In the V2 module, the process flow requires establishing electrical contact between Metal 2 and the upcoming Metal 3 layer (Engineering Practice).The previous ILD 2-2 Oxide Etch step creates the via cavity through the main interlayer dielectric but intentionally stops on the underlying ILD 2-1 layer, which is typically a silicon carbonitride (SiCN) etch-stop and copper diffusion barrier A1.The primary objective of the ILD 2-1 SiCN Etch is to punch through this remaining hermetic barrier to expos