JP2009060335A - Piezoelectric device - Google Patents

Abstract

Provided are a highly reliable piezoelectric device and piezoelectric oscillator in which the influence of thermal stress applied to a mounting terminal when mounted on an external mounting substrate is suppressed.
A crystal oscillator 1 includes a crystal resonator 20 having a plurality of external terminals 25a to 25d on an outer bottom portion of a package 21 and a crystal resonator element 40 being hermetically sealed therein, and one of a wiring board 11 and a wiring board 11. The circuit board 10 in which the connection terminals 15a to 15d corresponding to the external terminals 25a to 25d are formed on the surface, the plurality of mounting terminals 12a to 12d are formed on the other surface, and the IC 30 is mounted on one surface; have. In addition, the crystal resonator 20 is bonded and connected to the circuit board 10 by soldering the connection terminals 15a to 15d and the corresponding external terminals 25a to 25d via the spherical conductor 50. Further, the external terminals 25a to 25d and the mounting terminals 12a to 12d are formed at positions where they do not overlap in a plan view.
[Selection] Figure 1

Description

  The present invention relates to a piezoelectric device.

  Conventionally, a circuit element such as a semiconductor integrated circuit (IC) having a piezoelectric vibrating piece and an oscillation circuit as a clock source of an electronic circuit is the same in various electronic devices such as OA equipment such as information communication equipment and computers, and consumer equipment. A piezoelectric oscillator as a piezoelectric device sealed in a package is widely used. Recently, with the rapid progress of miniaturization and thinning due to the spread of mobile communication devices such as mobile phones, piezoelectric oscillators are required to be smaller and thinner, and thin mounting on external mounting boards Many surface mount type piezoelectric oscillators suitable for the above are used.

  In addition, the piezoelectric oscillators as described above are increasingly required to have higher functions as well as to be smaller and thinner. To cope with this, circuit elements constituting the oscillation circuit and temperature compensation circuit or adjustment circuit elements for finely adjusting the oscillation frequency of the oscillation circuit and the compensation amount of the temperature compensation circuit are mounted on the wiring board. A piezoelectric oscillator in which a package type piezoelectric vibrator is joined and connected on a circuit board has been proposed. For example, Patent Document 1 introduces a surface-mount type piezoelectric oscillator in which a connection terminal on a circuit board and an external terminal of a corresponding piezoelectric vibrator are joined and connected via a joining member made of a spherical conductor. .

  A piezoelectric oscillator (surface-mounted crystal oscillator) described in Patent Document 1 includes a piezoelectric vibrator (having a plurality of external terminals on an outer bottom portion of a package, and a piezoelectric vibrating piece (crystal vibrating element) hermetically sealed therein. And a circuit board on which circuit elements constituting an oscillation circuit and a temperature compensation circuit are mounted on a wiring board made of glass epoxy resin. A connection terminal (mount pad) corresponding to a plurality of external terminals of the piezoelectric vibrator is arranged on the circuit board of the circuit board, and the connection terminal and the external terminal corresponding to the connection terminal are solder-coated resin spheres Or it connects by soldering via the joining member (spherical conductor) which is metal spheres, such as copper. The bonding member has a structure in which the piezoelectric vibrator is bonded above the circuit board on which the circuit element is mounted on the wiring board, and the upper surface of the highest circuit element on the wiring board is in contact with the lower surface of the piezoelectric vibrator. It has a size necessary for ensuring a gap without any gap. A plurality of mounting terminals for mounting with an external mounting board (user board) are provided on the lower surface side of the wiring board, which is the outer bottom portion of the piezoelectric oscillator, in the vicinity of the position overlapping the connection terminal in plan view. Yes.

JP 2004-296455 A

  However, in the piezoelectric oscillator described in Patent Document 1, the connection terminals of the wiring board corresponding to the plurality of external terminals of the piezoelectric vibrator and solder-bonded via the bonding member, and the mounting formed on the outer bottom surface of the wiring board The terminal is disposed in the vicinity of the overlapping position in the plan view of the wiring board. For this reason, when mounting a piezoelectric oscillator on an external mounting substrate such as an electronic device by a surface mounting method, the heat of solder bonding applied to the mounting terminal is easily conducted to the bonding portion with the piezoelectric vibrator via the connection terminal. However, there is a problem that solder at a joint portion between the circuit board and the piezoelectric vibrator may be remelted to cause connection failure.

