The Properties Of Dual-frequency Capacitively Coupled Argon-oxygen And Argon-nitrogen Mixture Gas Plasma

Dual-Frequency Capacitive Coupled Plasmas(DF-CCPs)can control the ion flux and energy bombarded on the substrate surface separately.In the process of etching,both the etching rate can be increased and the device damage can be avoided.The plasma processing technology plays an important role in the manufacture of VLSI circuits,and plasma etching is an important technology in plasma processing technology.The basic parameters of plasma include electron temperature,electron density and so on.These two parameters play an important role in the study of plasma characteristics.In the experimental investigation of DF-CCPs,most of the discharge gases are argon,and the oxygen and nitrogen contents have certain significance for the plasma characteristics of argon-oxygen/argon-nitrogen mixture gases.In this paper,the changes of electron temperature and density with high frequency power(HF power),low frequency power(LF power)and gas pressure in argon-oxygen and argon-nitrogen mixed gas discharges are studied.Argon-oxygen mixed gas plasma and argon-nitrogen mixed gas plasma were obtained by dual-frequency capacitively coupled plasma device.The frequency of the high frequency source is adjustable in the range of 10-100 MHz,and the frequency of the low frequency source is fixed at13.56 MHz.In the experiment,the frequency of high frequency source is set to 94.92 MHz.The spectra of plasma were collected by spectrometer and the spectral properties of argon-oxygen and argon-nitrogen mixed gas plasma were analyzed.The Fermidirac model is used to diagnose the electron temperature of plasma,and the absolute intensity method of continuous spectrum is used to diagnose the electron density of plasma.The electron temperature of argon-oxygen mixture plasma increases with the increase of low frequency power,decreases with the increase of high frequency power and decreases with the increase of gas pressure.When other conditions remain unchanged(high frequency power,low frequency power,air pressure),the electron temperature tends to increase with the increase of oxygen content.There is a positive correlation between plasma electron density and high frequency power.With the increase of high frequency power,plasma electron density increases first and then decreases.With the increase of oxygen content,the electrondensity decreases gradually.Argon-nitrogen mixed gas plasma and argon-oxygen mixed gas plasma have similar properties.