Method for forming a displacement tin alloy plated film, displacement tin alloy plating bath and method for maintaining a plating performance

Abstract

Disclosed herein is a method for forming a displacement tin alloy plated film, on a copper or a copper alloy on a substrate, a tin alloy plated film containing at least one additive metal selected from silver, bismuth, palladium, indium, zinc and antimony, the method including the steps of: forming an under layer on the copper or copper alloy in a low temperature displacement tin alloy plating bath at a temperature of 10 to 50° C.; and forming an upper layer on the under layer in a high temperature tin alloy plating bath at a temperature of 40 to 80° C. to form the displacement tin alloy plated film formed of the under layer and the upper layer.

Dependencies are inferred from the claim text.