JP2007184806A - Piezoelectric device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric device downsized wherein a space for the provision of external connection terminals can be ensured. <P>SOLUTION: The piezoelectric device includes: a crystal resonator package 10 wherein a crystal resonator chip 12 is contained in a ceramic package 11 and the inside of the package is air-tightly sealed; and an integrated circuit element 20 connected to the outer surface of the crystal resonator package 10, each corner of the integrated circuit element 20 is arranged so as to be opposite to each side of the outer circumference of the crystal resonator package 10, electrode pads 16 formed on the outer surface of the crystal resonator package 10 and bumps 21 formed at the integrated circuit element 20 are connected with each other, and the external connection terminals 30 are formed at at least four corners of the face of the crystal resonator package 10 to which the integrated circuit element 20 is connected. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a surface-mount type piezoelectric device used for electronic equipment or communication equipment.

In recent years, downsizing of devices is rapidly progressing due to demands for improving portability of electronic devices and communication devices. For this reason, piezoelectric devices such as crystal oscillators used in these devices are required to be further reduced in size and height.
As an example corresponding to the reduction in size and height of the piezoelectric device, a structure as shown in Patent Document 1 is known. In this patent document, a piezoelectric element is hermetically sealed in a ceramic package (container), and an IC (integrated circuit element) is arranged on the lower surface of the ceramic package so that the sides of the ceramic package and the IC are substantially parallel. Down bonding. Further, for connection with the outside, solder balls are provided on the same surface as the IC mounting surface of the ceramic package to form external connection terminals.

Japanese Patent Laying-Open No. 2005-151116 (FIG. 4)

  However, in the structure of the conventional piezoelectric device, if the size of the IC is not changed in order to further reduce the size of the piezoelectric device, the size of the IC occupies a relatively large ratio with respect to the area of the ceramic package. Therefore, there is a problem that a space for providing the external connection terminal is reduced. That is, when the external connection terminal is small and the piezoelectric device is mounted on the external substrate, there is a problem that the bonding strength with the external substrate is small.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a piezoelectric device that can be downsized and can secure a space for providing external connection terminals.

  In order to solve the above-described problems, a piezoelectric device according to the present invention is connected to a piezoelectric element package in which a piezoelectric element is housed and hermetically sealed, and an outer surface of the piezoelectric element package. An integrated circuit element, wherein each corner of the integrated circuit element is arranged to face each side of the outer periphery of the piezoelectric element package, and the electrode pad formed on the outer surface of the piezoelectric element package; A connection terminal formed on an active surface of the integrated circuit element is connected, and external connection terminals are formed in at least four corners of the surface of the piezoelectric element package to which the integrated circuit element is connected.

  According to this configuration, since each corner of the integrated circuit element is disposed so as to face each side of the outer periphery of the piezoelectric element package, substantially triangular spaces are generated at the four corners of the piezoelectric element package. By utilizing this, the external connection terminal can be formed with a sufficient size. Therefore, even when using an integrated circuit element that occupies a relatively large proportion of the area of the miniaturized piezoelectric element package, a sufficient space for forming the external connection terminal can be secured and mounted on an external substrate. In addition, it is possible to provide a piezoelectric device that can ensure bonding strength with an external substrate.

  In the piezoelectric device of the present invention, it is preferable that the external connection terminal is composed of a metal columnar member.

  Thus, if a metal columnar member such as a metal ball is used as the external connection terminal, a terminal exceeding the thickness of the integrated circuit element connected to the piezoelectric element package can be easily formed, and the manufacturing cost can be reduced. it can.

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

1A and 1B show a configuration of a crystal oscillator according to the present embodiment. FIG. 1A is a schematic plan view, FIG. 1B is a schematic partial sectional view, and FIG. 1C is a schematic bottom view.
The crystal oscillator 1 includes a crystal resonator package 10 that houses a crystal vibrating piece 12 as a piezoelectric element and an integrated circuit element 20. In the crystal resonator package 10, a crystal vibrating piece 12 is accommodated in a concave portion of a ceramic package 11 serving as a container, and is fixed by a conductive adhesive 14 such as an Ag paste. In addition, a plurality of electrode pads 16 are provided on the bottom surface of the ceramic package 11, and predetermined electrode pads 16 among these are connected via the conductive adhesive 14 described above by wiring (not shown) in the ceramic package 11. Thus, it is configured to be electrically connected to the excitation electrode 13 formed on the crystal vibrating piece 12. Further, a lid 15 is provided on the upper portion of the ceramic package 11 and is hermetically sealed while maintaining the space of the concave portion in which the crystal vibrating piece 12 is accommodated in a reduced pressure atmosphere or an inert gas atmosphere.

