The work aims to study effects of different plasma etching processes on silicon substrate and tetrahedral amorphous carbon (ta-C) films, and further survey effects of different arc plasma etching time on ta-C films. Etching of different plasma and deposition of ta-C films were performed by a home-made 45o bend magnetic filtered cathodic vacuum arc (FCVA) coater. Plasma types and density were characterized with optical emission spectrometer (OES); thickness of ta-C films with ellipsometer; roughness of treated substrates after etching with atomic force microscope (AFM); the film structure with Raman spectroscopy and XPS; and film-to-substrate interface structure was analyzed with TEM, representatively. The results showed that the Ar+ of low density dominated in the effective plasma of glow etching process while Ar+ of high density and a few C+ emerged in arc plasma etching process. After the arc plasma etching, a nearly 15 nm thick interface layer was formed on the substrates surface, and pre-deposition of amorphous carbon film (a-C) was observed. Moreover, sp3 content of the ta-C film decreased as the arc etching time increased. Compared with glow etching process, arc etching facilitates the deposition of thicker ta-C films, primarily due to the formation of interfacial layer on the substrate surface and the pre-deposition of amorphous carbon films layer in arc etching, which contributes to formation of a special a-C/ta-C gradient film structure and improvement of adhesion strength.