JP2895975B2 - Ceramic package - 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, and more particularly, to a brazing portion formed on the surface of a ceramic package and formed of a metallized layer formed of an electric conductor such as tungsten, and a tip of a lead. The present invention relates to a ceramic package connected by brazing.

[0002]

2. Description of the Related Art In a conventional ceramic package, as shown in FIG. 3, a metallized layer formed on a corner surface of a ceramic package 10 is used as a brazing portion 14, and a tip of a lead 12 is formed on an exposed surface of the metallized layer. Had been brazed. Such a metallized layer is formed by applying a tungsten paste or the like to a predetermined portion of the ceramic package before firing and firing the same together with the ceramic package. In addition, silver (Ag) -copper (C
A u) type brazing material (hereinafter sometimes referred to as silver brazing) is widely used. Such a lead 12 of the ceramic package shown in FIG. 3 can easily position the lead end at the brazing portion 14 and can easily control the direction of the lead 12 and the like. However, the brazing strength of the lead 12 depends on the direction of the external force applied to the lead 12. That is, the direction parallel to the lead 12 (FIG. 3)
(In the direction of arrow A) of the lead 1
2, the brazing strength is high, and peeling between the tip of the lead 12 and the brazing portion 14 hardly occurs. On the other hand, the brazing strength of the lead 12 is low with respect to the tensile force acting in the direction perpendicular to the lead 12 (in the direction of the arrow B in FIG. 3), and peeling between the tip of the lead 12 and the brazing portion 14 occurs. Easy to do. On the other hand, the lead 32 shown in FIG. 4 has a convex portion 30 formed by bending the tip portion. The protrusion 30 of the lead 32
Are brazed while their tops are in contact with the surface of the brazing portion 34 of the ceramic package 10.

[0003]

In the ceramic package shown in FIG. 4, the directionality of the brazing strength of the leads 32 can be eliminated. However, recently, in order to respond to the demands of multi-pin ceramic packages and the like, when leads are formed to be extremely fine,
As in the case of the lead 32 shown in FIG. 4, it is extremely difficult to bend the tip portion. When the lead 32 having a bent tip is used, the positioning of the protrusion 30 in the brazing portion 34 is not easy, and it is difficult to control the direction of the lead 32 and the like.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a ceramic package in which the directionality of the brazing strength of the lead is eliminated and the positioning of the lead end in the brazing portion of the package is easy.

[0005]

SUMMARY OF THE INVENTION The present inventor has studied to achieve the above object, and found that the present invention is formed integrally with a brazing portion which forms at least a part of a bottom surface of a step formed near an edge of a package. The lead tip is silver brazed to a brazing portion that is made and extends near the outer peripheral edge of the step portion,
It has been found that the brazing strength of the lead can be improved by filling and solidifying the silver braze into the gap between the lead body and the inner wall surface of the step. The present inventor further studied based on the above findings, as a result, a concave meniscus is formed on the surface of the silver solder, in the gap between the lead body and the brazing portion constituting the step portion bottom surface, By filling and solidifying the silver braze, it has been found that the brazing strength of the lead is further improved and the directionality of the brazing strength is eliminated, and the present invention has been achieved.

[0006] Sunawa Chi, the present invention is to braze consisting of metallized layer formed by a conductor and tungsten is formed on the ceramic package surface, is connected tip of the lead is brazed In a ceramic package, a step is formed near the edge of the package.
And at least a part of the bottom surface of the step portion is formed as a step.
Formed at the brazing portion extending in the outer peripheral edge direction of the difference portion .
Ri, the filtrate earthenware pots with portions together are tip brazed lead, the lead and the meniscus surface concave brazing material filled and solidified in the gap between the brazed portion of the bottom surface of the step portion in a ceramic package, characterized in Tei Rukoto formed on.

