JPH0342699B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] A semiconductor device in which a thick layer of fusing material on a cap sealing surface is formed intermittently in the shape of convex portions at the bonded portion with a semiconductor package.

Also, a semiconductor device in which the sealing material of the cap sealing surface is formed into a thick layer intermittently or continuously in the shape of convex portions inside the bonded portion with the semiconductor package.

[Industrial Field of Application] The present invention relates to improvements in sealing caps used for hermetic sealing of semiconductor devices, particularly.

Semiconductor devices such as ICs are housed in semiconductor packages and hermetically sealed. This is because the semiconductor element is an active material that is easily influenced by the atmosphere.

Such semiconductor packages can be broadly classified into molded packages and ceramic packages, and the latter type of ceramic package is known to have good airtightness and high reliability.

However, with the ceramic type, the cap is fused and
Since this is an airtight sealing method, sufficient consideration must be given to the shape and other aspects of the fusing material applied to the cap.

[Prior Art] For ceramic packages, a method has traditionally been adopted in which the cap is bonded with a fusing material such as low melting point glass. A cap has been created that has been coated with

Figures 6a and 6b show a plan view and a cross-sectional view of conventional caps, 1 is a ceramic cap, 2 is a low melting point glass, and the cap is 0.6 to 0.7 mm thick, while the cap is about 0.2 mm thick. Melting point glass 2 is applied.

Thus, a cross-sectional view of a ceramic package in which such a cap is fused and hermetically sealed is shown in Fig. 7.
As shown in the figure, 3 is a lead base (element housing container) that houses a semiconductor element 4. In this way, the peripheral edge of the lead base 3 and the cap 1 are fused with the low melting point glass 2, and the inside is kept airtight. This is done by heating the temperature to approximately 400°C.

[Problems to be Solved by the Invention] By the way, the process of melting such low melting point glass and fusing the cap and lead base is as follows:
Usually, a cap is placed on a lead base at room temperature, placed in a heating furnace in a nitrogen atmosphere to heat and fuse, and then cooled and solidified.

At that time, since the cap is placed on the lead base at room temperature, the space S inside the lead base is isolated from the outside, and as it gradually heats up and the low melting point glass gradually melts, the gas in the cavity interior space S It becomes inflated. This causes a problem in that the low melting point glass is pushed outward, weakening the adhesive strength of the cap. In addition to weakening the adhesive force, in extreme cases, the fused low melting point glass may be broken and the gas in the space S may be blown out. In that case, the spout is not filled,
Hermetic seal becomes incomplete.

Furthermore, when heated and melted, the cap on the lead base floats on the molten glass, which may cause the cap to move and shift position, weakening the adhesive strength. Furthermore, if this becomes severe, the hermetic seal may become incomplete or the outer shape may be defective.

The present invention proposes a package that can prevent such a decrease in adhesive strength.

[Means for solving the problem] The problem lies in semiconductor sealing in which the fusion material provided on the cap sealing surface is formed intermittently in a convex and thick layer in the frame-shaped portion that adheres to the semiconductor package. The sealing cap or the sealing material provided on the cap sealing surface is formed in a thick layer intermittently or continuously in a convex shape on the inside of the adhesive part that contacts the frame-shaped adhesive part with the semiconductor package. The problem is solved by a semiconductor device that uses

[Function] In other words, if a thick, intermittently convex cap is used in the bonding frame-like portion with the semiconductor package (lead base), there will be a gap between the package and the cap, and the bonding material will melt. Until this happens, the space inside the package will not be pressurized, and the internal pressure will decrease.
Therefore, the problem of reduced adhesive strength due to extrusion of the fusion material is reduced.

In addition, if a thick cap is formed intermittently or continuously in a convex shape on the inside of the adhesive frame-shaped part with the semiconductor package (lead base), the adhesive material will also adhere to the side wall inside the adhesive part of the package. do,
The adhesive area becomes wider and the adhesive strength of the cap becomes stronger. In addition, misalignment caused by misalignment of the caps is also eliminated.

