JP2005150786A - Composite piezoelectric device and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composite piezoelectric device whose packaging area is small when packaged on a packaging substrate, and to provide a manufacturing method thereof. <P>SOLUTION: The composite piezoelectric device 10 has a configuration in which a piezoelectric device is joined to another piezoelectric device in a vertical direction via a lead frame 12, and the surroundings of the piezoelectric device and the other piezoelectric device are mold-sealed with a molding material 17. In this case, the lid of the piezoelectric device and the lid of the other piezoelectric device are positioned on the other side of the joining surface of the piezoelectric device and the other piezoelectric device. One end of the lead frame 12 protruding from the molding material 17 is bent downward along the molding material 17 to form packaging terminals 52. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a composite piezoelectric device, and more particularly to a composite piezoelectric device in which a plurality of piezoelectric devices are integrated and a method for manufacturing the composite piezoelectric device.

  A plurality of piezoelectric devices such as AT-cut piezoelectric vibrators and tuning-fork type piezoelectric vibrators are mounted on various electronic devices as reference frequency sources for electronic devices, reference signal sources for watches, and the like. A plurality of piezoelectric devices are separately mounted on a mounting substrate in accordance with the circuit configuration of the electronic device. In recent years, as electronic devices typified by mobile phones have been downsized, mounting boards mounted inside the electronic devices have also been downsized. In addition, since various functions are added to electronic devices, the amount of electronic components mounted on a mounting board is increasing. For this reason, the mounting area of the mounting substrate on which the electronic components are mounted has been reduced.

  Thus, a piezoelectric device has been invented in which a plurality of piezoelectric vibrating pieces having different oscillation frequencies are simultaneously mounted in one package to save space. That is, a frame-type insulating substrate is laminated on the upper and lower surfaces of a planar insulating substrate to form a recess, an AT-cut piezoelectric vibrating piece is mounted on one of the recesses, and a tuning fork-type piezoelectric vibrating piece is mounted on the other side. This is a piezoelectric device having an opening hermetically sealed with a lid (see Patent Document 1).

  Also, a plurality of frame-type insulating substrates having different frame widths are stacked on a planar insulating substrate, a recess having a step is formed on the side wall, and a tuning fork-type piezoelectric vibrating piece is mounted on the lowest step of the recess. There is also a piezoelectric device having a configuration in which an AT-cut piezoelectric vibrating piece is mounted on the upper surface of the substrate and the opening of the recess is hermetically sealed with a lid (see Patent Document 2).

In addition, a plurality of cylinder-type piezoelectric vibrators are arranged in the horizontal direction, lead terminals that are electrically connected to the piezoelectric vibrating pieces inside the cylinder are electrically joined to the inner leads, and the piezoelectric vibrator and inner leads are molded and sealed. There is also a device (see Patent Document 3).
JP 2003-78380 A JP 2003-69366 A JP 2000-59169 A

  However, in a configuration in which a plurality of piezoelectric vibrating pieces are mounted by forming a package having a recess, a conventionally used package cannot be used, and a dedicated package for mounting a plurality of piezoelectric vibrating pieces is required. There is a problem. In addition to the conventionally used piezoelectric vibrator manufacturing line, a new piezoelectric device manufacturing line for mounting a plurality of piezoelectric vibrating pieces is required. For this reason, there is a problem that new equipment must be introduced. In addition, in the manufacture of a piezoelectric device that mounts a plurality of piezoelectric vibrating pieces, a complicated operation, in particular, in a piezoelectric device in which concave portions are formed on both upper and lower sides of a planar insulating substrate and piezoelectric vibrating pieces are mounted in each concave portion, After mounting the piezoelectric vibrating piece, it is necessary to turn over the package and mount the piezoelectric vibrating piece in the other recess. For this reason, there exists a problem which the difficulty of a manufacturing technique becomes high.

