JP3445761B2 - Ceramic package for electronic devices - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic package for an electronic device, and more particularly to a ceramic package for an electronic device which prevents an electrical problem caused by excess solder melted when soldering with a metal cap.

[0002]

2. Description of the Related Art Generally, when a ceramic package body is sealed with a metal cap, a ceramic package for an electronic device is pre-soldered and soldered to a metallized pattern formed at each joint between the ceramic package body and the metal cap. A solder sealing method for remelting is used.

In this solder remelting, a preliminary solder surface is formed by dipping the solder on the metallized pattern of the ceramic package body or metal cap for preliminary soldering, and the presoldered ceramic package body or metal cap is joined by solder remelting. Is the way to do it. When this solder is remelted, the amount of mechanical warp or pre-solder that adheres to the ceramic package body or metal cap fluctuates, and there are some parts that are partially small. Due to the overlapping of a small number of parts, there was a problem that a gap was created and the airtightness could not be maintained.

FIG. 4 is a perspective view before encapsulation showing an example of a conventional ceramic package for electronic devices, and FIG. 5 is a perspective view after encapsulation.

Referring to FIG. 4, in a conventional ceramic package for electronic devices, an electronic device 3 having a piezoelectric property such as a surface acoustic wave element, an input / output electrode provided on the electronic device 3 and gold or aluminum bonding. An input / output connection portion 4 connected by a wire 5 and interposed between the external connection terminal 6 and a first-layer ceramic substrate 11 having a metal pattern to be the external connection terminal 6 when the electronic device 3 is die-bonded with an adhesive. , A hollow second-layer and third-layer ceramic substrates 12 and 13 arranged so as to surround the electronic device 3, and a metal cap manufactured by rolling a metal plate having a thermal expansion coefficient close to that of a solder plate and a ceramic 2 and
Composed of.

In the structure shown in FIG. 4, airtightness is ensured after the ceramic package body 1 including the first, second and third layers of ceramic substrates 11, 12, 13 and the metal cap 2 are sealed. For this reason, when sufficient pre-solder is applied to the metallized pattern 14 formed in the upper opening of the ceramic package body 1 and the joint surface of the metal cap 2, it is melted when it is passed through a solder sealing thermal furnace. As shown in FIG. 5, the excess solder becomes a solder pool 18 inside the metal cap 2 and comes into contact with the input / output connection bonding wire 5 of the electronic device 3 to cause an electrical failure or melted excess solder. Is the ceramic package body 1
Flowing along the inside or outside side surface of the ceramic package, the solder drips 19 and 20 shown in FIG. The problem arises.

[0007]

In the above-described conventional ceramic package for electronic devices, in order to ensure airtightness, when a sufficient amount of preliminary solder is applied, excess solder melted becomes a solder pool inside the metal cap. Electrical contact may occur inside the package, or it may flow along the inside or outside side of the ceramic package body and reach the external connection terminals or even the signal pattern around the ceramic package body to cause electrical failure. There is a problem.

SUMMARY OF THE INVENTION An object of the present invention is to provide a ceramic package for an electronic device in which excess solder melted does not cause an electrical failure in order to eliminate such conventional defects.

[0009]

A ceramic package for an electronic device according to the present invention comprises a first-layer ceramic substrate on which a metallized pattern for mounting the electronic device and connecting the electronic device to an external terminal is formed. The hollow ceramic substrate arranged so as to surround the electronic device, and a metal cap for joining and sealing the hollow ceramic substrate to the upper opening of the hollow ceramic substrate, the upper opening of the hollow ceramic substrate It is characterized in that the metallization pattern for sealing formed on the portion and the metallization pattern formed on the side surface of the hollow ceramic substrate are connected to each other.

Also, the hollow ceramic substrate is composed of two or more layers, and the metallized pattern on the side surface of the hollow ceramic substrate is formed so as not to reach the first layer ceramic substrate.

Further, the metallized pattern on the side surface of the hollow ceramic substrate is characterized by being four corners of the side surface of the hollow ceramic substrate.

Further, the metallized pattern on the side surface of the hollow ceramic substrate is characterized by being a central portion on four sides of the side surface of the hollow ceramic substrate.

Further, the electronic device is characterized by being an electronic device having piezoelectricity such as a surface acoustic wave element.

Further, the metal cap is characterized by being manufactured by rolling a metal plate having a thermal expansion coefficient close to that of the solder plate and the ceramic.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view before encapsulation showing one embodiment of a ceramic package for electronic devices of the present invention, and FIG. 2 is a perspective view after encapsulation.

In the present embodiment shown in FIG. 1, in addition to the structure of a conventional ceramic package for electronic devices, first, second and third layers of ceramic substrates 11, 12, 13 are provided.
The metallized pattern for connecting the metallized pattern 14 formed in the upper opening of the ceramic package body 1 consisting of the above to release the solder to the four side surfaces of the third-layer ceramic substrate 13 which is the uppermost layer of the ceramic package body 1. 15 is formed.

In FIG. 1 or 2, the components corresponding to those shown in FIG. 4 or 5 are designated by the same reference numerals or symbols, and the description thereof will be omitted.

Next, the ceramic package of this embodiment will be described in detail with reference to FIGS. 1 and 2.

In FIG. 1, a ceramic package body 1 has a first-layer ceramic substrate 11 and hollow second-layer and third-layer ceramic substrates 12 and 13, respectively, which are superposed on each other, and then the electric furnace at about 600.degree. It is baked inside and becomes one.

The piezoelectric electronic device 3 such as a surface acoustic wave device is die-bonded to the first-layer ceramic substrate with an adhesive after cooling the fired ceramic package body 1.

