In a 40nm BSI CIS flow, the bondpad opening process must navigate through multiple dielectric and etch stop layers to expose the pad without damaging surrounding structures P2.Previous steps etched the bulk silicon and pad oxide, followed by CESL 1 Etch, making the CESL 2 Etch necessary to break through the next layer of the multi-tiered contact etch stop layer stack P1.CESL films, typically formed of amorphous hydrogenated silicon nitride deposited via PECVD, are widely used to induce targeted