Simulation Of A Radio-frequency Capacitively-coupled Plasma With PIC/MCC Method

Radio-frequency (RF) capacitively coupled plasma etching in integrated circuit manufacturing is well recognized for its anisotropy, and the study of this plasma processing is therefore of great interest.The discharge process of single-frequency capacitively coupled plasma in argon gas has been investigated by 2-dimensional PIC/MCC method. At the beginning, the PIC/MCC calculating flow is analyzed, then the detailed examination has been carried out of plasma density, Electrical Field and potential, and the difference of the electron density and electric potential distribution in changed voltage, frequency and pressure has been discussed. The result shows that the rf voltage, frequency and pressure influence the density and potential deeply. Furthermore, the effect of various gas pressure, driven voltage and frequency on ion energy distribution (TED) and ion angle distribution (IAD) at the electrode is studied. It is found that when the gas pressure grows, the peak of energy decreases and the incident angle becomes larger. In the contrast, when the driven voltage grows, the peak of energy increases and the incident angle becomes smaller. When the driven- frequency grows, the relative number of high energy ions increases with a consequent decrease in the number of low energy ions, so the peak of energy decreases and the high energy ions distribution increase clearly.In the process of capacitively coupled plasma (CCP) etching, normally we put a radio-frequency source of 13.56MHz to the substrate. However, this single rf source discharge will not solve the confliction between generating high density plasma and etching rates. Recently, a dually rf driven CCP at widely different frequencies have been extensively studied. In this work, the discharge process of 1-dimensional dual-frequency CCP has also been simulated. The plasma discharge parameters and the ion energy distribution in Variation of Low-Frequency Voltage have been presented. The result shows that the low-frequency controls the ion energy which is an important factor in etching process.