JP2006157299A - Surface acoustic wave device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface acoustic wave device, wherein a degree of freedom of the arrangement to a printed wiring board is enhanced and also the occurrence of cracks of a package is avoided. <P>SOLUTION: The surface acoustic wave device includes: a surface acoustic wave element; and the package for housing the surface acoustic wave element, wherein the package includes a notch formed to its apex angle and a plurality of notches at least one of which is formed to each side, a conductive film is formed to side faces of the package corresponding to the notches, a rear side of the package has a region formed with a conductor pattern electrically connected to input output terminals of the surface acoustic wave element, a region formed with a conductor pattern electrically connected to a ground terminal of the surface acoustic wave element, and a region not formed with the conductor pattern at a plurality of positions corresponding to the notches of the rear side, and the region not corresponding to the notches of the rear side of the package and not formed with the conductor pattern is provided corresponding to the layout of the wiring pattern or the through-holes formed to the printed wiring board mounted on the surface acoustic wave device. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a surface acoustic wave (SAW) device. In particular, the present invention relates to a surface acoustic wave device configured by housing a surface acoustic wave element (chip) in a ceramic package.

  In the surface acoustic wave device, as shown in FIG. 1 showing a general configuration, a surface acoustic wave element 1 is accommodated in a ceramic package 2, and a signal input terminal (IN) for electrical connection with an external circuit and a signal output are provided. The configuration includes a terminal (OUT) and a ground terminal (GND). In the following description, the signal input terminal (IN) and the signal output terminal (OUT) are appropriately referred to as a HOT terminal with respect to the ground terminal (GND).

  FIG. 2 is a top view of the ceramic package 2 of one surface acoustic wave device, schematically showing a position where the surface acoustic wave element 1 is mounted and accommodated, and an electrode pattern formed on the bottom surface. ing. As an electrode pattern formed on the bottom surface of the ceramic package 2, a pattern of HOT terminals (IN and OUT) and a plurality of GND terminals for connection to an external circuit are formed.

  In such a surface acoustic wave device, as shown in FIG. 3 showing a manufacturing process, a plurality of surface acoustic wave devices are formed in a single wafer shape. In such a wafer state, electrode patterns of HOT terminals (IN and OUT) and a plurality of GND terminals are formed. Also, a connection electrode pattern in the height direction (electrode pattern formed on the side surface of the surface acoustic wave device) that is electrically connected to the electrode patterns of the HOT terminals (IN and OUT) and the plurality of GND terminals formed on the bottom surface. In order to form, a through hole 3 is formed in the center of each electrode pattern.

  Then, a conductive film is formed on the inner side surface of the through hole 3 by a refractory metal powder such as tungsten or molybdenum injected through the through hole 3.

  Subsequently, it is separated into a plurality of individual surface acoustic wave devices by cutting along the cutting line 4. Therefore, for example, as shown in Patent Document 1, a notch portion 3a is formed on the side surface and apex angle position of each surface acoustic wave device corresponding to the position of the through hole 3, and the notch portion 3a is formed in the notch portion 3a. A conductive film is formed.

  4 and 5 are surface acoustic wave devices individually separated in FIG. 3, and are conceptual configuration examples of side surfaces when cut along the line AB in FIG.

  4 and 5, the ceramic package 2 that accommodates the surface acoustic wave element 1 is made of an insulating material such as alumina ceramic, and has a multilayer structure of at least two layers (the examples of FIGS. 4 and 5 are a three-layer structure 20, 21 and 22).

  FIG. 4 is a cross-sectional view of a configuration example of a surface acoustic wave device in which the surface acoustic wave element 1 accommodated in the ceramic package 2 is connected to an external circuit by a gold bump 7, and FIG. 1 is a cross-sectional view of a configuration example of a surface acoustic wave device that connects a wave element 1 to an external circuit.

