JP2013026949A - Piezoelectric device and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a manufacturing method of a piezoelectric device with high reliability.SOLUTION: A manufacturing method of a piezoelectric device 10 includes the steps of: forming first bumps 72 and 75 on connection electrodes 42 and 45 of a circuit element 40; accommodating a piezoelectric vibration piece 30 in a package 21 and bonding a piezoelectric vibrator 20 that has external terminals 50 and 53 electrically connected to the piezoelectric vibration piece 30 and disposed on an outer bottom surface 22a of the package 21 and a wiring substrate 60 that has through holes 61 and 62; forming second bumps 77 and 78 at positions of the through holes 61 and 62 where the external terminals 50 and 53 are exposed; and, at arrangement positions of the through holes 61 and 62, bonding the first bump 72 and 75 and the second bump 77 and 78 and connecting the external terminals 50 and 53 and the connection electrodes 42 and 45.

Description

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

Piezoelectric devices such as crystal oscillators are required to be smaller and thinner, and to be more reliable with respect to changes in the external environment such as temperature, as electronic devices used become smaller.
Therefore, a piezoelectric vibrator that houses a piezoelectric vibrating piece inside a package having external terminals on the outer surface, an IC chip that drives the piezoelectric vibrating piece, an IC chip is disposed on one surface, and a piezoelectric vibrator is disposed on the other surface. The wiring board has a through hole through which at least a part of the external terminal of the piezoelectric vibrator is exposed in plan view, and the internal connection terminal formed on one surface and the piezoelectric vibration A piezoelectric device in which a child external terminal is connected by a metal wire through a through hole has been proposed (for example, see Patent Document 1).

JP 2011-101214 A

  According to Patent Document 1, a terminal (pad) of an IC chip and an internal connection terminal provided on the upper surface side of the wiring board are connected by a metal wire, and further, the internal connection terminal and an external provided on the outer surface of the piezoelectric vibrator. The IC chip and the piezoelectric vibrator are connected by connecting the terminal with a metal wire. Therefore, in addition to the process of fixing the IC chip to the wiring board, a two-stage wire bonding process is required, and this process increases the number of steps.

  Also, bonding work in the through hole is difficult, and in order to pass the capillary through the through hole, the through hole must be enlarged in order to make the metal wire into a loop shape in the thickness direction. Since the terminal and the internal connection terminal are connected by a metal wire, the planar size of the wiring board is increased, which is disadvantageous for miniaturization and thinning.

  Furthermore, since the connection between the IC chip and the piezoelectric vibrator is made with a metal wire, the heat conduction between the two is poor, and the temperature difference between the IC chip and the piezoelectric vibrator is likely to occur, so the frequency stability at the time of start-up is improved. There is a problem that it is not enough.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1] A piezoelectric device according to this application example is a piezoelectric device in which a piezoelectric vibrator, a wiring board, and a circuit element are sequentially stacked to be integrated, and a package having external terminals on an outer bottom surface, and A piezoelectric vibrator having a piezoelectric vibrating piece housed in the package and electrically connected to the external terminal, a circuit element having a connection electrode and driving the piezoelectric vibrator, and at least a part of the external terminal And a wiring board having a through hole or a notch for exposing the connection electrode, and a connection member that penetrates the through hole or the notch and connects the external terminal and the connection electrode. It is characterized by being.
Here, the circuit element is, for example, an IC chip including an oscillation circuit, and the connection electrode is a pad. In addition, as the connection member, for example, a metal material having good conductivity and thermal conductivity is employed.

  According to this application example, the connection electrode of the circuit element and the piezoelectric vibrator are electrically connected by the connection member through the through hole or the notch and are structurally joined. Therefore, compared with the prior art, the process of bonding the circuit element to the wiring board and the two-stage wire bonding process are not required, and the number of steps can be reduced.

  In addition, since the connection electrode of the circuit element and the piezoelectric vibrator are linearly joined within the range of the through-hole or notch by the connection member, it is smaller and thinner than the conventional technology that connects with metal wires. it can.

