The ILD 2-2 Oxide Etch is a critical back-end-of-line (BEOL) process step designed to pattern the trench for Metal 3 (MET3) interconnects within the inter-level dielectric P3.Following the MET3 photolithography, this step physically removes the exposed oxide or low-k material to create the cavity that will subsequently be filled with a Ta-based liner and copper seed layer P4.Unlike shallow front-end pad oxide etches that primarily clear protective layers, this BEOL trench etch must precisely con