  The bottom surface of the lowermost insulating substrate 20 of the multilayer ceramic package 2 is coated with a material such as tungsten or molybdenum for connection with signal wiring on a printed wiring (PC) board, and then gold plating or the like. A HOT terminal 5a subjected to processing (hereinafter referred to as metallization) and a grounding terminal (GROUND) of internal elements or a GROUND terminal 5b subjected to metallization to connect the package housing to the GROUND pattern of the PC board are formed. Yes.

  Similarly, in the configuration of FIG. 4, a wiring metallization 5 c for mounting the surface acoustic wave element 1 via the gold bumps 7 is formed on the upper surface of the lowermost insulating substrate 20.

  On the lowermost insulating substrate 20, one or more insulating frames 21 and 22 are laminated so as to surround the mounting portion of the surface acoustic wave element 1. Further, a sealing metallization 5d for joining the metal lid 6 with a conductive adhesive such as solder is applied to the upper surface of the uppermost insulating frame 22.

  The surface acoustic wave element 1 is electrically connected to the wiring metallization 5 c via the gold bumps 7 and is fixed to the ceramic package 2.

  On the other hand, as shown in FIG. 5, when the electrical connection is made with the gold wire 8 or the like, the metallization 5c is similarly applied to the mounting portion of the lowermost insulating base 20, but the ceramic is not used for wiring. The GROUND pattern of the package 2 is aimed.

  The surface acoustic wave element 1 is fixed to a mounting portion on the upper surface of the lowermost insulating base 20 of the ceramic package 2 with a resin such as epoxy, and a gold wire or the like 8 is attached to the wiring metallization 5e formed on the upper surface of the insulating layer 21 of the intermediate layer. The electrical connection is made.

  Here, the electrode pattern (see FIG. 2) formed on the bottom surface of the ceramic package 2 of the surface acoustic wave device has an elastic surface for connecting the element 1 to an external circuit, a common GND terminal, one input terminal IN, It suffices to have at least three electrode patterns corresponding to one output terminal OUT.

  However, in the conventional surface acoustic wave devices, the electrode pattern IN corresponding to one input terminal and one output terminal is considered in consideration of the strong connection with the ground potential or the formation of the common electrode pattern of the common package. , OUT and a common ground (GND) terminal electrode pattern, a plurality of GND terminal electrode patterns or dummy electrode patterns.

FIG. 6 shows electrode patterns 5a.. 5 formed on the bottom surface of the surface acoustic wave device. It is a schematic diagram which shows the connection with 5b and the wiring pattern 100 in the printed wiring board with which the surface acoustic wave apparatus is mounted. The wiring pattern 100 runs in parallel and is connected to a necessary electrode pattern of the surface acoustic wave device.
Japanese Patent Publication No. 2948998

  On the other hand, due to the recent increase in the density of mounted circuits, signal wiring 101 of a printed wiring board and through-holes 102 of a double-sided printed wiring board are provided under the mounted surface acoustic wave device as shown in FIG. There is a request.

  However, the surface acoustic wave device has a plurality of GND terminals 113 and dummy terminals 114 in addition to the common GND terminal 112, and the area that can be laid out is reduced, so that signal wiring is provided under the mounted surface acoustic wave device. 101 and the through hole 102 cannot be laid out, and the degree of freedom in designing a printed wiring board is reduced.

  For this purpose, the present inventor leaves the minimum number of GND terminals necessary for realizing the characteristics on the back surface of the surface acoustic wave device, and in accordance with the layout of the printed wiring board to be mounted, A ceramic package from which the metallization for wiring 3a was deleted was designed.

  FIG. 7 is a plan view (FIG. 7A), a back view (FIG. 7B), a side view (FIG. 7C), and a front view (FIG. 7D) of the surface acoustic wave device in a state where a part of the wiring metallization is deleted. . As shown in FIG. 7B, the electrode patterns I, II, and III are not formed on the back surface.

