Following the planarization of the Lower Vertical Grid via W CMP and subsequent cleaning, Optical Pad 2 Deposition establishes a critical optical and structural interface A2.Unlike Optical Pad 1, which typically acts as a base layer beneath the light shield grid, or Optical Pad 3, which interfaces with top-level micro-lenses or color filters, Pad 2 is specifically positioned to bridge the polished tungsten (W) grid and the incoming Lower OCL (On-Chip Lens) Planar Layer (Engineering Practice).Its