SMuK 2023 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 1: Low Pressure Plasmas and their Application I

P 1.6: Vortrag

Montag, 20. März 2023, 12:30–12:45, CHE/0089

Investigation of capacitively coupled radio frequency Ar/CF₄ discharges using a hybrid PIC/MCC simulation — •Katharina Nösges, Maximilian Klich, Sebastian Wilczek, and Thomas Mussenbrock — Ruhr University Bochum, Germany

Capacitively coupled radio frequency (CCRF) discharges are used in many dry etching processes in the semiconductor industry to realize micro- and nanometer-scale electronics. Low pressures of a few Pascal and voltages of about hundreds of volts are required to ensure anisotropic ion bombardment. Especially carbon tetrafluoride (CF₄) and mixed (Ar/CF₄) discharges are particularly important for etching. These discharges are investigated using a one-dimensional hybrid particle-in-cell/Monte Carlo collisions (PIC/MCC) simulation in the low-pressure regime (p = 6.67 Pa) with the inclusion of realistic particle-surface interactions. This approach considers the electrons kinetically and simultaneously solves the continuity equation based on the drift-diffusion approximation for all ion species. The transport coefficients, as well as the rate coefficients, can be determined with the help of swarm simulations. A closed group of particles moves in a background gas influenced by an externally applied constant electric field. The collective behavior gives information about transport features and collision probabilities. A variation of the electrode gap size and the applied voltage is then presented as a control tool to alter the discharge dynamics significantly. Additionally, it is shown that surface coefficients (i. e., electron reflection, and secondary electron emission) play a significant role.