[Examples] Hereinafter, examples will be described in detail with reference to the drawings.

Figures 1a and 1b show a plan view and a sectional view of a cap according to the present invention, in which 11 is a ceramic cap, 21 and 22 are low melting glasses, and the low melting glasses are coated on the entire surface of the cap to a thickness of 0.2 mm. A 0.1 mm thick frame-shaped intermittent convex shape is formed on the part to be bonded to the lead base and the low melting point glass 21.
It consists of a low melting point glass 22 with a width of about 1 mm. In this way, low melting point glass can be easily formed by first coating and baking the entire surface, then applying and baking a second time from above through a pattern mask.

FIG. 2 shows a partial cross-sectional view of a sealing process in which such a cap is fused to the lead base 3, and FIG. 2A shows the state before fusion bonding, and FIG. 2B shows the state after fusion bonding. Before fusing, the gas in the cavity interior space can escape through the gaps between the low melting point glass 22 formed in an intermittent convex shape, and after fusing, the amount of low melting point glass is increased by the amount of the convex low melting point glass 22. Because I have
The adhesive strength is strong, and the extrusion of the low melting point glass due to pressure from the internal space is reduced, and gas ejection from the internal space is of course suppressed.

Next, FIGS. 3a and 3b show a plan view and a sectional view of another cap according to the present invention, in which 11 is a ceramic cap, 21 and 23 are low melting glasses, and the low melting glasses are coated on the entire surface of the cap. thickness
It consists of a low melting point glass 21 of about 0.2 mm, and a low melting point glass 23 of about 0.1 mm thick and 1 mm wide, which is formed into a frame shape with intermittent convex shapes on the inside in contact with the part to be bonded to the lead base. .

A partial sectional view of the sealing part in the sealing process of fusing such a cap to the lead base 3 is shown in Fig. 4, where a shows the fused surface and b shows the state after welding. . Before fusing, the position of the cap 11 with respect to the lead base 3 is restricted by the low melting point glass 23 formed in an intermittent convex shape, and even after the low melting point glass 23 is melted, the portion does not become convex. Because of the shape, the cap moves less. After fusion, the increased convex low melting point glass 23
The portion of the lead base is fused to the inner side wall of the adhesive portion, increasing the adhesive strength accordingly. Therefore, accidents such as incomplete sealing are prevented.

Next, FIGS. 5a and 5b show a plan view and a sectional view of still another cap according to the present invention, and 1
1 is a ceramic cap, and 21 and 24 are low melting glasses. It consists of a melting point glass 24. This example achieves the same effect as the example shown in Figure 4, but since these caps have a large amount of adhesive on the side wall of the lead base adhesive part, there is no need to expect gas to escape from inside the cavity. Even if the convex low-melting point glass 24 is continuously provided on the surface, sealing with strong adhesive strength can be achieved.

[Effects of the Invention] As is clear from the above description, the present invention has a significant effect of improving the reliability of hermetic sealing in a ceramic package.

[Brief explanation of drawings]

Figures 1a and b, Figures 3a and b, and Figures 5a and b are plan views and sectional views of the cap according to the invention, Figures 2a and b, and Figures 4a and b are its sealing. A partial sectional view of the process (Figure a before fusion, Figure b after fusion), Figures 6a and b are a plan view and sectional view of a conventional cap, and Figure 7 shows a sealed ceramic package. FIG. In the figure, 1 and 11 are caps, 2 and 21 are low-melting glasses, 22, 23, and 24 are convex low-melting glasses, and 3 is a lead base.

Claims (1)

[Scope of Claims] 1. A semiconductor device characterized in that a fusion material provided on a cap sealing surface is formed in a thick layer intermittently in a convex shape in a frame-shaped portion that is bonded to a semiconductor package. 2. The adhesive material provided on the cap sealing surface is formed in a thick layer intermittently or continuously in a convex shape on the inside of the adhesive part that contacts the frame-shaped adhesive part with the semiconductor package. semiconductor devices.