  Thereby, in the side view of FIG. 7C, the formation of the conductive film in the portion II 'in the stacking direction corresponding to the side cutout portion 3a is omitted. In the front view of FIG. 7D, the formation of the conductive film in the portion III ′ in the stacking direction is omitted.

  This makes it difficult to lay out the printed wiring board of the surface acoustic wave device even when the signal wiring 101 and the through hole 102 of the double-sided printed wiring board exist in the printed wiring board as shown in FIG. Has been resolved.

  However, as described above with reference to FIG. 3, when the surface acoustic wave device is cut out from the wafer, the side cutout 3 a exists due to the presence of the through hole 3. For this reason, when a mechanical force from the outside is applied to the package, the present inventors have discovered for the first time that a crack of the package occurs from the package side cutout 3a and a crack A appears directly on the surface.

  As described above, there is a problem that the crack generation of the package increases due to the deterioration of the bending strength.

  Accordingly, an object of the present invention is to provide a surface acoustic wave device that increases the degree of freedom of placement on a printed circuit board and avoids the occurrence of package cracking.

  A first aspect of a surface acoustic wave device according to the present invention that achieves the above object has a surface acoustic wave element and a package that accommodates the surface acoustic wave element, and the package is formed at an apex angle thereof. A plurality of notches formed on each side, and a conductive film is formed on a side surface of the package corresponding to the notches, and the notch on the back surface of the package And a conductive pattern electrically connected to the ground terminal of the surface acoustic wave element and a region where a conductive pattern electrically connected to the input / output terminal of the surface acoustic wave element is formed. A surface acoustic wave device is provided in a region having a pattern and a region in which a conductive pattern is not formed and corresponding to the notch on the back surface of the package and in which a conductive pattern is not formed. Printed wiring board formed a wiring pattern or is characterized in that it is provided in correspondence with the layout of the through hole.

  A second aspect of the surface acoustic wave device according to the present invention that achieves the above object has a surface acoustic wave element and a package that accommodates the surface acoustic wave element, and the package is formed at the apex angle thereof. A plurality of notches formed on each side, and a conductive film is formed on a side surface of the package corresponding to the notches, and the notch on the back surface of the package At a plurality of positions corresponding to a region where a conductive pattern having a first size electrically connected to the input / output terminal of the surface acoustic wave element is formed, and a ground terminal of the surface acoustic wave element And a second conductive pattern smaller than the first conductive pattern electrically connected to the ground terminal of the surface acoustic wave element is formed. Territory Corresponding to the notch on the back surface of the package, and the region where the second conductive pattern is not formed is a wiring pattern formed on a printed wiring board on which the surface acoustic wave device is mounted, or It is provided corresponding to the layout of a through hole.

  A third aspect of the surface acoustic wave device according to the present invention that achieves the above object is the first or second aspect, wherein the package is formed of a ceramic material and has at least a multi-layer structure, and the cutting of the package is performed. The conductive film formed on the side surface corresponding to the notch is formed only on a part of the multilayer structure.

  The fourth aspect of the surface acoustic wave device according to the present invention that achieves the above object is that, in the third aspect, when the plurality of layers are three or more layers, the layers corresponding to the uppermost layer and the lowermost layer of the plurality of layers. The conductive film is formed only on.

  A fifth aspect of the surface acoustic wave device according to the present invention that achieves the above object is the surface acoustic wave device according to any one of the first to fourth aspects, wherein the notch portions are each a plurality of elastic surfaces separated by cutting lines. A wave device is formed in a wafer shape, and a through hole formed on a cutting line of an adjacent surface acoustic wave device is formed when each surface acoustic wave device is cut out along the cutting line. And

  It is possible to provide a surface acoustic wave device that avoids cracking of the package. At the same time, it saves labor in designing printed wiring boards.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, the Example shown in drawing is for understanding this invention, Comprising: The technical scope of this invention is not limited to this.

