Abstract: A semiconductor wafer etching apparatus is capable of anisotropically etching a large-diameter semiconductor wafer with high accuracy without causing the semiconductor wafer to be charged. First, the apparatus cools the wafer in an atmosphere of a nitrogen or a halogen gas so that the wafer adsorbs and is covered by atoms of the gas. Then, a fast atom beam source of the apparatus generates an electrically neutral fast atom beam of gas atoms or molecules to etch the semiconductor wafer. The etching speed is promoted by an interaction of the adsorbed atoms and the fast atom beam.

Abstract: An ion neutralizer which neutralizes electric charges on ions and produces a fast atom beam in an ultra-high vacuum comprising: an ion source disposed in a vacuum container; a hollow container disposed in the vacuum container, the hollow container being closed at both ends thereof except for an ion beam entrance hole provided in one end portion thereof and a fast atom beam exit hole provided in the other end portion thereof; a metal vapor generating source comprising a filament wound with a fine wire or ribbon of a metal selected from titanium, magnesium and aluminum, the filament being disposed in the hollow container in such a manner as to surround an axis connecting the ion beam entrance hole and the fast atom beam exit hole; a vacuum pump connected to the vacuum container; and a filament heating power supply disposed outside the vacuum container and the hollow container and connected to the filament.