JP2006013681A - Piezoelectric oscillator and package for piezoelectric oscillator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a package capable of surely fixing a surface acoustic wave chip while reducing the manufacturing cost by downsizing the surface acoustic wave chip and to provide a piezoelectric oscillator for utilizing the package above. <P>SOLUTION: The piezoelectric oscillator 30 accommodates an integrated circuit element 34 and the surface acoustic wave chip 33 connected to the integrated circuit element into the package 31, the package includes a lower packaging part S3 arranged at an inner lower side to accommodate the integrated circuit element, and an upper packaging part S4 including an opening larger than that of the lower side packaging part and placing and fixing the surface acoustic wave chip to upward steps 45, 46 formed to a circumferential edge of the opening of the lower side packaging part, and the upper side packaging part is located at a position biased to one side with respect to the lower side packaging part in the width direction X. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a piezoelectric oscillator, and more particularly to a piezoelectric oscillator having an improved package structure and a package for a piezoelectric oscillator.

  In recent years, in electronic parts and communication parts such as mobile phones and television receivers, a resonator formed by a surface acoustic wave device (SAW (Surface Acoustic Wave)) in which a surface acoustic wave chip and an integrated circuit element are accommodated in a package, Many piezoelectric oscillators used as bandpass filters or the like are used.

In the case of forming such a piezoelectric oscillator, there is known a configuration in which a piezoelectric element and an integrated circuit element connected to the piezoelectric element are accommodated in a package so as to be surface-mounted.
For example, the one described in Patent Document 1 prepares a ceramic package, mounts an integrated circuit element in a lower space inside the package, and fixes a piezoelectric element such as a crystal piece in the stepped space above the package. It is a thing of composition. By adopting such a configuration, the integrated circuit element and the piezoelectric element can be positioned vertically and accommodated in a package, so that the space on the board can be reduced when mounting on a mounting board, etc., and it is suitable for high-density mounting ing.
In this case, the structure of the housing space of the package is multi-staged, and the size of the inside is changed stepwise so as to cope with the difference in the size of the piezoelectric element to be housed (see Patent Document 1).

JP 2002-158558 A

FIG. 7 is a schematic plan view showing a general configuration of a piezoelectric oscillator using such a package and containing a surface acoustic wave chip and an integrated circuit element, and FIG. 8 is a schematic plan view taken along line AA of FIG. It is sectional drawing. Note that FIG. 7 illustrates the internal configuration through the lid for convenience of understanding.
The package 2 contains a surface acoustic wave chip 6 and an integrated circuit element 5. The surface acoustic wave chip 6 has a comb-shaped electrode (IDT (Inter Digital Transducer)) formed on an active surface of a rectangular substrate that is long in the Y direction shown in the figure.

A lower accommodating portion S1 is formed on the inner surface of the package 2, and an upper accommodating portion S2 is formed thereon, and accommodates the integrated circuit element 5 and the surface acoustic wave chip 6, respectively.
Specifically, the integrated circuit element 5 is electrically connected and fixed to an electrode (not shown) on the inner bottom surface of the package 2. The lower housing part S1 is smaller than the upper housing part S2, and therefore, two upper step parts 4, 7a, 7b are formed on the opening periphery of the lower housing part S1. The step portion 4 has a small width and is located on the inner side, and by providing necessary electrode terminals, electrical connection can be made between the electrode terminals and the terminals of the integrated circuit element 5 by bonding wires as shown in the figure. Has been.

In the package 2, the stepped portions 7 a and 7 b are formed inside each of the end portions in the longitudinal direction (Y direction) of the surface acoustic wave chip 6. The adhesive 7c is applied to one step 7a, and the base end 6a of the surface acoustic wave chip 6 is placed thereon, and the adhesive 7c is cured to be bonded.
On the other hand, the front end portion 6b of the surface acoustic wave chip 6 is placed on the other stepped portion 7b and stably mounted.
The package 2 has an electrode portion on the bottom surface (not shown), and is connected to the electrode portion inside the package to which the surface acoustic wave chip 6 is bonded by a conductive through hole or the like.

