Development of a dual inductively coupled plasma source for direct and remote plasma generation in a reactor

Abstract

A dual inductively coupled plasma (ICP) system consists of a remote ICP reactor with small volume and a main ICP reactor with a substrate. Two ICP antennas were connected in parallel and a variable capacitor (C(var)) was installed in series at the end of the main ICP antenna. By adjusting the capacitance of the variable capacitor, the plasma densities in the remote region and the main region are controlled. For the remote region, the plasma was considerably changed such that it had high density and the electron temperature was higher than that in the main region because of its small volume. As such, reactive species in the remote region appeared to be effectively generated. The dual ICP system was applied to Si etching. It was observed that Si etch rate increased by 20% as the plasma density in the remote region increased, even though the plasma density in the main region decreased. This might be understood by considering the role of the remote ICP as a radical generator.