GB1226004A - - Google Patents

Abstract

1,226,004. 004. Sputtering Apparatus. LITTON INDUSTRIES, Inc. April 30, 1968 [May 5, 1967], No. 20434/68. Heading C7F. A sputtering device comprises a low pressure gas discharge device containing at least one anode, at least one cathode, and a cage-like target electrode of spaced elements arranged so as to contain within their envelope a volume of plasma which is separated from the substrate. In Fig. 1, an evacuated chamber 12 contains an anode 22, and hot cathodes 24 in housing 25 whose neck 26 opens along the axis 38 of 12 toward the anode 22. Argon gas at 10<SP>-4</SP> to 10<SP>-2</SP> Torr is supplied from 18 via 20. The target structure is of mutually parallel bars 44, coaxial with chamber 12, equally spaced in a cylindrical disposition and held in place by rings 53 which are supported on tabs 56. The bars are supplied with negative potential by terminal ring 52 on glass collar 49. The individual bars 44 on energization of the apparatus are surrounded by an "ion sheath" of radius d and are spaced apart by about 2d so that a continuous ion sheath 59 Fig. 5, (not shown) is formed within the envelope of the target cage of volume V, which sheath serves to confine substantially all the plasma discharge, so that uncharged atoms are sputtered from elements 44, e. g. of W, Ta, or steel, on to a substrate 63 in the substantially plasma-free region R (Fig. 5). The substrate may be a plastics sheet 70 of width W mounted on vertical rollers. An alternative apparatus is described wherein the target structure, of the shape of Fig. 1, acts as both cathode and target, and alternative target cage structures such as a mesh cylinder or a helix are described. The elements 44 may be surrounded by hollow target tubes of glass or quartz through which a coolant is circulated and to which RF voltage may be applied, and compounds such as WC or W 2 C may be sputtered using mixed W and C elements 44.