Lower OCL (On-Chip Lens) Coating Deposition is a critical module in the Backside-Illuminated (BSI) CMOS image sensor flow for establishing the pixel-level optical transmission path A2.Following the sacrificial lower OCL etch and ashing steps, the wafer surface exhibits complex topography composed of sub-micron pixel isolation grids A2.This deposition step fills these cavities with an optically transmissive material, preparing a uniform, filled base for the subsequent Optical Pad 3 Deposition and