Evaluation of plasma deposited fluorocarbon films using experimental design methodology

Plasma technology is attractive for thin film deposition because films with various characteristics can be obtained by adjusting the process parameters. In this study, the experimental design methodology was used to investigate the influence of process parameters on the characteristics of fluorocarbon films deposited in CH2F2/CF4 plasma. It was found that the CF4 flow rate and substrate temperature were the most significant factors that affect the deposition rate and refractive index of the deposited film. A higher deposition rate was obtained in films deposited under moderate CF4 feed; lower substrate temperature and higher RF power conditions. The lower refractive index was obtained under higher CF4 feed; lower substrate temperature and moderate RF power conditions. It was also found that the fluorocarbon film with a higher F / C ratio was less cross-linked with a lower refractive index and less thermal stability. Potential reactions were proposed to explain the effect of process parameters on the film characteristics.