Investigation of Ion Energy Distributions with Two Positive Ions in a Dual-Frequency Sheath of Plasma Etching

Abstract

A one-dimensional fluid and Monte Carlo model is developed to study plasma sheath in dual ratio frequency plasma etching. Electrons and two positive ions are considerated. The influence of low frequency, ions mass diversity on IEDs and temperature uniformity of wafer is discussed. The results show that the IEDs are greatly modulated by the low frequency and ion mass, and the maximum and minimum ions energy can be predicted by using damped potential. The two ions with different ion mass affect each other little in IEDs but the total ion flux. The lower ion flux has higher averaged ion energy and the higher ion flux has lower averaged ion energy when keeping the total power fixed. It results in a similar temperature uniformity of wafer.