The Sacrificial Lower OCL Etch step serves to transfer the three-dimensional, hemispherical profile of the reflowed sacrificial polymer into the underlying permanent optical layer P1.Following the formation of the lens shape via thermal reflow and its structural stabilization through the final UV/Hard bake, an anisotropic dry etch is applied to carve this topology into the intermediate material of the lower on-chip lens (LOCL) P1.This step is distinctly different from subsequent standard Lower O