Confinement Effects on Evolution of Intermetallic Compounds During Metallurgical Joint Formation

In this work, we compare the microstructural evolution of Sn/Cu/Sn and Cu/Sn/Cu ‘sandwich’ configurations under metallurgical bonding conditions. These simulations are relevant in explaining experimental observations that suggest that the resulting dominant intermetallic compound in Cu-Sn systems depends on the relative supply of Cu and Sn. Through the analysis of morphological evolution and growth rate, it is shown that the Cu 6 Sn 5 layer becomes dominant in the Sn/Cu/Sn structure, while the Cu/Sn/Cu structure is dominated by Cu 3 Sn after extended reaction periods.