Material characterization and failure analysis of through-silicon vias

In this paper, the effects of Cu microstructure on the mechanical properties of TSV and via extrusion are studied using two types of through-silicon vias (TSVs) with different grain size distributions. A direct correlation is found between the Cu grain size and the mechanical properties of the TSVs. An analytical model is used to explore the relationship between the mechanical properties and via extrusion. The results show that small and uniform grains in the Cu vias led to smaller via extrusion. Such grain structures are effective for reducing via extrusion failure to improve TSV reliability.