JPH069232U - Package structure of surface acoustic wave device - Google Patents

Abstract

(57) [Summary] [Object] The present invention has a simple structure to improve the isolation between the input and output electrodes so that frequencies other than the pass band can be relatively greatly attenuated. It is an object to provide a package structure for a wave element. [Structure] A ceramic chip carrier 11 and a surface acoustic wave element 12 mounted on the inner surface of the chip carrier,
A package structure 10 for a surface acoustic wave device, comprising: a metal lid 13 that hermetically seals an open upper portion of the chip carrier by seam welding or the like. The wave element is provided with a protrusion 13a that protrudes downward to the vicinity of the upper surface of the wave element so that the internal space of the package defined by the chip carrier and the lid is partitioned between the input / output electrodes by the protrusion. Then, the package structure 10 of the surface acoustic wave device is constructed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention is a package of a surface acoustic wave device in which a surface acoustic wave device is placed on the inner surface of a ceramic chip carrier, and an open upper part of the chip carrier is hermetically sealed by a metal lid. It is about structure.

[0002]

[Prior art]

 Conventionally, such a surface acoustic wave device has a package structure, for example, as shown in FIG. That is, referring to FIG. 5, a package structure 1 of a surface acoustic wave device comprises a ceramic chip carrier 2 and a surface acoustic wave device 3 mounted on the inner surface of the chip carrier 2 and bonded by a conductive adhesive or the like. And a lid 4 made of metal such as Kovar for airtightly sealing the open upper portion of the tip carrier 2 by seam welding or the like.

Here, in the surface acoustic wave element 4, the input / output electrode portions 3a and 3b are provided near both ends of the chip carrier 2 by bonding wires 5 made of ultrafine wires such as gold or aluminum. It can be electrically connected to a bonding pad (not shown).

According to the surface acoustic wave device package structure 1 configured as described above, the surface acoustic wave device 4 is mechanically fixed to the inner surface of the chip carrier 2 by a conductive adhesive and is electrically fixed. The chip carrier 2 can be electrically connected to the bonding pad of the chip carrier 2 as well.

[0005]

[Problems to be solved by the device]

 However, in such a surface acoustic wave device package structure 1, the upper surface of the elastic surface acoustic wave device 3 is covered with the lid 4 to be shielded from the outside, but is surrounded by the lid 4. In the created internal space, spaces between the input / output electrodes 3a and 3b are substantially evenly spaced.

As a result, the direct wave from 3a to 3b on the input electrode 3a side of the surface acoustic wave element 3 is transmitted to the internal space to reach the output electrode 3b side of the surface acoustic wave element 3. Will be reached.

Therefore, the isolation between the input / output electrodes 3a and 3b is not so good, and the amount of attenuation of frequencies other than the pass band does not increase, resulting in deterioration of performance. .

In view of the above points, the present invention has a simple structure to improve the isolation between the input and output electrodes so that frequencies other than the pass band can be relatively greatly attenuated. It is an object to provide a package structure for a surface acoustic wave device.

[0009]

[Means for Solving the Problems]

 According to the present invention, the above object is to hermetically seal a chip carrier made of ceramic, a surface acoustic wave element mounted on the inner surface of the chip carrier, and an open upper part of the chip carrier by seam welding or the like. In a package structure of a surface acoustic wave element including a metal lid, the lid includes a protrusion protruding downward at least at a part thereof to a position near an upper surface of the elastic surface wave element. The package structure of the surface acoustic wave device is characterized in that the internal space of the package defined by the chip carrier and the lid is configured to be partitioned between the input and output electrodes by the protrusion. Is achieved by

[0010]

[Action]

 According to the above structure, since the lid has the protrusion protruding downward, the internal space located above the surface acoustic wave element is partitioned by the protrusion. The direct wave from 3a to 3b on the input electrode side of the surface acoustic wave element does not reach the output electrode side by being blocked by the protrusion, so that the isolation between the input and output electrodes can be improved. However, the amount of attenuation of frequencies other than the pass band becomes large, and the performance can be improved.

