| 摘要 |
PROBLEM TO BE SOLVED: To provide a lead frame easy to remove its oxide by electrolytic reduction, rigid not to much with interlayers made of materials whose corrosion resistances are equal to or smaller than its substrate material. SOLUTION: This lead frame 1 is constituted to have a chip mounting portion 4 for mounting a semiconductor clip thereon, inner leads 2 for connecting electrodes on the semiconductor chip therewith, and outer leads 3 for connecting printed boards, etc., therewith. In this case, on both whole surfaces of a lead frame substrate 5 made of Cu alloy or Fe-Ni alloy, Co or Co-alloy plating films 6 are formed so that each film 6 has a film thickness of 0.5-20μm. On the top surfaces of the respective Co or Co-alloy plating films 6, Pd plating films 7a or composite films each of which comprises the Pd plating film 7a and an Au plating film 7b are formed so that the film 7a or the composite film has a film thickness of 0.05-0.2μm.
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