  In addition, since the connection between the circuit element and the piezoelectric vibrator can be performed with a connecting member having good conductivity and thermal conductivity and a cross-sectional area larger than that of the metal wire, heat conduction between the two is good, and the heat generation of the circuit element is piezoelectric. Since it is easy to be transmitted to the vibrator and is thermally integrated, there is an effect that the frequency stability at the time of starting is good and the reliability is high.

Application Example 2 In the piezoelectric device according to the application example, it is preferable that the connection member is a bump formed on the external terminal and / or the connection electrode.
Here, as the bump as the connecting member, for example, an Au stud bump or the like can be used.

  The Au stat bump can be formed on one of the external terminal or the connection electrode, or both the external terminal and the connection terminal, and since it can be formed in multiple stages, the height can be easily adjusted, and the cross-sectional area can also be increased. There is an advantage that an appropriate size can be selected.

Application Example 3 A method for manufacturing a piezoelectric device according to this application example includes a step of forming a first bump on a connection electrode of a circuit element, and a piezoelectric vibration in which a piezoelectric vibrating piece is housed in a package having an external terminal on an outer bottom surface. Bonding the outer bottom surface of the child and a wiring board having a through hole or notch;
The external terminal and the connection electrode are electrically connected by connecting the first bump to the external terminal exposed by the through hole or the notch at the position where the through hole or the notch is disposed. And a step of performing.

According to this application example, the piezoelectric bump and the circuit element are structurally bonded by bonding the first bump formed in the circuit element through the through hole or notch and the external terminal, and Connect electrically. Therefore, compared with the above-described connection method using the metal wire in the prior art, the step of bonding the circuit element to the wiring board and the wire bonding step are unnecessary, and the number of steps can be reduced.
Furthermore, since there is no need for a plane size required for the wire bonding process and a height margin for securing a metal wire loop, it is possible to realize a smaller and thinner size than the conventional technology.

  Furthermore, since the circuit element and the piezoelectric vibrator are connected by the first bump having good conductivity and thermal conductivity and a cross-sectional area larger than that of the metal wire, the heat conduction between the two is good and the circuit element generates heat. Since it is easily transmitted to the piezoelectric vibrator and is thermally integrated, there is an effect that the frequency stability at the start is good.

  Application Example 4 In the method of manufacturing a piezoelectric device according to the application example, a step of forming a second bump on the external terminal exposed by the through hole or the notch, and an arrangement of the through hole or the notch It is preferable to include a step of electrically connecting the external terminal and the connection electrode by bonding the first bump and the second bump at the installation position.

  By joining the first bump formed in the circuit element through the through hole or notch and the second bump formed in the external terminal, the piezoelectric vibrating piece and the circuit element are structurally joined, and the electric Connect. Therefore, in contrast to the above-described connection method using the metal wire in the prior art, the step of bonding the circuit element to the wiring board and the wire bonding step are unnecessary, and the number of steps can be reduced.

  Application Example 5 In the piezoelectric device manufacturing method according to the application example, it is preferable that the height of the second bump is substantially the same as the thickness of the wiring board.

  The first bump formed on the circuit element includes a bump for connecting to an external terminal and a bump for connecting to an external device or the like, for example. Therefore, when forming the first bump, it is preferable to perform the bump forming process under the same conditions for all the first bumps, and the first bump sizes (planar area and height) are substantially the same. In such a case, it is conceivable that a height sufficient to penetrate the wiring board and connect to the second bump cannot be secured. Therefore, by forming the second bump formed on the external terminal side substantially the same as the height of the wiring board, the first bump and the second bump can be reliably bonded. Since the second bump is formed in a separate process from the first bump, it can be arbitrarily formed at a height.

  Application Example 6 In the method for manufacturing a piezoelectric device according to the application example, after the second bump is formed, a step of flattening the upper surface of the second bump to substantially the same height as the upper surface of the wiring board is further performed. It is preferable to have it.

  Both the first bump and the second bump can be stud bumps, solder bumps or the like, but the upper surfaces of these bumps do not become flat. Therefore, by flattening the second bump, it is possible to increase the area of the bonding surface with the first bump and increase the bonding reliability.

  Application Example 7 In the piezoelectric device manufacturing method according to the application example, it is preferable that the step of forming the second bump is a multi-step bump formation step of stacking a plurality of bumps.

