Method for forming metal layer of a semiconductor device

摘要

A method for forming a metal layer including the steps of heat treating a semiconductor substrate for a predetermined time at an intermediate temperature between 200 DEG C. and 400 DEG C., then depositing the metal layer on the semiconductor substrate at a temperature below 200 DEG C., in a vacuum, then thermally treating the metal layer at a temperature between 0.6 Tm-1.0 Tm (where Tm is the melting point of the metal layer), without breaking the vacuum, thereby reflowing the grains of the metal layer, and then gradually cooling the metal layer. Alternatively, the intermediate heat-treatment step can be performed after the metal layer is thermally treated, in which case, the metal layer should thereafter be rapidly cooled.