Modeling of inductively coupled plasma source with argon/oxygen gas mixture for etching

Summary form only given. The plasma module included in COMSOL multiphysics software was used to simulate the gaseous electronics conference RF reference cell (GEC) in the inductively coupled plasma mode. Both argon and a mixture of argon/oxygen plasmas were considered. The dependence of the radial distribution of the electrons and ions densities at the wafer surface on the pressure, the ICP coil power as well as on the oxygen concentration was investigated. Within the range of values considered, the highest electron density was found to be achieved inside the pure argon discharge at a pressure of 20 mtorr and applying a coil power equal to 1500 W. The addition of oxygen provided high densities of negative oxygen ions especially toward the end of the wafer. With O₂ concentration set equal to 30%, the increase in the power results in higher electron densities along with lower negative oxygen ion densities.