JP2007036535A - Piezoelectric device and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric device excellent in characteristic capable of raising productivity, and to provide its manufacturing method. <P>SOLUTION: The device includes a substrate 10 having a wiring pattern; a crystal vibrator package 20 which is arranged at one surface side of the substrate 10 and internally stores a crystal vibrating piece 22; a circuit module 15 which is arranged at one surface side of the substrate 10, and mounts circuit elements 17 on a module substrate 16; and a resin 28 for coating the substrate 10, the crystal vibrator package 20, and the circuit module 15. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a piezoelectric device including a piezoelectric element and a circuit element, and a method for manufacturing the piezoelectric device.

  As a conventional piezoelectric device such as a crystal oscillator, a circuit element (transistor, resistor, capacitor, thermistor, etc.) constituting a crystal resonator package and an oscillation circuit is mounted on a substrate as shown in Patent Document 1 (FIG. 2). The structure is known. When mounting these crystal resonator packages and circuit elements on a substrate, a method is generally employed in which cream solder is applied to the mounting pattern of the substrate, and each is soldered to the substrate in a batch by a reflow method.

Japanese Patent Laid-Open No. 11-355047 (FIG. 2)

  When mounting a crystal unit package and multiple circuit elements on a substrate, the frequency of the crystal unit is likely to shift in a high-temperature environment such as reflow, and mounting is performed at the lowest possible temperature. ing. For this reason, in particular, in mounting small circuit elements, soldering defects are likely to occur, and when a soldering defect occurs, soldering is performed again, which reduces productivity, and in addition to the vibrator There was a problem that the frequency of the shift further shifted.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a piezoelectric device having improved productivity and excellent characteristics and a method for manufacturing the piezoelectric device.

  In order to solve the above problems, a piezoelectric device according to the present invention includes a substrate having a wiring pattern, a piezoelectric element package disposed on one surface side of the substrate and containing a piezoelectric element therein, and disposed on one surface side of the substrate. And a circuit module having a circuit element mounted on the module substrate, and a resin portion that covers the piezoelectric element package and the circuit module from the substrate.

In the manufacture of the piezoelectric device in this configuration, since the circuit element can be mounted on the module substrate in advance, the heating condition such as reflow can be performed under the condition according to the circuit element, and soldering defects can be reduced. it can. Thereafter, the piezoelectric element package and the circuit module may be mounted on the substrate of the piezoelectric device, and the soldering again due to the poor soldering of the circuit element is prevented. Thus, productivity in manufacturing a piezoelectric device can be improved, and furthermore, a piezoelectric device with good characteristics can be provided by reducing a frequency shift when mounting a piezoelectric element package on a substrate.
In addition, since the resin portion is formed so as to cover the piezoelectric element package and the circuit module from the substrate, the resin portion functions to reinforce the substrate even when the substrate is thinly formed, while maintaining the strength as a piezoelectric device. Thinning is possible.

  The method for manufacturing a piezoelectric device according to the present invention includes a step of preparing a substrate on which wiring patterns of a plurality of piezoelectric devices are arranged, and fixing a circuit module having circuit elements arranged on the module substrate to the wiring pattern on one side of the substrate, A step of fixing a piezoelectric element package containing a piezoelectric element therein to a wiring pattern on one side of the substrate; a step of resin molding so as to cover the circuit module and the piezoelectric element package in each piezoelectric device; And cutting the substrate into a plurality of piezoelectric devices.

According to this manufacturing method, the circuit element is mounted on the substrate of the piezoelectric device by mounting the circuit module on which the circuit element is mounted in advance, and the assembly of the piezoelectric device can be facilitated. In addition, re-soldering due to defective soldering of circuit elements is eliminated, and productivity can be improved.
Furthermore, productivity can be further improved by performing circuit module, piezoelectric element package fixing and resin molding on a single substrate for multiple piezoelectric devices, and finally cutting the piezoelectric device into pieces by dicing or the like. .

  In the piezoelectric device manufacturing method of the present invention, a substrate on which a wiring pattern is arranged is prepared, a step of fixing a circuit module in which a circuit element is arranged on a module substrate to one surface side of the substrate, and a piezoelectric element inside A step of fixing the piezoelectric element package to the one surface side of the substrate, and a step of resin molding so as to cover the circuit module and the piezoelectric element package.

