To provide a new QFP type lead frame for semiconductor integrated circuits that prevents wire-bonding properties and the joint properties with the terminal of an external circuit substrate from being lost and a migration phenomenon from being generated, allowing armor solder-plating processes to be abbreviated, is reliable, and can be manufactured inexpensively.
In the lead frame that is used for a semiconductor integrated circuit, base Ni plating that is as thick as 0.3-1.5 μm and is superb in flexibility is performed to a material surface, and then a ring-like 0.2-5 μm Ag plating, and extremely thin Au plating that is as thick as 0.003-0.02 μ or extremely thin hard Au alloy plating containing either or both of 0.01-3 wt.% Ni and Co are performed to the tip of all inner leads to be subjected to wire bonding, and an outer lead part, respectively.
KAWAKAMI YOSHIMI