Molecular Dynamics Simulation of Cu-Cu Solid-State Bonding under Various Bonding Parameters

A solid-state bonding technology, particularly Cu-Cu bonding, has attracted attention to overcome crucial drawbacks of conventional Sn-based solders in the latest three-dimensional integrated circuits. In this study, the effects of bonding parameters on its bonding behavior were investigated by an atomistic-scale simulation method, molecular dynamics (MD) simulation. MD simulations with various bonding temperatures and interfacial crystalline structures were performed focusing on interfacial densification behavior. The results indicated that the interfacial densification rapidly occurred with increasing the bonding temperature. It was also suggested that the combination of crystal orientations of the bonding surfaces constituting the interface would be important for its bondability.