LOW REFRACTIVE INDEX SIO2 FILM AND ITS PRODUCTION

摘要

PROBLEM TO BE SOLVED: To provide an SiO2 film having a refractive index lower than that of a conventional film by using a raw material used in the formation of the SiO2 film. SOLUTION: Gas containing F-atom, gas wherein a part or all of H-atoms of an alkyl group having 1-4 Si-atoms and carbon atoms or an alkyl group are substituted by F-atoms and gas containing O-atoms are used as raw material gases and subjected to a plasma CVD method within a vacuum chamber 1 to form an SiO2 film on a web in a plasma zone 5. The obtained SiO2 film has one or more kind of a low refractive index element selected from an alkyl group having 1-4 F-atoms and C-atoms or a group wherein a part or all of H-atoms of an alkyl group having 1-4 C-atoms are substituted by F-atoms introduced thereinto and has a refractive index lower than that of an SiO2 film into which no refractive index element is introduced.