  The oscillation frequency of the piezoelectric device is adjusted at the final stage of the manufacturing process, that is, after the piezoelectric vibrating piece is mounted on the package and sealed with a lid. Therefore, it cannot be determined whether the operation of the piezoelectric vibrating piece is good or bad until the oscillation frequency is adjusted. Therefore, a piezoelectric device mounted with a plurality of piezoelectric vibrating pieces is discarded even if the operation of one of the piezoelectric vibrating pieces is poor and the other piezoelectric vibrating piece is good, which increases the manufacturing cost. There is a point.

  In addition, since the cylinder-type piezoelectric vibrator includes a piezoelectric vibrating piece inside the cylinder, the piezoelectric vibrator cannot be reduced in size. For this reason, there is a problem that a piezoelectric device in which a plurality of cylinder-type piezoelectric vibrators are molded and sealed cannot be reduced in size.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a composite piezoelectric device that can be easily manufactured at low cost and a method for manufacturing the same.

  In order to achieve the above object, a composite piezoelectric device according to the present invention is characterized in that a piezoelectric device and another piezoelectric device are joined vertically. Even when a plurality of piezoelectric devices are mounted on a mounting substrate, the mounting area can be reduced by joining the piezoelectric devices vertically.

  In the composite piezoelectric device described above, the piezoelectric device and the other piezoelectric device are joined via a lead frame, and the piezoelectric device and the other piezoelectric device are sealed with a molding material. . In addition, an external terminal electrically connected to the piezoelectric device piece mounted in the piezoelectric device is joined to one lead frame, and an external terminal electrically connected to the other piezoelectric device piece mounted in the other piezoelectric device is the other lead. It is characterized by being joined to a frame. Further, the present invention is characterized in that a lead frame is interposed between the piezoelectric device and the other piezoelectric device to form a ground terminal. In this case, it is preferable that one end of the lead frame protrudes from the molding material and is bent on the lower surface of the molding material to form a mounting terminal. By sealing the periphery of the piezoelectric device and the other piezoelectric device, the bonding strength between the piezoelectric device and the other piezoelectric device can be improved. In addition, since the external terminal that is electrically connected to the piezoelectric device piece and the external terminal that is electrically connected to the other piezoelectric device piece are joined to the lead frame alternately, the piezoelectric device and the other piezoelectric device are not electrically connected. The piezoelectric device piece may be a piezoelectric vibrating piece or a surface acoustic wave element piece. Further, by grounding the ground terminal, it is possible to block the shielding effect and the influence of mutual interference of electromagnetic waves caused by the high frequency current flowing in the circuit pattern of the piezoelectric device and the circuit pattern of the other piezoelectric device.

  In the composite piezoelectric device described above, the lid of the piezoelectric device and the lid of the other piezoelectric device are located on the opposite side of the joint surface between the piezoelectric device and the other piezoelectric device, and a part of the molding material is opened. Thus, one or both of the lid of the piezoelectric device and the lid of another piezoelectric device are exposed to the outside. When a glass lid is used for the lid of the piezoelectric device, the piezoelectric device piece can be visually recognized from the outside even after the composite piezoelectric device is formed. Furthermore, after the composite piezoelectric device is formed, the oscillation frequency can be adjusted by irradiating the piezoelectric device piece with laser light through the opening and the lid.

  The piezoelectric device and the other piezoelectric device are any one of an AT cut piezoelectric vibrator, an AT cut piezoelectric oscillator, a tuning fork type piezoelectric vibrator, a tuning fork type piezoelectric oscillator, a surface acoustic wave resonator, or a surface acoustic wave oscillator. It is characterized by that. Thus, a composite piezoelectric device can be configured by combining various piezoelectric devices.

  The method for manufacturing a composite piezoelectric device according to the present invention includes a step of manufacturing a piezoelectric device, a step of manufacturing another piezoelectric device, and a step of bonding the piezoelectric device and another piezoelectric device through a lead frame. And a step of sealing the periphery of the piezoelectric device and the other piezoelectric device with a molding material, and a step of bending the lead frame protruding from the molding material into a U-shape to form a mounting terminal. It is said. Piezoelectric devices and other piezoelectric devices can be manufactured in existing manufacturing equipment. The process of assembling the composite piezoelectric device can use existing manufacturing equipment. For this reason, a new manufacturing facility is not required, and an existing manufacturing facility can be used. Further, if an operation check is performed after manufacturing a piezoelectric device and another piezoelectric device, it can be determined whether or not it is a non-defective product, so that a composite piezoelectric device can be manufactured using only the non-defective product. Therefore, it is possible to reduce the occurrence of malfunctioning composite piezoelectric devices.

