Behaviors of Metallic Contaminants in Si Wafer Processing

摘要

It was found that the levels of metallic contamination depend on the pH of solutions. The contamination levels of Co and Ni in SC2 are significantly lower than those in SC1 solutions. It was also found that metallic contaminants on Si surface diffuse into bulk or oxide during oxidation. For Fe and Co contaminated wafers, decreases in lifetimes were found, and they depend on contamination levels. On the other hand, for Ti and Ni wafers, lifetimes were not different from that for uncontaminated wafer. Interestingly, Fe influenced bulk lifetime rather than near surface lifetimes, while Ni and Co affected near surface lifetime.