Thin film deposition by plasma beam of a vacuum arc with refractory anodes

Abstract

Thin film deposition using hot anode vacuum arcs developed in the last decade is described. Two configurations were used: (i) with an open gap—the hot refractory anode vacuum arc (HRAVA) and (ii) with a closed gap—the vacuum arc with black body assembly (VABBA). In both configurations, the anode was heated by the arc with current I = 145–340 A, and a relatively dense plasma plume of cathode material (Cu, Ti, Cr, Al, Sn, Mo, Nb), was formed by re-evaporation of cathode material from the hot (2000–2500 K) anode, which was fabricated from graphite, Mo, Ta, or W. A steady state mode was reached when the anode was sufficiently hot and a plasma plume expanded, either radially (HRAVA) or directly from the front hot anode surface. As an example, the deposition rate measured in 300 A HRAVAs at distances of 80 mm from the arc axis, to be 3.6; 1.4 and 1.8 μm/min for Cu, Cr and Ti cathodes respectively. Interconnector trenches (100 nm wide ×300 nm deep) on microelectronic wafers were filled using a Cu HRAVA at a rate of 0.5 µm/min.