  Hereinafter, preferred embodiments of a composite piezoelectric device and a method for manufacturing the same according to the present invention will be described. In this embodiment, a composite piezoelectric device using an AT cut piezoelectric vibrator and a tuning fork type piezoelectric vibrator will be described. However, this is only one embodiment of the present invention, and the present invention is not limited to this. Not. FIG. 1 shows a cross-sectional view of the composite piezoelectric device. FIG. 2 is an exploded perspective view of the composite piezoelectric device. In FIG. 2, the mold sealing package is removed. The main structure of the composite piezoelectric device 10 is that an AT-cut piezoelectric vibrator 14 and a tuning fork type piezoelectric vibrator 16 are joined up and down via a lead frame 12 and their periphery is sealed with a molding material 17 such as a resin. It is.

  The tuning fork type piezoelectric vibrator 16 has a configuration in which a tuning fork type piezoelectric vibrating piece 18 is sealed inside a package 20. In other words, a package base 26 having a rectangular flat substrate 22 and a wall portion 24 formed by raising a side of the flat substrate 22 upward is formed. As the material of the package base 26, an insulating material such as ceramic or a metal is used. When the package base 26 is made of metal, it is necessary to provide wiring for electrically connecting the tuning fork type piezoelectric vibrating piece 18 and the external terminal 28 and an insulating member on the back surface of the package base 26.

  External terminals 28 are formed at the four corners of the back surface of the package base 26. A mount electrode 30 for mounting the tuning fork type piezoelectric vibrating piece 18 is formed on the bottom surface of the package base 26. The mount electrode 30 becomes a gate side electrode and a drain side electrode of the tuning fork type piezoelectric vibrating piece 18, and one mount electrode 30 is formed so as to be drawn toward one corner on one short side of the package base 26, and the other mount The electrode 30 is drawn out toward the other corner. The external terminal 28 is electrically connected through a castellation formed on the side surface of the package base 26. The mount electrode 30 and the external terminal 28 may be electrically connected through a via hole or a through hole that penetrates the planar substrate 22.

  The tuning fork type piezoelectric vibrating piece 18 is cantilever mounted on the mount electrode 30 using a conductive adhesive 34, and the excitation electrode formed on the tuning fork type piezoelectric vibrating piece 18 and the mount electrode 30 are electrically connected. In the case of using a tuning fork type piezoelectric vibrating piece provided with a support portion for supporting the tuning fork type piezoelectric vibrating piece main body, both of the tuning fork type piezoelectric vibrating pieces may be mounted. Further, in the case of using a tuning fork type piezoelectric vibrating piece provided with a frame type support portion around the tuning fork type piezoelectric vibrating piece main body, a configuration may be adopted in which hook-shaped packages are joined to the top and bottom of the frame type support portion.

  A lid 32 is bonded to the upper surface of the package base 26, and the inside of the package 20 is hermetically sealed in an inert gas atmosphere or vacuum. At this time, when a glass lid is used, it is bonded to the upper surface of the package base 26 through a low melting glass, and when a metal lid is used, it is joined to the upper surface of the package base 26 by seam welding. Note that when the oscillation frequency is adjusted by irradiating the piezoelectric vibrating piece with laser light after the package 20 is hermetically sealed, a glass lid is used.

  The AT-cut piezoelectric vibrator 14 has a configuration in which an AT-cut piezoelectric vibrating piece 36 is sealed inside a package 38. The detailed configuration of the AT cut piezoelectric vibrator 14 is the same as that of the tuning fork type piezoelectric vibrator 16 described above.

