Following the ILD 2-2 Oxide Etch, the wafer surface and trench sidewalls are coated with hardened photoresist and highly crosslinked fluorocarbon (CFx) polymeric residues P1.This Ashing & Strip/Clean step is critical to remove these contaminants before the subsequent Ta-based liner deposition A3.If left uncleaned, these residues will prevent the conformal deposition and adhesion of the barrier layer, leading to high contact resistance and downstream integration failures P1.Unlike earlier front-e