Silicon nitride chamber dry cleaning with carbonyl fluoride and nitrous oxide additives

Abstract To decrease greenhouse gas emissions, studies have focused on finding dry cleaning replacement gases with low global warming potential (GWP). Carbonyl fluoride (COF2) is a promising candidate for plasma enhanced chemical vapor deposition (PECVD) chamber cleaning due to its lower GWP. We investigated the effects of N2O addition on the Si3N4 cleaning with COF2/Ar mixtures. By comparing numerical analysis and experimental results, we confirmed that the addition of N2O gas via remote plasma system (RPS) increased the chamber cleaning efficiency. Addition of N2O promotes COF2 dissociation, removes carbon-based inhibitors, and facilitates nitrogen extraction from the Si3N4 surface. However, excessive N2O concentrations induce surface re-oxidation and the formation of a passivation layer, which limits cleaning efficiency. We conclude that N2O addition significantly alters species production mechanisms and rates, ultimately determining the overall cleaning performance on nitride surfaces.