  In this application example, the second bump is formed in multiple stages and bonded to the first bump. The first bump is formed with uniform dimensions for all connection electrodes, and the second bump is formed in multiple stages. By forming, the bump height can be controlled more easily and appropriately.

  Application Example 8 In the method for manufacturing a piezoelectric device according to the application example, the first bump and the external terminal are joined at the position where the through hole or the notch is disposed, and the connection electrode and the external terminal are joined. And the step of forming the first bump is preferably a multi-stage bump forming step of stacking a plurality of bumps.

  In this application example, the bump (including the first bump) is formed only on the circuit element side. The first bump can be easily formed higher than the thickness of the wiring board by stacking a plurality of bumps, and the thickness of the wiring board can be selected by selecting the number of bumps. As a result, the bump height can be appropriately controlled.

  Application Example 9 In the piezoelectric device manufacturing method according to the application example described above, the first bump and the external terminal are joined at the position where the through hole or the notch is disposed, and the connection electrode and the external terminal are joined. The connection electrode includes a connection electrode connected to the external terminal and a connection electrode connected to another terminal, and the step of forming the first bump includes: Forming a bump on the connection electrode connected to the external terminal; and forming a bump on the connection electrode connected to the other terminal; and forming the bump on the connection electrode connected to the external terminal. The bump is preferably formed to be higher than the thickness of the wiring board.

  In this application example, bumps (first bumps) are formed only on the circuit element side. Then, the first bump connected to the external terminal has a height penetrating the wiring board, and the bump formed on the other connection electrode has a height that can be joined to the electrode on the upper surface of the wiring board, so that the circuit element and the external A terminal or a circuit element and another terminal can be joined in the same process.

1A and 1B show an example of a main configuration of a piezoelectric device according to Embodiment 1, wherein FIG. 1A is a plan view viewed from a circuit element side, and FIG. Sectional drawing which shows the main processes of the manufacturing method which concerns on Example 1. FIG. (A) is sectional drawing which shows Au stud bump, (b) is sectional drawing which shows the planarization process which concerns on Example 2. FIG. Sectional drawing which shows a part of manufacturing method of the piezoelectric device which concerns on Example 3. FIG. Sectional drawing which shows the manufacturing method of the 1st bump which concerns on Example 4. FIG. The top view of the piezoelectric device which shows the structure which provides a notch in a wiring board.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The drawings referred to in the following description are schematic views in which the vertical and horizontal scales of each member or part are different from actual ones in order to make each member a recognizable size.
(Embodiment 1)

First, the configuration of the piezoelectric device 10 will be described with reference to FIG.
1A and 1B show an example of a main configuration of a piezoelectric device according to Embodiment 1, wherein FIG. 1A is a plan view viewed from a circuit element side, and FIG. 1B is a cross-sectional view showing a cross section taken along line AA in FIG. is there.
As shown in FIG. 1, the piezoelectric device 10 is configured integrally with a piezoelectric vibrator 20, a wiring board 60, and a circuit element 40 that are stacked in order. The piezoelectric vibrator 20 houses the piezoelectric vibrating piece 30 inside the package 21. In the present embodiment, the piezoelectric vibrating piece 30 is a crystal vibrating piece, and thus the piezoelectric vibrator 20 is a crystal vibrator. As the piezoelectric vibrating piece 30, for example, a tuning fork type quartz vibrating piece, an AT cut type quartz vibrating piece, or the like is used.

  The piezoelectric vibrating piece 30 is bonded and fixed to the internal electrodes 25 and 26 formed on the inner bottom surface 23 of the container-shaped package base 22 using a conductive adhesive 27, and the opening is sealed with a lid 24. Each of the internal electrodes 25 and 26 is connected to an excitation electrode (not shown) formed on the piezoelectric vibrating piece 30. For the package base 22, an aluminum oxide sintered body formed by firing a ceramic green sheet is used. The lid 24 is made of glass or the like.