  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 includes a piezoelectric vibrator having a plurality of external terminals on an outer bottom portion of a package, and a piezoelectric vibrating piece hermetically sealed therein, and one surface of a wiring board. A connection board is formed, a plurality of mounting terminals are formed on the other surface, and a circuit board is further mounted on the one surface, and the connection terminal and the external terminal are connected to each other. A piezoelectric device in which the piezoelectric vibrator is bonded onto the circuit board by soldering via the external circuit board, and the external terminal and the mounting terminal are formed at positions that do not overlap in a plan view. It is characterized by.

  According to this configuration, when the piezoelectric device is mounted on the external mounting board by the surface mounting method, the heat of the solder bonding applied to the mounting terminal is a bonded portion between the connection terminal and the external terminal bonded via the connection member. It is possible to suppress the conduction. This prevents problems such as re-melting of the solder where the connection terminal and the external terminal are solder-bonded via the bonding member to cause poor connection, and deterioration of the solder due to deterioration of the solder. Therefore, a highly reliable piezoelectric device can be provided.

  Application Example 2 In the piezoelectric device according to the application example described above, the piezoelectric vibrator has at least three external terminals, and the center of gravity of the piezoelectric vibrator is located inside a polygon formed by connecting substantially the centers of the external terminals. It is characterized by being arranged.

  According to this configuration, when the piezoelectric vibrator is joined to the circuit board via the joining member, the three points surrounding the center of gravity of the piezoelectric vibrator are supported by the joining member. Posture is stable. As a result, in the process of joining the piezoelectric vibrator on the circuit board via the joining member at the time of assembling the piezoelectric device, the circuit board and the piezoelectric are used without using a special support for maintaining the posture of the piezoelectric vibrator. Bonding can be performed while maintaining parallelism with the vibrator. Accordingly, since uniform bonding is possible via a bonding member between a plurality of external terminals and corresponding connection terminals, a highly reliable piezoelectric device with good connection reliability between the circuit board and the piezoelectric vibrator is obtained. Can be provided.

  Application Example 3 In the piezoelectric device according to the application example, the center of the polygon formed by connecting the external terminals of the plurality of external terminals substantially coincides with the center of gravity of the piezoelectric vibrator. It is characterized by being arranged.

  According to this configuration, since the piezoelectric vibrator is supported evenly and in a balanced manner on the wiring board, a piezoelectric device with better connection reliability can be provided.

  Application Example 4 In the piezoelectric device according to the application example described above, the plurality of mounting terminals are disposed in the vicinity of each corner portion of the wiring board, and the plurality of connection terminals are provided on two opposing sides of the wiring board. It is arranged between the mounting terminals.

  According to this configuration, since the space on the two sides orthogonal to the two opposite sides of the wiring board on which the connection terminals are disposed is vacant, it is possible to design a board on which the wiring pattern is efficiently arranged on the wiring board. For example, it is possible to further enhance the functionality of the piezoelectric device by adding circuit elements connected to the wiring board.

  Application Example 5 In the piezoelectric device according to the application example, the connection member is spherical.

  According to this configuration, since the joining member has a spherical shape, when the piezoelectric vibrator is soldered to the circuit board via the joining member, the contact area between the external terminal and the connection terminal and the joining member is reduced. Since it is small, a large amount of solder spreads over each terminal part, forming a good fillet and improving the bonding strength. In addition, since the self-alignment action at the time of solder bonding is easy to work, good solder bonding of the piezoelectric vibrator to the wiring board can be performed with high positional accuracy.

  Application Example 6 In the piezoelectric device according to the application example described above, at least a bonding portion between the piezoelectric vibrator and the circuit board is sealed with a sealing resin in a state where the plurality of mounting terminals are exposed to the outside. It is characterized by.

  According to this configuration, the circuit board on which the circuit elements on the wiring board are mounted, and the joint portion with the piezoelectric vibrator are sealed and protected by the sealing resin, thereby providing a highly reliable piezoelectric device. can do.

  Application Example 7 In the piezoelectric device according to the application example described above, the circuit element includes a circuit element constituting an oscillation circuit.

  According to this configuration, it is possible to provide a piezoelectric oscillator as a piezoelectric device having a small size and precise frequency control and having high reliability.

  Hereinafter, a crystal oscillator which is an embodiment of a piezoelectric oscillator will be described with reference to the drawings.

(First embodiment)
FIG. 1A is a schematic plan view for explaining a crystal oscillator 1 according to the present embodiment, and FIG. 1B is a cross-sectional view taken along line AA of FIG. ) Is a plan view of the crystal oscillator 1 viewed from the bottom side. In FIG. 1A, for convenience of explanation of the internal structure of the crystal resonator 20 as a piezoelectric resonator, a part of the sealing resin 19 that covers the outside of the crystal oscillator 1 is notched, and the crystal resonator Illustration of the lid 29 joined to the upper part of 20 is omitted, and a lid joining position 29 ′ is shown by a one-dot chain line.

