Upgrading Pb-free soldering technology (2) -flow soldering

In this study the challenge is the upgrading of wave soldering for Sn-Ag-Cu system lead free solder, especially under conventional soldering temperatures of 523K. In order to improve solderability of Sn-Ag-Cu solder, a solderability test using practical wave soldering equipment and a wettability test have been conducted. As a result, it has become clear that the shape of wave former and wave width were the significant factors in good solderability, and therefore this wave soldering equipment is required to be more sophisticated and to improve. Moreover, it has become clear that the wettability of Sn-Ag-Cu solder is rarely changed or improved by the addition of other elements. From the point of view of wettability, there has been almost no problem with the influence of impurities.