| 摘要 |
PROBLEM TO BE SOLVED: To provide a nickel-plated copper alloy lead frame to which die bonding equal to that performed to a silver-plated lead frame can be performed even in an atmosphere containing oxygen at a high concentration by adjusting the mirror reflectivity of the plated nickel to a specific value or larger and the sulfur content in the surface layer of the nickel to a specific depth to a specific value or smaller. SOLUTION: The mirror reflectivity of plated nickel is specified to >=25% and the sulfur content in the surface layer of the nickel to a depth of 0.1μm is specified to <=0.0005wt.%. Alternatively, the cobalt, palladium, or cobalt and palladium content of the outermost nickel is adjusted to 0.5-10.0wt.%. The thickness of the plated nickel is required to be >=0.5μm when, for example, the corrosion, thermal oxidation, and diffusion of copper are to be prevented and, usually, set at 2-5μm. In addition, in order to adjust the sulfur content in the surface layer of the nickel to the specific value or smaller and mirror reflectivity to the specific value or larger, only the surface layer of the plated nickel is plated by using a nickel plating solution containing no brightener, etc. |
