Role of O3and OH·Radicals in Ozonated Aqueous Solution for the Photoresist Removal of Semiconductor Fabrication

The role of direct oxidation by aqueous O3 and advanced oxidation by OH· in the removal of photoresist was studied by chemical kinetic simulation and experiments of O3 reactivity and decomposition in homogeneous aqueous solutions. O3 is the main species responsible for the removal of conventional photoresist in the ozonated water cleaning process, and the timing of initiator addition to ozonated water is important to maintain high O3 concentration. Simulation using t-butanol implies that maintenance of a high OH· concentration is required to remove highly implanted photoresists that O3 itself cannot easily remove.