External terminals 50, 51, 52, 53 are formed on the outer bottom surface 22a of the package 21 (package base 22). Although not shown, the internal electrodes 25 and 26 formed on the piezoelectric vibrator 20 are electrically connected to the external terminals 50 and 53, respectively.
The internal electrodes 25 and 26 and the external terminals 50 to 53 are formed of a metal film obtained by laminating films such as Ni and Au on a metallized layer such as tungsten by plating.
A wiring substrate 60 is fixed to the outer bottom surface 22a side of the piezoelectric vibrator 20 with an adhesive or the like.

  The wiring substrate 60 uses a polyimide or glass epoxy substrate, and has a shape substantially similar to the planar shape of the piezoelectric vibrator 20. A through hole 61 is opened at a position intersecting with a part of the external terminal 50, and a through hole 62 is opened at a position intersecting with a part of the external terminal 53. Therefore, the through hole 61 exposes a part of the external terminal 50, and the through hole 62 exposes a part of the external terminal 53.

On the upper surface 60a of the wiring substrate 60, island-shaped connection terminals 55 to 58 connected to connection electrodes 41, 43, and 46 (see FIG. 1A) provided in the circuit element 40 described later are formed. . In addition, external connection terminals 65 to 68 are formed at four corners of the wiring board 60.
The circuit element 40 is disposed on the upper surface 60 a of the wiring board 60.

  The circuit element 40 is an IC (Integrated Circuit) chip including an oscillation circuit, and a surface facing the wiring substrate 60 is an active surface 40a, and connection electrodes 41 to 46 are provided. The connection electrodes 41 to 46 are pads in the IC chip. Of these connection electrodes, the connection electrode 42 is disposed within the range of the through hole 61 of the wiring substrate 60, and the connection electrode 45 is disposed within the range of the through hole 62. The connection electrode 42 and the external terminal 50 provided on the piezoelectric vibrator 20 are connected by the connection member 70, and the connection electrode 45 and the external terminal 53 are connected by the connection member 70. In the connection member 70, first bumps 72 and 75 (see FIG. 2) formed on the circuit element 40 and second bumps 77 and 78 (see FIG. 2) provided on the piezoelectric vibrator 20 are joined. It represents the state.

  The connection electrodes 41, 43, 44, 46 provided on the circuit element 40 side are connected to connection terminals 55, 56, 57, 58 provided on the wiring board 60 by bumps 71, 73, 74, 76, respectively. Specifically, the connection electrode 41 and the connection terminal 55 are provided by the bump 71, the connection electrode 43 and the connection terminal 56 are provided by the bump 72, the connection electrode 44 and the connection terminal 57 are provided by the bump 73, and the connection electrode 46 and the connection terminal. 58 is connected by a bump 74. These connections are not only electrically connected but also structurally connected.

  Here, the function of the connection electrode of the circuit element 40 is illustrated. The connection electrode 41 is a VAFC terminal, the connection electrode 43 is a GND terminal, the connection electrode 44 is an O / P terminal, the connection electrode 46 is a VDD terminal, and the connection electrodes 42 and 45 are input terminals to the excitation electrode. Among these terminals, terminals for input, power supply, and the like are connected to predetermined external connection terminals 65, 66, 67, and 68 by wiring patterns (not shown) of the wiring board 60, respectively. The external connection terminals 65, 66, 67, and 68 are connected to an external device by the mounting terminal 80. For example, the external connection terminal 65 is connected to GND, the external connection terminal 66 is connected to OUT, the external connection terminal 67 is connected to VDD, and the external connection terminal 68 is connected to VCC.

  Although not shown, the gap after joining the wiring board 60 and the circuit element 40 is filled with resin. In this way, the active surface of the circuit element 40 is protected from moisture and the like, and the bonding by the bumps is reinforced.

  In the piezoelectric device 10 according to the present embodiment described above, the circuit element 40 and the piezoelectric vibrator 20 are electrically connected and structurally joined by the connecting member 70 penetrating the through holes 61 and 62. Therefore, compared with the prior art, the process of bonding the circuit element 40 to the wiring substrate 60 and the two-stage wire bonding process are unnecessary, and the number of man-hours can be reduced.

  In addition, since the circuit element 40 and the piezoelectric vibrator 20 are linearly joined within the range of the through holes 61 and 62 by the connecting member 70, the size and thickness can be reduced as compared with the conventional technique in which the metal wire is connected. it can.

