ELECTRONEGATIVE ION CONTROL CAPACITY IN A CAPACITIVELY COUPLED PLASMA REACTOR WITH ARGON/OXYGEN PLASMA DISCHARGE UTILIZING CUSTOM VOLTAGE WAVEFORM*

Modern semiconductor fabrication necessitates plasma etching with control approaching the atomic scale to meet industry demands. In plasma etching, electronegative gases are often used because of the chemically reactive radicals they produce, but the presence of negative ions can influence the plasma dynamics. Custom voltage waveforms in a dual frequency capacitively coupled plasma (CCP) reactor can provide unprecedented and precise control over ions.

In this study, mixtures of argon and oxygen gas in a CCP are investigated with computational modeling for various applied custom waveforms. A particle-in-cell Monte Carlo Collision (PIC-MCC) code, EDIPIC, was used to study the CCP. The plasma dynamics, such as the plasma potential and sheath behavior, change in the presence of negative ions. The ion energy distribution and electron energy distribution in the presence of attachment reactions will also be explored. The impact of the high frequency (60 MHz) voltage amplitude will also be studied. The custom voltage waveform amplitude is varied, and the impact of potential atomic layer etching processes is discussed. The effect of the Ar/O₂ ratio on the ion angular distribution and electron energy distribution will also be explored.