| 摘要 |
PURPOSE:To etch and remove only one surface in thin-films formed on both surfaces of a substrate easily by directing a thin-film surface to be removed to the upper side and dropping concentrated hydrofluoric acid onto said thin-film surface while forwarding air in the upper direction from the lower direction of the substrate. CONSTITUTION:A substrate 1, both surfaces thereof have silicon dioxide films formed by a thermal oxidation method, is placed on a fixed base 2 under the state in which the thin-film side to be removed is directed to the upper side. The size of the fixed base 2 is made smaller than the area of the substrate 1, and an air current 4 can be flowed around the fixed base. When the thin-film on the upper surface section of the substrate 1 is removed, concentrated hydrofluoric acid 3 is dropped to the surface of the thin-film and etched while generating said air current. Creeping to a semiconductor surface on the lower side of concentrated hydrofluoric acid is prevented by the air current 4 at that time. According to such constitution, the thin-film can be removed easily by facilities, cost thereof is low, without attaching an acid-resistant substance such as wax to the substrate. |