  1A to 1C, a crystal oscillator 1 includes a circuit board 10 having an IC 30 as a circuit element connected on a wiring board 11, and a crystal vibrating piece 40 as a piezoelectric vibrating piece in a package 21. And a crystal resonator 20 which is bonded and hermetically sealed. The crystal resonator 20 is bonded to the upper side of the circuit board 10 by solder 59 via a spherical conductor 50 as a bonding member, and the bonded circuit board 10 and the crystal resonator 20 are sealed with a sealing resin 19. Yes.

〔Crystal oscillator〕
As shown in FIGS. 1A and 1B, a crystal resonator 20 is a package 21 made of a ceramic insulating material or the like, and has a recess 22 formed substantially at the center, and a plurality of external terminals 25a to 25a on the outer bottom. A package 21 provided with 25d is provided. In the present embodiment, four external terminals 25a to 25d are disposed in the vicinity of the corner portion of the outer bottom portion of the package 21 that is substantially rectangular in plan view. A plurality of mount terminals 27 a and 27 b to which the crystal vibrating piece 40 is bonded are formed on the concave bottom portion of the concave portion 22 of the package 21.
Of the plurality of external terminals 25a to 25d, the external terminals corresponding to the mount terminals 27a and 27b are connected by an internal wiring such as a through hole (not shown) or a lead wiring. In the present embodiment, the mount terminals 27a and 27b and the corresponding external terminals 25c and 25d are respectively connected, and the external terminals 25a and 25b are external terminals for bonding that do not contribute to electrical connection. These electrode terminals and wiring patterns are generally formed by screen-printing and firing a metal wiring material such as tungsten (W) or molybdenum (Mo) on a ceramic insulating material, and nickel (Ni) or gold (Au) thereon. It is formed by plating.

Excitation electrodes 41 are formed on both main surfaces of the crystal vibrating piece 40 made of crystal cut into a flat plate shape (in FIG. 1A, the excitation electrode on the lower surface side of the crystal vibrating piece 40 is on the upper surface side. (It is hidden by the excitation electrode 41 and not shown). The excitation electrodes 41 on both main surfaces of the quartz crystal vibrating piece 40 are drawn out to one end side in the longitudinal direction of the quartz crystal vibrating piece 40 and connected to the connection electrode 45.
In the crystal vibrating piece 40, the connection electrodes 45 corresponding to the mount terminals 27 a and 27 b provided on the concave bottom portion of the concave portion 22 of the package 21 are aligned. Then, the conductive adhesive 49 applied so as to cover and cover each of the mount terminals 27a and 27b and the corresponding connection electrode 45 is solidified to be electrically connected, and cantilevered. It is joined in the state.

On the upper side of the package 21, for example, a metal lid 29 is seam welded via a seal ring (not shown) formed by punching out an iron-nickel (Fe—Ni) alloy or the like into a frame shape, The quartz crystal vibrating piece 40 bonded to is hermetically sealed.
As another lid 29 joining method, the lid 29 can be joined to the upper surface of the package 21 with a low melting point glass or the like by using a metal brazing material such as solder or a glass lid.

[Circuit board]
As shown in FIGS. 1B and 1C, a circuit board 10 includes a wiring board 11 having a plurality of mounting terminals 12a to 12d on the lower surface side, and an IC 30 as a circuit element on the upper surface side of the wiring board 11. Are connected by a bonding wire 39.
Here, the detailed structure of the circuit board 10 is demonstrated along FIG. FIG. 2 is a plan view for explaining the circuit board 10 of the crystal oscillator 1.

  In FIG. 2, the circuit board 10 has a wiring board 11 made of an insulating material such as glass epoxy resin. A plurality of mounting terminals 12 a to 12 d for connecting to an external mounting substrate (not shown) are disposed on the lower surface side of the wiring substrate 11 which is the outer bottom portion of the crystal oscillator 1. In the present embodiment, four mounting terminals 12a to 12d are arranged in the vicinity of the corner portion on the lower surface side of the substantially rectangular wiring board 11 in plan view.

In addition, an oscillation circuit, a temperature compensation circuit, a correction circuit that corrects the frequency of the oscillation circuit, a compensation value of the temperature compensation circuit, and the like are integrated at a substantially center on the upper surface side of the wiring board 11 to form a circuit. An IC 30 as a circuit element in which a plurality of electrode pads 35 are provided on the active surface) is bonded and fixed by a die attach agent or a die attach film (not shown) which is a thermosetting adhesive.
On the wiring board 11, IC connection terminals 17a to 17f connected to the plurality of electrode pads 35 of the IC 30 are formed. The plurality of electrode pads 35 of the IC 30 and the corresponding IC connection terminals 17 a to 17 f are connected by bonding wires 39.

