Gas baffle optimization for CF₄ plasma uniformity in inductively coupled plasma etching: numerical simulations

In this work, a two-dimensional fluidic model of a cylindrical inductively coupled plasma (ICP) source is developed, and the effects of gas baffles on the plasma properties within the etching chamber are investigated. By simulating the electron dynamics and particle transport processes, the effects of the gas baffle on the electron density, F-radical density and plasma uniformity are analyzed. The results demonstrate that the presence of the gas baffle increases the ionization reaction intensity in the upper chamber, with a more uniform plasma density reaching the wafer table surface. Furthermore, it was determined that by adjusting the aperture size, distribution and height of the gas holes in the baffle, the particle distribution in the lower chamber can be optimized, thereby significantly reducing the etching inhomogeneity. For instance, the configuration of gas holes with different apertures, both inside and outside the baffle, has been shown to reduce the etching inhomogeneity from 33.4% to 30%. This study provides a theoretical foundation for the optimal design of gas baffles in etching equipment, with the potential to enhance the uniformity and etching efficiency of the process.