JPH0974328A - Package for surface acoustic wave device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a sealing member from flowing in/out and to improve air tightness by providing a mechanism for restricting the movement of the sealing member between the packaged part of a surface acoustic wave(SAW) element and a seal bonding part on a ceramic base. SOLUTION: A surface layer conductor pattern for connecting the seal bond part and the packaged part of the SAW element is formed so that its breadth is narrow and its distance is not shortest. The ceramic base forming a front layer conductor pattern 2 for the section sealed and bonded by silver (Ag) or silver palladium (Ag/Pd) and a surface layer conductor pattern 3 for the SAW element packaged section on a low-temperature (900 deg.C)-burned ceramic base 1 with a screen print method is prepared. While using the provided ceramic base, a package for SAW device is assembled and concerning the results of sealed air-tightness inspection (leak inspection) and opened can observation inspection, both the leak inspection and the opened can observation inspection are satisfactory concerning the package for SAW device using the ceramic base.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface acoustic wave device package which is sealed and joined via a sealing material.

[0002]

2. Description of the Related Art In recent years, many surface acoustic wave devices have been used as elements such as filters, delay lines, and oscillators of electronic equipment utilizing radio waves. In particular, surface acoustic wave filters, which are compact and lightweight and have high sharp cutoff performance as filters, have come to be widely used as filters for RF stages and IF stages of mobile terminal devices in the mobile communication field. There is a demand for a highly reliable surface acoustic wave device capable of responding to changes in the operating environment as well as improving characteristics such as out-of-band attenuation near the band.

Conventionally, a surface acoustic wave device package, which affects the reliability of the surface acoustic wave device, protects the element from external influences and at the same time accurately holds the internal element and operates its function to the outside. Is needed. Such a surface acoustic wave device package includes a ceramic base to which a surface acoustic wave element having an electrically functioning electrode pattern is adhered, and a hollow portion on the electrode pattern of the surface acoustic wave element. And a sealing material for joining the ceramic base and the metal cap together. The ceramic base is generally made of alumina, glass ceramic, etc., and is used as a single-layer or multi-layer flat plate, and the surface layer conductor pattern is formed on this by etching the Ag / Pd alloy layer etc. The electrode pattern on the surface acoustic wave element is electrically connected by wire bonding or the like.

In the surface acoustic wave device, a surface acoustic wave element is placed on a ceramic base, and then wire bonding or the like for electrically connecting the ceramic base and the surface acoustic wave element is performed, and finally, the cap and the ceramic base. It is manufactured by joining and with a sealing material. Here, the sealing joint surface is on the same plane as the mounting surface of the surface acoustic wave element, and the width of the surface conductor pattern connecting the sealing joint portion and the mounting portion of the surface acoustic wave element is wide and the shortest distance. Met. The electrical connection between the sealing joint portion and the surface acoustic wave element mounting portion by the surface layer conductor pattern is necessary to bring out the electrical characteristics of the surface acoustic wave element sufficiently. Otherwise, the surface acoustic wave device, which is a high-frequency electronic component, will have poor inductive characteristics and poor electrical characteristics.

[0005]

However, the above-mentioned surface acoustic wave device package has the following problems. That is, if the mounting portion and the sealing joint portion of the surface acoustic wave element are on the same plane, and the width of the surface layer conductor pattern connecting the sealing joint portion and the mounting portion is wide and at the shortest distance, it is sealed. The stop material flows into the mounting portion. Further, the connection between the sealing joint portion and the surface acoustic wave element mounting portion is made by the surface layer conductor pattern on the same plane, so that the sealing material flows into the mounting portion. Furthermore, the structure in which the mounting surface and the sealing joint are flush with each other also causes the sealing material to flow into the mounting portion. As a result, the sealing material flows into the vicinity of the surface acoustic wave element on the mounting surface, which adversely affects the wire bonding and the surface acoustic wave element thermally, electrically, and physically, and the electrical characteristics deteriorate, and There is a problem that the sealing material flows out from the sealing joint surface, the amount of the sealing material is reduced, the sealing strength and airtightness are deteriorated, and the sealing yield is deteriorated.