  Further, on the upper surface side of the wiring substrate 11, connection terminals 15 a to 15 d connected corresponding to the plurality of external terminals 25 a to 25 d of the crystal resonator 20 are disposed on the lower surface side of the wiring substrate 11. The mounting terminals 12a to 12d are arranged at positions that do not overlap in plan view. In the present embodiment, the connection terminals 15a to 15d are mounted between the mounting terminals 12a and 12b, between the mounting terminals 12b and 12d, of the mounting terminals 12a to 12d disposed at the respective corners on the lower surface side of the wiring board 11. It is arranged on the upper surface side of the wiring board 11 at the approximate center between the mounting terminals 12c and 12d and between the mounting terminals 12a and 12c.

  In the wiring board 11 of the present embodiment, the connection terminals 15c and 15d connected to the external terminals 25c and 25d that contribute to the electrical connection among the external terminals 25a to 25d of the crystal resonator 20 and the IC connection terminal 17b. , 17e are connected via inter-terminal wiring. Further, the IC connection terminals 17a, 17c, 17d, and 17f are the mounting terminals 12a, 12b, 12c, and 12d provided on the lower surface side of the wiring board 11, and internal wiring such as through holes (not shown) or routing wiring, etc. Connected by.

  In FIG. 2, a spherical conductor arrangement position 50 ′, which is a circular two-dot chain line illustrated in the approximate center of each connection terminal 15 a to 15 d, is a circuit corresponding to each external terminal 25 a to 25 d of the crystal resonator 20. The arrangement | positioning position of the spherical conductor 50 mentioned later used for each connection with each connection terminal 15a-15d of the wiring board 11 of the board | substrate 10 is shown.

[Crystal oscillator]
Next, returning to FIGS. 1A to 1C, the structure of the crystal oscillator 1 formed by bonding the crystal resonator 20 and the circuit board 10 described above will be described in detail.
In FIG. 1B, the crystal resonator 20 is bonded above the circuit board 10 in which the IC 30 is connected to the wiring board 11 by the bonding wires 39. The connection terminals 15a and 15b formed on the wiring board 11 of the circuit board 10 and the corresponding external terminals 25a and 25b of the crystal resonator 20 are joined by solder 59 via a spherical conductor 50 as a joining member. Yes.
Similarly, the connection terminals 15c and 15d of the wiring board 11 shown in FIG. 1C and the corresponding external terminals 25c and 25d of the crystal resonator 20 are connected via a spherical conductor arranged at the spherical conductor arrangement position 50 ′. Soldered together. As described above, the external terminals 25c and 25d connected to the mount terminals 27a and 27b of the crystal resonator 20 and the corresponding connection terminals 15c and 15d of the circuit board 10 are arranged at the spherical conductor arrangement position 50 ′. They are electrically connected by soldering via a spherical conductor. On the other hand, the external terminals 25a and 25b of the crystal resonator 20 and the connection terminals 15a and 15b of the circuit board are not electrically connected, and the spherical conductors between the connection terminals 15a and 15b and the corresponding external terminals 25a and 25d. The crystal resonator 20 joined to the upper part of the circuit board 10 together with the joint part via the contact hole contributes to supporting the crystal oscillator 20 with a stable posture by four-point support by a spherical conductor. In other words, in the crystal resonator 20 of the present embodiment, the center of the quadrilateral formed by connecting the approximate centers of the external terminals 25a to 25d and the center of gravity of the crystal resonator 20 are arranged so as to substantially coincide. Therefore, the crystal unit 20 is stably supported on the circuit board 10 by the four spherical conductors 50 in a balanced manner.

  Next, the connection portion between the crystal resonator 20 and the circuit board 10 will be described in detail with reference to the drawings. FIG. 3 is an enlarged view of a portion of the crystal oscillator 1 shown in FIG. 1B in which the connection terminal 15b of the circuit board 10 and the external terminal 25b of the crystal resonator 20 are connected via the spherical conductor 50. FIG.

