This process step transfers the Via 2 lithographic pattern into the ILD 2-2 oxide layer to establish vertical electrical connections within the BEOL dual-damascene architecture P2.Following the Via 2 photoresist definition, an anisotropic plasma etch removes the exposed ILD material and stops precisely on the underlying ILD 2-1 SiCN layer A2.Unlike pad oxide etches that clear thin sacrificial layers over active silicon or hard mask etches used strictly for shallow pattern transfer, this specific