Following the demanding sequence of CESL 1, Pad Oxide, and Poly/Si Back Etches in the contact module, a highly crosslinked photoresist shell and complex fluorocarbon post-etch residues (PER) remain on the wafer P1.This specific Ashing & Strip/Clean step is critical because it directly precedes Ti/TiN barrier layer deposition, which requires an ultra-clean interface to form a low-resistance ohmic contact T1.Unlike earlier strip steps that may only deal with bulk dielectric etches, this step must