PRODUCTION OF POROUS ANTIREFLECTION FILM

摘要

PURPOSE:To form a porous antireflection film which has the high resistance to a laser and is small in absorption. CONSTITUTION:The film forming surface of a substrate consisting of quartz is cleaned by an etching treatment and a film mixture is deposited by evaporation on the film forming surface of the substrate in such a manner that the volumetric mixing ratio of SiO2 and NaF is a 1 to 3 range. The porous antireflection film is produced by executing a water treatment immersing the substrate deposited with the film mixture by evaporation for 20 minutes into water kept at 80 deg.C water temp. while stirring the water in a water tank. The refractive index and absorption are small and the film thickness is large if the volumetric mixing ratio of the NaF to the SiO2 is within a 1 to 3 range.