Experimental And Simulation Study On Discharge Characteristics Of Low-pressure Dual-frequency Capacitively Coupled Ar/O₂ Plasma

Dual frequency capacitive coupled plasma is etched in integrated circuit because it can independently control ion flux and ion energy,and has simpler structure and lowwer cost.Plasma cleaning has a very wide range of applications.In this paper,argon-oxygen mixed plasma was prepared by DF-CCP device,The high frequency was 94.92 MHz,and the low frequency was 13.56 MHz.The plasma characteristics were investigated with the change of high frequency power?HF?,low frequency power?LF?,air pressure and mixed ratio.In the first part,a stable argon-oxygen mixed plasma was obtained under these conditions of pressure of 50 mTorr and Ar/O₂ of 1:9.The emission spectrum of argon-oxygen mixed plasma was analyzed by emission spectroscopy.The electron temperature was calculated by the double-strength intensity ratio method.The electron temperature,electron density,potential and electric field distribution were simulated by PIC-MC?Partical-in-cell and Monte-Carlo?numerical model.These results show that the numerical results of the electron temperature are in good agreement with the experimental results.The electron temperature decreases with the increase of high frequency power and increases with the increase of low frequency power.The electron density increases with the increase of high frequency power and decrease with the low frequency power increase.The sheath width is greatly affected by high frequency power.Electric field and potential peak are greatly affected by high frequency power.In the second part,when the low-frequency power and high-frequency power are fixed at 60 W,the discharge spectrum of the argon-oxygen mixed plasma at different pressures and different Ar/O₂ ratios is also analyzed by emission spectroscopy.The electron temperature was calculated by the intensity ratio method.By using the PIC-MC numerical model,the electron temperature,electron density,potential and electric field distribution were obtained.These results show that the numerical results of the electron temperature have same trend with the experimental results.The electron temperature decreases first and then increases with the increase of gas pressure,and decreases linearly with the increase of Ar content.The electron density increases first and then decrease with the increase of gas pressure,linearly increases with the increase of Ar content.The relationship between air pressure and sheath is obvious,and the sheath becomes thinner with the increase of air pressure;the peak of electric field potential is greatly affected by air pressure.In this paper,the combination of experimental and numerical simulation methods is used to systematically study the discharge characteristics of mixed plasma when different experimental parameters,and provide basic research for the next step to generalization and application.