Two-dimensional ion flux distributions in inductively coupled plasmas: Effect of adding electronegative gases to Ar

The ion current density and corresponding uniformity in Ar/SF₆ and Ar/Cl₂ discharges were measured using a two-dimensional array of planar Langmuir probes which were built on a 200 mm diameter silicon wafer. Experiments were conducted in a high-density inductively coupled plasma reactor which was equipped with multiple plasma and surface diagnostics. Results indicated that the ion current density in a pure argon discharge increased with increased pressure and the discharges became more uniform as ion diffusion rate slowed down at high pressures.