| 摘要 |
PURPOSE:To prevent the breakdown of a mask pattern formed on a transparent substrate due to static electricity and to eliminate the charging-up due to the irradiation of electron beam by coating the whole surface of the substrate with an electrically conductive translucent film to protect the mask pattern. CONSTITUTION:The whole surface of a photomask having a mask pattern made of metallic film, metallic oxide film or their mixed film is coated with an electrically conductive translucent film of indium oxide or tin oxide to protect the mask pattern. The suitable thickness of the protective film is 200-500Angstrom . An org. indium soln. is applied and heat treated at 300-500 deg.C for 20-60min to decompose the org. substance, whereby the org. indium is converted into indium oxide. When the photomask is coated with indium oxide, the indium oxide acts as an electric conductor to prevent charging-up, and the mask pattern is not scratche by electrostatic discharge even if brought into contact with a semiconductor substrate and transferred. In addition, the amount of dust stuck is reduced remarkably. |
