Investigating the plasma dynamics of capacitive discharges driven by pulsed radio-frequency (RF) at low-pressure using particle-in-cell simulation*

Capacitively coupled plasma (CCP) discharges have been widely used in semiconductor industry for etching processes over last few decades. Among the various innovative techniques applied in CCP discharges to get high quality uniform etching, pulsed radio-frequency (RF) CCP discharges is one of the well-known method which provide finer control over ion fluxes and ion energies. It is also observed that 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. In this work, we use a 1D/2D Electrostatic Direct Implicit Particle-In-Cell (EDIPIC) code to investigate the plasma 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, densities in different energy ranges etc.