In the fabrication of nanoscale Backside Illuminated (BSI) CMOS Image Sensors, forming electrical connections requires etching through the backside dielectric stack to access the buried frontside metallization A2. Following the etching of the upper anti-reflective layer (HKD/AR2), the HKD/AR1 Etch step removes the primary high-k dielectric and anti-reflective coating (AR1) from the bond pad regions P3. High-k materials such as Ta2O5, HfO2, or Al2O3 are utilized in the BSI stack because their spe