their major axis directions are different from each other. This is because more stable support is possible.

  In the embodiment of the present invention, the shape of the bonding material made of conductive bumps in plan view is an ellipse, but the present invention can be applied to other shapes such as a circle and a rectangle. The bumps are not limited to plating bumps, and may be stud bumps. These bumps may be formed not only on the piezoelectric vibration piece side in advance but also on the mounting pad side in advance.

  In the embodiment of the present invention, the bonding material consisting of two points is exemplified, but for example, the insulating material having the same thickness (height) as the bonding materials 8 and 9 is formed on the connection electrode 281 of the protruding portion 24 protruding to the right side in FIG. Bumps (dummy bumps) may be formed. In the case of this configuration, in addition to the two mounting pads, a pad having a height equivalent to the mounting pad (a dummy pad that is not electrically connected to the piezoelectric vibrating piece) is provided on the container side at three points. Since the tuning fork type piezoelectric vibrating piece can be supported, the tuning fork type piezoelectric vibrating piece can be supported more stably.

  In the above-described embodiment of the present invention, the conductive bump is exemplified as the bonding material. However, the bonding material is not limited to the bump, and may be, for example, a conductive adhesive. That is, the bonding material only needs to be a conductive material.

  In the embodiment of the present invention, a tuning fork type crystal resonator is taken as an example, but the present invention can also be applied to a piezoelectric oscillator in which an integrated circuit element in which an oscillation circuit or the like is integrated and a tuning fork type piezoelectric vibrating piece are combined. .

  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.

  The present invention can be applied to mass production of piezoelectric vibrators using tuning fork type piezoelectric vibrating pieces.

DESCRIPTION OF SYMBOLS 1 Container 2 Tuning fork type crystal vibrating piece 3a, 3b, 3c Mounting pad 8, 9, 80 Bonding material J1-J6 Bonding part VL1, VL2, VL3 Virtual straight line 24, 111 Protrusion part

Claims (3)

The other end of the base of the 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 is connected to two mounting pads provided inside the container via a bonding material. A cantilever-supported piezoelectric vibrator,
The joint portions of the tuning fork type piezoelectric vibrating piece and the two mounting pads are separated from each other,
An imaginary straight line passing through each joint is inclined with respect to the width direction of the base in plan view.   The said each junction part is located in the area | region of the said base part in planar view, Comprising: It is located in the other end side of a base part with respect to the vibration node of the vibration arm of a base part. Piezoelectric vibrator.   The base includes a protrusion that protrudes from the other end surface or side surface of the base, and in a plan view, one of the joints is located at the protrusion, and the other joint is within the region of the base. The piezoelectric vibrator according to claim 1, wherein the piezoelectric vibrator is located at a position.

Images