Mitsubishi Shindoh Co., Ltd.

Shunichi Chiba

Rensei Futatsuka

Junichi Kumagai

Tadao Sakakibara

A high-strength Cu based alloy, consists of:

High-strength copper based alloy free from smutting during pretreatment

There is provided a lead frame material formed of a Cu alloy for a resin sealed type semiconductor device, wherein the Cu alloy consists essentially of 2 to 4% Ni, more than 0.5 to 1%, Si, 0.1 to 2% Zn, more than 0.01 to 0.05%, Mg, 0.05 to 1% Sn, and the balance of Cu and inevitable impurities, the inevitable impurities containing 20 ppm or less sulfur (S) and 20 ppm or less carbon (C). The lead frame material formed of the Cu alloy has improved adhesion strength to an epoxy resin as a sealing material. A semiconductor device prepared from said lead frame material is also provided.

Lead frame material formed of copper alloy for resin sealed type

A copper base lead material for leads of a semiconductor device, which consists essentially of from 0.05 to 0.25 percent by weight tin, from 0.01 to 0.2 percent by weight silver, from 0.025 to 0.1 percent by weight phosphorus, from 0.05 to 0.2 percent by weight magnesium, and the balance of copper and inevitable impurities, wherein the P/Mg ratio is within a range from 0.5 to 0.85, preferably within a range from 0.60 to 0.85, so as to form a compound of magnesium and phosphorus or Mg.sub.3 P.sub.2. The copper base lead material possesses satisfactory properties required of a metal material for leads in semiconductor devices, such as strength, thermal resistance, and stampability, and further possesses excellent heat radiation to an extent suitable for use as leads of semiconductor devices having high wiring densities. The invention also includes the semiconductor device containing said leads.

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Aizuwakamatsu, Japan

Shunichi Chiba