This step defines the spatial boundaries for the N-type well implants in the periphery region of the 40nm BSI CMOS image sensor A1.Following the pre-lithography clean, a photoresist layer is applied and patterned to expose only the periphery regions designated for PMOS device bodies A1.Unlike the Pixel Array P-Well or Photocathode photo steps, which tailor the doping for the photodiode and pixel-level transistors to optimize light capture, this step is exclusively dedicated to the logic and read