JP2008166884A - Manufacturing method of piezoelectric vibration device and piezoelectric vibration device by the manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a piezoelectric vibration device which is suitable for miniaturization and does not easily generate the bonding strength dispersion of a metal bump and a piezoelectric vibration piece, and to provide the piezoelectric vibration device. <P>SOLUTION: In the manufacturing method of the piezoelectric vibration device for which a package is constituted by bonding a base 3 and a lid 4, the piezoelectric vibration piece 2 is held on the base inside the package, and the inside of the package is airtightly sealed, the piezoelectric vibration piece for which an excitation electrode and a pull-out electrode are formed on both main surfaces of the piezoelectric vibration piece and a through-hole passing through the pull-out electrode and both main surfaces of the piezoelectric vibration piece is formed is used, the through-hole of the piezoelectric vibration piece is inserted to an integrated type metal bump formed at the upper part of the base and provided with a wide bottom part and a narrow body part, and the body part of the metal bump projected from the through-hole of the piezoelectric vibration piece is electromechanically bonded while impressing ultrasonic waves by a bonding tool. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a piezoelectric vibration device and a piezoelectric vibration device.

  Currently, examples of the piezoelectric vibration device include a crystal oscillator and a crystal resonator. In this type of piezoelectric vibration device, the casing is formed of a rectangular parallelepiped package. This package includes a base and a lid, and a piezoelectric vibrating piece is held and joined to the base by a conductive adhesive inside the package. And the piezoelectric vibration piece inside a package is airtightly sealed by joining a base and a lid | cover (for example, refer patent document 1 mentioned below).

JP 2005-191709 A

  By the way, in Patent Document 1 described above, when the piezoelectric vibrating piece is held on the base, the piezoelectric vibrating piece is bonded to the base with a conductive adhesive. In addition, electrodes having different polarities are arranged on the base, and a conductive adhesive is applied on each electrode. Therefore, in the case of the piezoelectric vibration device disclosed in Patent Document 1 described above, in order to avoid a short circuit between electrodes having different polarities, an application region (joining region) of the conductive adhesive on the base inside the package is secured, And it is necessary to set the application amount (use amount) of a conductive adhesive according to this application | coating area | region, and the piezoelectric vibration device disclosed by this patent document 1 is not suitable for size reduction. For these reasons, attention has been focused on a structure in which a piezoelectric vibrating piece is bonded onto a base by an FCB method using metal bumps such as gold.

  However, in the FCB method using such metal bumps, the metal bump shape variation and the metal bump arrangement position variation, and the placement parallelism of the piezoelectric vibrating piece and the base when the metal bump is ultrasonically applied by a bonding tool are used. The ultrasonic wave application conditions differed due to deviations in the intensity, and intensity variations sometimes occurred between the plurality of bonded metal bumps. If variations in bonding strength occur in this way, the state of stress from the metal bumps to the piezoelectric vibrating piece is different, or the bonding strength is insufficient for some metal bumps. In some cases, such as peeling off. As a result, this has caused a variation in frequency of the piezoelectric vibrating piece and deterioration of aging characteristics.

  Accordingly, in order to solve the above problems, the present invention provides a more reliable method of manufacturing a piezoelectric vibrating device and a piezoelectric vibrating device that are suitable for miniaturization and are less likely to cause variations in bonding strength between a metal bump and a piezoelectric vibrating piece. With the goal.

In order to achieve the above object, a method for manufacturing a piezoelectric vibration device according to the present invention includes a base and a lid joined to form a package, and an external connection electrode is formed on the base inside the package. In the method of manufacturing a piezoelectric vibrating device in which the piezoelectric vibrating piece is held on the external connection electrode and the inside of the package is hermetically sealed,
At least one excitation electrode is formed on each of the two main surfaces of the piezoelectric vibrating reed, and each of the excitation electrodes is drawn out from the excitation electrode to electromechanically join the excitation electrode with the external connection electrode of the base An electrode is formed, and at least one of the extraction electrodes is formed with a through-hole or a notch that penetrates both main surfaces of the extraction electrode and the piezoelectric vibrating piece, and a through-hole on the opposite surface of the extraction electrode or A step of preparing a piezoelectric vibrating piece in which an extraction auxiliary electrode is formed around the notch;
Forming an integrated metal bump having a wide bottom portion on the lower side and a narrow body portion on the upper side on the external connection electrode of the base, and
Thereafter, the body portion of the metal bump is inserted into the through hole or notch of the piezoelectric vibrating piece and positioned, and the body portion of the metal bump protruding from the through hole or notch of the piezoelectric vibrating piece is superposed by a bonding tool. While applying a sound wave, crush part of the body of the metal bump to form the head of the metal bump,
The lead electrode and lead auxiliary electrode of the piezoelectric vibrating piece are electrically and mechanically joined by the bottom of the metal bump and the top of the metal bump.

