Properties and production of F-doped silica glass

Fluorine-doped silica glass is an optical material with high transmission in the vacuum ultraviolet region, specifically at 157 nm. This feature, along with low thermal expansion and ease of polishing make it the material of choice for the photomask substrate for the 157 nm lithography node. We report the synthesis of fluorine-doped silica glass using various dopants. Characterization of the glasses was achieved by measuring vacuum UV and IR spectra and by refractive index measurements. Transmission and refractive index are both found to depend on fluorine concentration.