Performance of China Alloy SnAgCuCe in Reflow Soldering

摘要

Work on assisting China's Ministry of Information Industry (MII) to assess the performance of a solder paste using the China alloy Sn3.0Ag0.5Cu0.019Ce (SACCe) was completed. Two Indium fluxes were incorporated as controls. Ce showed no effect on paste printing, slump, or probe testability on flux residue for SAC system. The difference between SACCe and SAC mainly resides in soldering. SACCe exhibits a slightly lower solder beading rate, comparable voiding, a considerably higher tombstoning rate, and is more prone to oxidation hence wets poorer under harsh reflow conditions. No difference in IMC structure or growth rate can be discerned for joints formed on either Cu or NiAu. Overall, China alloy is acceptable in reflow applications. The paste made from the China alloy exhibits a poorer print and a considerably narrower reflow window than the two paste controls.