  According to the manufacturing method of the present invention, when the metal bump, the piezoelectric vibrating piece, and the base are bonded by the FCB (Flip Chip Bonding) method, which is a method using ultrasonic bonding, the upper portion of the base is provided on the external connection electrode. By inserting and positioning the through hole or notch of the piezoelectric vibrating piece with respect to the body portion of the metal bump, there is no mounting displacement. In other words, the variation in the placement position of the metal bumps, and the displacement of the piezoelectric vibrating piece and the base when the metal bumps are ultrasonically applied with the bonding tool are suppressed, thereby eliminating the variation in the ultrasonic application conditions. It is possible to eliminate variations in strength among the plurality of bonded metal bumps.

  In addition, the head portion of the metal bump is formed by crushing a part of the body portion of the metal bump, and a single integrated type is used without stacking a plurality of metal bumps for each extraction electrode. Electromechanical joining of the external connection electrode of the base, the extraction electrode of the piezoelectric vibrating piece, and the extraction auxiliary electrode can be performed only with a metal bump having a substantially I-shaped cross section.

  In other words, since the electromechanical joining region can be enlarged between the extraction electrode and the extraction auxiliary electrode including the through hole or notch, the bonding strength between the base and the piezoelectric vibrating piece is greatly improved, and the metal The bumps are never peeled off from the electrode film of the piezoelectric vibrating piece. Therefore, the electromechanical connectivity over time is extremely stabilized, so that the frequency variation of the piezoelectric vibrating piece and the deterioration of the aging characteristics are not caused.

  In addition, compared to the case where a plurality of metal bumps are laminated, the FCB can be electrically and mechanically connected to the external connection electrode of the base and the electrode of the piezoelectric vibrating piece with only one FCB. At this time, it can be performed in an optimum state, and the bonding state of the metal bumps does not change, and as a result, it is possible to prevent a decrease in bonding strength. In addition, the mechanical and thermal strain that the metal bump receives from the outside only needs to be applied once. As a result, the piezoelectric vibrating piece is repeatedly subjected to distortion, resulting in a decrease in the electrical characteristics of the piezoelectric vibrating device (lowering of the series resonance resistance value). , Frequency shift, inclination of frequency temperature characteristics, etc.) can be suppressed.

  When the lead-out electrode in which the through hole or notch is formed is connected to the excitation electrode on the upper main surface, the excitation electrode on the upper main surface of the piezoelectric vibrating piece is a metal bump disposed in the through hole or notch The body portion of the piezoelectric vibrator can be reliably routed to the external connection electrode on the lower base of the piezoelectric vibrating piece. As a result, it is possible to contribute to a reduction in the height of the piezoelectric vibrating device, and there is no problem of disconnection at the ridge portion of the piezoelectric vibrating piece caused by drawing the extraction electrode through the side end surface of the piezoelectric vibrating piece.

  The piezoelectric vibration device obtained by the above manufacturing method is characterized in that the top of the metal bump is formed with the same volume as the bottom of the metal bump or a smaller volume than the bottom of the metal bump.

  In this case, the same operational effects as the above manufacturing method can be obtained, and the following operational effects can also be obtained. That is, since the thermal mechanical stress applied to the piezoelectric vibrating piece by the metal bump is also reduced, the holding form does not hinder the vibration of the piezoelectric vibrating piece, and as a result, the electrical characteristics of the piezoelectric vibrating device become more stable. . In particular, if the head of the metal bump has the same volume as the bottom of the metal bump, the symmetry from the metal bump to the upper and lower main surfaces of the piezoelectric vibrating piece is maintained, so the stress applied to each is uniform. Thus, the mechanical strain and thermal strain that the piezoelectric vibrating piece receives from the metal bumps become uniform, and a piezoelectric vibrating device having excellent aging characteristics can be obtained.

