Sumitomo Metal Mining Company, Ltd.

Tokai University

Hideyasu Nikaido

Yen-Ching Huang

In a lead frame for an IC which is provided on a wire bonding part of the inner lead unit thereof with an aluminum coating, possible detrimental diffusion of the component elements of the lead frame into the aluminum coating can be effectively precluded by having a layer of a high melting point metal interposed between the lead substrate and the aluminum coating in the wire bonding part without appreciably increasing the cost of production.

Lead frame for IC having a wire bonding part composed of multi-layer

A lead frame with an Al coating which enjoys satisfactory tightness of adhesion and sufficiently low hardness is manufactured by a method, comprising the steps of covering the lead frame with a mask sheet possessing an opening for exposing an inner lead part of the lead frame, keeping the lead frame at a temperature in the range of 100.degree. to 240.degree. C. under a high degree of vacuum exceeding the level of 10.sup.-5 Torr, and depositing aluminum on the inner lead part by arc-discharge type ion plating.

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Oume, Japan

Hideyasu Nikaido