MANUFACTURE OF SEMICONDUCTOR DEVICE

PURPOSE:To increase the thermal resistance between a semiconductor substrate and an electrode plate to be brazed to the semiconductor substrate while improving the reliability, by covering the sides as well as the surface of the electrode plate with an Ni layer formed by electroless plating. CONSTITUTION:A composite electrode consisting of an Mo plate 4 and a Cu substrate 5 is disposed in an electroless nickel-phosphorus plating bath and used as a cathode when electric current is supplied to form an Ni film 10. When a silicon plate 1 is brazed to this composite electrode. Solder 2 can be applied also on the Ni film 10 on the sides of the Mo plate 4 and therefore an amount of the solder excessing the required amount for bonding the silicon plate 1 can be let flow on the sides of the Mo plate 4. Accordingly, a this and uniform solder film 2 can be formed. Further, since any gas contained in the solder also flows out together, the solder film 2 can be freed of air bubbles. The presence of the thin, uniform and defect-free solder film 2 between the semiconductor substrate 1 and the electrode plate decreases the thermal resistance and enables a semiconductor element to be formed with high reliability.