  FIG. 8 is a first embodiment of a surface acoustic wave device according to the present invention, and is a plan view (FIG. 8A), a back view (FIG. 8B), a side view (FIG. 8C), and a front view (FIG. 8D). Is shown.

  As a feature, as shown in FIG. 8B, there are portions I, II, and III where the electrode pattern of the cutout portion 3a is not formed on the bottom surface.

  The provision of the portion where the electrode pattern is not formed is to avoid contact with the wiring pattern or the through hole on the printed wiring board when the surface acoustic wave device is mounted on the printed wiring board. This facilitates the layout design of the wiring pattern or the through hole on the printed wiring board.

  At the same time, as a feature, a conductive film is formed on the side surface corresponding to the notch portion 3a where the electrode pattern is not formed in the stacking direction as in the side surface corresponding to the notch portion 3a where the other electrode pattern 3a is formed. Is formed. This avoids the occurrence of package cracking.

  FIG. 9 is a second embodiment of a surface acoustic wave device according to the present invention, and a plan view (FIG. 9A), a back view (FIG. 9B), a side view (FIG. 9C), and a front view (FIG. 9D). Is shown.

  Characteristically, as in the embodiment of FIG. 8, as shown in FIG. 9B, there are portions I, II, and III where the electrode pattern of the cutout portion 3a is not formed on the bottom surface.

  The provision of the portion where the electrode pattern is not formed is to avoid contact with the wiring pattern or the through hole on the printed wiring board when the surface acoustic wave device is mounted on the printed wiring board. This facilitates the layout design of the wiring pattern or the through hole on the printed wiring board.

At the same time, as a feature, the side surface corresponding to the notch 3a where the electrode pattern is not formed differs from the side surface corresponding to the notch 3a where the other electrode pattern 3a is formed,
A conductive film is partially formed only on the lowermost layer and the uppermost layer of the stack. Even in such a case, generation of cracks in the package is avoided.

  FIG. 10 is a third embodiment of a surface acoustic wave device according to the present invention, and is a plan view (FIG. 10A), a back view (FIG. 10B), a side view (FIG. 10C), and a front view (FIG. 10D). ).

  As a feature, unlike the embodiment of FIG. 8 and FIG. 9, as shown in FIG. 10B, it has portions I, II and III in which partial electrode patterns are formed corresponding to the notches 3a on the bottom surface. ing.

  Furthermore, a conductive film is formed on the side surface of the cutout portion 3a corresponding to the partial electrode pattern in the stacking direction, similarly to the side surface corresponding to the cutout portion 3a where the other electrode pattern 3a is formed.

  As described above, in the portions I, II, and III where the partial electrode pattern is formed, the area of the electrode pattern is small, so that contact with the wiring pattern or the through hole on the printed wiring board can be easily avoided. Is possible. This facilitates the layout design of the wiring pattern or the through hole on the printed wiring board.

  At the same time, as a feature, a conductive film is formed on the side surface corresponding to the cutout portion 3a in which the partial electrode pattern is formed, similarly to the side surface corresponding to the cutout portion 3a in which the other electrode pattern 3a is formed. ing. Therefore, the occurrence of package cracking can be avoided.

  FIG. 11 is a graph showing the effect of the present invention. As a comparative sample, the surface acoustic wave device having the conventional configuration shown in FIG. 7 and the surface acoustic wave device having the configuration according to the present invention shown in FIG. 10 were used.

  FIG. 12 is a diagram showing a method for measuring the effect of the present invention, in which 5 samples each of the sample having the conventional configuration and the sample having the configuration of the present invention are removed from the metal lid 6, and as shown in FIG. The tip of the V-shaped tool shown in FIG. 12B was pressed, and the pressing pressure when cracking occurred was measured and plotted.

  As is apparent from FIG. 11, the five samples having the configuration of the present invention all have higher bending strength than the conventional product, and the effect of the present invention is clear.

  According to the present invention, it is possible to provide a surface acoustic wave device that increases the degree of freedom of placement on a printed wiring board and at the same time avoids the occurrence of cracks in the package. But it ’s big.

