| 摘要 |
PURPOSE:To enable the assembling of a semiconductor device having stability for thermal load at assembling time, good quality and reliability by plating Cu of the prescribed thickness on an Ni-plated lead frame, and plating Ag of the prescribed thickness on the Cu-plated lead frame as an outer layer. CONSTITUTION:A blank ribbon made, for example, of 50%-Ni iron material is punched in the shape of a lead frame, Ni plating of 2-4mum thick is achieved by glossy leveling solution, and Cu-plating of 0.05-0.3mum thick is performed on the lead frame by CuCN series plating solution. Subsequently, Ag plating of 0.5-3mum thick is formed by AgCN series plating solution on the Cu-plated layer, and a lead frame which mounts a semiconductor pellet is produced. Thus, the plating thickness is formed thinner than the conventional example, thereby eliminating a swell or exfoliation of the Ag-plated layer even if an annealing step is not ahcieved, thereby improving the quality and reliability of the assembling apparatus. |