The inventions of claims 1 to 8 have been made in order to cope with such a problem, and flow of the sealing material into the surface acoustic wave element mounting portion and sealing bonding in the sealing step. It is an object of the present invention to provide a surface acoustic wave device package that prevents the sealing material from flowing out from the surface and has high airtightness.

[0007]

According to another aspect of the present invention, there is provided a surface acoustic wave device package comprising a metal cap, a conductor pattern formed on a front surface and a back surface, and an electric connection with the conductor pattern. In a surface acoustic wave device package in which a single-layered or multi-layered ceramic base on which is mounted is sealed and joined by a sealing material in a sealing joint portion of the ceramic base, the ceramic base is a surface acoustic wave element. It is characterized by comprising a mechanism for limiting the movement of the sealing material between the mounting portion and the sealing joint portion.

A surface acoustic wave device package according to a second aspect is the same as the surface acoustic wave device package according to the first aspect, wherein the mechanism for restricting the movement of the encapsulant has a sealing joint portion and a surface acoustic wave element mounting portion. It is characterized in that the surface layer conductor pattern for connecting to and is configured to have a narrow width and not a shortest distance.

A surface acoustic wave device package according to a third aspect of the present invention is the surface acoustic wave device package according to the first aspect, wherein the mechanism for restricting the movement of the encapsulant is the surface conductor pattern of the encapsulation joint and the surface acoustic wave element. The mounting portion is electrically connected to the surface layer conductor pattern via an interlayer conductor pattern or a bottom surface conductor pattern other than the mounting portion surface.

A surface acoustic wave device package according to a fourth aspect of the present invention is characterized in that, in the surface acoustic wave device package according to the third aspect, the potential of the connecting portion between the surface conductor patterns is ground potential.

A surface acoustic wave device package according to a fifth aspect of the present invention is the surface acoustic wave device package according to the first aspect, wherein the mechanism for restricting the movement of the encapsulant is at least between the encapsulation joint portion and the mounting portion. It is characterized in that a sealing material inflow and outflow prevention member is provided in the region of the curved portion.

A surface acoustic wave device package according to a sixth aspect is the same as the surface acoustic wave device package according to the fifth aspect, wherein the preventing member is made of a material having a lower thermal conductivity than the sealing joint portion and the mounting portion region. It is characterized by

A surface acoustic wave device package according to a seventh aspect is the surface acoustic wave device package according to the sixth aspect, in which the preventing member is provided with a stepped portion which is concave or convex with respect to the mounting portion surface. Is characterized by.

A surface acoustic wave device package according to an eighth aspect is the same as the surface acoustic wave device package according to the fifth aspect, wherein the sealing material inflow / outflow prevention member has a sealing joint portion and a surface acoustic wave element mounting portion. It is characterized in that the surface layer conductor pattern to be connected has a narrow width and is formed in a region which is not the shortest distance.

The mechanism for restricting the movement of the sealing material between the mounting portion and the sealing joint portion of the surface acoustic wave device according to the surface acoustic wave device package of claim 1 includes a metal cap and a ceramic base. In the process of joining through the sealing material,
It is possible to prevent the fluidized sealing material from flowing into the mounting portion of the surface acoustic wave element, and to prevent the amount of the sealing material from decreasing at the sealing joint portion due to the inflow of the sealing material. The mechanism.

As preferable mechanisms, the mechanisms of claims 2, 3, 5, 7, and 8 can be cited.

By using the surface acoustic wave device package having such a mechanism, it is possible to improve airtightness and sealing strength, which are important items for improving the productivity of the surface acoustic wave device package. . Moreover, the sealing material does not flow into the vicinity of the mounting portion of the surface acoustic wave element, and the wire bonding and the surface acoustic wave element are thermally and
Eliminates adverse electrical and physical effects.

