Advanced BEOL Materials, Processes, and Integration to Reduce Line Resistance of Damascene Cu, Co, and Subtractive Ru Interconnects.

Recent progress in materials, processes and integration schemes to reduce line resistance (Line-R) of damascene Cu and alternative conductors (damascene Co and subtractive Ru) are reviewed, including (1) graphene/Co capped Cu to achieve both EM reliability and Line-R reduction (2) nanosecond laser anneal of Ru blanket films for subtractive-etched interconnects, (3) single damascene Cu, which is potentially one way to extend Cu to extreme nodes, and (4) Co/Cu composite integration to preserve Cu power rails. Finally, the technology shift from Cu to alternative conductors is discussed from the viewpoint of Line-R crossover.