RF 바이어스 유도결합 플라즈마 장치에서 플라즈마 변수와 전자 수송 가열에 관한 연구

Abstract

RF biased inductively coupled plasma (ICP) is widely used in semiconductor and display etch processes and laboratory research. Up to now, researches on how RF bias power affects parameters have been focused on the controls of dc self-bias voltages. However, an effect of the RF bias on plasma parameters which give a crucial role in the processing result and device performance has been little studied. In this dissertation, studies on the correlations between the RF bias and plasma parameters and the electron heating mechanism are presented. As the RF bias power was increased in the RF biased ICP, the plasma density increased at the high ICP power and decreased at the low ICP power, and this result can be explained by the global model. This change in the plasma density suggests that the RF bias affects the plasma parameters, as well as the self bias voltage. Plasma uniformity was changed by the non-uniform power deposition of the RF bias. Electron heating mechanism by the ICP (inductive field) and the RF bias (capacitive field) was investigated. It was observed that with small RF bias powers, a collisionless sheath heating was weak, while in the capacitive RF bias dominant regime the high energy electrons by the RF bias were heated on the (electron energy distribution functions) EEDFs in the presence of the ICP and the collisionless heating mechanism of the high energy electrons transited from the anomalous skin effect by the ICP to the capacitive coupled collisionless heating by the electron bounce resonance in the RF biased ICP. A study on the observation of the collisionless heating by the inductive field was investigated in the RF biased system (asymmetric CCP). A significant heating of low energy electrons was seen in the E mode and it indicates that collisionless heating in the skin layer is an low energy electron heating mechanism, even in the E mode of the low pressure ICP. The combined effect of collisionless heating by the capacitive and the induced electric fields was also investigated in the Ar/O2 RF biased ICP.