An a-C:F:H Film with High Thermal Stability by Electron Cyclotron Resonance Chemical Vapor Deposition at Room Temperature

Using CHF₃/C₆H₆ gases, amorphous fluorinated hydrocarbon films (a-C:F:H) were deposited by electron cyclotron resonance (ECR) chemical vapor deposition at room temperature. Dependence of the film properties on variable flow ratios RCHF₃/CHF₃+C₆H₆ was investigated by infrared absorption, x-ray photoelectron spectroscopy, measurements of the film thickness and dielectric constant. Evidences show that the film deposition rate decreases linearly with the increasing flow ratios R and the adding of C₆H₆ source gas to ECR plasma enhances structural cross-linking in the a-C:F:H films. In order to obtain good structural stability of these films, it is necessary to reconcile configurations between C-C bond and H or F terminal atoms carefully. The experimental results indicate that an a-C:F:H film with low dielectric constant (k < 3) and high thermal stability ( > 400°C) has been deposited successfully at R = 56.3%.