Abstract: In a vacuum system for subjecting a workpiece such as a semiconductor wafer to a beam of energy, for example as in cathodic sputtering, temperature rise of the workpiece is inhibited by mounting the workpiece in minimal thermal contact with the support structure, and orienting it so that the back surface of the workpiece, that is, the face opposite to that upon which the energy beam impinges, is directed to a black body or low temperature portion of the vacuum chamber. In combination with this technique, the back surface is suitably treated to increase its emissivity such as, for example, by applying thereto a black coating.

Abstract: During the removal of material selectively, by the sputter etching of the surface of a semiconductor wafer, the wafer is moved so as to produce a continuously varying angle of incidence between the ion beam and the wafer surface. There is also provided a field-free region adjoining the surface of the wafer which is being etched. As a consequence, the sputtering beam strikes the wafer surface over a range of angles which results in more complete removal of material, particularly material overlying stepped portions of the surface.