On the material depletion rate due to electromigration in a copper TSV structure

We investigate the material depletion rate from a fatal void due to electromigration in a Cu interconnect structure ended by a TSV. Experiments show the formation of a fatal void above the TSV. Its volumetric growth rate is practically constant for an extended period, but at longer times a significant increase is observed. We have carried out numerical simulations to reproduce the aforementioned void growth behavior. The model incorporates the void size dependence on the incoming flux of vacancies due to electromigration. The simulation results have provided a good description for the void volume and for the growth rate increase for the entire time window of the experiments.