Electromigration reliability of Mn-doped Cu interconnects for the 28 nm technology

Electromigration (EM) reliability of Cu interconnects for the 28 nm node with Mn doping was studied by investigating the effects of line width and length on void formation kinetics, EM lifetime and statistics. Failure modes and mass transport mechanism responsible for EM degradation of CuMn interconnects were examined. Although immortality was not observed, EM lifetime of short lines was significantly improved together with a reduction in lifetime deviation. This is attributed to the effectiveness of Mn in repairing process defects, particularly for via-related void formation in V1M2 electron flow direction.