Capacitively Coupled Plasma Breakdown: Simulation of Mechanisms, Circuitry, and Dynamics
POSTER
Abstract
This presentation synthesizes comprehensive investigations into radio-frequency (RF) capacitively coupled plasma (CCP) breakdown dynamics across diverse conditions, including Argon (Ar) and Carbon Tetrafluoride (CF₄) gases, pressures from mTorr to Torr, and varying RF frequencies and external circuitry. Utilizing primarily one-dimensional (1D) and two-dimensional (2D) implicit Particle-in-Cell/Monte Carlo Collision (PIC/MCC) simulations, with fluid models for specific medium-pressure regimes, elucidating intricate plasma initiation.
Breakdown processes are characterized through distinct pre-breakdown, breakdown, and post-breakdown phases, with focus on particle/power balance. Secondary Electron Emission (SEE), especially electron-induced SEE (ESEE), is critical at low pressures and high frequencies (e.g., 60 MHz), revealing glow, multipactor (normal/abnormal), and various failure modes (e.g., BFD, RFD).
External circuitry (e.g., L-type matching networks ) significantly impacts breakdown. Sheath formation dynamically alters plasma impedance and CCP equivalent capacitance, affecting circuit signals and harmonic generation. Matching optimization shows pressure-dependent effects. CF₄ discharges exhibit distinct pressure-dependent mode shifts.
2D simulations reveal spatial non-uniformities, electrode edge effects, and unique reversed breakdown patterns at very low pressures (e.g., 50 mTorr Ar). EEPF analysis shows non-Maxwellian distributions. Electrode self-bias evolution and detailed energy transport (absorption, flow, dissipation) are also investigated. These insights are crucial for optimizing industrial plasma processes (etching, PECVD), enhancing uniformity, and advancing gas discharge physics.
Breakdown processes are characterized through distinct pre-breakdown, breakdown, and post-breakdown phases, with focus on particle/power balance. Secondary Electron Emission (SEE), especially electron-induced SEE (ESEE), is critical at low pressures and high frequencies (e.g., 60 MHz), revealing glow, multipactor (normal/abnormal), and various failure modes (e.g., BFD, RFD).
External circuitry (e.g., L-type matching networks ) significantly impacts breakdown. Sheath formation dynamically alters plasma impedance and CCP equivalent capacitance, affecting circuit signals and harmonic generation. Matching optimization shows pressure-dependent effects. CF₄ discharges exhibit distinct pressure-dependent mode shifts.
2D simulations reveal spatial non-uniformities, electrode edge effects, and unique reversed breakdown patterns at very low pressures (e.g., 50 mTorr Ar). EEPF analysis shows non-Maxwellian distributions. Electrode self-bias evolution and detailed energy transport (absorption, flow, dissipation) are also investigated. These insights are crucial for optimizing industrial plasma processes (etching, PECVD), enhancing uniformity, and advancing gas discharge physics.
*This work was supported by the National Natural Science Foundation of China (12275095 and 11975174).
Publication: [1] Z. Chen, Z. Chen, H. Wu, D. Xia, W. Jiang, and Y. Zhang, Two-Dimensional simulation of capacitively coupled plasma breakdown under low-pressure conditions, submitted.