  In FIG. 3, the external terminal 25 b of the crystal unit 20 and the connection terminal 15 b disposed on the wiring board 11 of the circuit board 10 are soldered via a spherical conductor 50. The spherical conductor 50 is formed by coating or plating a metal film 52 made of a metal with good solder wettability such as solder or tin (Sn) on the surface of a spherical metal 51 such as copper (Cu) serving as a core. The

  In the process of bonding the crystal resonator 20 on the circuit board 10, the spherical conductor 50 is first positioned and temporarily fixed to either the connection terminal 15b or the external terminal 25b. As a method for temporarily fixing the spherical conductor 50, a method of applying a flux to the connection terminal 15b or the external terminal 25b and placing the spherical conductor 50 at a predetermined position, followed by reflowing at a temperature equal to or higher than the melting temperature of the metal film 52. Etc. are applicable. Then, a suitable amount of solder paste is applied to either the connection terminal 15b or the external terminal 25b to which the spherical conductor 50 is temporarily fixed, and the circuit board 10 and the crystal resonator 20 are aligned and then reflowed. The connection terminal 15 b and the external terminal 25 b are soldered via the spherical conductor 50.

  The metal film 52 of the spherical conductor 50 has an effect of improving the wettability of the molten solder to the spherical metal 51 because the affinity of the solder paste that melts during reflow is good. As the solder reflow progresses, the metal film 52 is fused with the solder of the molten solder paste and is diffused into the spherical metal 51 of the spherical conductor 50 together with the tin in the solder of the solder paste, thereby making a strong solder joint. . For this reason, the metal film 52 is shown by a virtual line (two-dot chain line) in FIG. 3 showing the state after soldering.

  Each connection terminal 15a of the circuit board 10 shown in FIGS. 1A to 1C in the same manner as the solder bonding of the connection terminal 15b of the crystal resonator 20 and the external terminal 25a via the spherical conductor 50 described above. , 15c, 15d and the corresponding external terminals 25a, 25c, 25d of the crystal resonator 20 are soldered via spherical conductors 50, respectively.

Next, the effect of the crystal oscillator 1 of the above embodiment will be described.
(1) In the configuration of the crystal oscillator 1 of the above embodiment, the connection terminals 15a to 15d of the circuit board 10 and the external terminals 25a to 25d of the corresponding crystal resonator 20 are soldered via the spherical conductor 50. The external terminals 25a to 25d are arranged at positions that do not overlap with the mounting terminals 12a to 12d formed on the outer bottom portion of the circuit board 10 in plan view.
Thereby, when the crystal oscillator 1 is mounted on the external mounting substrate by the surface mounting method or the like, the heat of solder bonding applied to the mounting terminals corresponds to the connection terminals 15 a to 15 d bonded via the spherical conductor 50. It becomes difficult to be conducted to the junction with the terminals 25a to 25d. Therefore, it is possible to prevent problems such as re-melting of solder at the solder joint portions between the connection terminals 15a to 15d and the corresponding external terminals 25a to 25d to cause connection failure or deterioration of the solder and deterioration of reliability. Therefore, the crystal oscillator 1 having high reliability can be provided.

(2) In the above embodiment, the four external terminals 25a to 25d of the crystal unit 20 are formed so that the quadrangle center formed by connecting the approximate centers of the external terminals 25a to 25d and the center of gravity of the crystal unit 20 are approximately. Arranged to match.
With this configuration, the crystal resonator 20 is uniformly supported in a balanced manner at four points around the center of gravity on the circuit board 10. Thus, when the crystal oscillator 1 is assembled, a special support jig or the like for maintaining the posture of the crystal resonator 20 is not used in the step of soldering the crystal resonator 20 onto the circuit board 10 via the spherical conductor 50. However, soldering can be performed in a state where the parallelism between the circuit board 10 and the crystal unit 20 is maintained. Accordingly, since the external terminals 25a to 25d of the crystal unit 20 and the corresponding connection terminals 15a to 15d of the circuit board 10 can be uniformly joined via the spherical conductor 50, the circuit board 10 and the crystal unit 20 can be connected to each other. It is possible to provide a crystal oscillator 1 having a high connection reliability and a high reliability.

(3) In the above embodiment, the spherical conductor 50 is used as a joining member interposed in the solder joint between the circuit board 10 and the crystal unit 20.
According to this configuration, since the spherical conductor 50 has a spherical shape, the connection terminals 15 a to 15 d of the circuit board 10 and the corresponding external terminals 25 a to 25 d of the crystal resonator 20 are connected via the spherical conductor 50. When soldering, the contact portions between the external terminals 25a to 25b and the connection terminals 15a to 15d and the joining member are small, so that a large amount of solder is distributed to each terminal part, forming a good fillet and improving the joining strength. . In addition, since the self-alignment action at the time of soldering is easy to work, good soldering between the circuit board 10 and the crystal unit 20 can be performed with high positional accuracy.

