JP2009296115A - Tuning fork type piezoelectric vibration piece, tuning fork type piezoelectric vibration device, and manufacturing method of tuning fork piezoelectric vibration piece - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tuning fork type piezoelectric vibration piece which can be electromechanically bonded through a bump to a base stably, a tuning fork type piezoelectric vibration device, and a manufacturing method of the tuning fork piezoelectric vibration piece. <P>SOLUTION: A tuning fork type crystal vibration piece 2 comprises a first leg 21 and a second leg 22 which are vibration parts, and a base 23 where the first leg 21 and the second leg 22 are protrusively provided. The base 23 has a bonding part 27 bonded to the outside, and a pair of plating bump groups 3 are formed on the bonding part 27. The pair of plating bump groups 3 are configured by forming a plurality of plating bump points 31, and the total area of one plating bump group 3 is set to 4×10<SP>-3</SP>to 6×10<SP>-3</SP>mm<SP>2</SP>. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a tuning fork type piezoelectric vibrating piece, a tuning fork type piezoelectric vibrating device, and a method for manufacturing a tuning fork type piezoelectric vibrating piece.

  As one of the piezoelectric vibrating devices, there is a tuning fork type crystal resonator using a tuning fork type crystal vibrating piece including a base and a vibrating portion having two legs protruding from the base (see, for example, Patent Document 1). ).

In the tuning fork type crystal resonator as described above, the main body case is composed of a base and a lid. Inside the main body case, a tuning fork type crystal vibration is formed by conductive bumps (specifically, stud bumps) on the base. The pieces are joined electromechanically, and the joined tuning fork type crystal vibrating piece is hermetically sealed inside the main body casing.
JP 2008-79014 A

  By the way, in the tuning fork type crystal resonator described in Patent Document 1 described above, stud bumps are formed on the base, and the tuning fork type piezoelectric vibrating piece is joined to the base via the formed stud bumps.

  Therefore, the stud bump formation position on the base is set based on the size of the tuning fork type crystal vibrating piece to be mounted and the position of the extraction electrode. However, the tuning fork type crystal resonator and the tuning fork type crystal vibrating piece are miniaturized. Along with this, the influence of misalignment during the firing of the base becomes obvious. For this reason, the contact point (contact position) of the tuning fork type crystal vibrating piece to the stud bump is likely to shift. In addition, the formation of the stud bumps at the desired position of the base becomes difficult in proportion to the miniaturization of the tuning fork type crystal vibrating piece. With the current technology, the accuracy of the formation of the stud bumps at the desired position of the base is low. It tends to fall.

  As a result, the tuning fork type crystal vibrating piece is bonded onto the base with the stud bump protruding from the desired position, or the tuning fork type crystal vibrating piece is bonded onto the base with the stud bump not protruding from the desired position. However, there is a problem that the extraction electrode of the tuning fork type crystal vibrating piece and the stud bump are not electrically connected.

  Accordingly, in order to solve the above-described problems, the present invention provides a tuning fork type piezoelectric vibrating piece, a tuning fork type piezoelectric vibrating device, and a tuning fork that can stably join a tuning fork type piezoelectric vibrating piece to a base via a bump. An object of the present invention is to provide a method for manufacturing a piezoelectric piezoelectric resonator element.

In order to achieve the above object, a tuning-fork type piezoelectric vibrating piece according to the present invention is composed of a plurality of legs that are vibrating parts, and a base part that protrudes from the legs, and the base part has an external portion. A bonding portion to be bonded is provided, and a pair of plating bump groups is formed in the bonding portion, and the pair of plating bump groups is configured by forming a plurality of plating bumps, and each of the plating bump groups The total area is set to 4 × 10 ^{−3 to} 6 × 10 ⁻³ mm ² .

According to the present invention, the plurality of leg portions and the base portion are configured, the joint portion is provided on the base portion, a pair of plating bump groups is formed on the joint portion, and the pair of plating bumps Each group is formed by forming a plurality of plated bumps, and the total area of each plated bump group is set to 4 × 10 ^{−3 to} 6 × 10 ⁻³ mm ^2. It is possible to electromechanically join the tuning fork type piezoelectric vibrating piece on the top via the pair of plating bump groups.

  Specifically, according to the present invention, even if the mounting position of the tuning fork type piezoelectric vibrating piece on the outside (base) is deviated from a desired position, the pair of plated bump groups on the tuning fork type piezoelectric vibrating piece. Since the tuning fork type piezoelectric vibrating piece is bonded to the base in a state in which the tuning fork is formed, the plating fork type piezoelectric piece to the stable base is always formed by forming the plated bump at a desired position (extraction electrode) of the tuning fork type piezoelectric vibrating piece. It becomes possible to mount the resonator element.

Further, since the total area of each of the pair of plating bump groups is 4 × 10 ^{−3 to} 6 × 10 ⁻³ mm ² , the transfer rate of the pair of plating bump groups to the base is good, and the tuning fork to the base is concerned. It is possible to stably perform the bonding of the type piezoelectric vibrating piece. The transfer rate here means that when the bonded tuning fork type piezoelectric vibrating piece and the base are peeled off, bumps formed on the tuning fork type piezoelectric vibrating piece before bonding remain on the base side (transfer). It means rate. Specifically, each of the pair of plating bump groups is formed by forming a plurality of plating bumps, and the total area of each of the pair of plating bump groups is 4 × 10 ^{−3 to} 6 × 10 ⁻³ mm ^2. Therefore, it is possible to increase the transfer rate to the base of each one-point plated bump, and to increase the transfer rate to the base of the plating bump group in which each one-point plated bump consists of a plurality of points. .

