Process for forming silica films.

摘要

A process for forming a silica film on a substrate which comprises bringing the substrate into contact with an aqueous solution of hydrosilicofluoric acid supersaturated with silica, wherein the supersaturated solution is filled in an inner vessel which is opened downwardly so as to allow the introduction of the substrate thereinto and is arranged inside an outer vessel at a distance from the side walls and the bottom of the outer vessel, and a liquid material having substantially no reactivity and miscibility with the supersaturated solution and having a higher specific gravity than the supersaturated solution is charged in the outer vessel so as to retain the supersaturated solution in the inner vessel without flowing down toward the bottom of the outer vessel, and whereby the supersaturated solution is prevented from being exposed to the atmosphere and accordingly the process can be practiced at high deposition rate in high efficiency and yield without evaporating effective Si components which result in formation of silica particles outside the vessels. <IMAGE>