  According to the present invention, it is possible to provide a more reliable method of manufacturing a piezoelectric vibrating device and a piezoelectric vibrating device that are suitable for miniaturization and are less likely to cause variations in bonding strength between a metal bump and a piezoelectric vibrating piece. As a result, the frequency variation of the piezoelectric vibrating piece and the deterioration of the aging characteristics can be suppressed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, a case where the present invention is applied to a crystal resonator as a piezoelectric vibration device is shown.

  In the crystal resonator 1 according to the present embodiment, as shown in FIG. 1 (FIGS. 1A and 1B), a thickness-shear vibration type crystal vibrating piece 2 (piezoelectric vibrating piece referred to in the present invention) and A base 3 for holding the crystal vibrating piece 2 and a lid 4 for hermetically sealing the crystal vibrating piece 2 held on the base 3 are provided.

  In this crystal unit 1, a package is constituted by a base 3 and a lid 4, and the base 3 and the lid 4 are joined to form an internal space of the package, and metal bumps are formed on the base 3 in the internal space of the package. The crystal vibrating piece 2 is held via 5 and the internal space of the package is hermetically sealed. In addition, although the joining method of the metal bump 5 of this embodiment, the shape creation method of the metal bump 5, and the like will be described later, the base 3, the crystal vibrating piece 2, and the metal bump 5 are ultrasonically formed by FCB (Flip Chip Bonding) method. Bonded and electromechanically bonded. Further, the metal bump 5 used in this embodiment is made of a metal material such as gold, and has a cross section including a wide bottom portion 51 on the lower side and a wide head portion 53 on the upper side of the narrow body portion 52 in the center. An integral metal bump having a substantially I shape is used. Next, each configuration of the crystal resonator 1 will be described.

  As shown in FIG. 1, the base 3 is formed in a box-like body including a bottom portion 31 and a wall portion 32 extending upward from the bottom portion 31. The base 3 is formed by laminating a rectangular parallelepiped of a ceramic material on a single plate having a rectangular shape in a plan view made of a ceramic material, and integrally firing in a concave shape. The wall portion 32 is formed along the outer periphery of the surface of the bottom portion 31. The upper surface of the wall portion 32 is a bonding area with the lid 4, and the bonding area 33 (for example, a structure in which nickel and gold are plated on the tungsten metallized layer in this order) is bonded to the lid 4. Or a structure made of tin and gold, tin and silver, or a glass layer). The base 3 is formed with a plurality of external connection electrodes 33 and 34 that are electromechanically joined to the excitation electrodes 231 and 232 of the crystal vibrating piece 2. These external connection electrodes 33 and 34 are each electromechanically joined to terminal electrodes (not shown) formed on the outer peripheral back surface of the base 3. These terminal electrodes are connected to external parts and external devices. The terminal electrodes and the external connection electrodes 33 and 34 are formed by integrally baking with the base 3 after printing a metallized material such as tungsten or molybdenum. Some of these terminal electrodes and external connection electrodes are formed by forming nickel plating on the upper portion of the metallization and forming gold plating on the upper portion thereof.

  The lid 4 is made of a metal material, a ceramic material, or the like, and is formed into a single plate having a rectangular shape in plan view, as shown in FIG. The lid 4 is formed with a sealing bonding material (not shown) on the lower surface, and is joined to the base 3 by seam welding, beam welding, brazing filler metal, glass or the like by a method of heating the atmosphere. 3 constitutes a package 6 of the crystal unit 1. In the present embodiment, the lid 4 formed into a rectangular parallelepiped on a single plate on a rectangular plan view and the base 3 formed into a concave shape are used, but the present invention is not limited to this. If the crystal vibrating piece 2 can be hermetically sealed by the base 3 and the lid 4, the shapes of the base and the lid may be arbitrarily set.

  As shown in FIGS. 1 and 2, the crystal vibrating piece 2 includes an AT-cut crystal piece substrate 21 and is formed into a rectangular parallelepiped having a rectangular shape in plan view. That is, the outer peripheral shape of the substrate 21 is a rectangular parallelepiped shape. On both main surfaces 221 and 222 of this substrate 21 (221 is the bottom surface side and 222 is the top surface side), a recess 201 is formed (reverse mesa shape) to cope with the higher frequency of the crystal vibrating piece 2. Excitation electrodes 231 and 232 are formed inside 201, respectively, in order to electromechanically join these excitation electrodes 231 and 232 with external electrodes (in this embodiment, external connection electrode pads 33 and 34 of the base 3). Extraction electrodes 241 and 242 extracted from the excitation electrodes 231 and 232 are formed. Further, the quartz crystal vibrating piece 2 is bonded to the external connection electrode pads 33 and 34 of the base 3 by the metal bumps 5 in one region 26 of the substrate 21. Note that one region 26 of the substrate 21 in this embodiment is in the vicinity of one side portion 27 of the substrate 21.

