1987 年 38 巻 2 号 p. 50-54
The heat resistance of gold or silver that was plated on SUS 430 stainless steel with various underlayers was examined by evaluating the solderability and the wire bonderability of the plated surface subjected to aging in air at 460°C. It was found that heat resistance improved if suitable underlayers were provided. In terms of providing heat resistance as an intermediate layer on the Ni activation layer, Ag or Ni-Co was preferred for Au plating, while Pd-Ni, Ni-P or Au was preferred for Ag plating.
The Ni-Co activation layer without an intermediate layer was excellent, especially for Au plating. Surface analysis by X-ray photoelectron spectroscopy and Auger electron spectroscopy suggest that a thin 0.02μm of Ni-Co activation layer is more effective than a one of Ni as a diffusion barrier layer against Fe-diffusion. The oxidation of the underlayer in the Ag-plated sample was confirmed.