Next, the input / output end electrodes provided on the electronic device 3 are connected to the external connection terminals 6 of the first-layer ceramic substrate 11 by gold or aluminum bonding wires.
Is connected to the input / output connection portion 4 interposed therebetween.

Finally, the metal cap 2 manufactured by rolling a metal plate such as Kovar having a thermal expansion coefficient close to that of the solder plate and ceramic is pre-soldered on the metallized pattern 14 in the upper opening of the ceramic package body 1. After being attached, the solder is usually passed through a thermal furnace of about 240 ° C. and the solder is melted and joined to complete the sealing.

Here, when the solder surface of the metal cap 2 is aligned with the side of the ceramic package body 1 and passed through a solder-sealing thermal furnace, excess molten solder is produced as in the conventional case, but as shown in FIG. In addition, since the excess melted solder flows into the metallized pattern 15 formed at the four corners of the uppermost third-layer ceramic substrate 13 and becomes the solder pool 16, as shown in the conventional example of FIG. The solder pool 18 is not formed inside the cap 2, and it flows along the inner or outer side surface of the ceramic package body 1.
It is possible to prevent the solder dripping 19, 20 from reaching the external connection terminal 6 of the ceramic package body 1 or the signal pattern around the ceramic package body 1 and making contact therewith to cause an electrical failure.

FIG. 3 is a perspective view showing another embodiment of the ceramic package for electronic devices of the present invention.

As shown in FIG. 3, the metallized pattern 14 formed in the upper opening of the ceramic package body 1 including the first, second, and third layer ceramic substrates 11, 12, and 13 is connected to the metallized pattern 14. , A metallized pattern 1 for escaping solder to the center of four sides of the side surface of the third layer ceramic substrate 13 which is the uppermost layer of the ceramic package body 1.
7, the molten excess solder flows into the metallized pattern 17 formed at the center of the four sides of the side surface of the uppermost third ceramic substrate 13, as in FIG. Therefore, as shown in the conventional example of FIG.
The solder pool 18 is not formed inside the metal cap 2, and it flows along the inside or outside side surface of the ceramic package body 1 to allow the dripping of the solder 19, 20 and the external connection terminal 6 of the ceramic package body 1 or the ceramic. The signal pattern around the package body 1 does not reach and come into contact with the signal pattern to cause an electrical failure.

In the above two embodiments, the ceramic package body 1 is described as being composed of three layers of ceramic substrates, but the metallized patterns 15 and 17 formed on the side surface of the ceramic package body 1 are described.
Is the minimum number of layers that does not reach the first ceramic layer 11 on which the metallized pattern serving as the external connection terminal 6 is formed, and the ceramic package body 1 may have three or more ceramic substrates.

Further, the metallization patterns at the four corners or the central portions of the four sides of the uppermost third layer ceramic substrate 13 are formed on the entire circumference of the side surface so as not to reach one or both or the first ceramic layer 11. May be.

[0029]

As described above, the ceramic package for an electronic device of the present invention is solder-sealed with a metal cap on at least the four side faces or the center of the four sides of the uppermost layer of the ceramic substrate having three or more layers. By forming a metallized pattern that allows the excess solder that is melted at that time to escape, it is possible to prevent electrical defects caused by the excess solder.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a ceramic package for an electronic device of the present invention before sealing.

FIG. 2 is a perspective view showing an embodiment of a ceramic package for an electronic device of the present invention after encapsulation.

FIG. 3 is a perspective view showing another embodiment of the ceramic package for electronic devices of the present invention.

FIG. 4 is a perspective view showing an example of a conventional ceramic package for electronic devices before sealing.

FIG. 5 is a perspective view showing an example of a conventional ceramic package for electronic devices after sealing.

[Explanation of symbols] 1 Ceramic package body 2 metal caps 3 electronic devices 4 I / O connection 5 Bonding wire 6 External connection terminal 11 Ceramic substrate of the first layer 12 Second layer ceramic substrate 13 Third layer ceramic substrate 14, 15, 17 metallized patterns 16, 18 Solder pool 19, 20 Solder dripping

Claims (6)

(57) [Claims] 1. A first layer ceramic substrate on which an electronic device is mounted and a metallized pattern for connecting the electronic device to an external terminal is formed, and a hollow ceramic which is arranged so as to surround the electronic device. A substrate and a metal cap for joining and sealing to the upper opening of the hollow ceramic substrate, and a metallizing pattern for sealing formed in the upper opening of the hollow ceramic substrate and the hollow The ceramic package for an electronic device, wherein the ceramic package is formed in contact with the metallized pattern formed on the side surface of the ceramic substrate. 2. The hollow ceramic substrate is composed of two or more layers, and the metallized pattern on the side surface of the hollow ceramic substrate is formed so as not to reach the ceramic substrate of the first layer. A ceramic package for an electronic device as described above. 3. The ceramic package for an electronic device according to claim 1, wherein the metallization pattern on the side surface of the hollow ceramic substrate is a four-sided corner of the side surface of the hollow ceramic substrate. 4. The ceramic package for an electronic device according to claim 1, wherein the metallization pattern on the side surface of the hollow ceramic substrate is a central portion on four sides of the side surface of the hollow ceramic substrate. . 5. The ceramic package for an electronic device according to claim 1, wherein the electronic device is an electronic device having piezoelectricity such as a surface acoustic wave element. 6. The electronic device according to claim 1, wherein the metal cap is manufactured by rolling a metal plate having a thermal expansion coefficient close to that of a solder plate and a ceramic. Ceramic package for devices.