  The plurality of plated bumps are formed on the tuning fork type piezoelectric vibrating piece, that is, the multipoint plated bump is formed on the tuning fork type piezoelectric vibrating piece. For example, when a defect such as peeling of one plated bump occurs. Even if it exists, it becomes possible to hold | maintain the stable joint strength with another plating bump.

  The said structure WHEREIN: The shape of the said plating bump may be ellipsoidal planar view.

  In this case, since the plated bump has an elliptical shape in plan view, the plated bump has a long diameter. Therefore, for example, when using the FCB method (Flip Chip Bonding) when mounting the tuning-fork type piezoelectric vibrating piece on the base, the vibration direction when ultrasonically bonding the tuning-fork type piezoelectric vibrating piece to the base by the FCB method is set. By making it correspond to the long diameter of the plating bump, it becomes possible to increase the area (grounding area) of the bonding region with respect to the vibration direction of the plating bump, and it is possible to further improve the bonding property.

  In order to achieve the above object, a tuning fork type piezoelectric vibrating device according to the present invention includes a tuning fork type piezoelectric vibrating piece according to the present invention, a base on which the tuning fork type piezoelectric vibrating piece is mounted, and a base mounted on the base. And a lid for hermetically sealing the tuning fork type piezoelectric vibrating piece.

  According to the present invention, since the tuning fork type piezoelectric vibrating piece according to the present invention, the base, and the lid are provided, the tuning fork type piezoelectric vibrating piece is stably placed on the base with the pair of plating bump groups. It is possible to perform electromechanical joining.

  Specifically, according to the present invention, even when the mounting position of the tuning fork type piezoelectric vibrating piece on the base is deviated from a desired position, the plating bump is formed on the tuning fork type piezoelectric vibrating piece. Since the tuning-fork type piezoelectric vibrating piece is joined to the base, the tuning-fork type piezoelectric to the base is stably formed by always forming the pair of plated bump groups at a desired position (extraction electrode) of the tuning-fork type piezoelectric vibrating piece. It becomes possible to mount the resonator element.

Further, since the total area of each of the pair of plating bump groups is 4 × 10 ^{−3 to} 6 × 10 ⁻³ mm ² , the transfer rate of the pair of plating bump groups to the base is good, and The tuning fork type piezoelectric vibrating piece can be stably joined.

  Since the multi-point plated bumps are formed at the joint, that is, the multi-point plated bump is formed at the joint, for example, even when a problem such as peeling of one plated bump occurs, It is possible to maintain a stable bonding strength with the plated bump.

  In the above configuration, at least two points of the plurality of plating bumps may be coupled in the plating bump group.

  In this case, when the tuning fork type piezoelectric vibrating piece on which the plurality of plated bumps are formed is joined to the base, at least two points of the plurality of plated bumps are coupled to each other. Bonding strength to the base can be increased.

  In the above configuration, the tuning fork type piezoelectric vibrating piece may be ultrasonically bonded to the base by the FCB method via the pair of plating bump groups.

  In this case, in the ultrasonic bonding by the FCB method, the tuning fork type piezoelectric vibrating piece is pressed and swung to the base, and the tuning fork type piezoelectric vibrating piece is thermally melt bonded to the base. This is a suitable joining method.

Further, in order to achieve the above object, a tuning fork type piezoelectric vibrating piece according to the present invention includes a tuning fork type piezoelectric vibrating piece including a plurality of leg portions which are vibrating portions, and projecting these leg portions. A pair of plating bumps, each of which is formed by forming a plurality of plating bumps at each of the joints. And the total area of each of the plating bump groups is set to 4 × 10 ^{−3 to} 6 × 10 ⁻³ mm ² , respectively.

According to the present invention, there is a step of forming a pair of plating bump groups each formed by forming a plurality of plating bumps at the joint, and the total area of the plating bump groups is 4 × 10 4 each. ^{Since -3 to} 6 × 10 ^-3 mm ² is set, the tuning fork type piezoelectric vibrating piece can be stably electromechanically bonded to the outside (base) via the pair of plated bump groups. Become.

  Specifically, according to the present invention, even if the mounting position of the tuning fork type piezoelectric vibrating piece on the outside (base) is deviated from a desired position, the pair of plated bump groups on the tuning fork type piezoelectric vibrating piece. Since the tuning fork type piezoelectric vibrating piece is bonded to the base in a state in which the tuning fork is formed, the plating fork type piezoelectric piece to the stable base is always formed by forming the plated bump at a desired position (extraction electrode) of the tuning fork type piezoelectric vibrating piece. It becomes possible to mount the resonator element.

