Investigation of barrier and slurry effects on the galvanic corrosion of copper
Galvanic corrosion of copper as a function of barrier metal type together with the effect of acid type is investigated. Refractory metals such as Ta, Ti, and W are used as the barrier metals. HNO3-based and H2O2-based aqueous solutions are used to analyze the effect of acid type of the CMP slurry on the galvanic corrosion. The results show that the galvanic etch rate of copper is affected by the barrier metal type. In addition, the type of solution used is found to influence the barrier metal as well as the copper. Especially for the case of W, the change in the direction of the electrical current flow between copper and the barrier metal depending on the type of solution used seems to alter the galvanic reaction mechanism.
galvanic corrosion barrier metal copper interconnect chemical mechanical polishing (cmp) slurry