Influence of Flux on Wetting Behavior of Lead-Free Solder Balls during the Infrared-Reflow Process

摘要

The effects of two different fluxes (A6 and B6) on the wetting performance of Sn-3.5Ag-0.5Cu lead-free solder balls were investigated during the reflow process.Solder ball wetting behavior in real time via an optical microscope coupled with a video recorder during the reflow process was studied.The lead-free solder balls started to melt and wet at 210degC by using A6,which is 8degC lower than the melting point (218degC) of the solder material used.The wetting performance of the lead-free solder ball was dramatically enhanced by using A6.The wettability test indicated that the height of the solder ball after the reflow process with flux A6 was significantly lower than that with B6.It was found that strong fluxing capability caused these phenomena.