The Pre Litho Cleaning step in the ILD3 module is critically positioned between the deposition of the ILD 3-2 dielectric layer and the Via 3 (V3) photolithography patterning step (Engineering Practice).Unlike post-CMP cleaning steps that must remove heavy metallic contamination, or post-etch cleans that target heavily crosslinked fluorocarbon polymer residues P4, this specific pre-litho clean addresses a freshly deposited dielectric surface (Engineering Practice).Its primary objective is to remo