  Specifically, as shown in FIGS. 1 and 2, the leading end portions 251 and 252 of the leading electrodes 241 and 242 are pulled out in the vicinity of the one side portion 27 of each of the main surfaces 221 and 222. Through holes 261 and 262 are formed in the 252 so as to penetrate both the main surfaces of the extraction electrodes 241 and 242 and the substrate 21 as a quartz crystal vibrating piece. Leading auxiliary electrodes 271 and 272 are formed around the through-holes 261 and 262 on the opposing surfaces of the leading ends 251 and 252 of the leading electrode. The excitation electrodes 231 and 232, the extraction electrodes 241 and 242 and the extraction auxiliary electrodes 271 and 272 are formed by photolithography, for example, in order of chromium and gold (Cr—Au) from the substrate 21 side, or It is formed by stacking nickel and gold (Ni—Au) in this order.

  Each of these electrodes and through-holes, and as a final form, an integrated type having a substantially I-shaped cross section including a wide bottom portion 51 on the lower side and a wide head portion 53 on the upper side of the narrow body portion 52 in the center. The bonding state of the metal bumps 5 is as follows. The bottom portions 51 and 51 of the metal bumps 5 and 5 perform electromechanical joining between the external connection electrodes 33 and 34 of the base, the extraction electrode 241 (extraction tip portion 251) of the quartz crystal vibrating piece, and the extraction auxiliary electrode 272, The body parts 52 and 52 of the metal bumps 5 and 5 are inserted into the through holes 261 and 262 of the crystal vibrating piece, and a part of the body part is electrically and mechanically joined to a lead electrode formed inside the through hole. The heads 53 and 53 of the metal bumps 5 and 5 are electrically and mechanically connected to the extraction electrode 242 (extraction leading end portion 252) and the extraction auxiliary electrode 271 of the crystal vibrating piece.

  Next, a method for manufacturing the piezoelectric vibration device will be described with reference to FIG.

First Step Excitation electrodes 231 and 232, extraction electrodes 241 and 242 and through-holes 261 and 262 are formed in the leading ends 251 and 252 of the extraction electrodes on both main surfaces of the substrate 21 as described above. Around the hole, a crystal vibrating piece 2 in which extraction auxiliary electrodes 271 and 272 are formed is prepared.

Second Step Next, as shown in FIG. 3A, the upper portions of the external connection electrodes 33 and 34 of the base 3 are metal bumps made of gold or the like and have wide bottom portions 51 and 51 on the lower side. And integrated metal bumps 5 and 5 having narrow body portions 52 and 52 on the upper side are continuously formed from a bonding tool T1 (capillary or the like) by a bump bonder using a wire bonding technique such as thermocompression bonding. . The body 52 is formed by forming metal bumps on the external connection electrodes 33 and 34, then drawing a wire at least as thick as the crystal vibrating piece and then fusing. The order of the first step and the second step may be switched.

Third Step Next, as shown in FIGS. 3B and 3C, the quartz crystal vibrating piece 2 prepared in the first step is moved by a bonding tool T2 with an adsorption nozzle (such as an ultrasonic welder). After mounting on the metal bumps 5 and 5 on the base external connection electrodes formed in the second step, the crystal vibrating piece 2 is pressed onto the metal bumps 5 and 5 and a static pressure is applied. Then, by vibrating the bonding tool T2 at a predetermined frequency, the base 3, the crystal vibrating piece 2, and the metal bumps 5 and 5 are ultrasonically bonded by the bonding tool T2 by the FCB (Flip Chip Bonding) method, and are mutually connected. Electromechanically joined.

