Electromigration-Induced Failure in Rough TGV With Tilted Angle Sidewalls

Due to its excellent thermal and electrical properties, through-glass-via (TGV) technology has been regarded as one of the most promising 3-D interconnection solutions for advanced packaging. The electromigration (EM) phenomenon detrimentally affects the long-term reliability of TGV interconnects by driving the redistribution of Cu atoms under high-current stress. The electron wind force induces directional Cu atom transport, which leads to localized material depletion and accumulation, forming voids and uneven deposits that may trigger electrical discontinuities in high-power applications. Furthermore, the surface irregularities arising from laser drilling and electroplating fabrication steps aggravate interfacial stress concentration and promote crack initiation along the Cu/glass boundary, thereby accelerating structural degradation. The mechanism of the rough interface on EM has not been clearly investigated. In this study, a novel EM modeling method based on the Weierstrass–Mandelbrot (W–M) fractal function is proposed, which enables systematic investigation of EM behavior and its evolution mechanism under different interfacial roughness conditions. The results reveal that increasing interface roughness leads to pronounced current and stress concentration at the Cu/glass interface, which intensifies atomic flux divergence and promotes the formation of voids and protrusions. Furthermore, larger sidewall tilted angles intensify EM effects, inducing higher stress localization and defect accumulation, thereby significantly reducing the thermal stability and service reliability of TGV structures in high-power electronic applications.