Cu is used for the MET5 interconnect layer to significantly reduce RC delay compared to traditional aluminum systems P2.However, Cu diffuses rapidly into adjacent SiO2 or low-k dielectrics, which can cause deep trap levels and catastrophic device failure P2.Therefore, a barrier and liner system is mandatory before the subsequent Cu seed deposition P2.The Ta-based system, typically a TaN/Ta bilayer, is deposited into the etched and cleaned MET5 trenches and vias P3.TaN acts as the primary diffusi