Ion cleaning of silicone-based contaminants

The use of low-energy (25-100 eV) ions to remove silicone-based polymer films from spacecraft operational and optical surfaces by controlled sputtering to avoid damage to the substrate surfaces was investigated. The source of contamination was McGann-Nusil 2566 which was heated to deposit a film on the front surface of a temperature-controlled quartz crystal microbalance (TQCM). Removal of the silicone film by the ion beam was quantified by measuring the change in frequency of the TQCM. An ion gun was used to select the ion species of interest and to vary the beam energy. Cleaning rates were determined as a function of ion beam energy and selected beam gases of oxygen, nitrogen, and argon. The results indicate that controlled sputtering can remove of silicone-based contamination films without damaging the substrate