Oxidation failure of Lead Frame Copper alloys with Surface Electroplated Pure Cu

Influence of surface electroplated pure copper on oxidation failure of lead frame copper alloys for IC package were investigate. Pure copper layer will benefit the diffusion of copper ion, so the thickness of copper oxide films increase but the velocity of CuO formation decrease and the oxidation only occurs at pure copper layer. As electroplating pure copper layer on copper alloy exceed a critical thickness, surface electroplating treatment can improve copper alloy´s resistance against oxidation failure greatly. The oxide film structure of copper alloys is CuO/Cu₂O/Cu substrate, after electroplate treated, and the oxide film structure change to CuO (no or trace)/Cu₂O/Cu. The oxide films with only Cu₂O have higher adhesion strengths.