  Furthermore, the connection between the circuit element 40 and the piezoelectric vibrator 20 can be performed by the connection member 70 having good conductivity and thermal conductivity and having a cross-sectional area larger than that of the metal wire. This heat is easily transmitted to the piezoelectric vibrator 20 and is thermally integrated, so that there is an effect that the frequency stability at the start is good.

The connection member 70 is formed by bonding first bumps 72 and 75 formed on the circuit element 40 and second bumps 77 and 78 formed on the wiring board 60.
Au stud bumps or the like can be used for the first bumps 72 and 75 and the second bumps 77 and 78. Since the Au stat bump can be formed in multiple stages in the thickness direction, the bump height can be easily adjusted, and the cross-sectional area can be selected to an appropriate size.

Then, the manufacturing method of the piezoelectric device 10 which concerns on this embodiment is demonstrated. The method for manufacturing the piezoelectric device 10 described below is characterized by a method of forming the first bumps 72 and 75 on the circuit element 40 side and the second bumps 77 and 78 on the piezoelectric vibrator 20 side.
(Piezoelectric Device Manufacturing Method / Example 1)

  2A, 2 </ b> B, and 2 </ b> C are cross-sectional views illustrating the main steps of the piezoelectric device manufacturing method according to the first embodiment. 2 illustrates a connection structure between the circuit element 40 and the piezoelectric vibrator 20 illustrated in FIG. This will be described with reference to FIG.

As shown in FIG. 2A, bumps 71, 72, 73, 74, 75, and 76 are formed on the connection electrodes 41, 42, 43, 44, 45, and 46 of the circuit element 40, respectively. For the connection electrodes 44 and 46 and the bumps 74 and 76, refer to FIG.
In this embodiment, the bumps 71 to 76 are formed by Au stud bumps so as to have substantially the same height. Here, the bumps 72 and 75 are first bumps 72 and 75 in order to distinguish them from others.

  Further, as shown in FIG. 2B, the wiring board 60 is bonded to the piezoelectric vibrator 20 with an adhesive, and then the external terminal 50 exposed in the through hole 61 and the external terminal exposed in the through hole 62. Second bumps 77 and 78 are formed on each of 53. The second bumps 77 and 78 are formed by Au stud bumps so as to be almost the same height as the total thickness of the wiring board 60 (thickness including the connection terminals 55, 56, 57, and 58).

  Subsequently, as shown in FIG. 2C, the bump formation side of the circuit element 40 is disposed so as to face the wiring substrate 60 side, and the first bumps 72 and 75 and the second bumps 77 and 78 are joined. . At this time, the other bumps 71, 73, 74, and 75 are bonded to the connection terminals 55, 56, 57, and 58 of the wiring board 60 in the same bonding process. These bondings are performed using a flip chip mounting method. A state where the first bumps 72 and 75 and the second bumps 77 and 78 are joined is represented as a connection member 70.

  The mounting terminal 80 is covered with a resist so that only the external connection terminals 65, 66, 67, and 68 are exposed after the piezoelectric vibrator 20 and the circuit element 40 are joined, and the external connection terminals 65, 66, 67, and A thick plating of Cu or the like is performed on the upper portion of 68, and the resist is removed and formed. Alternatively, it may be formed in advance on the wiring board 60.

  Although illustration is omitted, after the wiring board 60 and the circuit element 40 are joined, a resin is filled in the gap between the two. As a result, the active surface 40a of the circuit element 40 is protected from moisture and the like, and the bonding is reinforced by the bumps.

  According to the method for manufacturing the piezoelectric device 10 described above, the first bumps 72 and 75 formed in the circuit element 40 through the through holes 61 and 62 and the second bumps 77 and 78 formed in the piezoelectric vibrator 20 are provided. By joining, the piezoelectric vibrating piece 30 and the circuit element 40 are electrically joined, and the piezoelectric vibrator 20 and the circuit element 40 are structurally joined. Therefore, in contrast to the above-described connection method using the metal wire in the prior art, the step of bonding the circuit element 40 to the wiring substrate 60 and the two-step wire bonding step are unnecessary, and the number of steps can be reduced.

