| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide palladium plated lead frame having excellent bonding property, excellent solder wettability and excellent Ag paste adhesion. SOLUTION: Within this lead frame 3 on the surface thereof after performing the Au or Ag flush plating step on side Pd plated surface layer 13, a diffused layer 14 of Pd and Au or Pd and Ag in thickness of 0.005-0.05μm is provided on said layer 13 for providing a thin oxide layer on the Pd part only of the surface of the diffused layer 14 or Pd-Au alloy plated layer or Pd-Ag alloy plated layer is provided on the surface. In such a constitution, the lead frame is heat-treated in the atmosphere after respective alloy plating steps so as to provide the thin oxide layer on the Pd part only on the alloy layer surfaces. Through these procedures, the lead frame composed of Pd oxide and Au or Ag can be provided on the topmost layer.</p> |
