Fabrication of SiO2-Humps on Silicone Rubber Using F2 Laser

The surface of silicone rubber swelled and was modified to a SiO2 glass layer when irradiated by a 157-nm F2 laser. Ten minutes of irradiation of the laser with fluence of 14 mJ/cm2 operating at 20 Hz produced 3-µm-thick SiO2 humps, but the surface was not modified when a 193-nm ArF laser was used. High photon energy of the F2 laser may cause the two phenomena. This is a useful new technique which enables both processing and modification to be carried out at the same time.