In the fabrication of a 40nm Backside Illuminated (BSI) CMOS Image Sensor, the bondpads located at the device periphery must be cleared of all overlying optical and dielectric layers to enable final electrical packaging A1.The Lower OCL (On-Chip Lens) Etch is a critical clearance step within the BONDPAD module, designed to selectively remove the inner micro-lens material—typically a high-refractive-index silicon nitride or hybrid organic-inorganic layer—from the bondpad regions A1.This step sequ