| 摘要 |
PURPOSE:To improve the functions and to decrease the cost, by covering the base material of a lead frame with high purity Cu having the Vickers hardness of 90 or less, covering an after lead part with Sn or Sn alloy to a thickness of 3mum or more, packaging an element in a non-oxidizing atmosphere, and sealing the element with a resin mold. CONSTITUTION:A Cu covering is applied so as to shield the harmful action to the raw material of a lead frame. Thus the amount of use of noble metal and the like is reduced, and reliability can be largely improved. In this case pure Cu applied by electric plating is suitable. Bonding can be performed based on the conditions of hardness, relative roughness and the like. The relative roughness (Rmax) of 0.4-1.5mum improves adhesion when resin molding is performed. Low Sn alloy at the after lead part has a high melting point. Thus the oxidation of Cu is suppressed, solderability is excellent and bending and cracking in leads are hard to occur. Since plating and Hot dipping after the resin molding are not required, the manufacturing process is simplified, and can contribute to the improvement in the quality and the reliability. |