The encapsulating material according to claim 1 includes solder, and specifically, lead-tin (Pb-Sn) solder, lead-silver (Pb-Ag) solder, tin-silver (Sn-). Ag) solder, gold-tin (Au-S
Examples thereof include n) solder, lead-silver-tin (Pb-Ag-Sn) solder, lead-antimony (Pb-Sb) solder, tin-bismuth (Sn-Ag) solder, and the like. As the surface layer conductor pattern, gold (Au), silver (Ag), silver-palladium alloy (Ag / Pd), or the like can be used.

In the surface acoustic wave device package of claim 2, the surface layer conductor pattern having a narrow width and not having the shortest distance means that the surface acoustic wave device mounting portion and the sealing joint portion are on the same plane. A surface layer conductor pattern to be connected is not linear but has at least one or more bent linear portions or curved portions, and has a width narrower than that of a linear pattern.

In the surface acoustic wave device package according to a third aspect of the invention, the surface layer conductor patterns are connected to each other on a surface other than the surface on which the surface acoustic wave element is mounted, so that the surface acoustic wave element is sealed and joined to the mounting portion. It is not necessary to connect the portion directly with the surface conductor pattern. Therefore, the ceramic layer exists between the mounting portion and the sealing joint portion of the surface acoustic wave element, so that the sealing material flows into the mounting portion and the sealing material flows out from the sealing joint portion. Can be suppressed.

In the surface acoustic wave device package according to the fourth aspect of the present invention, the potential of the connection portion between the surface conductor patterns is set to the ground potential to improve the induction characteristics of the surface acoustic wave device which is a high frequency electronic component, and to stabilize the device. Reliable surface acoustic wave device characteristics can be obtained.

It is preferable that the sealing material inflow / outflow prevention member according to any one of claims 5 to 8 is formed of a material different from the material forming the sealing joint portion and the surface acoustic wave element mounting portion region. Specifically, alumina ceramics, glass, etc. can be mentioned. According to the surface acoustic wave device package of the sixth aspect, it is possible to prevent the encapsulating material from flowing into and out of the mounting portion, and also to prevent heat conduction to the surface acoustic wave device.

In order to provide the preventive member on the ceramic base, it is possible to screen-print black glass or the like, which is a model of the preventive member, on the ceramic base and simultaneously fire it.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A surface acoustic wave device package of the present invention will be described with reference to the drawings. Example 1 and Example 2 FIGS. 1 and 2 relate to a ceramic base relating to a package for a surface acoustic wave device according to claims 1, 2 and 8. FIG. 1 shows a shape (Example 1) in which the surface conductor pattern connecting the sealing joint portion and the mounting portion of the surface acoustic wave element has a narrow width and is not the shortest distance (Example 1). The shape (Example 2) which added the part is shown, respectively.

In FIG. 1, silver (Ag) or silver-palladium (Ag / Pd) is placed on a low temperature (900 ° C.) fired ceramic base 1.
) Etc., the surface layer conductor pattern 2 of the sealing joining part and the surface layer conductor pattern 3 of the surface acoustic wave element mounting part were prepared by the screen printing method. Here, the dimensions of the ceramic base are 6.3 mm × 7.7 mm,
The surface acoustic wave element mounting portion is 2.2 mm x 4.6 mm, and the surface conductor pattern 4 for connecting the sealing joint and the surface acoustic wave element mounting portion 4
The maximum width was 0.3 mm, and the shape was intricate.

Further, as shown in FIG. 2, a sealing material outflow prevention portion 5 is additionally provided in the region of the surface layer conductor pattern 4 of the connection portion. The outflow prevention portion 5 was formed by screen-printing glass and firing it. Note that FIG. 7 shows a conventional ceramic base in which the width of the surface layer conductor pattern for connecting the sealing joint portion 2 and the surface acoustic wave element mounting portion 3 is sufficiently large for a comparative experiment.