(4) In the above embodiment, the circuit board 10 and the crystal unit 20 joined through the spherical conductor 50 are exposed to the outside, and the plurality of mounting terminals 12 a to 12 d formed on the outer bottom portion of the circuit board 10 are exposed to the outside. In this state, the crystal oscillator 1 was formed by sealing with a sealing resin 19.
As a result, the circuit board 10 on which the IC 30 is mounted on the wiring board 11 and the solder joint portion through the spherical conductor 50 between the circuit board 10 and the crystal unit 20 are sealed and protected by the sealing resin 19. The crystal oscillator 1 having high reliability can be provided.

  As described above, in the crystal oscillator 1 of the above-described embodiment, the four external terminals 25a to 25d of the crystal resonator 20 and the center of the quadrangle formed by connecting the approximate centers of the external terminals 25a to 25d and the crystal resonator 20 are provided. The center of gravity was arranged so as to substantially coincide with the center of gravity. The number of external terminals is not limited to this, and the number of external terminals only needs to be plural. When three or more external terminals are used, the polygon formed by connecting the approximate centers of the external terminals has the center of gravity of the crystal resonator. What is necessary is just to arrange | position so that it may be included.

(Modification 1)
FIG. 4 is a plan view illustrating a modified example of the crystal oscillator according to the embodiment including a crystal resonator having four external terminals as the arrangement of the connection terminals of the circuit board corresponding to the external terminals. . In this modification, the arrangement of the external terminals of the crystal resonator on the circuit board is described by the arrangement of the corresponding connection terminals, and the circuit elements and the like bonded to the circuit board have the same configuration as in the above embodiment. The illustration and description are omitted.

  On the lower surface side of the wiring board 61 of the circuit board 60 shown in FIG. 4, four mounting terminals 62 a to 62 d are arranged in the vicinity of the corner portion of the substantially rectangular wiring board 61 in plan view. On the upper surface side of the wiring board 61, four connection terminals 65 a to 65 d corresponding to the external terminals of the crystal resonator bonded to the upper side of the wiring board 61 are mounted terminals arranged on the lower surface side of the wiring board 61. It arrange | positions in the position which does not overlap with 62a-62d by planar view. The connection terminals 65a to 65d of this modification are between the mounting terminals 62a and 62b and between the mounting terminals 62b and 62c of the mounting terminals 62a to 62d disposed at the respective corners on the lower surface side of the wiring board 61. And the mounting terminals 62c and 62d and the mounting terminals 62a to 62d between the mounting terminals 62a and 62d are arranged on the upper surface side of the wiring board 61 in a region that does not overlap in plan view.

  In the drawing, a circular spherical conductor arrangement position 50 ′ illustrated by a virtual line (two-dot chain line) at the center of each of the connection terminals 65 a to 65 d is interposed in a joint portion where a crystal resonator is solder-joined on the circuit board 60. The installation position of the spherical conductor is shown. In addition, center points 67a to 67d in the figure indicate the center points of the connection terminals 65a to 65d. That is, the center points 67a to 67d also indicate the center points of the external terminals corresponding to the connection terminals 65a to 65d of the crystal resonator bonded to the upper side of the circuit board 60. In the circuit board 60, the four connection terminals 65 a to 65 d are arranged at the center of gravity of the crystal resonator bonded on the circuit board 60 inside the square formed by connecting the center points 67 a to 67 d of the connection terminals 65 a to 65 d. It is arranged to include G.

  According to this configuration, when the crystal unit is bonded to the circuit board 60 via the spherical conductor, the four points surrounding the center of gravity G of the crystal unit are supported by the spherical conductor 50. The attitude of the crystal unit is stabilized. Thus, in the process of bonding the crystal resonator on the circuit board 60 when the crystal oscillator is assembled, the circuit substrate 60 and the crystal vibration are not used without using a special support jig or the like for maintaining the orientation of the crystal resonator. Bonding can be performed while maintaining parallelism with the child. Accordingly, since it is possible to uniformly join the plurality of external terminals of the crystal resonator and the corresponding connection terminals 65a to 65d via the spherical conductor, the connection reliability between the circuit board 60 and the crystal resonator is good. A crystal oscillator having high reliability can be provided.

  In addition, not only in the arrangement of the four connection terminals 65a to 65d of the circuit board 60 described in the present modification, but in a configuration in which the crystal resonator is supported on the circuit board 60 via the spherical conductors, What is necessary is just to arrange | position so that the center of gravity of a crystal oscillator may exist in the inner side of the square formed by connecting a center. For example, two connection terminals are arranged between each mounting terminal on two opposite sides of the circuit board so that the center of gravity of the crystal resonator is inside the quadrilateral connecting the centers of the connection terminals. May be. According to this, since the wiring space is vacant on the other two sides orthogonal to the two sides where the connection terminals on the wiring board of the circuit board are arranged, circuit elements are added for higher functionality of the crystal oscillator. It becomes possible.

