Evaluation of ultratrace metallic impurities in thin copper layers, barrier metals and silicon wafers for copper metallization technology

An analytical method for the determination of ultratrace concentrations of metals in several semiconductor-related materials for copper metallization technology such as thin Cu layers, barrier metals and silicon wafers has been developed. Using this method, the concentration of Cu impurities in Si wafers resulting from diffusion of Cu from Cu metallization layers through barrier layers of TiN, TiSiN, or WSiN was found to be less than 10 12 atoms/cm 3 .