JPS606543B2 - Method of manufacturing semiconductor stem - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a semiconductor stem, and more particularly to a method for manufacturing a semiconductor stem having standoffs for insulating a metal outer ring from a chassis or the like.

When attaching a semiconductor stem to a chassis or mounting board, it is necessary to float the stem to ensure insulation from the chassis and the like.

The stem can be made to float by attaching it to the chassis via a thin silicone rubber plate, or by sealing a rod-shaped protrusion with an insulating material called a standoff on the back of the stem, and attaching it to the chassis via the standoff. There is. FIG. 1 is a vertical cross-sectional view showing a state in which a semiconductor stem having a standoff, which is the background of the present invention, is attached to a mounting substrate.

In the figure, a lead terminal 2 is located at a predetermined position on a metal 1 made of iron, nickel, cobalt alloy, etc.
Through-holes 11 and 12 are bored into which holes 1 and 22 are inserted.
Cord terminals 21 and 22 made of, for example, iron-nickel-cobalt alloy are arranged in the through holes 11 and 12. Each lead terminal 21, 22 has a connection thin wire 61,
62, it is electrically connected to the semiconductor chip 5 disposed approximately on the center of the metal outer ring 1. Approximately at the inner center of the metal outer ring 1 is a rod-shaped standoff 3 formed from sealing glass, such as filler glass made by adding alumina powder with a higher melting point to shelf silicate glass.
is placed. The lead terminals 21, 22 and the standoff 3 are sealed with a glass 4 made of silicate glass or the like. Then, this semiconductor stem is attached to the chassis 7 by the standoffs 3 in a floating state from the chassis 7. FIG. 2 is a longitudinal sectional view showing a method for manufacturing a semiconductor stem having standoffs shown in FIG. 1, and FIG. 3 is a longitudinal sectional view of a semiconductor stem having standoffs formed by a conventional manufacturing method. . next,
A conventional method for manufacturing a semiconductor stem will be described with reference to FIGS. 1 to 3. The metal outer ring 1 is placed on a carbon jig 81 called graphite, which is formed to accommodate the metal outer ring 1 and the protruding portions of the lead terminals 21 and 22. Furthermore, a glass tablet 4a made of shelf silicate glass is arranged inside the metal outer ring 1, and the through holes 11, 1 of the metal outer moat 1 are passed through the through holes of the glass tablet 4a.
2, lead terminals 21 and 22 are set up as a shield. A standoff 3 is inserted through a through hole in the center of the glass tablet 4a. Then, metal outer ring 1, lead terminals 2i, 22
, the carbon filth 82 is remounted so as to cover the standoff 3 and the glass tablet 4a, and heated to about 100,000 in a neutral (N2) or weakly reducing atmosphere.
At this time, if the material of the standoff 3 is made of only shelf silicate glass, the glass tablet 4a arranged on the outer periphery of the standoff 3 and the standoff 3 will simultaneously soften and flow during heating, and the standoff 3 cannot be maintained in a predetermined shape. Therefore, conventionally, the glass tablet 4a is formed by mixing, for example, 60% of 150 to 200 mesh pass porcelain glass powder and 40% of 325 mesh pass alumina powder to raise the apparent melting point. This prevents the standoff 3 from deforming during sealing. However, since the standoff 3 contains 60% shelf silicate glass, the shelf silicate glass is eluted onto the surface of the standoff 3 during heating, resulting in a layer of only shelf silicate glass (20 to 100 ml). ) is generated. Therefore, the wettability with the molten glass of the glass tablet 4a arranged on the outer periphery of the standoff 3 becomes very good, and in the process of softening and flowing the glass tablet 4a on the outer periphery of the standoff 3, as shown in FIG. standoff 3
The standoffs 3 are pulled upward and tilted, making it impossible to form the standoffs 3 into a normal shape. Therefore, when the stem having the inclined standoffs 3 is attached to the chassis 7 or the like, the stem is inclined and the metal outer ring 1 comes into contact with the chassis 7, which is a problem. If the carbon jig 82 is used to press down the standoff 3 from above in order to prevent this inclination, the surface of the sealing glass 4 will be contaminated, which is undesirable. Therefore, the main object of the present invention is to provide a method for manufacturing a semiconductor stem in which the standoff does not tilt during glass sealing.

