On the Multiscale Finite Element Analysis for Interfacial Fracture in Cu/Low-K Interconnects

The interface crack problem in integrated circuit devices was considered by using global and local modeling approach. In the global analysis the thin film interconnect was modeled by a homogenized layer with material constants obtained from representative volume element (RVE) analysis. Local analyses were then considered to determine fracture mechanics parameters. It was shown that the multiscale model with RVE approach gives accurate fracture mechanics parameters for an interface crack under either thermal or mechanical loads; while significant error was observed when the thin film layers are ignored in the global analysis. The problem of an interface crack between low-k dielectric and etch-stop thin film in a flip-chip package under thermal loading was also investigated as an application example of the multiscale modeling.