SU301236A1 - METHOD OF soldering leads to thin - Google Patents

Description

This invention relates to the field of soldering.

There is a known method of soldering the leads to thin metal films, in which a solder is applied in the form of a drop in the soldering zone. However, existing methods for attaching leads to thin metal films have several disadvantages. The melting of the solder and the formation of a drop are produced by a stream of heated gas directly on the surface of the metal film. As a result, the substrate is very hot, which negatively affects the quality of the device. The heated substrate promotes the spreading of solder on a metal film, which expands the soldering zone and makes it impossible to obtain the minimum dimensions of the solder joint. In addition, the heated solder dissolves the metallic coating of the substrate.

To prevent dissolution of the metal film and increase the quality of the solder joint, a drop of solder is jetted with a hot gas that is directed to the brazing material in the form of a wire fed into the soldering zone by a vertically relatively thin metal film.

solder forms a droplet which lies on the surface of the metal film. When solder solidifies with a pin inserted into it, a solder joint is formed. The described method is illustrated in the drawing.

On the table / set the semiconductor device 2 with a crystal covered with a thin metal film, to which should

solder the output. A thin stream of heated gas (nitrogen or argon) coming out of steam 3, which is a narrow tube with a heating element located inside, whose temperature is regulated, is supplied to the soldering zone from the side. The temperature of the gas is controlled by a thermocouple 4. The solder wire 5 is automatically fed to the soldering zone, which is melted by a stream of heated gas and in the form of a drop

6 lies on the surface of the metal film. The size of a drop of molten solder will vary depending on the diameter of the solder wire. Then from the opposite side into a drop of melted

solder is automatically introduced into the end of the wire lead 7, a jet of heated gas is withdrawn from the soldering zone, and the solder solidifies with the lead, after which the lead is formed at a predetermined length. Detail ready

The proposed method makes it possible to reduce the soldering zone and obtain minimum dimensions of the solder joint. This is due to the fact that the solder formed during melting contains a small amount of heat that does not heat the semiconductor crystal. As a result, solder does not flow on the metal substrate, and the solder joint is formed in the correct shape and minimum size.

Subject invention

A method of soldering the leads to thin metal films, in which a solder is applied in the form of a drop in the soldering zone, characterized in that, in order to improve the quality of soldering by eliminating the dissolution of the metal film, a drop of solder is formed by a stream of heated gas, which is directed to solder the form of wire fed to the soldering zone vertically with respect to a thin metal film.

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