  The lead frame 12 is joined to the external terminal 28 of the tuning fork type piezoelectric vibrator 16. At this time, the external terminal 28a electrically connected to the tuning fork type piezoelectric vibrating piece 18 and the lead frame 12a are joined by a conductive joining material such as solder. Further, the external terminal 28b that is not electrically connected to the tuning fork type piezoelectric vibrating piece 18 and the lead frame 12b are joined by a non-conductive joining material. An AT-cut piezoelectric vibrator 14 is bonded on the lead frame 12. At this time, the external terminal 40a that is electrically connected to the AT-cut piezoelectric vibrating piece 36 is joined to the external terminal 28b of the tuning fork type piezoelectric vibrator 16 that is not electrically connected to the tuning fork type piezoelectric vibrating piece 18 by a conductive bonding material such as solder. It is joined with. The external terminal 40b that is not electrically connected to the AT-cut piezoelectric vibrating piece 36 is joined to the lead frame 12a that is joined to the external terminal 28a of the tuning fork type piezoelectric vibrator 16 that is electrically connected to the tuning fork type piezoelectric vibrating piece 18 by a non-conductive bonding material. ing. Therefore, the tuning fork type piezoelectric vibrator 16 and the AT cut piezoelectric vibrator 14 are not electrically connected.

  The periphery of the tuning fork type piezoelectric vibrator 16 and the AT cut piezoelectric vibrator 14 is sealed with a molding material 17 such as a resin. The tuning fork-type piezoelectric vibrator 16 and / or the AT-cut piezoelectric vibrator 14 may have a configuration in which the surfaces of the lids 32 and 46 are not molded and the opening 42 is provided so that the lids 32 and 46 are exposed to the outside.

  Further, the lead frame 12 interposed between the tuning fork type piezoelectric vibrator 16 and the AT cut piezoelectric vibrator 14 protrudes from the molding material 17 and is bent along the molding material 17 to the lower surface. The lead frame 12 located on the lower surface becomes the mounting terminal 52 of the composite piezoelectric device 10. In this way, the composite piezoelectric device 10 is configured.

  A lead frame 12 is interposed between the tuning fork type piezoelectric vibrator 16 and the AT-cut piezoelectric vibrator 14, and the lead frame 12 is further protruded from the molding material 17 and bent along the molding material 17 to the lower surface. A ground terminal 44 may be provided (see FIG. 2). Further, an external terminal is formed on the tuning fork type piezoelectric vibrator 16 and / or the AT cut piezoelectric vibrator 14 corresponding to the position of the ground terminal 44, and a metal film that does not conduct with the mount electrodes 30, 50 is formed inside the packages 20, 38. The external terminal may be electrically connected to the metal film through a castellation formed on a side surface, and the external terminal and the ground terminal 44 may be electrically connected. In this case, via holes and through holes may be provided in the package bases 26 and 48 so that the external terminals and the metal film are electrically connected.

  Next, a method for manufacturing the composite piezoelectric device 10 will be described. FIG. 3 shows an explanatory diagram of the manufacturing process of the composite piezoelectric device 10. First, the tuning fork type piezoelectric vibrator 16 and the AT cut piezoelectric vibrator 14 are manufactured on separate manufacturing lines using existing manufacturing equipment. Thereafter, operation checks of the tuning fork type piezoelectric vibrator 16 and the AT cut piezoelectric vibrator 14 are performed to check whether or not the tuning fork type piezoelectric vibrator 16 and the normal operation are performed. Only the normally operating piezoelectric vibrators 14 and 16 are sent to the production line of the composite piezoelectric device 10.

  Next, in the process of assembling the composite piezoelectric device 10, first, a conductive bonding material 56 is applied on the external terminal 28 a that is electrically connected to the tuning fork type piezoelectric vibrating piece 18 in the tuning fork type piezoelectric vibrator 16, and the tuning fork type piezoelectric vibrating piece 18 and A non-conductive bonding material 58 is applied on the non-conductive external terminal 28b. Then, the lead frame 12 is placed on the external terminal 28, and the lead frame 12 is joined to the tuning fork type piezoelectric vibrator 16 (see FIG. 3A).

