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

The dual cylindrical inductively coupled plasma source, compared to the conventional structure of inductively coupled plasma source, can significantly improve the uniformity of plasma. It has an enhanced potential for application in processes, such as etching and ashing. A uniform plasma can be obtained by allowing the remote plasma from the upper chamber modulate the main plasma generated in the lower chamber. In this study, a fluid model was employed to investigate a dual cylindrical inductively coupled Ar/O₂ discharge. The effects of external parameters on electron density, electron temperature, O atomic density, and plasma uniformity in the main chamber were studied, and the reasons were analyzed. The results of this study show that remote power can control the plasma uniformity and increase the plasma density in the main chamber. As the remote power increased, plasma uniformity improved initially and then deteriorated. The main power affected the plasma density at the edge of the main chamber and can modulate the plasma density in the main chamber. The gas pressure affected both the uniformity and density of the plasma. As the gas pressure increased, the plasma uniformity deteriorated, but the free radical density improved.