Development of internal-antenna-driven large-area RF plasma sources using multiple low-inductance antenna units

Large-area and high-density radio frequency (RF) plasmas at 13.56 MHz have been produced by inductive coupling of internal-type low-inductance antenna units. The present study has been carried out to develop the basic discharge techniques which can be applied to production of meter-scale large-area and/or large-volume plasma sources with high density for a variety of plasma processes. The plasma source could be operated stably to attain plasma density as high as 1×1012 cm−3 at argon pressures of approximately 1 Pa. It has been demonstrated that high plasma density can be obtained efficiently using the low-inductance internal antenna configuration with effectively suppressed electrostatic coupling. Discharge experiments in a meter-scale chamber demonstrated uniform plasma production with densities as high as 6×1011 cm−3 at an argon pressure of 1.3 Pa and a RF power of 4 kW.