The numerical study of mechanical improvement of the metal annealing process during the manufacturing of the IC backend Damascene structure.

This research establishes a set of transient finite element models to represent the mechanical impacts during the w/b process. Moreover, a finite element model of the BEOL structure, which consisted of 7 layers of copper metal stacks and an aluminum pad to represent the current frequent-used technology, is established to investigate the stress pattern. The results show that the Cu/low-k system produces larger stress levels in the column structure and induces a larger amount of deformation than the Al/TEOS system, and different annealing temperatures can affect the deformation behavior of the Cu stack.