Further, since the total area of each of the pair of plating bump groups is 4 × 10 ^{−3 to} 6 × 10 ⁻³ mm ² , the transfer rate of the pair of plating bump groups to the base is good, and the tuning fork to the base is concerned. It is possible to stably perform the bonding of the type piezoelectric vibrating piece. Specifically, each of the pair of plating bump groups is formed by forming a plurality of plating bumps, and the total area of each of the pair of plating bump groups is 4 × 10 ^{−3 to} 6 × 10 ⁻³ mm ^2. Therefore, it is possible to increase the transfer rate to the base of each one-point plated bump, and to increase the transfer rate to the base of the plating bump group in which each one-point plated bump consists of a plurality of points. .

  Since the multi-point plated bumps are formed at the joint, that is, the multi-point plated bump is formed at the joint, for example, even when a problem such as peeling of one plated bump occurs, It is possible to maintain a stable bonding strength with the plated bump.

  In the method, after the plurality of plated bumps are formed at the joint, the multiple plated bumps may be annealed.

  In this case, since the plurality of plating bumps are annealed after the plurality of plating bumps are formed on the joint, the plurality of plating bumps are annealed, and the plurality of plating bumps are applied to the joint. The stress (residual stress) generated when forming the point plating bump is eliminated.

  By the way, in the prior art, the tuning fork type piezoelectric vibrating piece is ultrasonically bonded to the base by the FCB method using the stud bump. In the ultrasonic bonding by the FCB method, the tuning fork is mounted when the tuning fork type piezoelectric vibrating piece is mounted on the base. In some cases, the piezoelectric resonator element is displaced from the predetermined position on the base. In this case, since the position of the tuning fork type piezoelectric vibrating piece with respect to the stud bump occurs, mounting failure of the tuning fork type piezoelectric vibrating piece to the base occurs, or the tuning fork type piezoelectric vibrating piece is joined to the base in a shifted state. It is difficult to obtain a stable bonding strength.

  On the other hand, according to the present invention, when the tuning fork type piezoelectric vibrating piece is mounted on the base, even if the tuning fork type piezoelectric vibrating piece is arranged on the base out of a predetermined position, Since the tuning fork type piezoelectric vibrating piece is bonded to the base with the pair of plated bump groups formed on the tuning fork type piezoelectric vibrating piece, a plating bump is always formed at a desired position (extraction electrode) of the tuning fork type piezoelectric vibrating piece. Thus, the tuning fork type piezoelectric vibrating piece can be bonded to the base with a stable bonding strength.

  In addition, when stud bumps are used, stud bumps need to be ejected and formed on the base, and displacement may occur when ejecting and forming stud bumps on the base. In particular, as the size of the main body casing is reduced, the frequency of positional deviation increases and the amount of deviation increases.

  On the other hand, according to the present invention, since the tuning fork type piezoelectric vibrating piece is joined to the base in a state where the pair of plated bump groups are formed on the tuning fork type piezoelectric vibrating piece, it is possible to prevent the occurrence of displacement. Is possible.

  In addition, when stud bumps are used, the stud bumps are crushed when the tuning fork type piezoelectric vibrating piece is joined to the base via the stud bumps. Sometimes That is, a stress is applied to the tuning fork type piezoelectric vibrating piece when the stud bump is crushed, and this stress remains as a residual stress. In some cases, the tuning fork type piezoelectric vibrating piece may crack.

  On the other hand, according to the present invention, since the tuning fork type piezoelectric vibrating piece is joined to the base in a state where the pair of plated bump groups are formed on the tuning fork type piezoelectric vibrating piece, the tuning fork type to the base is provided. Stress is unlikely to occur in the pair of plated bump groups when the piezoelectric vibrating piece is joined.

  In addition, when the stud bump is used, the stud bump is crushed when the tuning fork type piezoelectric vibrating piece is joined to the base via the stud bump, and the joining area of the stud bump to the tuning fork type piezoelectric vibrating piece is widened. . Therefore, a short between the electrodes such as a pair of excitation electrodes occurs due to the crushed stud bump.

  On the other hand, according to the present invention, since the pair of plated bumps is formed on the tuning fork type piezoelectric vibrating piece, the tuning fork type piezoelectric vibrating piece is joined to the base like a stub bump. The pair of plating bumps is not crushed, and this does not cause a short circuit between the pair of excitation electrodes.

  According to the tuning fork type piezoelectric vibrating piece, the tuning fork type piezoelectric vibrating piece, and the tuning fork type piezoelectric vibrating piece manufacturing method according to the present invention, the tuning fork type piezoelectric vibrating piece is stably electromechanically bonded to the base via the bump. it can.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiment, a case where the present invention is applied to a tuning fork type crystal resonator as a tuning fork type piezoelectric vibration device is shown. However, this is a preferred example, and the present invention is not limited to a tuning fork type crystal resonator, and may be a tuning fork type piezoelectric vibration device equipped with a tuning fork type piezoelectric vibrating piece using a piezoelectric material.

  In the tuning fork type crystal resonator 1 (hereinafter referred to as a crystal resonator) according to the present embodiment, as shown in FIG. 1, a tuning fork type crystal resonator element 2 (a piezoelectric resonator element referred to in the present invention) formed by photolithography is used. Yes, hereinafter referred to as a quartz crystal resonator element), a base 11 on which the crystal resonator element 2 is mounted (held), and a lid for hermetically sealing the crystal resonator element 2 mounted on (maintained on) the base 11 (illustrated). Are omitted).