  Next, the non-conductive bonding material 60 is applied on the lead frame 12 a that is electrically connected to the tuning fork type piezoelectric vibrating piece 18 through the conductive bonding material 56, and is electrically conductive on the lead frame 12 b that is not electrically connected to the tuning fork type piezoelectric vibrating piece 18. The adhesive bonding material 62 is applied. Further, a conductive bonding material 64 such as solder is applied on the lead frame 12 to be the ground terminal 44 (see FIG. 3B).

  Then, the AT frame piezoelectric vibrator 14 is bonded onto the lead frame 12 together with the lead frame 12 and the external terminal 40 of the AT cut piezoelectric vibrator 14. At this time, the lead frame 12b not connected to the tuning fork type piezoelectric vibrating piece 18 and the external terminal 40a connected to the AT-cut piezoelectric vibrator 14 are joined. Further, the lead frame 12a electrically connected to the tuning fork type piezoelectric vibrating piece 18 and the external terminal 40b not electrically connected to the AT cut piezoelectric vibrator 14 are joined (see FIG. 3C).

  Next, the periphery of the tuning fork type piezoelectric vibrator 16 and the AT cut piezoelectric vibrator 14 is sealed with a molding material 17 to form a mold sealed package. At this time, the surfaces of the lids 32 and 46 of the tuning fork type piezoelectric vibrator 16 and / or the AT cut piezoelectric vibrator 14 are not sealed with the molding material 17. Then, the lead frame 12 protruding from the mold sealing package is bent in a U shape to the lower surface along the mold sealing package to form the mounting terminals 52 (see FIG. 3D).

  Next, the oscillation frequencies of the tuning fork type piezoelectric vibrator 16 and the AT cut piezoelectric vibrator 14 are adjusted. This adjustment is performed by irradiating laser light toward the piezoelectric vibrating reeds 18 and 36 from the portion where the lids 32 and 46 are exposed to the outside without being mold-sealed. In this way, the composite piezoelectric device 10 is manufactured.

  Thus, the tuning fork-type piezoelectric vibrator 16 and the AT-cut piezoelectric vibrator 14 are arranged vertically to form the composite piezoelectric device 10, so that the mounting area when mounted on a mounting board mounted on an electronic device is reduced. be able to.

  Further, it is not necessary to newly make a package dedicated to the composite piezoelectric device 10, and the composite piezoelectric device 10 can be manufactured using an existing package. The tuning fork type piezoelectric vibrator 16 and the AT cut piezoelectric vibrator 14 can be manufactured using existing manufacturing equipment. Since the assembly process of the composite piezoelectric device 10 can use existing manufacturing equipment, it is not necessary to introduce new manufacturing equipment for manufacturing the composite piezoelectric device 10. Furthermore, the technical difficulty in manufacturing the composite piezoelectric device 10 does not increase.

  Further, the tuning fork type piezoelectric vibrator 16 and the AT cut piezoelectric vibrator 14 are formed, and the composite piezoelectric device 10 is manufactured after the operation of the piezoelectric vibrators 14 and 16 is checked. Can be joined. Therefore, the occurrence of malfunctioning composite piezoelectric device 10 can be reduced.

  Further, when the tuning fork type piezoelectric vibrator 16 and the AT cut piezoelectric vibrator 14 are joined vertically, an electromagnetic wave caused by a high-frequency current flowing in each circuit pattern is generated, causing interference to the other circuit pattern. Then, mutual interference occurs between the circuit patterns of the tuning fork type piezoelectric vibrator 16 and the AT-cut piezoelectric vibrator 14, thereby causing a problem that the oscillation of the piezoelectric vibrating pieces 18 and 36 becomes unstable. However, in this embodiment, since the ground terminal 44 is interposed between the tuning fork type piezoelectric vibrator 16 and the AT cut piezoelectric vibrator 14 and the ground terminal 44 is grounded, mutual interference can be blocked. Further, a shielding effect can be obtained.

