| 摘要 |
A semiconductor device comprises a semiconductor integrated circuit, an external connection terminal connecting the semiconductor integrated circuit to an external device, and a plurality of tin or tin-alloy plating layers formed on the external connection terminal as multiple unleaded metal plating layers. The multiple unleaded metal plating layers comprise a first layer made of a tin alloy and provided as an inner layer of the multiple unleaded metal plating layers, the tin alloy of the first layer containing as a second element one of bismuth, silver, copper, indium, and zinc, and a second layer made of either 100% tin or a tin alloy and provided as an outer surface layer of the multiple unleaded metal plating layers, the 100% tin or the tin alloy of the second layer having a percentage of tin content greater than that of the first layer.
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