The Cu CMP step within the Direct Bond Interconnect (DBI) module is critical for removing the bulk copper overburden deposited during the Metal 6 phase, leaving the copper isolated within the trench structures P4.Positioned immediately before the Ta-based liner CMP and the final oxide CMP, the primary objective of this step is to selectively clear the bulk copper and stop precisely on the underlying Ta-based liner P3.Unlike earlier standard BEOL Cu CMP steps (such as steps #158 or #174), this DB