The ILD 4-1 SiCN Etch is a critical patterning step within the BONDPAD module of a 40nm Backside Illuminated (BSI) CMOS Image Sensor P4.This process directly follows the ILD 4-2 Oxide Etch and prepares the wafer for the subsequent ILD 3-2 Oxide Etch A2.In this integration scheme, the bondpad via must penetrate multiple alternating dielectric layers, requiring sequential etching through successive oxide and SiCN films A2.The primary objective of this specific step is to completely break through t