| 摘要 |
PURPOSE:To stengthen a lead frame against deformation, and moreover to check generation of a crack when the lead frame is bent by a method wherein a process to project laser or an electron beam to the surface of a lead frame material to reduce hardness of the surface of the lead frame material is provided. CONSTITUTION:By projecting laser or an electron beam to a lead frame material, and heating the surface layer in a short time, the surface layer is softened. According to such a method, a material is obtained has high hardness at the central part by receiving the influence of a rolling process up to that time, and has lower hardness in proportion to approach the surface layer. Because hardness of the central part of such a material is high, it is strong against deformation, and moreover hardness of the surface part to generate the maximum stress when it is bent is low. Namely, because extension is large, a crack is hardly generated. |
