COMPARISON OF EXTERNAL AND INTERNAL PLANAR RADIO-FREQUENCY ANTENNAE FOR INDUCTIVELY-COUPLED PLASMA

Radio frequency (rf) antennae, coated with glass, were inductively cou pled to an Ar plasma inside the processing chamber. Coupling efficienc y eta and electron density N-e were measured for moderate pressures (0 .1-200 T) and rf power (10-2000 W). Decreasing the dielectric thicknes s between the antenna and the Ar led to an increase in eta and a decre ase in N-e. Instabilities and hysteresis were observed for the interna l antennae. (C) 1997 American Institute of Physics.