  In this crystal unit 1, a main body housing 12 is configured by joining a base 11 and a lid. The base 11 and the lid are joined via a joining material (not shown), and the interior space 13 of the main body housing 12 is formed by this joining. The crystal vibrating piece 2 is held and joined to the base 11 in the internal space 13 of the main body casing 12 via a pair of plated bump groups 3 (see below) made of gold. The internal space 13 is hermetically sealed. At this time, the crystal vibrating piece 2 is ultrasonically bonded to the base 11 by the FCB method using a pair of plated bump groups 3 and is electromechanically bonded.

  Next, each configuration of the crystal resonator 1 will be described.

  As shown in FIG. 1, the base 11 is formed in a box-like body composed of a bottom portion 14 and a bank portion 15 extending upward from the bottom portion 14. The base 11 is formed by integrally firing a rectangular parallelepiped of a ceramic material on a single rectangular plate in a plan view made of a ceramic material. Moreover, the bank part 15 is shape | molded along the planar view outer periphery of the bottom part 14 shown in FIG. On the upper surface of the bank portion 15, a metallized layer 18 for bonding to the lid is provided. The metallized layer 18 has a configuration in which, for example, nickel and gold are plated in this order on a tungsten layer or a molybdenum layer. Further, as shown in FIG. 1, a step portion 16 is formed on the side wall in the internal space 13 of the base 11 which is laminated and fired integrally in a concave shape, and a pair of electrodes is formed on the step portion 16. Pads 17 are formed, and the crystal vibrating piece 2 is held and provided on the electrode pads 17. These electrode pads 17 are electrically connected to terminal electrodes (not shown) formed on the back surface of the base 11 through corresponding routing electrodes (not shown), and these terminal electrodes are connected to external parts or external parts. Connected to the external electrode of the device. The electrode pad 17, the lead electrode, and the terminal electrode are formed by printing integrally with the base 11 after printing a metallized material such as tungsten or molybdenum. A part of the electrode pad 17, the routing electrode, and the terminal electrode is formed by forming nickel plating on the metallized upper portion and forming gold plating on the upper portion.

  The lid is made of a metal material and formed into a single plate having a rectangular shape in plan view. A part of the bonding material is formed on the lower surface of the lid. The lid is joined to the base 11 via a joining material by a technique such as seam welding, beam welding, heat fusion joining, and the like, and the main body housing 12 of the crystal unit 1 is configured by the lid and the base 11.

  Next, each configuration of the crystal vibrating piece 2 disposed in the internal space 13 will be described.

  The quartz crystal vibrating piece 2 is a quartz crystal Z plate formed by wet etching from a quartz base plate (not shown) that is a quartz crystal piece of anisotropic material. Therefore, this crystal vibrating piece 2 is suitable for mass production.

  The crystal vibrating piece 2 has an outer shape composed of two first leg portions 21 and second leg portions 22 that are vibration portions, and a base portion 23, and includes two first leg portions 21 and second leg portions. The part 22 is provided so as to protrude from the one end face 28 of the base part 23.

  The tip portions 211 and 221 of the first leg portion 21 and the second leg portion 22 are formed wider in the direction perpendicular to the protruding direction than the other portions of the first leg portion 21 and the second leg portion 22. Has been. By forming the tip portions 211 and 221 wide in this way, the tip portions 211 and 221 (tip regions) can be used effectively, which is useful for downsizing the crystal vibrating piece 2 and reducing the frequency. Is also useful.

  In addition, the two main surfaces 24 (the front-side main surface and the back-side main surface) of the two first leg portions 21 and the second leg portion 22 have series resonance resistance values that deteriorate due to the miniaturization of the crystal resonator element 2 (this embodiment). Then, in order to improve the CI value (hereinafter the same), the groove portions 25 are respectively formed. Further, the side surface 26 of the outer shape of the quartz crystal vibrating piece 2 is formed so as to be inclined with respect to both the main surfaces 24. This is because the etching speed in the crystal direction (X, Y direction) of the substrate material is different when the quartz crystal resonator element 2 is formed by wet etching.

  In the quartz crystal resonator element 2, two first excitation electrodes 41 and second excitation electrodes 42 configured with different potentials, and the first excitation electrode 41 and the second excitation electrode 42 are electrically connected to the electrode pad 17. For this purpose, an extraction electrode 43 extracted from the first excitation electrode 41 and the second excitation electrode 42 is provided. The extraction electrode 43 in this embodiment refers to an electrode pattern extracted from the two first excitation electrodes 41 and the second excitation electrodes 42.

  Further, part of the two first excitation electrodes 41 and the second excitation electrode 42 is formed inside the groove 25. For this reason, even if the crystal vibrating piece 2 is downsized, vibration loss of the first leg portion 21 and the second leg portion 22 is suppressed, and the CI value can be kept low.

  The first excitation electrode 41 is formed on both main surfaces 24 (the front-side main surface and the back-side main surface) of the first leg portion 21 and on both side surfaces 26 of the second leg portion 22. Similarly, the second excitation electrode 42 is formed on both main surfaces 24 (front side main surface and back side main surface) of the second leg portion 22 and both side surfaces 26 of the first leg portion 21.

