STRIPPING LIQUID FOR STRIPPING TIN OR TIN ALLOY ON COPPER ALLOY

摘要

PROBLEM TO BE SOLVED: To obtain a stripping liquid capable of surely stripping not only a tin layer or a tin alloy layer on a copper alloy but a copper-tin alloy layer on the under part thereof by preparing the stripping liquid containing at least ferric nitrate, an alkanesulfonic acid and chlorine respectively in a specific concentration. ;SOLUTION: The stripping liquid containing at least 30-300 g/l, preferably 30-120 g/l ferric nitrate (ferric nitrate.9-hydrate or the like), 120-200 g/l, preferably 140-235 g/l alkanesulfonic acid (methane; sulfonic acid, ethane, sulfonic acid or the like, ≥20 mg/l, preferably 20-60 mg/l chlorine (hydrochloric acid, sodium chloride) is prepared. And if necessary, 1.0-200 g/l acetic acid and 0.05-2 wt.% additives such as a surfactant can be contained and the use temp. of the stripping liquid is controlled to 15-40°C. As a result, the solubility of the copper alloy is held remarkably low and the surface of the copper alloy after stripping is made flat.;COPYRIGHT: (C)1999,JPO