The Metal 0 - Photo step defines the first horizontal local routing layer in the back-end-of-line (BEOL) interconnect system T1.Unlike earlier contact-opening photolithography steps that define vertical vias to access the semiconductor device terminals, this step specifically patterns horizontal interconnect lines directly atop the previously deposited blanket tungsten (W) film P2.The primary objective of this module is to create a polymeric or hybrid mask that protects the underlying W during t