2009 Volume 50 Issue 5 Pages 1135-1138
Wettability of low silver (Ag) content Sn-xAg-0.7Cu-0.5In lead-free solder (x=0.1,0.3,0.5) on copper substrate was investigated. Wetting balance test results indicated that varying small Ag content in the alloy affects the wettability of solders with higher Ag content showing better wettability. The contact angles of the solder alloy showed dependence on Ag content in solder and temperature. Solder alloy with no Ag content and 0.5 mass% Ag content displayed similar contact angle and qualitatively similar surface tension; however, the maximum wetting force is significantly difference, which indicates difference in the density of solder alloy. Effects of different fluxes on wettability were also studied.