Production of large-diameter plasma using multi-slotted planar antenna

Abstract

It is reported that a large-diameter uniform plasma is obtained by microwave discharges using multi-slotted planar (MSP) antenna. The MSP antenna radiates the microwave field from a large number of slots so as to form a uniform radial distribution of the field in the outer radii. Overdense plasmas are produced with ±3-4% uniformity of the ion saturation current over a 30 cm diameter for Ar pressures of 5-10 mTorr and microwave powers of 1-3 kW. The efficient production of overdense plasmas may be due to the enhancement of the microwave field of oblique incidence at the plasma resonance.