In the above structure, in particular, the surface acoustic wave chip 6 is produced by forming an IDT on a relatively thick piezoelectric substrate, so that it is heavy and cantilevered only by the base end portion 6a as described above. In this case, it is necessary to make the area of the adhesive 7c as large as possible.
Here, it is preferable that the surface acoustic wave chip 6 can be reduced in size so that the manufacturing cost can be reduced. However, if the size of the surface acoustic wave chip 6 in the Y direction is reduced in FIG. 8, the tip of the surface acoustic wave chip 6 is reduced. The part 6b does not reach the stepped part 7b.

That is, the base end portion 6a must be placed on the stepped portion 7a with a predetermined size in order to ensure a certain degree of adhesive strength, and the surface acoustic wave chip 6 is downsized. At the same time, the package 2 must be made smaller to reduce the distance to the stepped portion 7b.
However, since the size of the integrated circuit element 5 is determined to some extent, the lower housing portion S1 cannot be made very small. Therefore, in the structure of FIGS. 7 and 8, the tip portion 6b of the surface acoustic wave chip 6 is supported. Is difficult.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, to form a surface acoustic wave chip in a small size and reduce the manufacturing cost, and to securely fix the surface acoustic wave chip, and to provide such a package. The present invention is to provide a piezoelectric oscillator using the same.

According to the first aspect of the present invention, there is provided a piezoelectric oscillator in which an integrated circuit element and a surface acoustic wave chip connected to the integrated circuit element are accommodated in the package. A lower housing portion disposed on the lower side for housing the integrated circuit element, and an upward step formed on the periphery of the opening of the lower housing portion, having an opening larger than the opening of the lower housing portion An upper receiving portion for mounting and fixing the surface acoustic wave chip, and the upper receiving portion is biased to one side with respect to the lower receiving portion with respect to the width direction. This is achieved by a piezoelectric oscillator placed in position.
According to the configuration of the first invention, the upper accommodating portion provided inside the package has a larger opening than the lower accommodating portion, and the upper accommodating portion is located with respect to the lower accommodating portion. Thus, they are arranged at positions biased to one side in the width direction. For this reason, a step portion is formed on one side in the width direction inside the package.
For this reason, the surface acoustic wave chip can be mounted stably because the side edge portion thereof can be mounted on the stepped portion, and is thus supported by both the base end portion and the side edge portion. In addition, since the adhesion area of the adhesive at the base end can be increased, sufficient bonding strength can be obtained. That is, the surface acoustic wave chip can be manufactured at a low cost by shortening its entire length and forming it small.
Thus, it is possible to provide a piezoelectric oscillator capable of reliably fixing the surface acoustic wave chip while reducing the manufacturing cost by forming the surface acoustic wave chip small.

According to a second invention, in the configuration of the first invention, a base end portion of the surface acoustic wave chip is fixed to an upward step portion positioned in a length direction of a package, and the surface acoustic wave chip is provided. The bottom portion near the side edge is placed on a step portion arranged on one side in the width direction of the package.
According to the configuration of the second aspect of the invention, the base end portion of the surface acoustic wave chip is fixed to the upward stepped portion located in the length direction of the package, and further, near the side edge of the surface acoustic wave chip. By placing the bottom portion on the step portion arranged on one side in the width direction of the package, the adhesive adhesion area of the base end portion can be secured, and the bonding strength can be further improved.

According to a third aspect of the present invention, there is provided a piezoelectric oscillator in which an integrated circuit element and a surface acoustic wave chip connected to the integrated circuit element are accommodated in the package. A lower housing portion disposed on the lower side for housing the integrated circuit element, and an upward step formed on the periphery of the opening of the lower housing portion, having an opening larger than the opening of the lower housing portion A convex portion having a flat upper surface is formed on the inner side wall of the lower accommodating portion so as to protrude inward, and the upper accommodating portion A base end portion of the surface acoustic wave chip is fixed to the upward stepped portion, and a bottom portion near a side edge of the surface acoustic wave chip is placed on the flat upper surface of the convex portion. This is achieved by a piezoelectric oscillator.
According to the configuration of the third invention, the base end portion of the surface acoustic wave chip is fixed to the upward stepped portion, and the bottom portion near the side edge of the surface acoustic wave chip with respect to the flat upper surface of the convex portion Is placed. That is, the surface acoustic wave chip can be mounted stably because the side edge portion can be placed on the convex portion and is supported by both the base end portion and the side edge portion. Furthermore, since the adhesive adhesion area of a base end part can be ensured, sufficient joint strength can be obtained. That is, the surface acoustic wave chip can be manufactured at a low cost by forming the surface acoustic wave chip shorter and smaller.
Thus, it is possible to provide a piezoelectric oscillator capable of reliably fixing the surface acoustic wave chip while reducing the manufacturing cost by forming the surface acoustic wave chip small.

