The electromigration (EM) behavior of Through Silicon Via (TSV) interconnects used for 3D integration is studied. Impact of the TSV section size on EM lifetime and consideration of increasing metal level thickness are reported. Void nucleates and grows right after TSV, in the adjacent metal level. The TSV section size at metal level interface is critical for high EM performance. Thickness increase of metal level is revealed to not directly increase EM robustness, since irregular void nucleation and growth impact expected performances.
Introduction3D integrated circuits based on TSV interconnects have become realistic approaches, increasing performances thanks to higher bandwidth [1, 2]. Regarding recent advances in TSV processes maturity, reliability investigation becomes critical to maximize performances, and especially to enable high current demands through the stacked package. Maximal direct current is given by the ageing of metallization under électromigration (EM) phenomenon, which is the movement of metal atoms, in response to current density. At interfaces of atoms flux divergences, EM leads to latencies accumulation and therefore to open circuit failure. Recent papers studied EM concerns at TSV interfaces, through simulation [3 -5], and also through first experimental approaches [6 -8].