  More specifically, as shown in FIG. 3B, the through holes 261 and 262 of the crystal vibrating piece are inserted and positioned with respect to the body portions 52 and 52 of the metal bumps. As shown in (c), while applying ultrasonic waves to the body portions 52, 52 of the metal bumps protruding from the through holes 261, 262 of the quartz crystal vibrating piece with the bonding tool T2, a part of the body portion of the metal bumps is applied. By crushing, metal bump heads 53 and 53 are formed, and as a final form, a cross-sectional shape having a wide bottom 51 on the lower side and a wide head 53 on the upper side of the narrow body 52 is substantially I-shaped. An integrated metal bump 5 having a shape is obtained. At this time, it is preferable that the width of the body portion of the metal bump is made small with respect to the diameter of the through-holes 261 and 262 so as not to prevent the vibration caused by the application of the ultrasonic wave and not to prevent the insertion property. . For example, the present invention is not limited to a through hole having a similar shape, and may be formed in an oval shape or a rectangular shape that is elongated in the ultrasonic wave application direction, or may be a notch shape without being limited to a through hole. Although the bonding tool T2 is formed as a tool for transferring and bonding the crystal vibrating piece 2 to the metal bump 5 at one time, the transfer and bonding may be performed using separate tools. Further, the bonding tool T2 of this embodiment includes the recesses T21 and T22 for forming the heads of the metal bumps, and the head shape and volume of the metal bumps finally formed are the recesses T21, T22. It can be easily formed depending on the shape of T22.

  Subsequently, by applying ultrasonic waves with the bonding tool T2, the metal bumps 5 and 5, the extraction electrode of the crystal vibrating piece, and the extraction auxiliary electrode are electrically and mechanically joined. That is, the final bonding state by the metal bump 5 is as follows. The bottom portions 51 and 51 of the metal bumps 5 and 5 perform electromechanical joining between the external connection electrodes 33 and 34 of the base, the extraction electrode 241 (extraction tip portion 251) of the quartz crystal vibrating piece, and the extraction auxiliary electrode 272, The body parts 52 and 52 of the metal bumps 5 and 5 are inserted into the through holes 261 and 262 of the crystal vibrating piece, and a part of the body part is electrically and mechanically joined to a lead electrode formed inside the through hole. The heads 53 and 53 of the metal bumps 5 and 5 are electrically and mechanically connected to the extraction electrode 242 (extraction leading end portion 252) and the extraction auxiliary electrode 271 of the crystal vibrating piece.

Fourth Step After that, necessary processing such as a frequency adjustment step and an annealing step is performed, and the crystal vibrating piece 2 ultrasonically bonded onto the external connection electrodes 33 and 34 of the base 3 is shown in FIG. The lid 4 is hermetically sealed. A sealing bonding material (not shown) is formed on the lower surface of the lid 4, and the lid 4 and the base 3 are bonded to the base 3 by a method of seam welding, beam welding, brazing filler metal, glass, or the like by atmospheric heating. A package 6 of the crystal unit 1 is configured. Thus, the piezoelectric vibration device according to the present invention is obtained.

  According to the present invention, when the metal bump 5, the crystal vibrating piece 2 and the base 3 are joined by the FCB (Flip Chip Bonding) method, which is a method using ultrasonic bonding, the upper part of the base external connection electrodes 33 and 34 is provided. By inserting and positioning the through holes 261 and 262 of the crystal vibrating piece with respect to the body portions 52 and 52 of the metal bumps 5 and 5 provided, there is no mounting displacement at all. That is, it is possible to suppress ultrasonic wave application by suppressing variations in the arrangement positions of the metal bumps 5 and 5 and displacement of the crystal vibrating piece 2 and the base 3 when the metal bumps 5 and 5 are ultrasonically applied by the bonding tool T2. It is possible to eliminate variations in conditions, and as a result, it is possible to eliminate variations in strength between the bonded metal bumps 5 and 5.

  Further, the metal bump head portions 53 and 53 are formed by crushing part of the body portions 52 and 52 of the metal bump, and a plurality of metal bumps are laminated on the lead electrodes 241 and 242. Without use, only one metal bump 5, 5 having a substantially I-shaped cross section, the external connection electrodes 33, 34 of the base 3, the extraction electrodes 241, 242 of the quartz crystal vibrating piece, the extraction auxiliary electrodes 271, 272, Electromechanical joining can be performed.

  That is, since the electromechanical joining region including the through holes 261 and 262 and between the lead electrodes 241 and 242 and the lead auxiliary electrodes 271 and 272 can be enlarged, the joint strength between the base 3 and the quartz crystal vibrating piece 2 is increased. Is greatly improved, and the metal bumps 5 and 5 are not peeled off from the electrode film of the crystal vibrating piece 2 at all. For this reason, the electrical and mechanical connectivity over time is extremely stabilized, so that the frequency variation of the crystal vibrating piece 2 and the deterioration of the aging characteristics are not caused.

