| 摘要 |
PURPOSE: To obtain a clad material which prevents an influence on an inner lead due to an abnormal precipitation in the electrolytic plating operation of an inner lead and due to an etching treatment in the formation of an outer lead by a method wherein a barrier layer composed of a metal material which is different from that of an etching stop layer is formed between the etching stop layer and a close contact layer. CONSTITUTION: A clad material 20 comprises a sheetlike metal base 21, an etching stop layer 22 formed on one face of it, a barrier layer 23 formed on it, and a close contact layer 24 formed on the barrier layer 23. It is constituted in such a way that many three-layer laminates which are composed of the etching stop layer 22, the barrier layer 23 and the close contact layer 24 whose area is much smaller than that of the metal base 21 are formed in prescribed positions of the metal base. The metal base 21 is a sheet material composed of copper, a copper alloy or a 42 alloy, and it is to be used as a member which forms outer leads for a lead frame. The etching stop layer 22 is composed of aluminum, the barrier layer 23 is composed of chromium, and the close contact layer 24 is composed of copper. |
