The preceding Pixel Array P-Well IIP step introduces high-energy p-type dopants to form the isolation and transistor body of the image sensor array P4.During this implantation, the photoresist acts as a protective mask, absorbing the high-energy ions and transforming the resist surface into a High-Dose Ion-implanted Photoresist (HDI-PR) with a highly cross-linked, hardened crust P1.This Ashing & Strip/Clean step is strictly required to completely eradicate this hardened polymeric layer and any m