  Further, as compared with the case where a plurality of metal bumps are laminated, the base external connection electrodes 33 and 34, the extraction electrodes 241 and 242 of the quartz crystal resonator element 2, and the extraction auxiliary electrode can be performed only by one FCB. Since the electromechanical bonding with the 271 and 272 can be performed, the FCB can be performed in an optimum state, the bonding state of the metal bumps 5 and 5 does not change, and as a result, the bonding strength is prevented from being lowered. It becomes possible. Furthermore, the mechanical and thermal strains that the metal bumps 5 and 5 receive from the outside are only required once. As a result, the crystal resonator piece (piezoelectric vibration device) has electrical characteristics that are repeatedly applied with strain. It is possible to suppress a decrease (such as a decrease in series resonance resistance value, a frequency shift, or a gradient of frequency temperature characteristics).

  Further, the excitation electrode 232 on the upper main surface of the quartz crystal vibrating piece can be reliably routed to the external connection electrode 34 on the lower side of the quartz crystal vibrating piece by the body portion 52 of the metal bump disposed in the through hole 262. . As a result, it is possible to contribute to a reduction in the height of the crystal resonator (piezoelectric vibration device), and the problem of disconnection at the ridge portion of the crystal resonator element caused by drawing the extraction electrode through the side end surface of the crystal resonator element. Will disappear.

  In the present embodiment, since the head 53 is formed with a volume smaller than the bottom 51 as the final form of the metal bump 5, the thermal mechanical stress applied to the crystal vibrating piece 2 by the metal bump 5 is also reduced. Therefore, it becomes a holding form which does not inhibit the vibration of the crystal vibrating piece 2. Not only in such a final form, but as shown in FIG. 4 (the same parts as in the above embodiment are given the same numbers and a part of the description is omitted), the head 53 of the metal bump 5 is connected to the bottom 51. Almost the same volume may be used. With this configuration, the symmetry of the metal bump 5 with respect to both the main surfaces 221 and 222 of the crystal vibrating piece 2 is maintained, so that the stress applied to each of them is uniform, and the crystal vibrating piece 2 is attached to the metal bump 5. As a result, the mechanical strain and thermal strain received from the substrate become uniform, and a piezoelectric vibration device having excellent aging characteristics can be obtained.

  Further, in the quartz crystal resonator element 2 according to the present embodiment, as shown in FIGS. 1 and 2, one through hole is formed in the leading end portions 251 and 252 of the leading electrodes 241 and 242 and is inserted into each through hole. The metal bumps 5 and 5 having a single I-shaped cross section are electrically and mechanically joined to the external connection electrode pads 33 and 34 of the base 3. Absent. For example, a through hole is formed only with respect to the extraction electrode 242 connected to the excitation electrode 232 on the upper main surface, and is electrically and mechanically joined by a metal bump having a substantially I-shaped cross section on the lower side. For the lead-out electrode 241 connected to the excitation electrode 231 on the main surface, a mechanical bump is formed between the crystal resonator element and the external connection electrode of the base using a normal metal bump without forming a through hole. You may join to. Alternatively, a plurality of integral-type metal bumps having a substantially I-shaped cross section inserted into the respective through holes may be used. Specifically, as shown in FIG. 5 (the same parts as in the above embodiment are given the same numbers and a part of the description is omitted), two through holes are formed for each leading end of the drawer, and two metals are formed. The bump 5 may be joined at the leading end portion (leading auxiliary electrode) along the short direction of the crystal vibrating piece 2 in a state where the bump 5 is inserted into each through hole. In this case, since the plurality of metal bumps 5 are used for one lead electrode 241 (242), the connection position of the crystal vibrating piece 2 on the substrate 21 with the external connection electrode is set to one side portion of the main surface 221. 27, which is suitable for reducing the size of the crystal vibrating piece 2, and can increase the bonding strength between the crystal vibrating piece 2 and the external connection electrode. This effect becomes particularly prominent as the quartz crystal resonator element 2 is downsized.

  Further, in the above-described embodiment, the concave portions 201 are formed on both the main surfaces 221 and 222 of the quartz crystal vibrating piece 2 and the one corresponding to high frequency is taken as an example, but the present invention is not limited to this. A simple plate-shaped crystal vibrating piece may be used. Furthermore, in the present embodiment described above, one excitation electrode 231, 232 is formed on each of the two main surfaces 221, 222 of the quartz crystal vibrating piece 2, but the present invention is not limited to this. The number of excitation electrodes formed on both main surfaces 221 and 222 may be arbitrarily set. For example, two excitation electrodes may be formed on both main surfaces, or a filter element configuration in which one excitation electrode is formed on one main surface and two excitation electrodes are formed on the other main surface. Good.

