| 摘要 |
PURPOSE:To improve the tensile strength and electric conductivity of a lead frame by providing a pressurizing laminate of Cu in which specific oxide is dispersed on a Cu or Cu alloy surface. CONSTITUTION:A Cu or Cu alloy layer has high electric and thermal conductivities, and a pressurizing laminate made of Cu having 0.5-2.0wt% of ultrafine particles of at least one of Al2O3, BeO are dispersed is provided. It is preferred that the diameter of the dispersed particles is 5.0mum or less. A method of forming a composite layer employs a composite plating method which has plating by a plating bath in which ultrafine particles of Al2O3 or BeO are dispersed in a plating solution containing mainly copper sulfate and forming a composite layer of Cu-Al2O3 or BeO on the Cu or Cu alloy. The laminate is heat treated, then cold rolled, and formed in the prescribed thickness and size, thereby forming the lead frame. |
