Following the ILD 5-1 SiCN Etch, the underlying M5 copper interconnect is physically exposed at the bottom of the via (Engineering Practice).During this upstream anisotropic etch, fluorocarbon-containing plasmas deliberately deposit highly crosslinked fluoropolymer (CFx) residues on the dielectric sidewalls to maintain profile control and etching anisotropy P1.However, these residues, along with any remaining heavily crosslinked photoresist, must be completely removed to ensure high adhesion and