Comparative Study of Sn-based Solder Wettability on Aluminum Substrate

Abstract

To have a better understanding of the wetting behavior of Sn-based solders on the aluminum substrate, s series of comparative experiments with Sn, Sn-3.5Ag (SA), and Sn-3.0Ag-0.5Cu (SAC305) were performed by direct heating on the hot plate with normal flux in the air. The wetting morphology was measured by the cross-section images using a scanning electron microscope (SEM), and the intermetallic compounds, at the interface after heating, were identified by the phase diagram calculated by the FactSage, and confirmed by the energy dispersive X-ray spectroscopy (EDS) equipped with the SEM. The results showed that the SA soldered aluminum samples had better wetting behavior after considering the non-reactive wetting stage and the interfacial reactions during the reactive wetting stage.