Electromigration Characterization of DC Magnetron-Sputtered AL-SI Metallization

The residual gas dependence of the life time of dc magnetron-sputtered Al-Si (1.2%) interconnects under temperature/current stress was investigated. Whereas the interconnect life time decreased with increasing H2O partial pressure, it increased with O2 partial pressure up to 4×1O¿9 Torr. Narrow interconnects were more sensitive to the residual gas conditions during metal deposition than wide ones. The Al-Si films were further characterized with respect to microstructure, reflectivity and residual resistivity. Correlations between life time and Al-Si-properties available immediately after film deposition are discussed. The best correlation existed with the residual resistivity.