The effect of asynchronous pulse on ion energy and angle distributions in two-dimensional capacitively coupled Ar plasma

As the integration of semiconductors increases, the importance of pulsed plasma in the semiconductor etching process increases. The RF power repeats on and off periods, increasing the uniformity of plasma during the etching process and improving the characteristics of the etching profile. This study investigates the pulsed 40MHz high-frequency (HF) and 400kHz low-frequency (LF) power to the top and bottom electrodes of a capacitively coupled plasma. We investigate the effect of pulse synchronization from two power sources using a two-dimensional GPU-based particle-in-cell simulation. The changes in plasma potential, electron density, and ion flux are analyzed by delaying the pulse-on time of the LF source compared with the HF source. The etch rate is estimated by measuring the ion energy and angle distributions (IEADs) at the center and edge of the electrode. In the IEADs, LF and HF pulsing preferentially form the high-energy and low-energy ions. Adjusting the asynchronous time changes the sheath oscillations; thus, it is possible to control the IEADs.