JP2008252823A - Piezoelectric oscillator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance productivity by coping with miniaturization. <P>SOLUTION: A piezoelectric oscillator comprises a hollow type container having a hollow type space portion formed, external connection terminals formed at four corner portions of the hollow type container on a surface on the opposite side from a bottom surface of the hollow type space part, a lid body made of ceramic to airtightly seal the hollow type space portion, a piezoelectric vibrating element mounted on the lid body in the hollow type space portion, and an integrated circuit element electrically connected to the piezoelectric vibrating element through the lid body and connected to the external connection terminal through the lid body and hollow type container, and mounted on a main surface of the lid body facing the opposite side to the hollow type space portion. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a piezoelectric oscillator used in an electronic device such as a portable communication device.

  Conventionally, piezoelectric oscillators have been used in electronic devices such as portable communication devices. For example, as shown in FIG. 6, the conventional piezoelectric oscillator 200 mainly includes a concave container 210, a piezoelectric vibration element 220, a lid 230, and an integrated circuit element 240.

  The integrated circuit element 240 is mounted on the inner bottom surface of the concave container 210 whose wall is formed integrally with the substrate body. The piezoelectric vibration element 220 is mounted on the surface of the lid 230 facing the integrated circuit element 240 side. The lid 230 on which the piezoelectric vibration element 220 is mounted is joined to the concave container 210 on which the integrated circuit element 240 is mounted, and the piezoelectric vibration element 220 and the integrated circuit element 240 are hermetically sealed in the concave container 210. (For example, refer to Patent Document 1).

  The piezoelectric oscillator 200 having such a structure is mounted on an external wiring board such as a mother board, and external connection terminals provided on the back surface of the concave bottom surface of the concave container 210 are connected to the wiring of the external wiring board. For example, it is mounted by soldering. Here, the concave container 210 is usually formed of a ceramic material, and a wiring conductor is formed inside or on the surface thereof, and is formed using a conventionally known ceramic green sheet laminating method or the like.

  In addition, a temperature compensation circuit that corrects the oscillation frequency of the piezoelectric oscillator 200 based on the temperature compensation data created according to the temperature characteristics of the piezoelectric vibration element 220 is provided in the integrated circuit element 240. In order to store the temperature compensation data in the memory of the integrated circuit element 240 after the piezoelectric oscillator 200 is assembled, temperature compensation is performed on the surface opposite to the bottom surface of the concave portion of the concave container 210 or the outer surface. A temperature compensation control terminal for writing data is provided. The temperature compensation data is stored in the memory of the integrated circuit element 240 by applying the probe needle of the temperature compensation data writing device to the temperature compensation control terminal and inputting the temperature compensation data to the memory in the integrated circuit element 240. .

JP 2000-134037 A

However, in the conventional piezoelectric oscillator 200 having a structure in which the integrated circuit element 240 is accommodated inside the concave container 210, it is necessary to secure a space that can accommodate the integrated circuit element 240 when the external dimensions are further reduced. Therefore, in order to ensure the strength of the piezoelectric oscillator 200, the thickness of the portion that becomes the wall of the concave container 210 must be ensured, and there is a limit to downsizing the piezoelectric oscillator 200. Further, when the thickness of the wall portion is reduced, the strength of the piezoelectric oscillator 200 cannot be maintained, and there is a risk of damage due to impact or the like.
Further, since the integrated circuit element 240 is accommodated in the concave container 210, when the piezoelectric vibration element 220 mounted after the integrated circuit element is defective, the integrated circuit element 240 and the integrated circuit element 240 must be discarded. There is a problem that productivity is bad.

  Therefore, an object of the present invention is to provide a piezoelectric oscillator that solves the above-described problems, copes with downsizing, and improves productivity.