  Furthermore, as shown in FIG. 2, the crystal vibrating piece 2 made of an AT-cut crystal piece is used, but the present invention is not limited to this, and another piezoelectric vibrating piece may be used. Specifically, it is a tuning fork type crystal vibrating piece (hereinafter referred to as a crystal vibrating piece 8) as shown in FIG. 6 (the same parts as in the above embodiment are given the same numbers and a part of the description is omitted). Also good. The crystal vibrating piece 8 shown in FIG. 6 is formed by etching from a crystal piece made of anisotropic material. The substrate 81 of the quartz crystal resonator element 8 is composed of two leg portions 821 and 822 and a base portion 83, and the outer peripheral shape thereof is a substantially rectangular parallelepiped shape, and the two leg portions 821 and 822 project from the base portion 83. Has been. Further, in order to improve the series resonance resistance value that deteriorates due to the miniaturization of the crystal vibrating piece 8, the concave portions 85 are formed on both main surfaces 841 and 842 (841 not shown) of the two leg portions 821 and 822. Is formed. The two main surfaces 841 and 842 of the quartz crystal vibrating piece 8 are provided with two excitation electrodes 861 and 862 having different potentials, and these excitation electrodes 861 and 862 are used as electrode pads (not shown) of the base 3 as an electric machine. Lead electrodes 871 and 872 are formed to be joined to each other, and the lead electrodes 871 and 872 are drawn from the excitation electrodes 861 and 862 to the base 83. The leading end portions 881 and 882 of the leading electrodes 871 and 872 formed on the base 83 are provided with notches 891 and 892, and the leading end portions of the leading ends in the state in which the metal bumps 5 are inserted into the respective notches. 881, 882 and the external connection electrode of the base 3 are joined electromechanically.

  Further, in the above-described embodiment, the extraction electrode of the crystal vibrating piece and the external connection electrode of the base are directly electromechanically joined by the metal bump 5, but the present invention is not limited to this. 7 (the same parts as those in the above embodiment are given the same numbers and a part of the description is omitted). Specifically, the support material 7 is made of, for example, a brittle material such as a Z-plate crystal piece, an AT-cut crystal piece, or glass, and the outer shape is set to be substantially equal to the holding region of the crystal vibration piece 2 (substantially the same as the whole crystal vibration piece). It may be the same), and is formed into a rectangular parallelepiped having a rectangular shape in plan view. The support member 7 includes base connection electrodes 71 and 72 that are electrically and mechanically joined to the base external connection electrodes on the upper and lower main surfaces, the extraction electrode 251 and the extraction electrode auxiliary electrode 272 of the crystal vibrating piece. Crystal vibrating piece connection electrodes 73 and 74 that are electrically and mechanically joined, and through holes 75 and 76 that penetrate both main surfaces of the support material including the connection electrodes are formed.

  A specific bonding state between the crystal vibrating piece 2 using the support material 7 and the metal bumps 5A and 5B and the base external connection electrodes 33 and 34 is as follows. The bottom portions 51A and 51A of the metal bumps 5A and 5A arranged on the lower side perform electromechanical joining between the external connection electrodes 33 and 34 of the base and the base connection electrodes 71 and 72 of the support material 7, and on the lower side. The body portions 52A and 52A of the disposed metal bumps 5A and 5A are inserted into the through holes 75 and 76 of the support material, and a part of the body portion is electrically and mechanically joined to the extraction electrode formed inside the through hole. The heads 53A and 53A of the metal bumps 5A and 5A arranged on the lower side are electrically and mechanically joined to the crystal vibrating piece connecting electrodes 73 and 74 of the support material. In this embodiment, the crystal vibrating piece 2 is disposed on the support member 7 attached in this way. Further, the bottom portions 51B and 51B of the metal bumps 5B and 5B arranged on the upper side are arranged on the top of the head of the lower metal bump, and the leading end portion 251 of the lead electrode 241 of the quartz crystal vibrating piece and the lead auxiliary electrode The body portions 52B and 52B of the metal bumps 5B and 5B arranged on the upper side are inserted into the through holes 261 and 262 of the quartz crystal vibrating piece, and a part of the body portion penetrates. The heads 53B and 53B of the metal bumps 5B and 5B arranged on the upper side are electrically and mechanically joined to the lead electrode formed inside the hole, the lead tip 252 of the lead electrode 242 of the crystal vibrating piece, the lead Electromechanical joining with the auxiliary electrode 271 is performed.

