Electromigration void nucleation and growth is a failure mechanism of integrated circuit (IC) metallization. The time-to-failure of interconnect lines depends on the void nucleation time and the void growth time. While much work has been done to model the void nucleation stage, the current understanding of the void growth stage is minimal. The importance of characterizing the void growth and motion dynamics is essential to further explain electromigration performance of IC metal interconnections.
Electromigration-induced voids previously studied have been observed to grow, coalesce, and even heal, but quantitative information on these dynamics is lacking. This work uses high-resolution electron-beam lithography to define sub-micrometer voids of various sizes and shapes into gold lines in order to observe void growth and movement with respect to initial void size and shape. The electromigration-induced dynamic behavior of pre-defined voids was measured in a field-emission scanning electron microscope in-situ. Results showed these prepatterned voids can re-fill or grow, and can yield quantitative results on dynamic void behavior.