| 摘要 |
The invention features a composition for immersion plating comprising an aqueous solution of a noble metal salt and a complexing agent for ions of the noble metal, said solution having a pH of from about 0 to 5.5. The noble metal is preferably palladium in the form of palladium nitrate. The complexing agent is preferably oxalic acid. The composition is used in a method of immersion plating which comprises contacting a substrate which is preferably a copper or copper alloy component of a printed circuit board with the composition for a period of time sufficient to coat palladium onto the copper surface in a uniform manner. The methodology provides for a high degree of uniformity, good adhesion between the palladium and the copper as well as a relatively thin coating. Further, the palladium coating is carried out in a relatively short period of time and provides a longlived solderable finish. |
