The experimental analysis and the mechanical model for the debonding failure of TSV-Cu/Si interface

Abstract We have investigated the debonding failure of the through-silicon via (TSV)–Cu/Si interface during annealing treatment at 425 °C. The interface microstructure was characterized by two parameters: the TSV–Cu/Si interface roughness and the Cu seed layer grain size. Scanning electron microscopy observation of the cross-section of the TSV–Cu/Si interface was performed to analyze the effect of the interface microstructure on its microcrack failure. In addition, qualitative numerical simulations were performed to investigate the effect of the TSV–Cu/Si interface roughness and Cu seed layer grain size on the overall response of the TSV–Cu/Si interface crack. The experimental results indicate that most of the TSV interfacial cracks propagate along the Cu seed layer after annealing, and the crack length of the TSV–Cu/Si interface increases with increasing interface roughness and Cu seed layer grain size. The numerical simulation is constructed to reveal the interfacial crack mechanism, and the results suggest that the stress concentration in the Cu seed layer which influence by interface roughness and Cu grains size is the main driving force for interfacial cracking. Based on the experimental and simulation results, guidelines for controlling the TSV-Cu/Si interfacial cracking from the perspective of the TSV manufacturing process are proposed.