Simulation on Interplay Between Morphological Evolution and Defect in Polycrystalline TSV During EM

Through-silicon vias (TSVs) have now enabled a variety of state-of-the-art 3-D packaged microelectronic devices. Nevertheless, electromigration (EM) can induce local damages and eventually lead to open-circuit failures (OCFs) inside the Cu-TSVs. Here, a phase field (PF) model is developed to conduct a systematic and detailed study on the interplay between morphological evolution and defects in polycrystalline TSVs during EM. A decisive contribution from the alignment between grain boundaries (GBs) and the EM-induced flux is identified by analyzing three local fluxes and their net sum, i.e., the total flux. Four types of local damages can be classified according to the distribution of the total flux in the grain structure where the damages initiate. TSV models with complex and close-to-real grain structures show that the time to OCF in TSVs with a combined bamboo-like and poly-cluster (PC) structure is about 30% shorter than the counterpart with a combined columnar and PC structure. In addition, both voids and second phase particles (SPPs) can delay the OCF in TSVs under the GB dominant diffusion mechanism. Under the interfacial dominant diffusion mode, however, voids are found to significantly accelerate the OCF.