Radio frequency sputtering process of a polytetrafluoroethylene target and characterization of fluorocarbon polymer films

Abstract

Fluorocarbon polymer films have been deposited on glass, silicon, and carbon substrates by radio frequency (rf) sputtering of a polytetrafluoroethylene (PTFE) target in pure argon and Ar–C3F8 mixtures using either a conventional sputtering mode or a self-sustaining glow discharge mode. The substrates could be isolated from the plasma region by a grounded grid electrode. The deposition rate of films produced on glass and silicon substrates was measured as a function of the gas composition and total pressure. The grounded grid electrode effect on the deposition rate of films was also investigated. The polymer films were characterized by x-ray diffraction, infrared spectroscopy, and Rutherford backscattering spectroscopy. The morphology of films was examined before and after annealing at 450 °C in pure argon ambient for 4–24 h. The optimum deposition conditions to produce (CFx)n polymer films with high fluorine contents and high deposition rates by rf sputtering of a PTFE target are reported and discussed in the article.