The Post CMP Cleaning step in the F_DTI module immediately follows the chemical-mechanical planarization (CMP) used to remove excess silicon nitride from the Deep Trench Isolation (DTI) structures A2.During the preceding CMP process, the wafer surface becomes heavily contaminated with abrasive nanoparticles, pad debris, and organic chemical additives P1.This cleaning step exists to thoroughly remove these residues, exposing a pristine silicon nitride and pad oxide surface necessary for the subse