JPH0133943B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD The present invention relates to a method for hermetically sealing an aluminum alloy package. Conventional technology and problems Metal packages used in microwave amplifiers have traditionally been made of iron-based materials such as stainless steel, but they have the drawback of not being able to meet the demands for higher output and lighter weight amplifiers. It was hot. On the other hand, aluminum-based materials have good thermal conductivity,
Moreover, it has the advantage of being lightweight, but on the other hand, when laser welding the package case and cover,
Since the cooling rate of the welded portion is too high, cracks are likely to occur due to rapid cooling, and the package cannot be kept airtight. OBJECTS OF THE INVENTION It is an object of the present invention to provide a method for producing an aluminum alloy package that eliminates the above-mentioned drawbacks. Structure of the Invention The above-mentioned object of the present invention is to provide a method for manufacturing a semiconductor package consisting of an aluminum alloy case and a cover, in which silicon 4.0~ This can be achieved by an aluminum alloy package manufacturing method characterized by inserting an aluminum brazing filler metal containing 12.5% by weight, the remainder of which is aluminum except for unavoidable impurities, so as to protrude from the welding surface and laser welding it. can. Embodiment Figure 1 shows an outline of a semiconductor package, and Figure 2 shows an outline of a semiconductor package.
The figure shows an enlarged welded portion where a brazing material 3 is inserted between a case 1 and a cover 2 of the package. In this example, the case and cover are alloy number A5052 (2.2~2.8% Mg-Al) listed in JISH4000 and
Each consists of A1100 (99% Al). In this case, the above combination was used, but for example A6061 (0.8
Various aluminum alloys can be used, such as ~1.2% Mg-Al). Welding conditions are average output 250~350W
using a pulsed YAG laser with a pulse width of 4 to 6
mm/s, pulse rate 15-20P/s beam,
The filler metal in the weld was irradiated in an argon atmosphere.
The welding speed was 4 to 6 mm/s. The silicon content of the brazing filler metal was varied in the range of 0 to 12.5% by weight, and the thickness was varied in the range of 0 to 1000 μm, and the beam diameters were 0.3 mmφ and 0.7 mm.
A beam of φ was irradiated. In addition, in order to investigate the effect of weld build-up, the filler metal was made to protrude 0.5 mm from the weld surface.
Or welded with a beam diameter of 0.3mmφ without protruding. The former results are shown in Table 1, and the latter results are shown in Table 2. Table 3 shows the results of welding with the laser beam diameter set to 0.7 mmφ and the brazing filler metal protruding 0.5 mm. The welding results in these tables are rated good (〇) if there is no cracking, and poor (x) if there is.
And so. In addition, cases where the thickness is too thick for the beam diameter and sufficient welding can be performed, but the strength is insufficient (△)
It was displayed as As is clear from Tables 1 and 2, by arranging the brazing filler metal in a protruding manner, a build-up effect is produced and good crack-free welding is possible even when the thickness of the brazing filler metal is thin. An X-ray microanalyzer revealed that the welded part using an aluminum brazing filler metal with a silicon content of 4.0 to 12.5% by weight was an AlSi solid solution alloy with high hot strength.

【table】

[Table] If the silicon content of the brazing filler metal is less than 4.0% by weight,
Cracks are likely to occur in welded parts. This is because the amount of Si in the AlSi solid solution alloy formed in the weld is too small to have sufficient hot strength. Moreover, if it exceeds 12.5% by weight, the brazing material itself becomes hard and brittle, making it difficult to produce a thin plate of the brazing material, which is not preferable. If the thickness of the filler metal exceeds 1000 μm, it is too thick for the beam diameter of 0.3 mmφ, and only the filler metal will be melted during welding, making it impossible to obtain sufficient welding. However, the beam diameter is 0.7μ
m, welding is performed well as shown in Table 3, and no cracks occur. However, 1000μ
If it is thicker than m, good results cannot be obtained unless the beam diameter is further increased, which is not practical.

[Table] When the beam diameter is 0.3 mmφ, the thickness of the brazing material is most preferably 200 to 600 μm. When the material of the case and cover is aluminum alloy such as alloy number A5052, A6061, A1100 listed in JIS H4000, the silicon content as insert material is 4.0~
Using a thin plate of 12.5% brazing filler metal, from the welding surface
The package, which was protruded by 0.5 mm and overlay welded under the above preferable conditions, showed a leakage amount of less than 10 ^-10 atm.cc/s in a helium leak test and had sufficient airtightness. Effects of the Invention According to the present invention, it is possible to stably and reliably manufacture a lightweight, airtight package with good thermal conductivity and no practical problems from a case and cover made of an aluminum alloy material.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view of a semiconductor package;
FIG. 2 is an enlarged sectional view of the weld between the case and the cover. 1...Case, 2...Cover, 3...Brazing material.

Claims (1)

[Scope of Claims] 1. A method for manufacturing a semiconductor package consisting of an aluminum alloy case and a cover, in which 4.0 to 12.5 weight of silicon is added between the case and the cover in order to hermetically seal the case and the cover. %, the remainder of which is aluminum except for unavoidable impurities, is inserted so as to protrude from the welding surface, and laser welded. 2. The manufacturing method according to claim 1, wherein the aluminum brazing material has a thickness of 100 to 1000 μm.