  The first excitation electrode 41, the second excitation electrode 42, and the extraction electrode 43 of the crystal vibrating piece 2 described above are formed with a chromium layer on the first leg portion 21 and the second leg portion 22 by metal vapor deposition. It is a thin film formed by forming a metal thereon. The thin film is formed on the entire surface of the substrate by a technique such as vacuum deposition, and then formed into a desired shape by metal etching by photolithography. The first excitation electrode 41, the second excitation electrode 42, and the extraction electrode 43 are formed in the order of chromium and gold. For example, the order of chromium and silver, the order of chromium, gold, and chromium; , Silver, chromium, etc.

  Further, a metal film 44 as a frequency adjusting weight is formed at the tip of each first leg portion 21 and second leg portion 22. Specifically, the metal film 44, the first excitation electrode 41, and the extraction electrode 43 are integrally formed, and the metal film 44, the second excitation electrode 42, and the extraction electrode 43 are integrally formed.

  As shown in FIG. 1, the base portion 23 of the quartz crystal vibrating piece 2 is formed wider than the vibrating portions (the first leg portion 21 and the second leg portion 22).

  The base portion 23 is provided with a joint portion 27 for electromechanically joining the extraction electrode 43 to an external electrode (external in the present invention, which is the electrode pad 17 of the base 11 in this embodiment). . Specifically, the joint portion 27 is formed so as to protrude from the other end surface 29 facing the one end surface 28 of the base portion 23 from which the two first leg portions 21 and the second leg portion 22 protrude.

  The joint portion 27 protrudes from the other end surface 29 of the base portion 23, and is divided into two T-shapes extending from the other end surface 29 of the base portion 23 along the both side surfaces 26. 272 is directed in the same direction as the two first leg portions 21 and the second leg portions 22 that are formed so as to protrude from the one end face 28 of the base portion 23. That is, the two front end portions 271 and 272 of the joint portion 27 are formed adjacent to each other with a gap on both side surfaces 26 in the width direction of the base portion 23 as shown in FIG. Then, the first excitation electrode 41 formed on the first leg portion 21 and the second leg portion 22 and the extraction electrode 43 extracted from the second excitation electrode 42 are formed up to the two tip portions 271 and 272 of the joint portion 27. Has been.

Further, a pair of plating bump groups 3 is formed on one main surface 24 (the back main surface in FIG. 1) of the two tip portions 271 and 272 of the joint portion 27, respectively. Each of the pair of plating bump groups 3 includes a plurality of (in this embodiment, nine points) circular plating bumps 31 having a circular shape in plan view and formed in a matrix of 3 rows and 3 columns at equal intervals. The total area of each of the pair of plating bump groups 3 is set within a range of 4 × 10 ^{−3 to} 6 × 10 ⁻³ mm ² , and in this embodiment, it is 4.78 × 10 ⁻³ mm ² . ing. The pair of plating bump groups 3 used in the present embodiment is made of gold, and the pair of plating bump groups 3 is applied to the two tip portions 271 and 272 of the joint portion 27 of the crystal vibrating piece 2 by a technique such as electrolytic plating. After plating, a pair of plated bumps 3 is formed by metal etching by photolithography to form a desired shape (circular in plan view in this embodiment) and annealed. Specifically, for the pair of plating bump groups 3, nine plating bumps 31 are formed on the tip portions 271 and 272 of the joint portion 27 (step of forming the pair of plating bump groups 3), and then nine points are formed. The plated bump 31 is annealed.

  The extraction electrode 43 of the quartz crystal resonator element 2 having the above-described configuration and the electrode pad 17 of the base 11 are ultrasonically bonded by the FCB method through the pair of plating bump groups 3, and the extraction electrode 43 and the electrode pad 17 are connected. And the crystal vibrating piece 2 are mounted on the base 11 by this joining. At this time, in the pair of plating bump groups 3, it is preferable that at least two points of nine plating bumps 31 are coupled (not shown). The lid is bonded to the base 11 on which the crystal vibrating piece 2 is mounted via a bonding material, and the crystal vibrating piece 2 is hermetically sealed in the internal space 13.

In addition, although the extraction electrode 43 of the crystal vibrating piece 2 and the electrode pad 17 of the base 11 are ultrasonically bonded by the FCB method through the pair of plating bump groups 3, the direction of vibration during ultrasonic bonding is used. In addition, the area of the pair of plating bump groups 3 (specifically, nine plating bumps 31 in this embodiment) formed on the crystal vibrating piece 2 is increased. That is, the total area of one pair of plating bump groups 3 is increased from 4.78 × 10 ⁻³ mm ² when formed on the crystal vibrating piece 2 (in this embodiment, the total area is increased by about 10%). .

By the way, in the pair of plating bump groups 3 according to the present embodiment, as shown in FIG. 1, nine plating bumps 31 having a circular shape in plan view are formed on one main surface 24 of each of the tip portions 271 and 272 of the joint portion 27. Although formed in a matrix of 3 rows and 3 columns at equal intervals, the present invention is not limited to this, and a plurality of plating bumps are formed as one plating bump group, and the total area is 4 × 10 ^−3. Any material may be used as long as it falls within a range of ˜6 × 10 ⁻³ mm ² . Specifically, as another example of the present embodiment, a pair of plating bump groups 3 shown in FIGS.

