Effect of post-plasma treatment power on the properties of low dielectric fluorinated amorphous carbon films

The effects of plasma treatment power on the properties of fluorinated amorphous carbon (a-C:F) films were investigated. In this study, the a-C:F films were prepared by electron cyclotron resonance chemical vapor deposition (ECRCVD) system (AsTex AX4505) using a gas mixture of fluorocarbon (C2F6) and hydrocarbon (CH4). The chemical bonding structure, chemical composition and dielectric constant of a-C:F films were studied with a variety of techniques, such as Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and capacitance-voltage (CV) measurement. The surface energy of a-C:F films was evaluated by contact angle measurements using water and diiodomethane. As the plasma power increased, the fluorine concentration of the film surface decreased. The dielectric constant of a-C:F films remains nearly constant. The surface energy increased sharply with plasma treatment. From this study, it was found that the plasma treatment of a-C:F films produce more reactive surfaces and affect the fluorine concentration of the surface, the structure of chemical bonding and electric properties.