Alleviating electromigration through re-engineering the interface between Cu & dielectric-diffusion-barrier in 90 nm Cu/SiOC (k=2.9) device

Despite the initial success in integrating a 90 nm Cu/SiOC (k=2.9) device using the HSQ via-filler scheme, the reliability issues remain. By correlating electromigration (EM) with the moisture blocking capability of the dielectric-diffusion-barrier, we target the factors contributing to the moisture blockage, namely, the N and H-content within SiC. Consequently, increasing the N/H ratio in the SiCN film, we demonstrated a significant enhancement in EM reliability.