  For such bonding, the lower metal bumps 5A and 5A made of gold or the like are attached to the upper portions of the external connection electrodes 33 and 34 of the base 3 by bump bonding, and then the support material 7 is mounted and positioned. Then, they are ultrasonically bonded by the above bonding tool by the FCB (Flip Chip Bonding) method and are electrically and mechanically bonded to each other. After the upper metal bumps 5B, 5B made of gold or the like are attached to the upper parts of the heads 53A, 53A of the lower metal bumps of the support material 7 by bump bonding, the crystal vibrating piece 2 is mounted and positioned. Then, they are ultrasonically bonded by the above bonding tool by the FCB (Flip Chip Bonding) method and are electrically and mechanically bonded to each other. As a result, as a final form, a cross-sectional shape having a wide bottom portion 51 (51A, 51B) on the lower side and a wide head portion 53 (53A, 53B) on the upper side of the narrow body portion 52 (52A, 52B) at the center. A substantially I-shaped integrated metal bump 5 (5A, 5B) is provided between the support material 7 and the base 3 (lower metal bump), and between the support material 7 and the crystal vibrating piece 2 (upper metal bump). ) Respectively.

  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 piezoelectric vibrator such as a crystal vibrator.

FIG. 1 is a schematic configuration diagram of a crystal resonator according to the present embodiment. FIG. 1A is a schematic plan view showing the inside of the crystal resonator. FIG.1 (b) is XX sectional drawing of Fig.1 (a). FIG. 2 is a schematic configuration diagram of the quartz crystal vibrating piece according to the present embodiment. FIG. 2A is a schematic plan view of the crystal vibrating piece. FIG. 2B is a schematic back view of the crystal vibrating piece. FIG. 3 is a diagram schematically showing a manufacturing process of the crystal resonator according to the present embodiment. FIG. 4 is a schematic cross-sectional view showing the inside of a crystal resonator according to another example of the present embodiment. FIG. 5 is a schematic plan view showing the inside of a crystal resonator according to another example of the present embodiment. FIG. 6 is a schematic plan view showing the inside of a crystal resonator according to another example of the present embodiment. FIG. 7 is a schematic cross-sectional view showing the inside of a crystal resonator according to another example of the present embodiment.

Explanation of symbols

1 Crystal resonator (piezoelectric vibration device)
2 Quartz vibrating piece (piezoelectric vibrating piece)
3 Base 4 Lid 5 Metal bump 6 Package 7 Support member 8 Tuning fork type crystal vibrating piece (piezoelectric vibrating piece)

Claims (2)

A base and a lid are joined to form a package, an external connection electrode is formed on the base inside the package, a piezoelectric vibrating piece is held on the external connection electrode, and the inside of the package is hermetically sealed In the manufacturing method of the stopped piezoelectric vibration device,
At least one excitation electrode is formed on each of the two main surfaces of the piezoelectric vibrating reed, and each of the excitation electrodes is drawn out from the excitation electrode to electromechanically join the excitation electrode with the external connection electrode of the base An electrode is formed, and at least one of the extraction electrodes is formed with a through-hole or a notch that penetrates both main surfaces of the extraction electrode and the piezoelectric vibrating piece, and a through-hole on the opposite surface of the extraction electrode or A step of preparing a piezoelectric vibrating piece in which an extraction auxiliary electrode is formed around the notch;
Forming an integrated metal bump having a wide bottom portion on the lower side and a narrow body portion on the upper side on the external connection electrode of the base, and
Thereafter, the body portion of the metal bump is inserted into the through hole or notch of the piezoelectric vibrating piece and positioned, and the body portion of the metal bump protruding from the through hole or notch of the piezoelectric vibrating piece is superposed by a bonding tool. While applying a sound wave, crush part of the body of the metal bump to form the head of the metal bump,
A method for manufacturing a piezoelectric vibration device, wherein an extraction electrode and an extraction auxiliary electrode of the piezoelectric vibrating piece are electrically and mechanically bonded to each other by a bottom portion of the metal bump and a head portion of the metal bump. The piezoelectric vibration device obtained by the manufacturing method according to claim 1, wherein the head of the metal bump is formed with the same volume as the bottom of the metal bump or a volume smaller than the bottom of the metal bump. A piezoelectric vibration device characterized by the above.

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