Impact strength of Sn-58mass%Bi/Cu joints by laser process

With the miniaturization of electronic productions and the use of heat sensitive electronic components, the traditional reflow soldering often has difficulties. As an alternative soldering process, the laser reflow soldering has been recently proposed. The laser reflow soldering brings several advantages in terms of localized heating, rapid rise and fall in temperature, non-contact and easily automated process. Then, Sn-Bi eutectic solder has much lower melting temperature of 138 °C compared to Sn-Pb eutectic solder and Sn-Ag-Cu solder. In terms of low melting temperature solder, the Sn-Bi solder has attracted much attention. In this study, we investigated the interfacial reaction between Sn-58 mass%Bi solder and a Cu pad using the laser process, and the impact strength of Sn-58mass%Bi/Cu joints after laser soldering and after isothermal aging was also evaluated to elucidate the basic characteristics of the joints.