  According to this manufacturing method, the circuit element is mounted on the substrate of the piezoelectric device by mounting the circuit module on which the circuit element is mounted in advance, and the assembly of the piezoelectric device can be facilitated. In addition, re-soldering due to defective soldering of circuit elements is eliminated, and productivity can be improved.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described with reference to the drawings. In the following embodiments, a crystal oscillator as a piezoelectric device will be described as an example.
(First embodiment)

1A and 1B are explanatory views for explaining the configuration of a crystal oscillator as a piezoelectric device. FIG. 1A is a front partial sectional view, and FIG. 1B is a side partial sectional view.
The crystal oscillator 1 includes a substrate 10, a circuit module 15, a crystal resonator package 20 as a piezoelectric element package, and a resin portion 28 that covers the circuit module 15 and the crystal resonator package 20.

  The substrate 10 is made of glass epoxy resin or the like, and a wiring pattern is formed. For example, the terminal 12 is formed in the portion where the circuit module 15 is mounted, and the terminal 11 is formed in the portion where the crystal resonator package 20 is mounted. Further, external terminals 13 for connection to the outside are formed on the other surface side of the substrate, and each is configured to be electrically connected by a predetermined wiring pattern.

In the circuit module 15, a plurality of circuit elements (IC, transistor, resistor, capacitor, thermistor, etc.) 17 are soldered to a module substrate 16 such as glass epoxy resin. These circuit elements 17 constitute an oscillation circuit for oscillating a crystal resonator element to be described later, a temperature compensation circuit, or the like.
In the crystal resonator package 20, a crystal vibrating piece 22 as a piezoelectric element is accommodated in a container 21 such as ceramic. An electrode 26 is formed on the crystal vibrating piece 22, and the electrode 26 and a terminal 24 formed inside the container 21 are fixed via a conductive adhesive 25. The inside of the container 21 is sealed with a lid 23 while keeping the inside in a vacuum atmosphere or an inert gas atmosphere.

  The circuit module 15 and the crystal resonator package 20 are mounted on one surface side of the substrate 10 by soldering or the like, and a resin portion 28 that covers the circuit module 15 and the crystal resonator package 20 is formed. The resin portion 28 is resin-molded by a transfer mold apparatus and is formed of an epoxy resin or the like.

As described above, since the crystal oscillator 1 of the present embodiment can mount the circuit element 17 on the module substrate 16 in advance, the heating condition such as reflow can be performed under the condition matching the circuit element 17 and soldering. Defects can be reduced. Thereafter, the crystal resonator package 20 and the circuit module 15 may be mounted on the substrate 10 of the crystal oscillator 1, so that re-soldering due to poor soldering of the circuit element 17 is prevented. Thus, the productivity in manufacturing the crystal oscillator 1 can be improved, and further, the crystal oscillator 1 having good characteristics can be provided by reducing the frequency shift when the crystal resonator package 20 is mounted on the substrate 10.
In addition, since the resin portion 28 is formed so as to cover the crystal resonator package 20 and the circuit module 15 from the substrate 10, the resin portion 28 serves to reinforce the substrate 10 even if the substrate 10 is thinly formed. It is possible to reduce the thickness while maintaining the strength as the crystal oscillator 1.
(Second Embodiment)

Next, a method for manufacturing a crystal oscillator as a piezoelectric device will be described. Note that the same components as those described in the first embodiment are denoted by the same reference numerals and description thereof is omitted.
FIG. 2 is a process flowchart showing the manufacturing process of the crystal oscillator. FIG. 3 is an explanatory view showing an embodiment for manufacturing a plurality of crystal oscillators from one substrate, FIG. 3 (a) is a front partial sectional view, and FIG. 3 (b) is a side partial sectional view.

The manufacturing method of the crystal oscillator will be described with reference to FIG. 3 while following the order in the process flowchart of FIG.
First, a substrate 30 on which a plurality of wiring patterns are formed is prepared (Step S1). Further, the circuit module 15 in which the circuit element 17 is soldered to the module substrate 16 is prepared (step S2). Furthermore, a crystal resonator package 20 that accommodates a crystal resonator element and is tuned to a predetermined frequency is prepared (step S3).

Solder cream is applied to the terminals 12 on which the circuit module 15 is mounted on the substrate 30 to mount the circuit module 15 (step S4).
Next, solder cream is applied to the terminals 11 on the substrate 30 on which the crystal resonator package 20 is mounted, and the crystal resonator package 20 is mounted (step S5).
Then, the substrate 30 is passed through a reflow furnace, and each circuit module 15 and each crystal resonator package 20 are soldered to the substrate 30 (step S6).

Thereafter, resin part 28 is formed by resin molding with a transfer molding device so as to cover each circuit module 15 and each crystal resonator package 20 on one surface side of substrate 30 (step S7).
Then, along the resin-molded resin portion 28, the substrate 30 is cut by dicing, and the crystal oscillators 2, 3, and 4 are separated into individual pieces (step S8).
Finally, the characteristics of the separated crystal oscillators 2, 3, and 4 are inspected (step S9), and the crystal oscillators 2, 3, and 4 are completed.

