Significant improvement in electromigration of reflow-sputtered Al-0.5wt%Cu/Nb-liner dual damascene interconnects with low-k organic SOG dielectric

Reflow-sputtered Al-0.5wt%Cu/Nb-liner dual damascene interconnects with low-k organic spin-on glass (SOG) passivation were fabricated for the first time. A significant improvement in median time-to-failure (MTF) for electromigration (EM) was observed when the SOG was compared to a standard TEOS passivation. This improvement is due to the low Young's modulus of the SOG, which suppresses stress evolution in the Al interconnects near the via during EM testing.