Improvements in or relating to etching metals

Abstract

Abstract 779,347. Removing metal by electric discharges. EDWARDS & CO. (LONDON), Ltd., W. Nov. 18, 1954 [Aug. 18, 1953], No. 22764/53. Class 83 (4). The surface of a metal object is etched by making the object the cathode of a cathodic sputtering apparatus and using a magnetic field to permit lowering of the working pressure of the gas in which the glow discharge occurs. The apparatus comprises a sputtering chamber 1 formed by a glass tube connected at one end to a diffusion or other pump and closed at its other end by a plate 4 supporting two insulated aluminium negative electrodes 5 and 6, the former having the specimen 7 to be etched attached thereto and the latter acting as an auxiliary cathode to maintain symmetry of the glow discharge. The anode is constituted by a metal band 8 also supported from the plate 4, disposed between and in spaced relation with the cathodes 5 and 6. The magnetic field is provided by a semi-circular magnet 9 arranged around the chamber 1 so that the direction of the field is normal to both the auxiliary cathode and the specimen surface to be etched and overheating of the latter is prevented by a coolant, which may be solid carbon dioxide in methylated spirit, in a vessel 10 having a copper base carrying a brass rod 12 to which the element 5 is connected. The magnet 9 may be replaced by an electromagnet. Specification 736,512, [Group II], is referred to.

Inventors

• 👤 Leslie Arthur Holland

Bibliographic Details