  In addition, a circuit element is formed on one surface of the integrated circuit element 20 such as an IC, and an electrode pad (not shown) is formed on this surface. The electrode pad is made of a metal such as Au as a connection terminal. Bumps 21 are formed. The bumps 21 and the electrode pads 16 of the crystal resonator package 10 are connected, and the integrated circuit element 20 is so-called face-down bonded to the bottom surface of the crystal resonator package 10.

Here, the integrated circuit element 20 is arranged such that each corner portion thereof faces a substantially central portion of each outer peripheral side of the crystal resonator package 10.
The integrated circuit element 20 includes an oscillation circuit that excites the crystal resonator element 12, and a PLL circuit, a temperature compensation circuit, a memory circuit, and the like depending on circumstances.
Furthermore, electrode pads 17 are provided at the four corners of the bottom surface of the crystal resonator package 10, and external connection terminals 30 formed of metal balls such as solder balls are formed thereon as metal columnar members.
This metal ball is formed to be higher than the height (thickness) of the integrated circuit element 20 face-down bonded to the bottom surface of the crystal resonator package 10.

  In the crystal oscillator 1 having the above configuration, the crystal resonator element 12 is excited by the oscillation circuit provided in the integrated circuit element 20 and outputs a desired frequency signal from a predetermined external connection terminal 30.

According to the crystal oscillator 1 of this embodiment, each corner portion of the integrated circuit element 20 is disposed so as to face each side of the outer periphery of the crystal resonator package 10. A substantially triangular space is generated, and the external connection terminal 30 can be formed with a sufficient size using this space. Therefore, even if the integrated circuit element 20 occupying a relatively large proportion of the area of the miniaturized crystal resonator package 10 is used, a sufficient space for forming the external connection terminals 30 can be secured, and the external substrate can be secured. When mounted on the crystal oscillator 1, it is possible to provide the crystal oscillator 1 capable of ensuring the bonding strength with the substrate.
(Modification)

Next, another arrangement of the integrated circuit element in the modified example of the above embodiment will be described.
FIG. 2 is a schematic bottom view showing the arrangement of integrated circuit elements in a modified example.
In this modification, the corners of the integrated circuit element 20 are arranged so as to be separated from the center of each side of the outer periphery of the crystal resonator package 10 and face each other.
The arrangement of the integrated circuit element 20 is within a range in which a space capable of forming the external connection terminal 30 with a sufficient size is secured at the four corners of the crystal resonator package 10 and the integrated circuit element 20 and the external connection terminal 30 are not short-circuited. Any arrangement may be used.

  Even when the integrated circuit element 20 is arranged in the crystal resonator package 10 in this way, substantially triangular spaces are formed at the four corners of the crystal resonator package 10, and the external connection terminals 30 are sufficiently large using these spaces. As a result, the same effects as in the present embodiment can be obtained.

  In the above embodiment, after the integrated circuit element 20 and the crystal resonator package 10 are connected, an underfill (insulating resin) is filled in the gap between the integrated circuit element 20 and the crystal oscillator package 10, and the integrated circuit element 20 and the quartz crystal vibration are cured. The connection strength of the child package 10 may be improved and the integrated circuit element 20 may be protected.

As described above, in the above-described embodiment, the crystal oscillator using the crystal resonator has been described as an example. However, the piezoelectric element is not limited to the crystal, but a piezoelectric material using a piezoelectric material such as lithium tantalate or lithium niobate. A vibrator may be used.
In addition, the piezoelectric element can be used in a SAW oscillator using a SAW (surface acoustic wave) element, a vibration gyro element or the like instead of a piezoelectric vibrator such as a crystal vibrating piece, and a vibration gyro sensor. can do.

The structure of the crystal oscillator in this embodiment is shown, (a) is a schematic plan view, (b) is a schematic fragmentary sectional view, (c) is a schematic bottom view. The schematic bottom view which shows arrangement | positioning of the integrated circuit element in the modification of this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Crystal oscillator as a piezoelectric device, 10 ... Quartz crystal resonator package as a piezoelectric element package, 11 ... Ceramic package as a container, 12 ... Crystal vibrating piece, 15 ... Lid, 16, 17 ... Electrode pad, 20 ... Integrated circuit element, 21... Bump as connection terminal, 30... External connection terminal.

Claims (2)

A piezoelectric element package in which a piezoelectric element is housed and hermetically sealed; and
An integrated circuit element connected to the outer surface of the piezoelectric element package,
Each corner of the integrated circuit element is disposed so as to face each side of the outer periphery of the piezoelectric element package, and is formed on an electrode pad formed on the outer surface of the piezoelectric element package and an active surface of the integrated circuit element. Connected to the
An external connection terminal is formed in at least four corners of the surface of the piezoelectric element package to which the integrated circuit element is connected. The piezoelectric device according to claim 1.
The piezoelectric device characterized in that the external connection terminal is composed of a metal columnar member.

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