The bumps formed on the circuit element 40 include first bumps 72 and 75 for connection to the external terminals 50 and 53 and other bumps 71, 73, 74 and 76. Accordingly, it is preferable to perform the bump forming process on all the bumps under the same conditions as the first bumps 72 and 75, and the first bumps 72 and 75 have substantially the same shape. In such a case, it is conceivable that the height necessary for penetrating the wiring board 60 and joining to the second bumps 77 and 78 cannot be secured. Therefore, by forming the second bumps 77 and 78 formed on the external terminal side substantially the same as the thickness of the wiring board 60, the first bumps 72 and 75 and the second bumps 77 and 78 are reliably joined. Can be done. Since the second bumps 77 and 78 are formed in a separate process from the first bumps 72 and 75, the second bumps 77 and 78 can be formed at any appropriate height.
(Piezoelectric Device Manufacturing Method, Example 2)

  Next, a manufacturing method of the piezoelectric device 10 and Example 2 will be described with reference to the drawings. The second embodiment is characterized in that a process of flattening the upper surfaces of the second bumps 77 and 78 is added to the process of the first embodiment. Therefore, the same reference numerals are used to explain the differences from the first embodiment.

  FIG. 3A is a cross-sectional view showing an Au stud bump, and FIG. 3B is a cross-sectional view showing a planarization process according to the second embodiment. FIG. 3A illustrates the case where the second bump 77 is formed on the external terminal 50 provided in the piezoelectric vibrator 20. In forming the Au stud bump, the Au wire is sent out through the capillary 96, the tip of the Au wire is discharged and melted to form a ball, and this is joined to the surface of the second bump 77 by ultrasonic waves to cut the Au wire. Is. Therefore, as shown in FIG. 3A, the second bump 77 has a shape having a bump main body 77a and an Au wire cutting portion 77b like a crushed ball. Therefore, the Au wire cutting part 77 b protrudes from the bonding surface with the first bump 72. Therefore, in order to improve the bonding condition with the first bump 72, a planarization step is added.

  In the flattening step, after the second bumps 77 are formed on the surface of the external terminal 50 by Au stud bumps, the upper surface is pressed and flattened using a flattening jig 95 as shown in FIG. . In the Au stud bump, the Au wire cutting part 77 b protrudes from the wiring board 60. Therefore, in the planarization step, it is preferable to press the upper surface of the second bump 77 so that the upper surface of the second bump 77 is almost the same as the total thickness of the wiring substrate 60.

  According to the second embodiment, by flattening the second bumps 77 and 78, the area of the bonding surface with the first bump 72.75 can be increased, and the bonding reliability can be improved.

If the heights of the first bumps 72 and 75 are sufficiently high for bonding to the second bumps 77 and 78, the height after the planarization of the second bumps 77 and 78 is the same as that of the wiring board 60. It may be lower than the total thickness.
(Piezoelectric Device Manufacturing Method, Example 3)

  Next, a third embodiment of the method for manufacturing the piezoelectric device 10 will be described with reference to the drawings. The third embodiment is characterized in that the first bumps 72 and 75 are formed in multiple stages on the circuit element 40 and no bump is provided on the piezoelectric vibrator 20 side. Therefore, the description will be made by attaching the same reference numerals to the common parts, focusing on the differences from the first and second embodiments. Note that FIG. 1A is also referred to.

  FIG. 4 is a cross-sectional view illustrating a part of the method for manufacturing the piezoelectric device according to the third embodiment. FIG. 4 is a cross-sectional view corresponding to the AA cut surface of FIG. In the circuit element 40, bumps 71, 72a, 73, 74, 75, and 76 are formed on the connection electrodes 41, 42, 43, 44, 45, and 46, respectively. For the connection electrodes 44, 45, 46 and the bumps 74, 75, 76, refer to FIG. The bumps 71, 72a, 73, 74, 75, and 76 are formed to have substantially the same height by Au stud bumps.

