Prediction of interface reaction products between Cu and various solder alloys by thermodynamic calculation

Abstract

A new scheme to predict the intermetallic compound which forms first at the substrate/solder interface during the soldering process has been suggested. A local equilibrium was assumed at the interface between the substrate and the liquid solder. By calculating metastable equilibria between the substrate and the liquid solder phases and by comparing the calculated driving forces of formation for individual phases, the compound which forms first at the substrate/solder interface could be successfully predicted. The prediction of interface reactions between Cu substrate and Sn-Pb, Sn-Bi and Sn-Zn binary eutectic solder was in agreement with already known experimental results.