TiN薄膜の酸化溶解による銅の置換析出挙動

抄録

Electrochemical displacement of a portion of a TiN thin film, a diffusion barrier, on a Si-based wafer with copper was examined at ambient temperature, with the ultimate purpose of developing a novel copper metallization for the manufacture of ULSI-interconnects. The rate of oxidative dissolution of TiN was increased with a decrease in the pH of the solution used for displacement and was independent of Cu (II) ion concentration, suggesting that hydrogen ions act as an oxidizing agent even in the presence of Cu (II). The deposition rate of Cu was affected by both pH and fluoride ion concentration and increased with a decrease in fluoride ions. This dissolution/deposition behavior was discussed thermodynamically using a potential-pH diagram of the Cu-F-H₂O system.