According to a fourth aspect of the present invention, there is provided a piezoelectric oscillator package for housing an integrated circuit element and a surface acoustic wave chip connected to the integrated circuit element. A lower accommodating portion disposed on the side for accommodating the integrated circuit element, and an upward stepped portion formed on an opening periphery of the lower accommodating portion, the opening being larger than the opening of the lower accommodating portion. An upper receiving portion for mounting and fixing the surface acoustic wave chip, and the upper receiving portion is biased to one side with respect to the lower receiving portion in the width direction. This is achieved by the piezoelectric oscillator package being arranged.
According to the configuration of the fourth aspect of the present invention, the surface acoustic wave chip can be reliably fixed while reducing the manufacturing cost by forming the surface acoustic wave chip small by the same principle as the first aspect of the invention. A package that can be suitably used for an oscillator can be provided.

According to a fifth aspect of the present invention, there is provided a package for a piezoelectric oscillator for accommodating an integrated circuit element and a surface acoustic wave chip connected to the integrated circuit element. A lower accommodating portion for accommodating the integrated circuit element disposed on the side, and an upward stepped portion formed on an opening periphery of the lower accommodating portion, the opening being larger than the opening of the lower accommodating portion. And a piezoelectric oscillator package in which a convex portion having a flat upper surface is formed on the inner side wall of the lower housing portion so as to protrude inward. The
According to the configuration of the fifth aspect of the present invention, the surface acoustic wave chip can be reliably fixed while reducing the manufacturing cost by forming the surface acoustic wave chip small by the same principle as the third aspect of the invention. A package that can be suitably used for an oscillator can be provided.

FIG. 1 is a schematic plan view showing an example of a piezoelectric oscillator as a first embodiment of an electronic component of the present invention, FIG. 2 is a schematic cross-sectional view taken along line BB in FIG. 1, and FIG. FIG. 1 is a schematic cross-sectional view taken along line -C, and FIG. 1 shows the internal structure through the lid.
The piezoelectric oscillator 30 includes a package 31, a surface acoustic wave chip 33 accommodated in the package 31, and an integrated circuit element (hereinafter referred to as “IC chip”) 34.

The surface acoustic wave chip 33 is obtained by forming an interdigital electrode IDT (comb electrode) and a necessary reflector on a piezoelectric substrate. The piezoelectric substrate uses, for example, a multilayer substrate such as a single crystal substrate such as quartz, lithium tantalate (LiTaO ₃ ), lithium niobate (LiNbO ₃ ) or a substrate obtained by forming ZnO on a Si substrate as a piezoelectric material. be able to. In addition, IDT is a method in which a conductive metal such as aluminum is formed on the active surface of a piezoelectric substrate by vapor deposition or sputtering, and then a necessary comb-shaped electrode and / or reflector is provided using a photolithography technique. Formed.
The IC chip 34 is connected to the surface acoustic wave chip 33 to form an oscillator. Note that the electrode structure such as IDT of the surface acoustic wave chip 33 overlaps with the illustrated shape for understanding the structure of the package and is not illustrated in order to prevent understanding.

The package 31 is formed of, for example, an aluminum oxide ceramic green sheet as an insulating material, and has a rectangular outer shape in which the Y direction (length direction) is larger than the width direction (X direction), for example, as illustrated. It is formed as follows.
That is, it is formed by laminating a plurality of substrates using green sheets, removing the material inside each laminated substrate to form an internal space, and forming a laminated state, followed by sintering.
The package 31 is a box-shaped container having a lower housing part S3 and an upper housing part S4 on the inner side. The lower housing part S3 and the upper housing part S4 are both rectangular recesses or holes with a bottom, and the upper housing part S4 has a larger opening than the lower housing part S3, as shown in FIG. The dimension in the direction, that is, the length direction is also large.

  The lower housing portion S3 and the upper housing portion S4 are arranged at positions that are vertically overlapped and are formed to communicate with each other. In particular, as will be understood with reference to FIG. 1, the upper storage portion S4 is disposed at a position biased to one side in the width direction (X direction) with respect to the lower storage portion S3. In FIG. 1, the upper housing part S4 is provided at a position biased downward with respect to the lower housing part S3.

