Sn and Sn-Bi Alloy Plating Solution Development for High-speed Applications

摘要

There have been many studies done on tin and tin alloy plating issues, ranging from simple acid sulphate and methanesulfonate electrolytes to their complicated mixtures. However, the problem of good electrolyte performance still remains in reel-to-reel high-speed applications today. There are also issues in relation to tin-bismuth alloy plating on alloy42 leadframes. Firstly, it is difficult to prevent bismuth immersion plating on the surface of tin anode and secondly, it is necessary to use a corrosion inhibitor for prevention similar displacement reaction on the surface of alloy42. This paper summarizes the study of effects of bath composition, temperature and additives in methanesulfonate electrolyte and performance characteristics of tin and tin-bismuth electrodeposits.