Non-cyanide copper - tin alloy plating bath

摘要

PROBLEM TO BE SOLVED: To provide a plating bath yielding excellent film physical properties by avoiding embrittlement of the film, which is made possible by absence of liberation of pyridine caused by pH variation.SOLUTION: The provided cyanogen-free copper-tin alloy plating bath not only includes a divalent copper salt, a divalent tin salt, and a complexing agent but also includes, as a brightener, a reaction product of a pyridine compound and an organic sulfonic acid compound.