A self-aligned cap technology for Cu damascene interconnects by MO-CVD ZrN film

A metal capping process for Cu interconnects is developed. Fundamental properties of thin ZrN layers (less than 10 nm) formed by metal organic chemical vapor deposition (MO-CVD) are studied. Because ZrN behaves as a metal when deposited on Cu but as an insulator when deposited on a dielectric layer, such films can be easily integrated into the Cu damascene process. Metallic ZrN films on Cu interconnects can improve electromigration lifetimes and their electric properties are stable against later annealing processes. Also, ZrN insulating films deposited on dielectric materials suppress leakage current and the time dependent dielectric breakdown (TDDB) lifetime.