For this reason, the step part 45 is formed in the opening periphery of lower side accommodating part S3. The step 45 is arranged so that the left end side in FIG. This step portion 45 extends to the opening edge of the side edge of the lower housing portion S <b> 3 and serves as a side step portion 46.
Further, step portions 41 and 42 lower than the step portion 45 are formed inside the opening of the lower housing portion S3. As shown in FIGS. 1 and 2, the lower step portions 41 and 42 are provided at both ends in the length direction (Y direction) of the lower accommodating portion S <b> 3. As shown in FIG. 1, the lower step portions 41 and 42 are respectively formed with necessary electrode portions 43, and these electrode portions 43 are mounted on the bottom surface of the lower accommodating portion S3. The terminals of the IC chip 34 are connected by wire bonding as shown in the figure.

As shown in FIG. 2, a silicon-based adhesive 52 is applied to the left end region of the stepped portion 45 of the package 31, and the base end portion 33a of the surface acoustic wave chip 33 is mounted thereon. It is placed and fixed. Further, as shown in FIG. 1, electrode portions 51, 51 are formed on the side edge of the stepped portion 45, and wire bonding is performed to the electrode terminals of the surface acoustic wave chip 33 as shown in the figure. Are electrically connected.
Moreover, the side edge portion 33c of the surface acoustic wave chip 33 has its bottom portion placed on the side step portion 46, and the tip portion 33b of the surface acoustic wave chip 33 is not supported or fixed. .

The electrode portions 51 and 51 are connected to a mounting terminal (not shown) provided on the bottom surface of the package 31 by a predetermined conductive through hole or the like, and the electrode portions 51 and 51 of the step portion 45 are routed through the package 31. Further, the electrodes are connected to the electrode portions 43 of the lower step portions 41 and 42 by a pattern (not shown).
In this state, a lid 32 is fixed to the package 31 via a brazing material, and the inside is hermetically sealed. The lid 32 is, for example, a flat plate, and one formed of Kovar, which is an alloy of iron, nickel, and cobalt, or one plated with 42 alloy, which is an alloy of iron, nickel, is suitable.

The present embodiment is configured as described above, and the surface acoustic wave chip 33 can support the side edge portion 33c mounted on the side step portion 46, so that the base end portion 33a and the side edge portion 33c are supported. Therefore, sufficient bonding strength can be obtained. Thereby, the surface acoustic wave chip 33 can be formed small by shortening its entire length (dimension in the Y direction), and the manufacturing cost can be reduced accordingly. Here, if the side edge portion 33c is fixed, it is possible to further improve the bonding strength. However, stress is easily applied to the surface acoustic wave chip 33 due to deformation of the package. For example, the frequency characteristics of the surface acoustic wave chip 33 are deteriorated. Therefore, the fixing is preferably performed at one position of the base end portion 33a.
Thus, according to the present embodiment, it is possible to provide the piezoelectric oscillator 30 capable of reliably fixing the surface acoustic wave chip while reducing the manufacturing cost by forming the surface acoustic wave chip small.

  FIG. 4 is a schematic plan view showing an example of a piezoelectric oscillator as a second embodiment of the electronic component of the present invention, FIG. 5 is a schematic cross-sectional view taken along the line DD of FIG. 4, and FIG. FIG. 4 is a schematic cross-sectional view taken along the line -E, and FIG. 4 shows the internal structure through the lid. In these drawings, portions denoted by the same reference numerals as those used in the drawings representing the first embodiment have a common configuration, and thus redundant description will be omitted, and hereinafter, differences will be mainly described. .

Unlike the case of the first embodiment, in the package 31-1 of the piezoelectric oscillator 30-1, the upper housing portion S4 is not disposed at a biased position with respect to the lower housing portion S3. It is arranged at a position that almost overlaps.
And as shown in FIG. 4, the convex part 55 is formed in the side wall inside the lower accommodating part S3 of the package 31-1 so that it may protrude inward. As shown in FIG. 6, the convex portion 55 has a flat upper surface.

