The Metal 2 (M2) Cu deposition step is a critical Back-End-Of-Line (BEOL) metallization process designed to form the second-level conductive interconnects within the 40nm CMOS Image Sensor architecture A1.Following the physical vapor deposition of a Ta-based diffusion barrier and a conformal Cu seed layer, this step utilizes electroplating to completely fill the high-aspect-ratio vias and trenches defined in the dielectric A1.Copper is universally employed for these intermediate routing layers b