Robust low oxygen content Cu alloy for scaled-down ULSI interconnects based on metallurgical thermodynamic principles

Low oxygen content (LOC) CuAl with no barrier metal (Ta) oxidation is obtained by using an oxygen absorption process that is based on metallurgical thermodynamic principles. The studies have shown that the LOC CuAl damascene interconnects (DDIs) have improved via reliability against both stress-induced voiding (SiV) and electromigration (EM), which is applicable for 45-nm-node LSI devices with 140-nm-pitch lines.