Sn-Bi alloy-plating bath and method for forming plated Sn-Bi alloy film

摘要

An Sn--Bi alloy-plating bath comprises (i) Bi ions, (ii) Sn ions, (iii) ions of one metal selected from the group consisting of Cu, Co and Ag, and (iv) one member selected from the group consisting of carboxylic acids, lactone compounds, alkanesulfonic acids, alkanolsulfonic aicds, phenolsulfonic acids and salts thereof and is substantially free of lead ions. The bath permits the formation of an Sn-- Bi alloy-plated film, does not form any plated film having impaired quality even at a temperature higher than about 100° C. and does not form any whisker.