Selective Oxidation and Resistivity Reduction of Cu-Mn Alloy Films for Self-forming Barrier Process

摘要

Optimum conditions of annealing atmosphere and temperature for the reduction of Mn content from the Cu-Mn alloy layer in Cu-Mn self-forming barrier process were investigated. Mn was selectively oxidized at the surface by annealing in Ar gas containing an impurity level of O_2 (<0.01ppm). Resistivity of the film was decreased to 2.0 μΩcm after annealing. On the other hand, internal oxidation of Cu-Mn alloy was observed with no external protective surface oxide layer in Ar containing more than 10 ppm of O_2. An optimum oxygen concentration is found to be in between 0.01 and 10 ppm in 1atm of Ar gas at 350 ℃.