Formation of silicone thin films by ArF excimer laser induced photo-desorption

Low molecular weight silicones were ejected from silicone rubber target irradiated by a 193 nm ArF excimer laser through the photo-desorption. The ejected silicones were successfully deposited on a fused silica glass substrate in air. An approximately 0.3 mm of the target-substrate distance was required for the deposition. The deposited silicones became a thin film, showing an interference color when the ArF excimer laser was irradiated for a long time. Chemical bonding state of the formed thin films was analyzed by the Fourier transform infrared spectroscopy. The thin films were slightly different from the original silicone rubber structure, still it was composed of Si-O-Si bonds and Si-CH₃ bonds. Also, OH bonds were clearly produced in the silicone thin films. As a result, contact angle of water on the silicone thin films was measured to be approximately 20 degrees, indicating a hydrophilic property.