Study On The Discharge Characteristic Of Very High Frequency Capacitively Coupled Argon Plasma

In recent years,low-temperature capacitively coupled plasma has been widely used in industry,especially in the field of microelectronics industry,and technologies have become more mature.The discharge characteristics of capacitively coupled plasma are a key factor in promoting large-scale industrial applications.Based on the complexity of the discharge characteristics,it is particularly important to study the discharge characteristics under various conditions.This paper discusses the discharge characteristics of capacitively coupled argon plasma with the increase of power and pressure at four driving frequencies by collecting emission spectra and PIC/MCC numerical simulation.At four different frequencies(13.56 MHz,40.68 MHz,94.92 MHz and 100 MHz),when the power is increased from20 W to 70 W,the electron temperature all show a downward trend while the electron density all show an upward trend,meanwhile,the potentials gradually rise high,the width of the sheath increases,and the population of high-energy electrons gradually rises.When the driving frequency gradually increases,the plasma parameters show a non-linear change.The electron temperature first rises and then decreases,with a maximum value at a frequency of 40.68 MHz;while the electron density and sheath potential first decrease and then rise,with a minimum value at a frequency of 40.68 MHz.When the frequencies are 13.56 MHz and 40.68 MHz,the electron energy probability distribution function is a bi-Maxwellian distribution;when the frequencies are 94.92 MHz and 100 MHz,the electron energy probability distribution function is nearly the Maxwell distribution.At four different frequencies,when pressure is lower(?30 m Torr),the electron temperature showed a downward trend with the increase of pressure,and the electron density showed an upward trend at a lower frequency and a downward trend at a higher frequency;When the gas pressure is higher(> 30 m Torr),the electron temperature has a different trend at each frequency,and the electron density has a small change range;the electric potential of the bulk plasma gradually decreases with the increase of the pressure,and the trend changes under higher pressure gradually flatten out.However,the electron energy probability distribution function does not change significantly.In addition,the PIC/MCC simulation results are in good agreement with the experimental results,and the change trend of electron density is consistent under the same discharge conditions.