  In order to solve the above problems, the present invention provides a concave container in which a concave space portion is formed, and a surface opposite to the bottom surface of the concave space portion at four corners of the concave container. The formed external connection terminal, a lid made of ceramic and hermetically sealing the concave space, a piezoelectric vibration element mounted on the lid within the concave space, and the lid A main surface that is electrically connected to the piezoelectric vibration element via the lid and the external connection terminal via the concave container and facing the opposite side of the concave space of the lid. And an integrated circuit element to be mounted.

  Moreover, this invention is characterized by comprising the anisotropic conductive resin layer which joins the said concave container and the said cover body in the said structure.

  Furthermore, the present invention is characterized in that an underfill is provided between the lid and the integrated circuit element.

  According to such a piezoelectric oscillator of the present invention, since the integrated circuit element is mounted on the outside of the concave container, there is no need to make the wall of the concave container thin even if the concave container is downsized. The strength of the body can be maintained.

  Further, since the anisotropic conductive resin layer that joins and conducts the concave container and the lid is provided, the inside of the concave container can be hermetically sealed, and the integrated circuit element can be connected via the external connection terminal. In addition, conduction of the piezoelectric vibration element can be ensured.

  In addition, since the underfill is filled between the lid and the integrated circuit element mounted on the surface of the lid, the conductive foreign matter that causes the malfunction does not enter the gap, and the reliability A high-performance piezoelectric oscillator can be obtained. Further, when foreign matter is attached to the integrated circuit element, the foreign matter can be confined in the underfill, so that troubles caused by the foreign matter can be avoided.

  Hereinafter, the best mode for carrying out the invention (hereinafter referred to as “embodiment”) will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a sectional view showing an example of a piezoelectric oscillator according to an embodiment of the present invention. FIG. 2 is a diagram illustrating a state in which metal bumps are provided on the integrated circuit element side electrode pads of the integrated circuit element. FIG. 3A is a diagram illustrating an example of one main surface of the lid body provided with the integrated circuit element mounting pad, and FIG. 3B is a diagram illustrating the other main surface of the lid body provided with the vibrator mounting pad. It is a figure which shows an example. FIG. 4A is a view showing an example of the concave container on the side where the concave container side connection terminal is provided, and FIG. 4B is an example of the main surface of the concave container provided with the external connection terminal. FIG. FIG. 5 is a diagram illustrating an example in which a piezoelectric vibration element is mounted on a lid.

  As shown in FIG. 1, the piezoelectric oscillator 100 according to the embodiment of the present invention mainly includes a concave container 10, a piezoelectric vibration element 20, a lid 30, and an integrated circuit element 40. In the piezoelectric oscillator 100, the piezoelectric vibration element 20 is mounted on the lid body 30, and the concave space of the concave container 10 is arranged so that the piezoelectric vibration element 20 is accommodated in the concave space portion K of the concave container 10. The portion K is hermetically sealed with a lid 30, and the integrated circuit element 40 is mounted on the lid 30.

  The piezoelectric vibration element 20 is made of, for example, quartz, and is configured by attaching and forming a pair of excitation electrodes 22 on both main surfaces of a piezoelectric plate 21 cut along a predetermined crystal axis. When applied to the piezoelectric vibration element 20 via the pair of excitation electrodes 22, thickness shear vibration is caused at a predetermined frequency.

The integrated circuit element 40 is, for example, a flip chip type formed in a rectangular shape, and is provided on a circuit forming surface on the surface of the integrated circuit element 40 in a temperature-sensitive element that detects an ambient temperature state and a concave container 10 described later. Based on the temperature compensation data from the written terminal W, a temperature compensation circuit for correcting the vibration characteristics of the piezoelectric vibration element 20 according to a temperature change, and a predetermined oscillation output is generated by being connected to the temperature compensation circuit. An oscillation circuit or the like is provided. Here, the oscillation output generated by the oscillation circuit is output to the outside of the piezoelectric oscillator 100 and then used as a reference signal such as a clock signal.
As shown in FIG. 2, an integrated circuit element side electrode pad 41 is provided on one main surface of the integrated circuit element 40, and the metal bump T is provided on the integrated circuit element side electrode pad 41. It has become.