In the form of the pair of plating bump groups 3 shown in FIGS. 2 and 3 (second example and third example), the three plating bumps 31 are oblique to the one main surface 24 of each of the tip portions 271 and 272 of the joint portion 27. Arranged side by side. The total area of the pair of plating bump groups 3 shown in FIGS. 2 and 3 is 4.56 μm ² .

In the form of the pair of plated bump groups 3 shown in FIG. 4 (fourth example), five plated bumps 31 are arranged on one side main surface 24 of each of the tip portions 271 and 272 of the joint portion 27. The total area of the pair of plating bump groups 3 shown in FIG. 4 is 5.09 μm ² .

In the form shown in FIG. 5 (fifth example), two plating bumps 31 are arranged in an oblique direction on the entire surface of one main surface 24 of each of the tip portions 271 and 272 of the joint portion 27. Note that the total area of the pair of plating bump groups 3 shown in FIG. 5 is 4.58 μm ² .

In the form of the pair of plated bump groups 3 (sixth example) shown in FIG. 6, each of the principal surfaces of the tip portions 271 and 272 of the joint portion 27 is composed of four plated bumps 31 with two plated bumps 31 as a pair. 24 are arranged side by side so as to intersect diagonally. The total area of the pair of plating bump groups 3 shown in FIG. 6 is 5.21 μm ² .

The CI value, the DLD characteristic, and the strength were measured for the above-described embodiment shown in FIG. 1 and the second to sixth examples shown in FIGS. 2 to 6, and the results are shown in FIGS. The data shown in FIGS. 7 to 9 is data obtained by performing measurement five times for each characteristic. Further, as a comparative example, a form (comparative example) in which one plated bump (area: 4.54 μm ² ) in a plan view is arranged on one main surface 24 of the tip portions 271 and 272 of the joint portion 27 is shown.

  First, regarding the CI values of the present example, the second to sixth examples, and the comparative example, as shown in FIG. 7, the CI values of the present example and the second to sixth examples are decreased with respect to the comparative example. I understand.

  Next, regarding the DLD characteristics of the present example, the second to sixth examples, and the comparative example, as shown in FIG. 8, the present example, the second to sixth examples, and the comparative example generally have the same amount of frequency variation. I know that there is.

  Next, regarding the strengths of the present example, the second to sixth examples, and the comparative example, as shown in FIG. 9, it is understood that the present example, the second to fifth examples, and the comparative example have substantially the same strength. .

  According to the crystal vibrating piece 2 and the crystal resonator 1 on which the crystal vibrating piece 2 according to the present embodiment is mounted, the crystal vibrating piece 2 is stably placed on the base 11 via the pair of plating bump groups 3. Can be joined.

  Specifically, according to the present embodiment, even when the mounting position of the crystal vibrating piece 2 on the outside (base 11) is deviated from the desired position, the pair of plated bump groups 3 is formed on the crystal vibrating piece 2. In this state, since the crystal vibrating piece 2 is bonded to the base 11, a pair of plated bump groups 3 are always formed at a desired position (extraction electrode 43) of the crystal vibrating piece 2 so that the crystal vibrating piece to the stable base 11 is obtained. 2 can be mounted.

Further, since the total area of each of the pair of plating bump groups 3 is 4 × 10 ^{−3 to} 6 × 10 ⁻³ mm ² , the transfer rate of the pair of plating bump groups 3 to the base 11 is good, and the transfer to the base 11 is good. The crystal vibrating piece 2 can be stably joined.

  The transfer rate here means that when the crystal vibrating piece 2 bonded to the base 11 is peeled off from the base 11, the plating bumps 31 formed on the crystal vibrating piece 2 before bonding remain on the base 11 side ( It means the rate of transcription.

Specifically, each of the pair of plating bump groups 3 is formed by forming nine plating bumps 31, and the total area of each of the pair of plating bump groups 3 is 4 × 10 ^{−3 to} 6 × 10 ⁻³ mm ^2. (In this embodiment, 4.78 × 10 ⁻³ mm ² ), for example, as shown in FIG. 10, the transfer rate of the plating bumps 31 to the base 11 is increased one by one. The transfer rate to the base 11 of the plating bump group 3 in which the number of the plating bumps 31 is nine can be increased. FIG. 10 shows the transfer rate of the plating bumps 31 to the base 11 with respect to the quartz crystal resonator element 2 of the fourth example. For reference, the transfer rate of the plating bumps 31 to the base 11 in the comparative example described above is shown in FIG. 10 and 11 are enlarged schematic views of a portion corresponding to the circled portion shown in FIG. 1, and a schematic schematic view of the crystal vibrating piece 2 and the base 11 showing the transfer rate of the plating bump 31. It is. These black portions shown in FIGS. 10 and 11 are portions where the plating bumps 11 are adhered when the crystal vibrating piece 2 is peeled off from the base 11. As shown in FIGS. 10 and 11, it can be seen that the transfer rate of the plating bump group 3 (plating bump 31) to the base 11 is higher in the fourth example than in the comparative example.

  In addition, since nine plating bumps 31 are formed in each joint 27, that is, a multipoint plating bump is formed in the joint 27, for example, when a defect such as peeling of one plating bump 31 occurs. However, stable bonding strength can be maintained by the other plated bumps 31.

