Particle-in-cell simulation of electron and ion dynamics in low pressure capacitively coupled plasma discharges operated by pulsed radio-frequency (RF)

In last few decades, Capacitively Coupled Plasma (CCP) discharges have been widely used in semiconductor industry for etching processes. Among the numerous innovative techniques applied in CCP discharges to get high quality uniform etching, pulsed radio-frequency (RF) CCP discharges is one of the renowned method which provide better control over ion fluxes and ion energies. It is also seen that by varying the properties of the driven pulsed power provides extra control over the electron energy distribution function (EEDF) and, subsequently, gives us the ability to tune the ion flux. We have used a 1D/2D Electrostatic Direct Implicit Particle-In-Cell (EDIPIC) code to investigate the electron and ion dynamics of low pressure (of the order of mTorr) argon CCP discharges driven by a high-frequency RF (MHz) power source with a low frequency tailored voltage waveform (kHz). We have observed that by varying input parameters, such as the amplitude of voltage, frequency, duty cycle, and ramp results in non-linear plasma dynamics which significantly changes the plasma properties. We track and present the observed trends in electron and ion distribution functions, power absorptions, electron densities in different energy ranges etc.