  As described above, the concave container 10 is formed with the concave space K as shown in FIGS. 1 and 4, and is opposite to the bottom surface of the concave container 10, that is, the bottom surface of the concave space K. External connection terminals 13 are provided at the four corners on the side surface (see FIG. 4B). A write terminal W (see FIGS. 1 and 5) is provided between the adjacent external connection terminals 13 and 13 on the long side.

The concave container 10 is made of a ceramic material such as glass-ceramic or alumina ceramic. Further, as shown in FIG. 4A, a concave container side connection terminal 11 for conducting electrical connection with an integrated circuit element 40 described later is provided at the upper edge of the opening of the concave space K of the concave container 10. Is provided.
As shown in FIG. 1, a concave container internal wiring 12 is provided in the concave container 10 and is connected to the concave container side connection terminal 11 and the external connection terminal 13. Further, it is also connected to a write terminal W so that writing to the integrated circuit element 40 is possible.

  The lid 30 is made of ceramic in the same manner as the concave container 10 and electrically connects the piezoelectric vibration element 20 and the integrated circuit element 40 while hermetically sealing the concave space K of the concave container 10. Also, it plays a role of ensuring electrical connection between the integrated circuit element 40 and the external connection terminal 13 provided in the concave container 10.

  As shown in FIGS. 1 and 3, the lid 30 is provided with a vibrator mounting pad 33 (see FIG. 3B) for mounting the piezoelectric vibration element 20 on one main surface thereof, and the other side. An integrated circuit element mounting pad 31 (see FIG. 3A) for mounting the integrated circuit element 40 is provided on the main surface, and is provided on the concave container 10 on the same plane as the vibrator mounting pad 33. A lid side connection terminal 32 is provided at a position corresponding to the concave container side connection terminal 11, and a lid internal wiring 34 is provided therein.

  When the piezoelectric vibration element 20 is mounted on the vibrator mounting pad 33, as shown in FIGS. 1 and 5, the conductive adhesive D is used, whereby the crystal vibration element 20 and the vibrator mounting pad 33 are used. Are electrically and mechanically connected.

  The lid internal wiring 34 is connected to the lid side connection terminal 32 and the integrated circuit element mounting pad 31, and is connected to the vibrator mounting pad 33 and the integrated circuit element mounting pad 31.

  For joining the lid 30 and the concave container 10, an anisotropic conductive resin S is used as shown in FIG. 1. The anisotropic conductive resin S is known in which a conductive filler is dispersed in an electrically insulating resin. The anisotropic conductive resin S is cured by heating in a viscous state before curing.

  The anisotropic conductive resin S is used as a bonding material when the concave space K is hermetically sealed, and is used for electrical conduction between the concave container 10 and the lid 30. 10 is provided between the upper edge of the opening 10 and the lid 30.

  For example, the anisotropic conductive resin S is applied over the entire upper edge of the opening of the concave container 10, and the lid side connection terminal 32 of the lid 30 and the concave container side connection terminal 11 on the concave container 10 side. With the anisotropic conductive resin S sandwiched between them and being heated, pressurized and cured, the lid 30 and the concave container 10 are joined.

  Thereby, the anisotropic conductive resin S does not have conductivity between the adjacent lid-side connection terminals 32 and 32 or the adjacent concave container-side connection terminals 11 and 11, and the concave container in the pressurizing direction. Only the portion in the direction sandwiched between the side connection terminal 11 and the lid side connection terminal 32 has conductivity. As described above, the hermetic sealing and the electrical conduction are realized at the same time by utilizing the property of the anisotropic conductive resin S.

  Also, as shown in FIG. 1, the structure is filled with an underfill F between the integrated circuit element 40 and the lid 30. As a result, foreign matter can be prevented from entering between the integrated circuit element 40 and the lid 30.