  On the piezoelectric vibrator 20 side, bumps 72b are formed by Au stud bumps so as to overlap the bumps 72a. A bump in a state where the bump 72 a and the bump 72 b are joined is referred to as a first bump 72. Similarly, in the bump 75, two bumps are stacked to form the first bump 75. On the piezoelectric vibrator 20 side, the external terminals 50 and 53 are exposed through the through holes 61 and 62 of the wiring board 60. Here, when the height of the first bumps 72 and 75 is expressed as h1 and the thickness of the wiring board 60 is expressed as h2, the height h1 of the first bumps 72 and 75 is set so that h1> h2. Note that the difference between the height h1 and the thickness h2 is that the first bumps 72 and 75 are joined to the external terminals 50 and 53, and the other bumps 71, 73, 74, and 76 are connected to the connection terminal 55 of the wiring board 60. It is assumed that the joining with 56, 57, 58 is a difference that can be performed simultaneously.

  As described above, when the height of the first bumps 72 and 75 is insufficient in the two-step bump configuration, the first bumps 72 and 75 may be configured in a multi-step configuration with three or more steps. Further, the second and subsequent bumps are not limited to the same size as the first bump (72a).

According to the third embodiment described above, the first bumps 72 and 75 can be easily made higher than the thickness of the wiring board 60 by stacking a plurality of bumps, and the number of bumps can be increased. By selecting, there is an effect that the bump height can be appropriately controlled in accordance with the thickness of the wiring board 60.
In addition, there is no need to form a pump on the piezoelectric vibrator 20, and thus there is an advantage that the manufacture of the piezoelectric vibrator 20 does not require a different Au stud bump process and equipment.

  The concept of forming the first bumps 72 and 75 described in the third embodiment with multi-stage bumps can be applied to the second bumps 77 and 78 of the first embodiment. For example, two or three or more bumps can be formed on the surfaces of the external terminals 50 and 53 by using Au stud bumps. This is effective even when the wiring board 60 is thick enough to be bonded to the first bumps 72 and 75 with a single-stage bump configuration. Further, the bumps 71, 72, 73, 74, 75, and 76 formed on the circuit element 40 are formed with uniform dimensions (height), and the second bumps 77 and 78 are formed in multiple stages, thereby increasing the bump height. It can be controlled more easily if appropriate.

Further, if the Au wire has the same diameter for the bumps 72a and 72b, the first bumps 72 and 75 having a multi-stage configuration can be formed using the same equipment.
(Piezoelectric Device Manufacturing Method, Example 4)

  Next, a fourth embodiment of the method for manufacturing the piezoelectric device 10 will be described with reference to the drawings. The fourth embodiment is characterized in that, among the bumps 71, 72, 73, 74, 75, 76 formed on the circuit element 40, the first bumps 72, 75 are formed higher than the other bumps. The description will be made by attaching the same reference numerals to the common parts, focusing on the differences from the third embodiment.

  FIG. 5 is a cross-sectional view illustrating the method for manufacturing the first bump according to the fourth embodiment. Reference is also made to FIG. First, bumps 71, 73, 74 and 76 are formed on the circuit element 40. The bumps 71, 73, 74, and 76 are formed to have substantially the same height by Au stud bumps.

  Next, first bumps 72 and 75 are formed. The first bumps 72 and 75 are made higher than the bumps 71, 73, 74 and 76 formed previously. The first bumps 72 and 75 are formed by making the diameter of the Au wire of the Au stud bump larger than the diameter of the Au wire used for the bumps 71, 73, 74 and 76, and appropriately adjusting the pressure, It can be formed. Here, the height h1 of the first bumps 72 and 75 is set such that h1> h2 when the thickness of the wiring board 60 is represented as h2. Note that the difference between the height h1 and the thickness h2 is that the first bumps 72 and 75 are joined to the external terminals 50 and 53, and the other bumps 71, 73, 74, and 76 are connected to the connection terminal 55 of the wiring board 60. It is assumed that the joining with 56, 57, 58 is a difference that can be performed simultaneously.

  In the fourth embodiment, bumps are formed only on the circuit element 40 side, and the first bumps 72 and 75 are formed higher than the other bumps, and the same effects as those of the above-described embodiments can be obtained. In addition, the 1st bumps 72 and 75 can make a junction cross-sectional area large by using a thing thicker than other bumps, and can make electroconductivity and thermal conductivity higher.

