| 摘要 |
PURPOSE:To avoid a wire cut which occurs when the wire is bonded to the side of a lead frame by making the wire of copper alloy with a specific composition. CONSTITUTION:When the content of unavoidable impurities of oxygen free copper is reduced to 10ppm or less, the hardness in the material state is reduced to Vickars' hardness of 40-50 and elongation is improved as well. However, the strength at the high temperature, which is necessary at the time of bonding operation, is reduced. If one or more types of alloy components among Mg, Ca, Be, Ge and Si are contained in the oxygen free copper by the content of 1-20ppm, the high strength at the high temperature, for instance the breaking strength of 20-30kg/mm<2> at the temperature of 250 deg.C, which corresponds to the bonding atmosphere, is provided without increasing the hardness and reducing the elongation. With this constitution, a bonding wire made of such copper alloy does not damage an Al wiring film and a chip and maintains a normal loop shape so that the occurrence of a wire cut can be significantly suppressed during the bonding process. |
