After W and TiN/Ti CMP in the CONTACT module, the wafer surface is covered in residual slurry particles, pad debris, and metallic/organic contaminants P4.If left uncleaned, these submicron particles and metallic residues will cause severe defectivity, such as short circuits between adjacent contact plugs or elevated contact resistance during the subsequent Low Temperature Anneal and PMD 5 Deposition steps P4.Unlike the STI CMP Post Cleaning step which primarily addresses silicon oxide and nitrid