Matsushita Electric Industrial Co., Ltd.

Tsuyoshi Tokiwa

Hisahiro Tanaka

Matsuo Masuda

Takashi Kubara

Lead frame for semiconductor device, process for producing the same and semiconductor device using the same

The present invention relates to a method for producing a tin-silver alloy plating film having an excellent wettability and improved in solderability and said method comprises a step of heat treating the surface of the tin-silver alloy plating film preferably the heat treating temperature is 70-210&deg; C.

Method for producing tin-silver alloy plating film, the tin-silver alloy plating film and lead frame for electronic parts having the film

A lead frame made from Ni, a Ni alloy, Cu, a Cu alloy, Fe or an Fe alloy, comprising an inner lead part with a surface treatment layer of Ag or a Ag-containing alloy and an outer lead part with a surface treatment layer of an alloy containing Ag and Sn, wherein the latter surface treatment layer has a brightness of not less than 0.6 and Sn has the body-centered tetragonal lattice with the crystal orientation indices of from 1.5 to 5 at the (220) plane, not more than 0.9 at the (211) plane and not less than 0.5 at the (200) plane. The surface treatment layer is plated with utilization of a plating solution which contains one or more selected from alkane sulfonic acid, alkanol sulfonic acid and sulfamine acid as the acid component, one or more of tin methane-sulfonate and SnO as a tin salt, and one or more slected from silver methane-sulfonate, Ag O and AgO as a silver salt. The outer lead part may be subjected to a preliminary etching treatment with utilization of a treatment agent of one or more selected from chloric acid, nitric acid and sulfic acid prior to forming the surface treatment layer. The formed surface treatment layer may be treated by a treating agent containing sodium triphosphate.

Semiconductor device with a coating of Pb-free Sn-base solder and manufacturing method therefor

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.

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Nakatsu, Japan

Tsuyoshi Tokiwa