Method and solution for electrodeposition of a dense, reflective tin or tin-lead alloy

摘要

New formulations for the electrodeposition of a dense, reflective tin or tin-lead alloy on a cathode have been developed. Such electrodeposition solutions are partially comprised of an additive which is comprised of at least one nonionic surfactant which is electrolyzed prior to starting the electrodeposition process. The electrodeposition solution is also comprised of an amount of an aliphatic dialdehyde kept low enough so that the solder deposits contain no more than 500 ppm of co-electrodeposited carbon. The additive and the aliphatic dialdehyde is mixed with a solution comprised of an alkane or alkanol sulfonic acid and a tin alkane or alkanol sulfonate or a mixture of a tin and lead alkane or alkanol sulfonate to form an electrodeposition solution. A dense, reflective finish is then electrodeposited on a cathode by using such an electrodeposition solution.