Influence of small ground surface on plasma property in an inductively-coupled plasma with floating liner

Abstract

Currently, the components of semiconductor processing chamber are coated with oxides to avoid metal contamination. As a result, electrical ground is hidden from the plasma. In this study, we experimentally investigate the effect of small ground surfaces in an inductively-coupled plasma (ICP) generated in an electrically floating liner. Peak-to-peak and DC voltages at a biasing stage and a floating liner are measured as a function of stage peak-to-peak voltage for various ICP powers and the ground surface areas. The results show that the stage and liner voltages vary with changing ground surface area due to a change in sheath thickness. The analytical plasma potentials, calculated from the experimental values are compared with the simulation results, show good agreement. It is suggested that under low biased voltage and high ICP power conditions, such as in the atomic layer etching process, the small ground surface affects the potential structure in the chamber.