A package for a surface acoustic wave device was assembled using each of the obtained ceramic bases, a sealing test was performed, and a sealing airtightness test (leak test) and a can open observation test were performed. Check for leaks in inert liquid at 125 ° C
The sample was immersed for 30 seconds and it was measured whether gas inside the sample leaked. The number of measurement samples is 50. In the can open inspection, it was inspected whether the inflow of the sealing material (solder) reached the bonding area and the mounting area. Number of measurement samples is 30
It is a sample. Table 1 shows the results.

[0028]

[Table 1] It can be seen from Table 1 that the surface acoustic wave device packages using the ceramic bases having the structures shown in FIGS. 1 and 2 are excellent in leak inspection and open can observation inspection.

Example 3 FIGS. 3 and 4 relate to a ceramic base relating to the surface acoustic wave device package of claims 1, 3 and 4. FIG. 3 is a view of the ceramic base as seen from the mounting / adhesion surface, and FIG. 4 is a perspective view thereof. FIG.
At the low temperature (900 ° C) firing ceramic base 1, screen the surface conductor pattern 2 of the sealing joint part and the surface conductor pattern 3 of the surface acoustic wave element mounting part with silver (Ag) or silver-palladium (AgPd). A ceramic base formed by the printing method was prepared. Here, the ceramic base has a two-layer structure, its dimensions are 6.3 mm × 7.7 mm, the mounting area is 2.2 mm × 4.6 mm, and the connection between the sealing joint and the surface acoustic wave element mounting part is via a via hole 6. Connected width 0.5
The inter-layer conductor pattern 8 having a thickness of mm was used. The interlayer conductor pattern 8 was set to the ground potential.

A package for a surface acoustic wave device was assembled using each of the obtained ceramic bases, a sealing test was performed, and a sealing airtightness test (leak test) and an open can were performed under the same comparative sample and conditions as in Example 1. Observation inspection was performed. The results are shown in Table 2.

[0031]

[Table 2] It can be seen from Table 2 that the surface acoustic wave device packages each using the ceramic base having the structure shown in FIG. 3 are excellent in leak inspection and open can observation inspection.

Example 4 FIGS. 5 and 6 relate to a ceramic base relating to a surface acoustic wave device package according to claims 1 and 5 to 7. FIG. 5 is a view of the ceramic base viewed from the mounting adhesive surface, and FIG. 6 is a perspective view thereof.
In FIG. 5, the surface conductor pattern 2 at the sealing joint portion of silver / palladium (Ag / Pd) and the surface conductor pattern 3 at the surface acoustic wave element mounting portion are formed on the ceramic base 7 made of white alumina by the screen printing method. Then, a base was prepared by screen-printing and firing a black glass sealing material outflow prevention portion 9 having a lower thermal conductivity than that of the surface conductor pattern. Here, the dimensions of the ceramic base are 6.3
mm × 7.5mm, mounting area 2.2mm × 4.6mm, wire bonding area 1.2mm × 0.4mm at 3 places. As the encapsulating material, tin-lead (Sn-Pb) solder was provided with a convex step on the mounting surface.

A surface acoustic wave device package was assembled using the obtained ceramic base, and a sealing test was conducted. A hermetically sealed sample was prepared under the same conditions as in Example 1 except that the ceramic base made of white alumina was used. A sex test (leak test) and an open can observation test were performed. Table 3 shows the results.

[0034]

[Table 3] From Table 3, it can be seen that the surface acoustic wave device package using the ceramic base having the structure shown in FIG. 5 is excellent in leak inspection and open can observation inspection. Even when tin-lead (Sn-Pb) solder as a sealing material was provided with a step difference of the recess with respect to the mounting surface, the same evaluation results as in Example 4 were obtained.