According to the manufacturing method of the crystal oscillators 2, 3, 4 described above, the circuit element 17 is mounted on the substrate 30 by mounting the circuit module 15 on which the circuit element 17 is mounted in advance. Assembling of 3 and 4 can be facilitated. In addition, the re-soldering due to the soldering failure of the circuit element 17 is eliminated, and the productivity can be improved.
Further, the plurality of crystal oscillators 2, 3 and 4 are fixed to the circuit module 15 and the crystal resonator package 20 and the resin molding with one substrate 30, and then the crystal oscillators 2, 3 and 4 are separated by dicing or the like. By improving the productivity, productivity can be further improved.

Moreover, although the said embodiment demonstrated embodiment which manufactured several crystal oscillators on one board | substrate, it is also possible to manufacture one crystal oscillator from one board | substrate.
Also in this manufacturing method, the circuit element is mounted on the substrate of the crystal oscillator by mounting a circuit module on which the circuit element is mounted in advance, and the assembly of the piezoelectric device can be facilitated. In addition, re-soldering due to defective soldering of circuit elements is eliminated, and productivity can be improved. In this case, substrate dicing is not required, and the process can be simplified and the number of facilities can be reduced.

Examples of applications of the piezoelectric device according to the embodiment of the present invention include TCXO (Temperature Compensated X'tal Oscillator). This TCXO is a piezoelectric device in which the frequency deviation is closely matched and the frequency fluctuation is reduced with respect to ambient temperature change and secular change, and has been widely used in portable communication devices in recent years. Since the structure according to the present embodiment can suppress the frequency shift of the vibrator in the manufacturing process and further reduce the thickness, it can be expected to be used for TCXO.
Further, it can be applied not only to an oscillator including a piezoelectric element and an oscillation circuit, but also to a piezoelectric device including another circuit element that does not include the piezoelectric element and the oscillation circuit.

In this embodiment, a glass epoxy substrate is used as the crystal oscillator and the module substrate, but a ceramic substrate can also be used.
In the embodiment of the present invention, a crystal oscillator is described as an example of a piezoelectric device. However, in addition to a crystal, a vibrator and a circuit element using a piezoelectric material such as lithium tantalate and lithium niobate are provided as a piezoelectric element. A piezoelectric device may be used. Moreover, it can replace with a vibrator | oscillator and can also be implemented as a SAW oscillator provided with the SAW resonator.

It is explanatory drawing explaining the structure of the crystal oscillator as a piezoelectric device, (a) is a front fragmentary sectional view, (b) is a side fragmentary sectional view. The flowchart which shows the manufacturing process of a crystal oscillator. It is explanatory drawing which shows one Embodiment for manufacturing several crystal oscillators from one board | substrate, (a) is a front fragmentary sectional view, (b) is a side fragmentary sectional view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2, 3, 4 ... Crystal oscillator as a piezoelectric device, 10 ... Board | substrate, 15 ... Circuit module, 16 ... Module board | substrate, 17 ... Circuit element, 20 ... Crystal oscillator package as a piezoelectric element package, 22 ... Piezoelectric element Quartz vibrating piece, 28 ... resin part, 30 ... substrate.

Claims (3)

A substrate having a wiring pattern;
A piezoelectric element package disposed on one side of the substrate and containing a piezoelectric element therein;
A circuit module in which a circuit element is mounted on a module substrate and disposed on one surface side of the substrate;
A resin portion covering the piezoelectric element package and the circuit module from the substrate;
A piezoelectric device comprising: A substrate on which wiring patterns of a plurality of piezoelectric devices are arranged is prepared,
Fixing a circuit module in which circuit elements are arranged on a module substrate to a wiring pattern on one side of the substrate;
Fixing a piezoelectric element package containing a piezoelectric element therein to a wiring pattern on one side of the substrate;
Resin molding to cover the circuit module and the piezoelectric element package in each piezoelectric device;
Cutting the substrate into a plurality of piezoelectric devices;
The manufacturing method of the piezoelectric device characterized by including. A board on which the wiring pattern is placed is prepared,
Fixing a circuit module having circuit elements arranged on a module substrate to one side of the substrate;
Fixing a piezoelectric element package containing a piezoelectric element inside to one side of the substrate;
Resin molding to cover the circuit module and the piezoelectric element package;
The manufacturing method of the piezoelectric device characterized by including.

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