  Further, according to the crystal resonator 1 according to the present embodiment, nine plating bumps 31 with respect to the pair of plating bump groups 3 are formed on the crystal vibrating piece 2, and the crystal vibrating piece 2 is bonded to the base 11. By joining at least two points of the plated bump 31, the bonding strength of the crystal vibrating piece 2 to the base 11 can be increased.

  Further, according to the crystal resonator 1 according to the present embodiment, in the ultrasonic bonding by the FCB method, the crystal vibrating piece 2 is pressed and swung to the base 11 and the crystal vibrating piece 2 is heat-melt bonded to the base 11. This is a joining method suitable for joining a plurality of plating bumps 31.

  Further, according to the method of manufacturing the quartz crystal vibrating piece 2 according to the present embodiment, after the nine plating bumps 31 are formed on the tip portions 271 and 272 of the joint portion 27, the nine plating bumps 31 are annealed. As a result, the nine plating bumps are annealed, and the stress (residual stress) generated when the nine plating bumps are formed on the joint portion 27 (tip portions 271 and 272) is eliminated.

  In addition, since the pair of plating bump groups 3 according to the above-described embodiment is formed by photolithography, the size, shape, and quantity of the plating bumps 31 can be arbitrarily set in each of the pair of plating bump groups 3. .

  By the way, in the prior art, the crystal vibrating piece 2 is ultrasonically bonded to the base by the FCB method using the stud bump, and in the ultrasonic bonding by the FCB method, the crystal vibrating piece 2 is mounted when the crystal vibrating piece 2 is mounted on the base. 2 may be arranged on the base out of a predetermined position. In this case, since the crystal resonator element 2 is displaced with respect to the stud bump, the crystal resonator element 2 is not properly mounted on the base, or the crystal resonator element 2 is bonded to the base in a shifted state. It is difficult to obtain strength.

  On the other hand, according to the present embodiment, even when the quartz crystal vibrating piece 2 is disposed on the base 11 while being displaced from a predetermined position when the quartz crystal vibrating piece 2 is mounted on the base 11, the quartz crystal vibrating piece 2. Since the crystal vibrating piece 2 is bonded to the base 11 in a state where the pair of plating bump groups 3 is formed, the pair of plating bump groups 3 is always formed at a desired position (extraction electrode 43) of the crystal vibrating piece 2. The crystal vibrating piece 2 can be bonded to the base 11 with stable bonding strength.

  In addition, when stud bumps are used, stud bumps need to be ejected and formed on the base, and displacement may occur when ejecting and forming stud bumps on the base. In particular, as the size of the main body casing is reduced, the frequency of positional deviation increases and the amount of deviation increases.

  On the other hand, according to the present embodiment, since the crystal vibrating piece 2 is bonded to the base 11 in a state where the pair of plated bump groups 3 is formed on the crystal vibrating piece 2, it is possible to prevent the positional deviation from occurring. Can do.

  In addition, when stud bumps are used, the stud bumps are crushed when the tuning fork type quartz vibrating piece is joined to the base via the stud bumps. Sometimes That is, the tuning fork type crystal vibrating piece is subjected to stress when the stud bump is crushed, and this stress remains as a residual stress, and in some cases, the tuning fork type crystal vibrating piece may crack.

  On the other hand, according to the present embodiment, since the crystal vibrating piece 2 is joined to the base 11 in a state where the pair of plated bumps 3 is formed on the crystal vibrating piece 2, the crystal vibrating piece 2 to the base 11 is bonded. Stress is not easily generated in the pair of plating bump groups 3 at the time of joining.

  Further, when the stud bump is used, the stud bump is crushed when the tuning fork type quartz vibrating piece is joined to the base via the stud bump, and the joining area of the stud bump to the tuning fork type quartz vibrating piece is widened. . Therefore, a short between the electrodes such as a pair of excitation electrodes occurs due to the crushed stud bump.

  On the other hand, according to the present embodiment, since the pair of plated bump groups 3 is formed on the crystal vibrating piece 2, a pair of plated bumps is formed when the crystal vibrating piece 2 is joined to the base 11 like a stub bump. The group 3 is not crushed, and this does not cause a short circuit between the pair of the first excitation electrode 41 and the second excitation electrode 42.

  In the present embodiment, the plated bump 31 has a circular shape in plan view. However, this is a preferable example, and is not limited to this. The rectangular shape in plan view, the square shape in plan view, and other polygonal shapes are not limited thereto. It may be.

  In the present embodiment, gold is used for the plating bumps 31, but the present invention is not limited to this, and other types of metals may be used.

In this embodiment, the plated bump 31 has a circular shape in plan view. However, the shape is not limited to this. For example, as shown in FIG. 12, vibration when ultrasonic bonding is performed by the FCB method. It is more preferable that it is an elliptical shape in plan view having a major axis in the direction.
In the example shown in FIG. 12, the plating bump 31 has a long diameter. Therefore, for example, when the FCB method is used when the crystal vibrating piece 1 is mounted on the base 11, the vibration direction when the crystal vibrating piece 1 is ultrasonically bonded to the base 11 by the FCB method corresponds to the long diameter of the plating bump 31. By doing so, the area (grounding area) of the bonding region with respect to the vibration direction of the plated bump 31 can be increased, and the bonding property can be further improved.