Further, the lids 32 and 46 of the piezoelectric vibrators 14 and 16 are not mold-sealed, and the surfaces of the lids 32 and 46 are exposed to the outside. Therefore, even after the composite piezoelectric device 10 is assembled, the piezoelectric vibrating piece 18. , 36 can be irradiated with laser light to adjust the oscillation frequency. Therefore, a highly accurate composite piezoelectric device 10 can be manufactured.
Since the tuning fork type piezoelectric vibrator 16 and the AT cut piezoelectric vibrator 14 are joined using the lead frame 12, the composite piezoelectric device 10 can be easily mass-produced.

  It should be noted that an oscillation circuit may be mounted on either the tuning fork type piezoelectric vibrator 16 or the AT cut piezoelectric vibrator 14 to form an oscillator. In this case, a temperature compensation circuit may be mounted on the oscillator. A surface acoustic wave resonator or a surface acoustic wave oscillator may be used in place of the tuning fork type piezoelectric vibrator 16 or the AT cut piezoelectric vibrator 14. Moreover, you may use a BT cut piezoelectric device and another piezoelectric device. Further, a composite piezoelectric device may be formed by vertically arranging AT-cut piezoelectric vibrators having different oscillation frequencies.

It is sectional drawing of the composite piezoelectric device which concerns on this Embodiment. It is a perspective view of the composite piezoelectric device which concerns on this embodiment. It is explanatory drawing of the manufacturing process of the composite piezoelectric device which concerns on this embodiment.

Explanation of symbols

10 ... …… Composite piezoelectric device, 12 ......... Lead frame, 14 ... AT-cut piezoelectric vibrator, 16 ......... Tuning fork type piezoelectric vibrator, 17 ......... Mold material, 28 ...... External terminal, 32 ......... Lid, 40 ......... External terminal, 42 ......... Opening, 46 ......... Lid, 52 ......... Mounting terminal.

Claims (8)

  A composite piezoelectric device characterized by joining a piezoelectric device and another piezoelectric device vertically. The composite piezoelectric device according to claim 1,
Bonding the piezoelectric device and the other piezoelectric device via a lead frame,
The piezoelectric device and the other piezoelectric device are sealed with a molding material,
A composite piezoelectric device characterized by that. The composite piezoelectric device according to claim 2,
An external terminal electrically connected to the piezoelectric device piece mounted in the piezoelectric device is bonded to one lead frame,
An external terminal connected to another piezoelectric device piece mounted in the other piezoelectric device is joined to the other lead frame.
A composite piezoelectric device characterized by that.   4. The composite piezoelectric device according to claim 1, wherein a lead frame is interposed between the piezoelectric device and the other piezoelectric device to form a ground terminal.   5. The composite piezoelectric device according to claim 2, wherein one end of the lead frame protrudes from the molding material and is bent to a lower surface of the molding material to form a mounting terminal.   The composite piezoelectric device according to any one of claims 1 to 5, wherein the lid of the piezoelectric device and the lid of the other piezoelectric device are located on a side opposite to a joint surface between the piezoelectric device and the other piezoelectric device, A composite piezoelectric device, wherein a part of a molding material is opened, and either one or both of the lid of the piezoelectric device and the lid of the other piezoelectric device are exposed to the outside.   The composite piezoelectric device according to any one of claims 1 to 6, wherein the piezoelectric device and the other piezoelectric device include an AT cut piezoelectric vibrator, an AT cut piezoelectric oscillator, a tuning fork type piezoelectric vibrator, a tuning fork type piezoelectric oscillator, A composite piezoelectric device characterized by being either a surface acoustic wave resonator or a surface acoustic wave oscillator. Manufacturing a piezoelectric device;
Manufacturing other piezoelectric devices;
Bonding a piezoelectric device and another piezoelectric device via a lead frame;
Sealing the periphery of the piezoelectric device and the other piezoelectric device with a molding material;
A step of bending the lead frame protruding from the mold material into a U-shape to form a mounting terminal;
A method of manufacturing a composite piezoelectric device characterized by comprising:

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