SILVER REDUCED IN α RAYS AMOUNT, ALLOY CONTAINING THE SAME AND METHOD OF PRODUCING THE SAME

摘要

PROBLEM TO BE SOLVED: To solve the problem that the requirements of high purities of solder materials and silver used close to semiconductor devices and availability of materials reduced in α rays amount are high and provide silver whose sample after melting and casting has an α rays amount of 0.002cph/cm² or smaller.;SOLUTION: An Sn-Cu-Ag alloy is produced by exuding raw silver of a purity level of 3N with nitric or sulfuric acid, refining electrolytically with an electrolytic solution of an Ag concentration of 700 g/L or lower, increasing the purities of commercial tin and copper to high levels by electrolysis to obtain 5N-Sn and 6N-Cu and adding the silver and copper to the tin as additive elements and melting and casting at 260°C to obtain an Sn-Cu-Ag alloy comprising 0.5% Cu, 3% Ag and remaining Sn.;COPYRIGHT: (C)2015,JPO&INPIT