(Modification 2)
The crystal oscillator described in the above embodiment and Modification 1 is not limited to the four-point support structure through the spherical conductors of the four external terminals and the connection terminals, but has a plurality of external terminals and connection terminals corresponding thereto. Good.
FIG. 5 is a plan view of the circuit board 70 for explaining the arrangement of the three connection terminals when there are three external terminals of the crystal resonator and corresponding connection terminals of the circuit board that are joined via the spherical conductor. It is. The circuit elements and the like bonded to the circuit board are the same as those in the above embodiment, and illustration and description thereof are omitted.
On the lower surface side of the wiring board 71 of the circuit board 70 shown in FIG. 5, four mounting terminals 72a to 72d are arranged in the vicinity of the corners of the substantially rectangular wiring board 71 in plan view. Further, on the upper surface side of the wiring board 71, three connection terminals 75a to 75a corresponding to the external terminals of the crystal resonator bonded to the upper side of the circuit board 70 through the spherical conductors arranged at the spherical conductor arrangement position 50 ′. 75c is disposed at a position that does not overlap with the mounting terminals 72a to 72d disposed on the lower surface side of the wiring board 71 in plan view. Further, the connection terminals 75 a to 75 c are arranged so that a triangle formed by connecting the center points 77 a to 77 c of the connection terminals 75 a to 75 c includes the center of gravity G of the crystal resonator joined above the circuit board 70. Has been.

  According to this configuration, when the crystal unit is bonded to the circuit board 70 via the spherical conductor, the three points surrounding the center of gravity G of the crystal unit are supported by the spherical conductor with three-point support. The attitude of the crystal resonator can be stabilized on the substrate 60.

(Modification 3)
In the above embodiment, the first modification, and the second modification, the external terminal of the crystal resonator connected via the spherical conductor and the connection terminal of the corresponding circuit board can be balanced with respect to the center of gravity of the crystal resonator. Three or more are arranged in the crystal so that the crystal resonator is stably supported. Not only this but the external terminal connected via a spherical conductor and a corresponding connection terminal should just be arrange | positioned so that it may not overlap with the terminal for mounting in planar view, and what is necessary is just to be plural.
In this modification, a crystal oscillator having two external terminals and connection terminals connected via a spherical conductor will be described with reference to the drawing showing the arrangement of connection terminals on a circuit board. FIG. 6 is a plan view of a circuit board 80 having two connection terminals corresponding to connection terminals (not shown) of a crystal resonator joined via a spherical conductor arranged at a spherical conductor arrangement position 50 ′. . The circuit elements and the like bonded to the circuit board are the same as those in the above embodiment, and illustration and description thereof are omitted.

  The wiring board 81 of the circuit board 80 shown in FIG. 6 is provided with four mounting terminals 82a to 82d in the vicinity of the corner portion on the back side of the substantially rectangular wiring board 81 in plan view. Further, on the upper surface side of the wiring board 81, two connections that are bonded via spherical conductors that are arranged at the spherical conductor arrangement position 50 ′ corresponding to the external terminals of the crystal resonator bonded to the upper side of the wiring board 81. The terminals 85a and 85b are disposed at positions that do not overlap the mounting terminals 82a to 82d in plan view.

  In this way, when joining the two connection terminals 85a, 85b and the corresponding external terminals of the crystal resonator via the spherical conductor, using a spacer jig having the same height as the spherical conductor, etc. The crystal resonator may be positioned on the circuit board 80 in a state where the posture of the crystal resonator is stabilized, and solder bonding may be performed. At this time, the spacer jig may be arranged so that the polygon formed by connecting the center points of the connection terminals 85a and 85b and the center point of the spacer jig includes the center of gravity of the crystal resonator. In this way, it is possible to support and position the crystal resonator in a stable manner by the spherical conductor and the spacer jig arranged at the spherical conductor arrangement position 50 ′ of each connection terminal 85a, 85b. become.

  As mentioned above, although embodiment of this invention and its modification made by the inventor were concretely demonstrated, this invention is not limited to above-described embodiment and its modification, and does not deviate from the summary. Various changes can be made in the range.

For example, in the embodiment and the modification, the crystal vibrating piece 40 is used as the piezoelectric vibrating piece, but the present invention is not limited to this. In addition to quartz materials, the thickness of a single crystal material such as lithium tantalate (LiTaO ₃ ) or lithium niobate (LiNbO ₃ ) or a polycrystalline material (piezoelectric ceramic material) such as barium titanate (BaTiO ₃ ) It is also possible to use a piezoelectric vibrating piece made of another piezoelectric material exhibiting a sliding vibration mode.

