Samsung Aerospace Industries, Ltd.

Joong-Do Kim

Young-Ho Baek

Kyoung-soon Bok

The lead frame includes outer leads plated with tin (Sn) alloy so as to withstand the high temperatures generated during a subsequent semiconductor packaging process. In addition to the outer leads, the lead frame includes a die pad and inner leads composed of a base metal, such as copper (Cu), a copper alloy, or a nickel alloy. The die pad and the inner leads are plated with silver for improved conductivity. In order to withstand relatively high temperatures as well as to resist corrosion and have good solder wettability, the outer leads are preferably plated with a tin antimony alloy, such as a tin-antimony alloy consisting of 90.+-.5 weight percent of tin and 10.+-.5 weight percent antimony. Alternatively, the outer leads can be plated with a tin-antimony-lead alloy, such as a tin-antimony-lead alloy consisting of 10.+-.5 weight percent of tin, 10.+-.5 weight percent of antimony and 80.+-.10 weight percent of lead. A method of plating a lead frame is also provided.

Lead frame containing leads plated with tin alloy for increased

A method for manufacturing a lead frame includes degreasing and activating the surface of a metal sheet, providing the plating solution containing nickel(II) sulfamate tetrahydrate, (Ni(H.sub.2 NSO.sub.3).sub.2.4H.sub.2 O), manganese(II) sulfamate tetrahydrate (Mn(H.sub.2 NSO.sub.3).sub.2.4H.sub.2), nickel (II) chloride hexahydrate (NiCl.sub.2.6H.sub.2 O) and boric acid, plating the metal sheet in the plating solution to form a Ni--Mn alloy layer, and forming a Pd or Pd alloy layer on the Ni--Mn alloy layer.

Lead frame having a Ni-Mn alloy layer and a Pd layer

A lead frame has a metal substrate directly coated with a palladium alloy layer to prevent diffusion of metal molecules from the metal substrate. The lead frame does not contain a nickel intermediate layer, thereby preventing the diffusion of nickel molecules which makes soldering difficult, and enhancing production.

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Kyungki-do, South Korea

Joong-Do Kim