Stevens, Davis, Miller & Mosher, L.L.P.
Semiconductor devices having tin-based solder film containing no lead and process for producing the devices
 In a lead frame formed out of at least one metal selected from the group consisting of nickel and nickel alloys, copper and copper alloys and iron and iron alloys, the inner lead part is provided with a surface treatment layer of Ag or an alloy containing silver and the outer lead part is provided at least with a surface treatment layer of an alloy containing silver and tin of the body-centered cubic structure preferentially oriented in the (101) plane and/or the (211) plane. According to the above-mentioned structure, a semiconductor device that uses a lead frame for electronic parts which does not contain lead, one of the environmentally harmful pollutants, has good characteristics including solder wettability and bonding strength and is of low cost and a process for producing the device are provided. 
Matsushita Electric Industrial Co., Ltd.
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Matsuo Takashi Hisahiro Tsuyoshi
Masuda Kubara Tanaka Tokiwa