[0007]

Generally, when the lead end is bonded to the brazing portion of the package with a brazing material such as silver brazing, FIG.
Alternatively, as shown in FIG. 4, forming the surface of the brazing material in a concave shape improves the brazing strength of the lead as compared with the case where the surface of the brazing material is formed in a convex shape due to a large amount of attachment of the brazing material. can do. It is presumed that when the brazing material surface is formed in a convex shape, the external force applied to the lead concentrates on the convex edge of the brazing material surface. Therefore, it is necessary to strictly control the adhesion amount of the brazing material. In this respect, in the present invention, since the brazing material is filled and solidified in the gap between the brazing portion on the bottom surface of the step portion and the lead, even if the amount of the brazing material adhered slightly, a meniscus having an ideal shape is reliably formed on the brazing material surface. And the management of the amount of the brazing material attached can be simplified. Also, since it can be bonded to the brazing part of the package without bending the lead tip,
Even if the lead is made very thin, processing is easy, and positioning of the tip of the lead in the brazing portion can be easily performed.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail with reference to the drawings.
FIG. 1 is a partial cross-sectional view showing one embodiment of the present invention, and a step portion 20 is formed at an edge portion of a ceramic package 10 (hereinafter, sometimes referred to as a package 10). The metallized layer that forms a part of the inner wall surface including the bottom surface of the step portion 20 extends beyond the upper edge of the step portion 20 and near the outer peripheral edge of the step portion 20. The metallized layer is a brazing portion 18 to which the tip of the lead 12 is brazed, and is formed by applying a tungsten paste or the like. In the package 10 of the present embodiment,
The tip of the lead 12 is brazed by a silver brazing 16 to a brazing portion 18 extending near the outer peripheral edge of the step portion 20. The silver solder 16 is also filled and solidified in a part of a gap formed by the brazing portion 18 forming the bottom surface of the step portion 20 and the main body of the lead 12, and the surface shape of the silver solder 16 is concave. I have. Such a concave surface shape of the silver solder 16 is for forming a concave meniscus when the silver solder in a molten state comes into contact with the brazing portion 18 and the main body of the lead 12. According to the package 10 of the present embodiment shown in FIG. 1, the concave surface of the silver solder 16 can be formed away from the edge of the package 10. In addition, since the surface shape of the silver solder 16 can be reliably made concave even if the amount of silver solder attached slightly changes, the silver solder 16 is combined with the position where the concave surface of the silver solder 16 is formed. In the above, the external force applied to the lead 12 can be dispersed.

The step portion 20 of the package 10 shown in FIG. 1 can be easily formed by the method shown in FIGS. 2A to 2C. First, as shown in FIG. 2A, a coating layer 180 is formed by applying a tungsten paste or the like to the green sheet 100 before firing. Thereafter, the surface of the green sheet 100 is pressed with a punch 130 so that a part of the coating layer 180 forms a bottom surface, thereby forming a recess 150 (FIG. 2).
b). Next, by cutting a predetermined portion (a portion indicated by a dotted line in FIG. 2B) of the bottom surface of the concave portion 150, the green sheet 100 having the step portion 120 formed at the edge is cut off
Can be obtained. The green sheet 100 of FIG. 2c obtained in this manner is fired in a firing step together with the coating layer 180, and is constituted by a brazing portion 18 in which a part of the bottom surface is formed of a metallized layer, as in the package 10 of FIG. A package in which the stepped portion is formed at the edge can be obtained. 2A to 2C, the green sheet 100 is pressed by the punch 130 so that the recess 150 is pressed.
Was formed by cutting with a cutting tool.
0 may be formed.

[0010]

According to the present invention, it is not necessary to strictly control the amount of the brazing material attached, and the management of the lead brazing operation can be simplified. In addition, since the brazing strength of the leads is improved, peeling of the brazed leads can be prevented, and the reliability of the finally obtained package can be improved. Furthermore, it is not necessary to perform bending or the like on the tip of the lead, and it is possible to meet the demand for increasing the number of pins.

[Brief description of the drawings]

FIG. 1 is a partial sectional view showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram for explaining a method of forming a step portion of a package.

FIG. 3 is a partial sectional view showing a conventional package.

FIG. 4 is a partial cross-sectional view showing a conventional package.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Ceramic package 12 Lead 16 Brazing material (silver brazing) 18 Brazing part 20 Step part

Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01L 23/04 H01L 23/08 H01L 23/12 H01L 23/48 H01L 23/50

Claims (1)

(57) [Claims] 1. A ceramic package in which the tip of a lead is connected by brazing to a brazing portion formed on the surface of a ceramic package and formed of a metallized layer formed of a conductor such as tungsten. A step is formed near the edge of the step, and at least a part of the bottom surface of the step is in the direction of the outer peripheral edge of the step.
Are formed in the brazed portion extending, the filtrate earthenware pots with portions together are tip brazed lead, it is filled and solidified in the gap between the brazed portion of the bottom surface of the lead and the step portion ceramic package surface of Taro material, characterized in Tei Rukoto a concave shape of the meniscus.