| abstract |
An electrode assembly for use in a plasma processing apparatus, e.g. for reactive dry etching or plasma deposition, comprises a primary electrode 13 with a conductive wall defining a plasma chamber 5 which is open at both ends and has an inlet 9 for gas, an insulator at one end of the plasma chamber for insulating the primary electrode when it is mounted on the body 2 of a vacuum chamber, r.f. generator 29, 10 associated with a dielectric member 8 extending across the other end of the chamber 5 for inductively generating a plasma in the gas in the plasma chamber 5 and a primary magnet arrangement 14, see also Figs 3-5 (not shown), which produces lines of magnetic flux within the plasma chamber which extend in a curve from the plasma chamber wall and return thereto so as to form an arch over a respective one of a plurality of wall regions which extend substantially longitudinally of the wall of the plasma chamber in a zone which is, in use, above and spaced from the substrate table 6, so as to trap electrons from the plasma adjacent the chamber wall. The r.f. generator coil 10 may be in the form of a substantially flat spiral which is adjacent to or embedded in the dielectric member 8 and additional secondary magnets 11, 12 provide a dipole field that penetrates the energising coil 10. <IMAGE> |