Effects of external parameters on plasma characteristics and uniformity in a dual cylindrical inductively coupled plasma

Abstract

The dual cylindrical inductively coupled plasma source, compared to the conventional structure of the inductively coupled plasma (ICP) source, can significantly improve the uniformity of the plasma. It has an enhanced potential for application in processes such as etching and ashing. A uniform plasma can be obtained by letting the remote plasma from the upper chamber modulate the main plasma generated in the lower chamber. In this study, a fluid model is employed to investigate dual cylindrical inductively coupled Ar/O2 plasma. The effects of external parameters on electron density, electron temperature, O atom density and plasma uniformity in the main chamber are studied and the reasons are analyzed. The results of the study show that the remote power can control plasma uniformity and increase plasma density in the main chamber. As the remote power increases, plasma uniformity improves initially and then deteriorates. The main power affects the plasma density at the edge of the main chamber and can modulate the plasma density in the main chamber. However, as the main power increases, the effect of the remote power on increasing the plasma density in the main chamber becomes poor. Gas pressure has an effect on both the uniformity and density of the plasma. As gas pressure increases, plasma uniformity deteriorates, but free radical density improves.