Abstract
Copper substrate with a double-layer silver/nickel film having copper strike plating between the layers was analyzed by Auger electron spectroscopy after thermal treatment in a nitrogen atmosphere, and the thermal diffusion behavior of several elements, including oxygen, was measured. These profiles were compared with those obtained after thermal treatment in air.
The results can be summarized as follows
(1) The thermal diffusion of the copper in the copper strike plating was considerably influenced by the oxygen concentration during thermal treatment.
(2) Some of the copper of the intermediate layer diffused onto the silver surface after thermal treatment in nitrogen. Diffused copper formed an oxide film with a slight amount of oxygen, and the surface discolored.
(3) Since inner oxidation of the plating layers did not occur with thermal treatment in nitrogen, the adhesion of the plating was good.