[0011]

【Example】

 Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings. FIG. 1 shows an embodiment of a surface acoustic wave device package structure according to the present invention.

The package 10 of the surface acoustic wave device includes a chip carrier 11 made of ceramic, a surface acoustic wave device 12 mounted on the inner surface of the chip carrier 11 and bonded by a conductive adhesive, and the chip carrier. It is composed of a lid 13 made of metal such as Kovar that hermetically seals the open upper part of 11 by seam welding or the like. The lid 13 is electrically connected to the ground line of the chip carrier 11 and grounded. It

The above structure is similar to the conventional surface acoustic wave device package structure shown in FIG. 5, but in the surface acoustic wave device package structure 10 according to the present invention, the lid 13 is As shown in FIG. 2, at least a part thereof is provided with a protrusion 13a protruding downward in the central region.

The lower end of the protrusion 13a extends to the vicinity of the upper surface of the surface acoustic wave element 12, so that the internal space of the package defined by the chip carrier 11 and the lid 13 is made elastic. Above the surface acoustic wave element 12, the projection 13a partitions the input / output electrodes 12a and 12b.

The package structure 10 of the surface acoustic wave device according to the present invention is configured as described above, and since the lid 13 has the protrusion 13a protruding downward, the surface acoustic wave device 12 is formed. The internal space located above the space is partitioned by the protrusion 13a.

Therefore, the vibration of the surface acoustic wave element 12 on the side of the input electrode 12a cannot reach the side of the output electrode 12b because it is blocked by the protrusion 13a. Thus, the isolation between the input and output electrodes can be improved.

FIG. 3 shows another example of forming the protrusion 13 a provided on the lid 13 described above. In the case of FIG. 3 (A), the protrusion 13a is formed to have a relatively large area, which can further improve the isolation between the input and output electrodes of the surface acoustic wave element 12. It is like this.

In addition, in the case of FIG. 3B, the protrusion 13 a is formed so as to spread over almost the entire lid 13, so that the internal portion above the surface acoustic wave element 12 is formed. Since the space is very narrow, the isolation can be further improved.

FIG. 4 shows another embodiment of the surface acoustic wave device package structure according to the present invention. In the case of FIG. Thus, a plurality of protrusions 13b, 13c, 13d, in the illustrated case, are arranged in a line, so that the isolation can be improved.

Further, in the case of FIG. 4B, the lid 13 has a protruding portion 13e that protrudes downward a little over substantially the entire portion thereof, and a lower portion in a central region of the protruding portion 13e. And a second protrusion 13f protruding in the direction. With such a double protrusion structure, the isolation between the input and output electrodes of the surface acoustic wave element 12 can be further improved.

[0021]

As described above, according to the present invention, with a simple structure, the isolation between the input and output electrodes can be improved, and frequencies other than the pass band can be relatively attenuated. Thus, an extremely excellent surface acoustic wave device packaging structure can be provided.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of a surface acoustic wave device package structure according to the present invention.

FIG. 2 is a perspective view of a lid in the embodiment of FIG.

FIG. 3 shows a modified example of the lid used in the embodiment of FIG. 1, and (A) and (B) are cross-sectional views, respectively.

FIG. 4 shows another modified example of the lid used in the embodiment of FIG. 1, and (A) and (B) are perspective views, respectively.

FIG. 5 is a schematic cross-sectional view showing an example of a conventional surface acoustic wave device package structure.

[Explanation of symbols]

 10 surface acoustic wave device package 11 chip carrier 12 surface acoustic wave device 12a input electrode 12b output electrode 13 lid 13a, 13b, 13c, 13d, 13f protrusion

Claims (1)

[Scope of utility model registration request] 1. A ceramic chip carrier, a surface acoustic wave device mounted on an inner surface of the chip carrier, and a metal lid for hermetically sealing an open upper portion of the chip carrier by seam welding or the like. In a package structure for a surface acoustic wave device, the lid includes at least a part of a protrusion projecting downward to a vicinity of an upper surface of the surface acoustic wave device. A package structure of a surface acoustic wave device, characterized in that the internal space of the package defined by (4) is configured to be partitioned between the input / output electrodes by the protrusion.