Unraveling the complex oxidation effect in sintered Cu nanoparticle interconnects during high temperature aging

Sintered Cu interconnection suffers from an oxidation issue in high temperature applications so that under-standing the oxidation mechanism is vital for joint design. This study systematically investigates the effect of oxidation on the microstructure and strength of sintered Cu during high temperature aging. The oxides tend to fill into the interspace of Cu nanoparticles and initially increase both the density and strength of sintered Cu overall. However, particle coarsening behavior occurs later and turns the deformable sintered Cu matrix into a brittle structure. Meanwhile, a novel mechanism of oxidation mediated nano-void formation along the grain boundary (GB) was revealed.