In the first to fourth embodiments described above, the through holes 61 and 62 are formed in the wiring board 60, and the circuit element 40 and the piezoelectric vibrator 20 are joined by bumps within the range of the through holes 61 and 62. However, notches may be provided in place of the through holes 61 and 62.
FIG. 6 is a plan view of the piezoelectric device showing a structure in which a notch is provided in the wiring board. The same parts as those in the first embodiment (see FIG. 1A) are denoted by the same reference numerals, and different points will be described. In FIG. 6, notches 63 and 64 including positions corresponding to the above-described through holes 61 and 62 are formed in the wiring board 60.

The notch 63 exposes a part of the external terminal 50, and the notch 64 exposes a part of the external terminal 53. Thus, the piezoelectric device 10 described above can also be configured with the structure in which the notches 63 and 64 are provided instead of the through holes 61 and 62, and the manufacture of the piezoelectric device described in the first to fourth embodiments is possible. It is possible to adapt the method.
Further, the notches 63 and 64 have an effect that air bubbles are easily removed when the gap after joining the wiring board 60 and the circuit element 40 is filled with resin.

  DESCRIPTION OF SYMBOLS 10 ... Piezoelectric device, 20 ... Piezoelectric vibrator, 21 ... Package, 22a ... Outer bottom surface, 30 ... Piezoelectric vibrating piece, 40 ... Circuit element, 41, 42, 43, 44, 45, 46 ... Connection electrode, 50, 51, 52, 53 ... external terminals, 60 ... wiring board, 61, 62 ... through hole, 71, 73, 74, 76 ... bump, 72, 75 ... first bump, 77, 78 ... second bump.

Claims (9)

A piezoelectric device in which a piezoelectric vibrator, a wiring board, and a circuit element are stacked and integrated in order,
A package having an external terminal on the outer bottom surface, and a piezoelectric vibrator having a piezoelectric vibrating piece housed in the package and electrically connected to the external terminal;
A circuit element having a connection electrode and driving the piezoelectric vibrator;
A wiring board having a through hole or a notch exposing at least a part of the external terminal and the connection electrode;
A connection member that penetrates the through hole or the notch and connects the external terminal and the connection electrode;
A piezoelectric device comprising: The connection member is a bump formed on the external terminal or / and the connection electrode;
The piezoelectric device according to claim 1. Forming a first bump on the connection electrode of the circuit element;
Bonding the outer bottom surface of the piezoelectric vibrator in which a piezoelectric vibrating piece is accommodated in a package having an external terminal on the outer bottom surface, and a wiring board having a through hole or a notch;
The external terminal and the connection electrode are electrically connected by connecting the first bump to the external terminal exposed by the through hole or the notch at the position where the through hole or the notch is disposed. And a process of
A method for manufacturing a piezoelectric device comprising: Forming a second bump on the external terminal exposed by the through hole or the notch;
Electrically connecting the external terminal and the connection electrode by bonding the first bump and the second bump at a position where the through hole or the notch is disposed;
The method for manufacturing a piezoelectric device according to claim 3, comprising: The height of the second bump is substantially the same as the thickness of the wiring board;
The method for manufacturing a piezoelectric device according to claim 4. After the second bump is formed, the method further includes a step of flattening the upper surface of the second bump to be substantially the same height as the upper surface of the wiring board.
The method for manufacturing a piezoelectric device according to claim 4. The step of forming the second bump is a multi-step bump forming step of stacking a plurality of bumps;
The method for manufacturing a piezoelectric device according to claim 4. Bonding the first bump and the external terminal at the position where the through hole or the notch is disposed, and electrically connecting the connection electrode and the external terminal,
The step of forming the first bump is a multi-stage bump forming step of stacking a plurality of bumps,
The method for manufacturing a piezoelectric device according to claim 3. Bonding the first bump and the external terminal at the arrangement position of the through-hole or the notch, and connecting the connection electrode and the external terminal,
The connection electrode has a connection electrode connected to the external terminal and a connection electrode connected to another terminal,
The step of forming the first bump includes a step of forming a bump on the connection electrode connected to the external terminal, and a step of forming a bump on the connection electrode connected to the other terminal. The bump formed on the connection electrode connected to the wiring board is formed higher than the thickness of the wiring board;
The method for manufacturing a piezoelectric device according to claim 3.

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