As shown in FIG. 6, the bottom near the side edge of the surface acoustic wave chip 33 is supported on the flat upper surface of the convex portion 55. That is, since the surface acoustic wave chip 33 can be supported by placing the side edge portion 33c on the convex portion 55, the surface acoustic wave chip 33 is supported by both the base end portion 33a and the side edge portion 33c. Can. Here, if the side edge portion 33c is fixed, it is possible to further improve the bonding strength. However, stress is easily applied to the surface acoustic wave chip 33 due to deformation of the package. For example, the frequency characteristics of the surface acoustic wave chip 33 are deteriorated. Therefore, the fixing is preferably performed at one position of the base end portion 33a.
Thus, also in the piezoelectric oscillator 30-1 according to the second embodiment, the surface acoustic wave chip 33 can be manufactured at a low manufacturing cost by shortening its overall length and forming it small. For this reason, the piezoelectric oscillator 30-1 can be provided that can securely fix the surface acoustic wave chip 33 while reducing the manufacturing cost by forming the surface acoustic wave chip 33 in a small size.

  The present invention is not limited to the above-described embodiment. Each configuration of the embodiment may be omitted as appropriate, or may be combined with other configurations not shown.

1 is a schematic plan view showing a first embodiment of a piezoelectric oscillator of the present invention. BB schematic sectional drawing of FIG. The CC sectional schematic sectional drawing of FIG. The schematic plan view which shows 2nd Embodiment of the piezoelectric oscillator of this invention. DD schematic sectional drawing of FIG. EE schematic sectional drawing of FIG. The schematic plan view of the conventional piezoelectric oscillator. AA line schematic sectional drawing of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 30 ... Piezoelectric oscillator, 31 ... Package, 33 ... Surface acoustic wave chip, 34 ... IC chip, 45 ... Step part, 46 ... Side step part, 55 ... Convex part , S3... Lower housing part, S4... Upper housing part.

Claims (5)

A piezoelectric oscillator containing an integrated circuit element and a surface acoustic wave chip connected to the integrated circuit element in a package,
The package is
A lower receiving portion disposed on the lower side of the inside for receiving the integrated circuit element;
The upper housing portion has an opening larger than the opening of the lower housing portion, and an upper housing portion for mounting and fixing the surface acoustic wave chip on an upward step formed on the opening periphery of the lower housing portion. And
The piezoelectric oscillator, wherein the upper housing part is disposed at a position biased to one side in the width direction with respect to the lower housing part.   A base end portion of the surface acoustic wave chip is fixed to an upward step portion positioned in the package length direction, and a bottom portion in the vicinity of the side edge of the surface acoustic wave chip is one in the width direction of the package. The piezoelectric oscillator according to claim 1, wherein the piezoelectric oscillator is placed on a step portion disposed on the side. A piezoelectric oscillator containing an integrated circuit element and a surface acoustic wave chip connected to the integrated circuit element in a package,
The package is
A lower receiving portion disposed on the lower side of the inside for receiving the integrated circuit element;
An upper housing portion having an opening larger than the opening of the lower housing portion and having an upward step formed on the periphery of the opening of the lower housing portion,
On the inner side wall of the lower housing part, a convex part having a flat upper surface is formed so as to protrude inward,
A base end portion of the surface acoustic wave chip is fixed to the upward stepped portion of the upper housing portion, and further, a bottom portion near a side edge of the surface acoustic wave chip with respect to the flat upper surface of the convex portion A piezoelectric oscillator characterized in that is mounted. A package for a piezoelectric oscillator for accommodating an integrated circuit element and a surface acoustic wave chip connected to the integrated circuit element,
A lower receiving portion disposed on the lower side of the inside for receiving the integrated circuit element;
The upper housing portion has an opening larger than the opening of the lower housing portion, and an upper housing portion for mounting and fixing the surface acoustic wave chip on an upward step formed on the opening periphery of the lower housing portion. And
The package for a piezoelectric oscillator, wherein the upper housing part is disposed at a position biased to one side with respect to the width direction with respect to the lower housing part. A package for a piezoelectric oscillator for accommodating an integrated circuit element and a surface acoustic wave chip connected to the integrated circuit element,
A lower receiving portion disposed on the lower side of the inside for receiving the integrated circuit element;
An upper housing portion having an opening larger than the opening of the lower housing portion and having an upward step formed on the periphery of the opening of the lower housing portion,
A package for a piezoelectric oscillator, wherein a convex portion having a flat upper surface is formed on an inner side wall of the lower housing portion so as to protrude inward.

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