The Post CMP Cleaning step in the Direct Bond Interconnect (DBI) module serves to prepare a pristine, planarized hybrid surface for subsequent CMOS Image Sensor (CIS) and Image Signal Processor (ISP) wafer bonding A3.Following the sequential chemical mechanical planarization (CMP) of bulk Cu, a Ta-based liner, and the final oxide layer, the wafer surface is left exposed to slurry abrasives, organic additives, and metallic by-products P4.This step must completely remove these residues to enable d