Metal 6 (M6) Cu deposition serves as the final, uppermost metallization step in the back-end-of-line (BEOL) flow before the Direct Bond Interconnect (DBI) module P1.Following the deposition of a Ta-based barrier and Cu seed layer, this step relies on electrochemical plating (ECP) to completely fill the dual-damascene trenches and vias P2.Once deposited, the M6 layer undergoes chemical mechanical polishing (CMP) to isolate the metal lines and create the highly planarized surface required for subs