An oxygen-doped silicon carbide (O-SiC) barrier film with a dielectric constant of 3.3 was tested using a downstream ashing plasma tool. We investigated the interactions of three plasma chemistries, O-2/H-2/N-2, H-2/N-2, and H-2/He plasmas, with the O-SiC films. The plasma damage to the films were evaluated and chemical structure changes were examined. While the O-2/H-2/N-2 plasma changed the O-SiC film into a SiO2-like film, the H-2/He plasma caused minimum damage to the film, and material removal can be controlled within 5%. The infrared spectra indicate no noticeable chemical structure changes after the H-2/He plasma exposures. Further, the electrical properties, including dielectric constant, leakage current, and dielectric breakdown voltage, were measured after the films were exposed to these plasmas. These electrical characteristics are preserved after the films were exposed to the H2/He plasma. The results indicate that the H-2/He plasma ashing chemistry can be effectively applied to the O-SiC films without generating degradation of the key film characteristics. (C) 2004 The Electrochemical Society.