  As described above, the characteristic part of the piezoelectric oscillator 100 according to the embodiment of the present invention is that the integrated circuit element 40 is recessed in the lid 30 placed so as to close the recessed space K as shown in FIG. Since the structure is mounted on the surface on the opposite side of the shape space K and the piezoelectric vibration element 20 is mounted on the lid 30, the size of the integrated circuit element 40 is reduced to the size of the concave container 10. It can be a size. Therefore, according to the structure of the piezoelectric oscillator 100 according to the embodiment of the present invention, the integrated circuit element 40 is not limited by the size of the inner bottom surface of the concave container 10, and the wall thickness is not reduced. Therefore, the piezoelectric oscillator 100 that does not weaken the mechanical strength of the wall of the concave container 10 can be obtained. In addition, since the lid 30 of the piezoelectric oscillator 100 according to the embodiment of the present invention is made of a plate-like ceramic, the lid internal wiring 34 is reliably connected to the inside of the lid 30 even if the lid 30 is thin and thin. And hermetically sealed. Further, with the lid 30 as a boundary, the piezoelectric vibration element 20 is mounted on the main surface of the lid 30 on the concave space K side, and the integrated circuit element 40 is mounted on the main surface facing away from the concave space K. With this configuration, the temperature difference sensed between the piezoelectric vibration element 20 and the integrated circuit element 40 can be reduced. That is, it is possible to obtain a piezoelectric oscillator that is not easily affected by heat generated when the integrated circuit element 40 is activated.

The present invention is not limited to the above-described embodiment, and various changes and improvements can be made without departing from the gist of the present invention. For example, the underfill F is applied and filled between the integrated circuit element 40 and the lid 30, but the underfill F is not applied and filled, and the gap between the integrated circuit element 40 and the lid 30 is not filled. A structure in which the underfill F is applied only to the peripheral portion may be used.
An anisotropic conductive resin may be used for joining the lid 30 and the integrated circuit element 40. Thereby, since it becomes the same as the material used for airtight sealing, the curvature of the cover body 30 can be prevented.

It is sectional drawing which shows an example of the piezoelectric oscillator which concerns on embodiment of this invention. It is a figure which shows the state which provided the metal bump in the integrated circuit element side electrode pad of the integrated circuit element. (A) is a figure which shows an example of one main surface of the cover body in which the integrated circuit element mounting pad was provided, (b) is an example of the other main surface of the cover body in which the vibrator mounting pad was provided. FIG. (A) is a figure which shows an example of the concave container of the side in which the concave container side connection terminal was provided, (b) is a figure which shows an example of the main surface of the concave container in which the terminal for external connection was provided. It is. It is a figure which shows an example which mounted the piezoelectric vibration element in the cover body. It is sectional drawing which shows an example of the conventional piezoelectric oscillator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Piezoelectric oscillator 10 Concave container 11 Concave container side connection terminal 12 Concave container internal wiring 13 External connection terminal 20 Piezoelectric vibration element 21 Piezoelectric plate 22 Excitation electrode 30 Cover body 31 Integrated circuit element mounting pad 32 Cover body side connection terminal 33 Vibrator Mounting Pad 34 Lid Internal Wiring 40 Integrated Circuit Element 41 Integrated Circuit Element Side Electrode Pad F Underfill K Concave Space S Anisotropic Conductive Resin T Metal Bump W Writing Terminal

Claims (3)

A concave container in which a concave space is formed;
An external connection terminal formed on the four corners of the concave container on the opposite side of the bottom surface of the concave space portion;
A lid made of ceramic and hermetically sealing the concave space;
A piezoelectric vibration element mounted in the lid body in the concave space portion;
It is electrically connected to the piezoelectric vibration element through the lid and is connected to an external connection terminal through the lid and the concave container, and is opposite to the concave space portion of the lid. An integrated circuit element mounted on the main surface facing;
A piezoelectric oscillator comprising:   The piezoelectric oscillator according to claim 1, comprising an anisotropic conductive resin layer that joins the concave container and the lid.   The piezoelectric oscillator according to claim 1, wherein an underfill is provided between the lid and the integrated circuit element.

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