Adsorption and desorption properties of Cu and Ag contaminants on Si substrate

Adsorption and desorption mechanisms of noble metals (Cu and Ag) on a Si surface were investigated. From this research, we found that (1) when a bare Si substrate was dipped in 1 ppm Cu containing O,-UPW (ozonized ultrapure water), Cu adhered almost to the Si oxide surface and could be easily removed by a wet oxidation mode cleaning; (2) Ag acted as an oxidizing agent against Cu contaminants on the Si substrate and replaced it; (3) To prevent noble metallic contaminations on the Si substrate, pre-oxidation treatment was very effective.