Following the ILD 6-1 Etch, the final trench and via cavities for the Direct Bond Interconnect (DBI) are defined, but the surfaces remain heavily contaminated with residual photoresist, bottom anti-reflective coating (BARC), and highly crosslinked fluorocarbon (CFx) polymeric etch residues P3.This specific Ashing & Strip/Clean step is critical because it serves as the final surface preparation before Ta-based liner and copper seed deposition, distinguishing it from earlier intermediate cleans th