| 摘要 |
PURPOSE:To make it possible to carry out wire bonding with an Au or Cu wire without a bad effect caused by a very small amount of sulfur, by rolling a pure copper layer all over and reducing a ratio of activation. CONSTITUTION:A lead frame comprises a base material made of copper allay and a pure copper layer on a surface of the base material. The pure copper layer is formed in a glossy or semi-glossy copper plating step and subjected to cold working. The surface of the pure copper layer has a peak intensity ratio of 0.01 or below in S2P spectre to Cu2P spectre in a X-ray photo-electron spectral analysis, and at the same time a residual plating-crystal region on the pure copper surface is 1% or below on an area-rate basis. In the glossy or semi-glossy copper plating step, an additive including no sulfur is used. After the cool working step, the pure copper layer is treated by heat at a temperature of 100 deg.C or above and the surface thereof is ground to complete the lead frame. |
