Magnetic field-enhanced ion energy flux and surface cleaning in transformer coupled plasma systems

Transformer coupled plasma (TCP) sources are widely used in etching processes due to their ability to generate low-pressure, highly uniform, and high-density plasma. However, byproducts generated during etching accumulate on chamber walls, degrading plasma reproducibility and increasing both the frequency and duration of cleaning steps, ultimately reducing process throughput. To address this, plasma-based dry cleaning is commonly employed. In conventional dry cleaning processes, however, ion kinetic energies and incidence angles are not actively controlled, which limits further improvement in cleaning performance. In this study, we propose a method to enhance cleaning efficiency in TCP chambers by modulating charged particle dynamics via Lorentz force control through externally applied magnetic fields. Fluid plasma simulations were conducted under various magnetic field configurations to identify efficient field strengths and geometric distributions that enhance ion kinetic energy flux and guide ion incidence angles into the optimal range for wall cleaning. Specifically, the simulations incorporated Maxwell coils installed along the chamber sidewalls to implement realistic magnetic field distributions and verify their effectiveness in controlling ion flux to the chamber walls. Cleaning performance was assessed based on the ion kinetic energy flux and average ion incidence angle on the wall. The results confirm that magnetic field-based control of ion dynamics is an effective strategy for improving the efficiency of plasma-based dry cleaning processes.