The BSI CMOS image sensor stack relies on a precise optical layer sequence comprising microlenses, color filters, and antireflective coatings A1.Traditional dye-doped polymer color filters are fabricated through a sequential, multi-stage lithographic process P1.Following the sequential patterning of individual colors (e (Engineering Practice).g., Red, Cyan), the Final Hard Bake serves as the ultimate thermal stabilization step for the entire Color Filter Array (CFA) before the Upper On-Chip Lens