Highly anisotropic etching of molybdenum thin films using Cl2/O2/HBr/Ar gas mixtures

초록

High density plasma reactive ion etching of Mo thin films was performed using halogen gases containing Cl2 and HBr. The addition of O2 to a Cl2/Ar mixture significantly increased the etch rate and produced a highly anisotropic etch profile. An optimum Cl2 to O2 ratio was identified, yielding both a high etch rate and good etch profile. The evolution of etch profiles in the Cl2/O2/Ar gas mixture was studied by varying the Cl2 to O2 ratio. Xray photoelectron spectroscopy confirmed the formation of MoCl5 and MoOxCly, as the primary etch products of Mo thin films in the Cl2/O2/Ar gas mixture. Further improvement in etch profile was achieved by adding HBr to the Cl2/O2/Ar mixture, which facilitated the formation of a passivation layer. Ultimately, a highly anisotropic etch profile of Mo thin films patterned with fine lines was obtained using the optimized Cl2/O2/HBr/Ar gas mixture.

키워드