On a dual inductively coupled plasma for direct and remote plasma in a reactor

Abstract

A dual inductively coupled plasma (ICP) system in which a remote ICP (upper ICP) with small volume is attached to a main ICP (lower ICP) is developed. Two ICP antennas are connected in parallel and a variable capacitor C-var is installed in series at the end of the main ICP antenna. By adjusting the capacitance of the variable capacitor, the plasma densities and the electron temperatures in the remote region and the main region are controlled. The electron energy distribution functions (EEDFs) and plasma potential from the EEDFs are measured along z axis. It is found that there is a potential dip in the midway of two ICP antennas and the potential dip is formed to keep two plasmas quasineutral. In two regions, the EEDFs in high energy range are almost same (nonlocal) but they are different in low energy range because low energy electrons cannot overcome the potential dip. (C) 2004 American Institute of Physics.