In summary, the present invention comprises forming a standoff using the same material as the sealing glass, for example, shelf silicate glass, and an insulating material having a higher melting point than the sealing glass, such as ceramic powder, and etching the surface of the standoff. After that, the lead terminal, the standoff, and the glass tablet are placed at predetermined positions on the metal outer ring, and heated to a temperature higher than the melting point of the glass tablet.

The above objects and other objects and features of the present invention will become more apparent from the detailed description given below with reference to the drawings.

The method for manufacturing a semiconductor stem according to an embodiment of the present invention is the same as the conventional manufacturing method shown in FIG. 2, except that the manufacturing process and heating temperature of the standoff 3' are different.

That is, the standoff 3 is made of, for example, 60% shelf silicate glass powder with a 150 to 200 mesh pass, which is the same as the glass tablet 4a, and an insulating powder with a higher melting point than this shelf silicate glass, for example, 40% alumina ceramic powder with a 325 mesh pass. % and an organic binder are mixed and granulated.Then, after being formed into a rod shape by press molding, it is fired to eliminate the organic binder.Furthermore, the surface of the standoff 3 is treated with, for example, hydrofluoric acid (HF). The etching treatment is performed by etching to dissolve the glazed acid glass between the ceramic particles on the surface and leave only the ceramic.
The standoff 3' has an alumina-rich (rough) surface. Then, the standoffs 3' are placed at predetermined positions on the metal outer ring 1 in the same manner as in FIG. Heat it up. At this time, since the surface of the standoff 3' is in an alumina-rich state, the elution speed of the shelf silicate glass within the standoff 3' is slowed down, and the wettability with the shelf silicate glass on the outer periphery is reduced. The standoff 3' does not soften and flow together with the glass tablet 4a.
As shown in FIG. 4, glass sealing can be carried out in a vertically erected state. The attached table is a table showing the defective rate of semiconductor stems manufactured according to an embodiment of the present invention.

As shown in this table, with the conventional manufacturing method in which the surface of the standoff 3 is not subjected to any treatment, 7 to 14 defects occurred when manufacturing 120 semiconductor stems, but according to the present invention, 7 to 14 defects were generated. I was able to reduce the rate to 0. In addition, when the outer diameter is reduced by 40 mm or 70 mm by hydrofluoric acid treatment on the surface of standoff 3, the defective rate is reduced to 0 in both cases.
I was able to do it. As described above, according to the present invention, the standoff is formed using the same glass as the sealing glass and an insulating material with a higher melting point than the sealing glass, and the surface thereof is etched. It is possible to prevent the glass from flowing out from the standoffs during glass sealing, thereby preventing the standoffs from coming loose and being sealed. therefore,
When the semiconductor stem is attached to a chassis or the like, the semiconductor stem can be held parallel to the chassis.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view showing a state in which a semiconductor stem having a standoff, which is the background of the present invention, is attached to a mounting substrate. FIG. 2 is a longitudinal sectional view showing a method for manufacturing the semiconductor stem shown in FIG. 1. FIG. 3 is a longitudinal sectional view of a semiconductor stem formed by a conventional manufacturing method. FIG. 4 is a longitudinal sectional view of a semiconductor stem formed according to an embodiment of the present invention. In the figure, 1 is a metal outer moat, 21 and 22 are lead terminals, 3' is a standoff, 4 is a sealing glass, 4a is a glass tablet, 5 is a semiconductor chip, 61 and 62 are connection wires, and 7 is a chassis. . Separate Table of Younger Brother's Drawing of Younger Brother Z Figure 3 Figure 4

Claims (1)

[Claims] 1. A semiconductor stem in which a lead terminal and a standoff for insulating the metal outer ring are arranged at a predetermined position of a metal outer ring, and the metal outer ring, lead terminal, and standoff are sealed with a sealing glass. The method of manufacturing comprises forming the standoff using the sealing glass component and an insulating material powder having a higher melting point than the sealing glass, and then treating the surface thereof to make it rich in the insulating material. . A method of manufacturing a semiconductor stem, comprising placing the standoff together with the lead terminal and the glass tablet at a predetermined position of the metal outer ring, and heating the standoff at a temperature equal to or higher than the melting point of the glass tablet.