  In the embodiment and the modification, the spherical conductor 50 made of the spherical metal 51 is used as a joining member that connects the crystal resonator 20 and the circuit boards 10, 60, 70, and 80. The circuit boards 10, 60, 70 are not limited to this, so that the highest mounting portion of the circuit elements such as the IC 30 bonded to the circuit boards 10, 60, 70, 80 does not contact the crystal unit 20. , 80 and the quartz crystal resonator 20 can be formed, and a joining member having a shape other than a spherical shape, such as a polygonal column shape or a cylindrical shape, can be used as long as it has at least a conductor that can be soldered. Is possible.

  In the embodiment and the modification, the circuit boards 10, 60, including the crystal resonator 20 as the piezoelectric resonator using the crystal resonator element 40 as the piezoelectric resonator element, and the IC 30 as the circuit element having the oscillation circuit, The crystal oscillator (piezoelectric oscillator) 1 constituted by 70 and 80 has been described in detail. The present invention is not limited to this, and a SAW device configured by connecting a SAW resonator as a piezoelectric vibrator and a circuit board, a gyro element including a gyro vibrating piece, and a circuit board are connected. The present invention can be applied to other piezoelectric devices such as a gyro sensor.

(A) is a schematic plan view explaining the crystal oscillator concerning this embodiment, (b) is the sectional view on the AA line of (a), (c) is a top view of the crystal oscillator seen from the bottom face side. The top view explaining the circuit board of this embodiment. FIG. 2 is an enlarged partial cross-sectional view illustrating a joint portion between the circuit board and the piezoelectric vibrator in FIG. The top view of the circuit board explaining the modification 1 of a crystal oscillator. The top view of the circuit board explaining the modification 2 of a crystal oscillator. The top view of the circuit board explaining the modification 3 of a crystal oscillator.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Crystal oscillator as a piezoelectric oscillator 10, 60, 70, 80 ... Circuit board, 11, 61, 71, 81 ... Wiring board, 12a-12d, 62a-62d, 72a-72d, 82a-82d ... Mounting terminal , 15a-15d, 65a-65d, 75a-75c, 85a, 85b ... connection terminal, 19 ... sealing resin, 20 ... crystal resonator as piezoelectric vibrator, 21 ... package, 25a-25d ... external terminal, 27a, 27b ... mount terminal, 29 '... lid bonding position, 29 ... lid, 30 ... IC as circuit element, 40 ... crystal vibrating piece as piezoelectric vibrating piece, 50 ... spherical conductor as bonding member, 59 ... solder, 67a- 67d, 77a to 77c: the center point of the connection terminal corresponding to the external terminal, G: the center of gravity of the crystal resonator as the piezoelectric resonator.

Claims (7)

A piezoelectric vibrator having a plurality of external terminals on the outer bottom portion of the package and in which a piezoelectric vibrating piece is hermetically sealed;
A connection terminal is formed on one surface of the wiring board, a plurality of mounting terminals are formed on the other surface, and a circuit board on which circuit elements are mounted on the one surface, and
A piezoelectric device in which the piezoelectric vibrator is bonded on the circuit board by soldering the connection terminal and the external terminal via a connection member,
The piezoelectric device, wherein the external terminal and the mounting terminal are formed at a position where they do not overlap in a plan view. The piezoelectric device according to claim 1,
A piezoelectric device comprising at least three external terminals, wherein the piezoelectric vibrator has a center of gravity inside a polygon formed by connecting substantially the centers of the external terminals. The piezoelectric device according to claim 1 or 2,
The piezoelectric device, wherein the plurality of external terminals are arranged so that a polygonal center formed by connecting substantially the centers of the external terminals and a center of gravity of the piezoelectric vibrator substantially coincide with each other. The piezoelectric device according to any one of claims 1 to 3,
The plurality of mounting terminals are disposed in the vicinity of each corner portion of the wiring board,
The piezoelectric device, wherein the plurality of connection terminals are disposed between the mounting terminals on two opposite sides of the wiring board. The piezoelectric device according to any one of claims 1 to 4,
The piezoelectric device, wherein the connecting member is spherical. The piezoelectric device according to any one of claims 1 to 5,
A piezoelectric device, wherein at least a joint portion between the piezoelectric vibrator and the circuit board is sealed with a sealing resin in a state where the plurality of mounting terminals are exposed to the outside. The piezoelectric device according to any one of claims 1 to 6,
A piezoelectric device characterized in that the circuit element includes a circuit element constituting an oscillation circuit.

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