Interfacial fracture toughness of sintered hybrid silver interconnects

The interfacial fracture toughness of sintered hybrid silver nanoparticles (AgNPs) on both Au and Cu substrates is studied as a function of sintering temperature. Interfacial microstructure and porosity evolution of Au/AgNPs and Cu/AgNPs are observed to impact the fracture toughness. An Au–Ag interfacial diffusion layer is resolved at the interface of Au/AgNPs interconnects, while an oxide layer is found at the interface of Cu/AgNPs interconnects. Both porosity and pore sizes of the sintered silver interconnects are analyzed across the micro- and macro-length scales and related to the interfacial fracture toughness. The experimental observations can be theoretically described, which permits to predict the fracture toughness of the sintered silver interconnects.