It is a figure which shows the general structure of a surface acoustic wave apparatus. It is a top view of a ceramic package of one surface acoustic wave device. It is a figure which shows the manufacture process of a surface acoustic wave apparatus. It is sectional drawing of the structural example of the surface acoustic wave apparatus which connects the surface acoustic wave element accommodated in a ceramic package with an external circuit by gold bumps. It is sectional drawing of the structural example of the surface acoustic wave apparatus which connects a surface acoustic wave element with an external circuit with a bonding wire. It is a schematic diagram showing the connection between the electrode pattern formed on the bottom surface of the surface acoustic wave device and the wiring pattern on the printed wiring board on which the surface acoustic wave device is mounted. FIG. 7B is a plan view (FIG. 7A), a back view (FIG. 7B), a side view (FIG. 7C), and a front view (FIG. 7D) of the surface acoustic wave device showing a state in which the metallization for wiring is partially deleted. 1 is a diagram showing a first embodiment of a surface acoustic wave device according to the present invention. It is a figure which shows the 2nd Embodiment of the surface acoustic wave apparatus according to this invention. It is a figure which shows the 3rd Embodiment of the surface acoustic wave apparatus according to this invention. It is a graph which shows the effect of the present invention. It is a figure which shows the measuring method of the effect of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Surface acoustic wave element 2 Ceramic package 3 Through hole 3a Notch part 4 Cutting line 5a-5e Conductive pattern 6 Metal lid part 7 Gold bump 8 Bonding wire

Claims (5)

A surface acoustic wave element;
A package containing the surface acoustic wave element;
The package includes a notch formed at the apex angle thereof and a plurality of notches formed at least one on each side,
A conductive film is formed on a side surface of the package corresponding to the notch,
A plurality of positions corresponding to the notches on the back surface of the package are provided with regions where conductive patterns electrically connected to input / output terminals of the surface acoustic wave element are formed, and grounding of the surface acoustic wave element A region where a conductive pattern electrically connected to the terminal is formed and a region where a conductive pattern is not formed;
The region corresponding to the notch portion on the back surface of the package and having no conductive pattern formed corresponds to the wiring pattern formed on the printed wiring board on which the surface acoustic wave device is mounted or the layout of the through hole. A surface acoustic wave device. A surface acoustic wave element;
A package containing the surface acoustic wave element;
The package includes a notch formed at the apex angle thereof and a plurality of notches formed at least one on each side,
A conductive film is formed on a side surface of the package corresponding to the notch,
A plurality of positions corresponding to the notches on the back surface of the package, a region having a first size conductive pattern electrically connected to an input / output terminal of the surface acoustic wave element; A region in which a first size conductive pattern electrically connected to the ground terminal of the surface acoustic wave element is formed, and the first conductive pattern electrically connected to the ground terminal of the surface acoustic wave element Having a region where a smaller second conductive pattern is formed;
A region corresponding to the notch on the back surface of the package and where the second conductive pattern is not formed is a layout of a wiring pattern or a through hole formed on a printed wiring board on which the surface acoustic wave device is mounted. A surface acoustic wave device comprising: a surface acoustic wave device. In claim 1 or 2,
The package is formed of a ceramic material and has at least a multi-layer structure;
The surface acoustic wave device according to claim 1, wherein the conductive film formed on the side surface corresponding to the notch of the package is formed in at least a part of the multilayer structure. In claim 3,
When the plurality of layers are three or more layers, the conductive film is formed only on the layers corresponding to the uppermost layer and the lowermost layer of the plurality of layers. In any one of Claims 1 thru | or 4,
A plurality of surface acoustic wave devices each divided by a cutting line are formed in a wafer shape, and the through holes formed on the cutting lines of adjacent surface acoustic wave devices are respectively formed along the cutting lines. The surface acoustic wave device is formed when the surface acoustic wave device is cut out.

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