| 摘要 |
PURPOSE:To reduce cost and improve corrosion resistance, wire-bonding property, and adhesion property with a sealing resin by forming a second plating layer consisting of palladium or a palladium base alloy only at an inner lead part and/or a pad part of the base of a lead frame where a first plating layer is formed. CONSTITUTION:A first plating layer consisting of an alloy made of tin and nickel is formed on a lead frame base. This plating treatment may be a partial treatment. In this case, it is desirable that Sn should be 55-70wt.% and Ni should be 30-45wt.% as a composition of tin/nickel alloy. Further, it is more desirable that Sn should be 60-65wt.% Ni should be 35-40wt.%. Also, copper strike treatment may be performed before the first plating treatment. Then, a second plating layer consisting of palladium or a palladium base alloy is formed only at an inner lead part and/or a pad part out of the lead frame base on the surface of the first plating layer. |