  Moreover, although the front-end | tip parts 271 and 272 of the junction part 27 shown in a present Example protrude and are formed to the one end surface 28 vicinity of the base 23, it is not limited to this, For example, as shown in FIG. Alternatively, the first leg portion 21 and the second leg portion 22 may be formed so as to protrude to the vicinity of the tip portions 211 and 221.

  Moreover, although the groove part 25 said by the present Example is made into cross-sectional concave shape as shown in FIG. 1, it is not limited to this, A through-hole may be sufficient and a hollow part may be sufficient.

  Further, in the present embodiment, the groove 25 is formed in the first leg 21 and the second leg 22, but this is a preferred example and is not limited thereto. For example, the first leg The present invention can also be applied to the crystal vibrating piece 1 in which the groove portion is not formed in the 21 and the second leg portion 22.

  It should be noted that the present invention can be implemented in various other forms without departing from the spirit, gist, or main features. For this reason, 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 a tuning fork type piezoelectric vibrating piece, a tuning fork type piezoelectric vibrating device, and a method for manufacturing a tuning fork type piezoelectric vibrating piece, and is particularly suitable for a tuning fork type crystal vibrating piece and a tuning fork type crystal resonator.

FIG. 1 is a schematic plan view showing the inside of a crystal resonator according to the present embodiment. FIG. 2 is a schematic plan view of a joint portion in which a pair of plated bump groups according to another example (second example) of the present embodiment is formed. FIG. 3 is a schematic plan view of a joint portion in which a pair of plated bump groups according to another example (third example) of the present embodiment is formed. FIG. 4 is a schematic plan view of a joint portion in which a pair of plating bump groups according to another example (fourth example) of the present embodiment is formed. FIG. 5 is a schematic plan view of a joint portion in which a pair of plating bump groups according to another example (fifth example) of the present embodiment is formed. FIG. 6 is a schematic plan view of a joint portion in which a pair of plated bump groups according to another example (sixth example) of the present embodiment is formed. FIG. 7 shows measurement data relating to the CI values of the present example, the second to sixth examples, and the comparative example. FIG. 8 shows measurement data relating to the DLD characteristics of this example, the second to sixth examples, and the comparative example. FIG. 9 shows measurement data relating to the strengths of this example, the second to sixth examples, and the comparative example. FIG. 10 is a schematic diagram of the quartz crystal vibrating piece and the base showing the transfer rate of the plating bump in the fourth example. FIG. 11 is a schematic diagram of the crystal vibrating piece and the base showing the plating bump transfer rate in the comparative example. FIG. 12 is a schematic plan view of a joint portion in which a pair of plated bump groups according to another example of the present embodiment is formed. FIG. 13 is a schematic plan view of a quartz crystal resonator element according to another example of the present embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tuning fork type crystal oscillator 11 Base 2 Tuning fork type crystal vibrating piece 21 1st leg part 22 2nd leg part 23 Base 24 Main surface 25 Groove part 27 Joint part 271,272 Joint part tip part 3 Plating bump group 31 Plating bump

Claims (7)

In tuning fork type piezoelectric vibrating piece,
It is composed of a plurality of legs that are vibration parts, and a base part that protrudes from these legs,
The base is provided with a joint for joining to the outside,
A pair of plating bump groups is formed in the joint portion,
Each of the pair of plating bump groups is formed by forming a plurality of plating bumps,
The tuning fork-type piezoelectric vibrating piece according to claim 1, wherein a total area of the plating bump group is set to 4 × 10 ^{−3 to} 6 × 10 ⁻³ mm ² . The tuning fork type piezoelectric vibrating piece according to claim 1,
The tuning fork-type piezoelectric vibrating piece according to claim 1, wherein the plated bump has an elliptical shape in plan view. In tuning fork type piezoelectric vibration device,
A tuning fork type piezoelectric vibrating piece according to claim 1, a base on which the tuning fork type piezoelectric vibrating piece is mounted, and a lid for hermetically sealing the tuning fork type piezoelectric vibrating piece mounted on the base are provided. A tuning-fork type piezoelectric vibration device characterized by being made. The tuning fork type piezoelectric vibration device according to claim 3,
The tuning fork-type piezoelectric vibration device according to claim 1, wherein at least two of the plurality of plating bumps are coupled in the plating bump group. The tuning fork type piezoelectric vibration device according to claim 3 or 4,
A tuning fork type piezoelectric vibrating device, wherein the tuning fork type piezoelectric vibrating piece is ultrasonically bonded to the base by the FCB method through the pair of plated bump groups. In the manufacturing method of the tuning fork type piezoelectric vibrating piece,
The tuning fork type piezoelectric vibrating piece is composed of a plurality of leg portions which are vibration portions and a base portion provided by projecting these leg portions, and the base portion is provided with a joint portion for joining to the outside. Is a piece,
A step of forming a pair of plated bump groups each formed by forming a plurality of plated bumps at the joint,
A method for producing a tuning-fork type piezoelectric vibrating piece, wherein a total area of each of the plating bump groups is set to 4 × 10 ^{−3 to} 6 × 10 ⁻³ mm ² . In the manufacturing method of the tuning fork type piezoelectric vibrating piece according to claim 6,
A method for producing a tuning-fork type piezoelectric vibrating piece, comprising: annealing the plurality of plating bumps after forming the plurality of plating bumps at the joint.

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