[0035]

According to the present invention, there is provided a mechanism for restricting the movement of the sealing material such as solder between the surface acoustic wave element mounting portion and the sealing joint portion of the metal cap. Therefore, it is possible to obtain a surface acoustic wave device package having high airtightness by preventing the sealing material from flowing into the surface acoustic wave element mounting portion and the sealing material from flowing out from the sealing joint surface in the sealing step. You can

The inventions of claims 1 to 8 are:
It is possible to obtain a surface acoustic wave device package that contributes greatly to the improvement of productivity and can be sealed without impairing the characteristics.

[Brief description of drawings]

FIG. 1 is a view showing a ceramic base having a shape in which a surface layer conductor pattern has a narrow width and is not the shortest distance.

FIG. 2 is a view showing a ceramic base having a shape in which a sealing material outflow prevention portion is additionally provided.

FIG. 3 is a view showing a ceramic base in which surface layer conductor patterns are connected via interlayer conductor patterns.

FIG. 4 is a perspective view of FIG.

FIG. 5 is a diagram showing a ceramic base having a shape provided with a sealing material outflow prevention portion.

FIG. 6 is a perspective view of FIG.

FIG. 7 is a view showing a ceramic base of a comparative example.

[Explanation of symbols]

1 ... Ceramic base, 2 ......... Surface layer conductor pattern of sealing joint part, 3 ......... Surface layer conductor pattern of surface acoustic wave element mounting part, 4 ......... Surface layer conductor pattern of connection part, 5 ...
...... Leakage prevention part, 6 ... Via hole, 7 ... Ceramic base, 8 ... Interlayer conductor pattern, 9 ... Encapsulation material outflow prevention part.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Naoki Akahori 8 Shinsita-cho, Isogo-ku, Yokohama-shi, Kanagawa Incorporated company Toshiba Yokohama Office

Claims (8)

[Claims] 1. A metal cap and a single-layer or multi-layer ceramic base on which surface acoustic wave elements formed by forming conductor patterns on the front and back surfaces and electrically connected to the conductor patterns are mounted. In a surface acoustic wave device package formed by sealing and joining with a sealing material at a sealing joint of a ceramic base, the ceramic base is provided between a mounting portion of the surface acoustic wave element and the sealing joint. A surface acoustic wave device package comprising a mechanism for restricting movement of the encapsulant. 2. The surface acoustic wave device package according to claim 1, wherein the mechanism has a narrow and shortest surface layer conductor pattern connecting the sealing joint portion and the mounting portion of the surface acoustic wave element. A package for a surface acoustic wave device, which is characterized by a shape that is not a distance. 3. The surface acoustic wave device package according to claim 1, wherein the mechanism is such that the surface layer conductor pattern of the sealing joint portion and the surface layer conductor pattern of the mounting portion of the surface acoustic wave element are connected. A package for a surface acoustic wave device, which is configured by being electrically connected via an interlayer conductor pattern or a bottom conductor pattern other than the mounting surface. 4. The surface acoustic wave device package according to claim 3, wherein the potential of the connection portion between the surface layer conductor patterns is ground potential. 5. The surface acoustic wave device package according to claim 1, wherein the mechanism prevents the inflow and outflow of the sealing material in at least an area between the sealing joint portion and the mounting portion. A surface acoustic wave device package comprising a member. 6. The surface acoustic wave device package according to claim 5, wherein the prevention member is made of a material having a lower thermal conductivity than the sealing joint portion and the placement portion region. A package for surface acoustic wave devices. 7. The surface acoustic wave device package according to claim 6, wherein the prevention member is provided with a step of a concave portion or a convex portion with respect to the mounting surface. Wave device package. 8. The surface acoustic wave device package according to claim 5, wherein the sealing material inflow and outflow prevention member has a thin surface layer conductor pattern for connecting the sealing joint portion and the mounting portion. A surface acoustic wave device package characterized by being formed in a region that is not the shortest distance.