Effects of coil structure and electromagnetic shielding on plasma distribution and uniformity in large-area radio-frequency inductively coupled plasmas

Abstract Improving plasma uniformity is a critical issue in the development of large-area radio-frequency (RF) inductively coupled plasma (ICP) sources. In this work, the effects of coil structure and electromagnetic shielding on the spatial distribution and uniformity of the plasma are systematically investigated using a three-dimensional fluid model. The model integrates plasma and electromagnetic field modules to simulate the discharge characteristics of a large-area RF ICP source with dimensions of 100 cm × 50 cm. The results reveal that the electron density distribution varies significantly with the coil structure. For the rotating and translating coil structures, the electron density is high at off-axis positions and low at the center. In contrast, the mirror coil structure exhibits a significantly higher electron density at the chamber center, resulting in a high-center and low-edge density distribution. Among the three configurations, the rotating coil structure provides the best plasma uniformity. The incorporation of electromagnetic shielding further improves plasma uniformity, particularly for the mirror coil structure. For the rotating and translating coil structures, the electron density exhibits a saddle-shaped distribution regardless of electromagnetic shielding. However, introducing electromagnetic shielding into the mirror coil structure reduces the electron density at the chamber center and decreases the non-uniformity degree by 18.4%. Overall, the mirror coil structure with electromagnetic shielding achieves the highest uniformity, with an exceptional plasma uniformity of 94%. This work offers valuable insights for the design of large-area ICP sources in advanced plasma processing systems.