Computational characterization of capacitive coupled HBr/Cl₂/O₂ plasma

Abstract

A self‐consistent two‐dimensional fluid model was used to study HBr/Cl2/O2 plasma discharge. A comprehensive set of 150 reactions comprising different processes (i.e., dissociation, ionization, and excitation) in tandem with 32 plasma species were considered in the computational model. The results revealed that the plasma reactions were dominated by 11 species (i.e., Cl, Cl+, Cl2+, H, H2, HCl, HCl+, Br, Br+, Br2, and HBr+), where the neutral species outnumbered the charged species. The density of charged species in the plasma reactor followed a bell shaped while the neutral species followed a double humped shaped distribution. The increase in plasma O2 concentration resulted in an initial decrease, followed by a gradual increase in the generation of Cl, Br, H, Cl+, and Br+ in the plasma discharge. A lower/higher concentration of oxygen in the plasma stimulated the densities of neutral/charged species, which facilitated the chemical/physical etching pathway. These findings provide new insights into the type of etching species and their optimization in the HBr/Cl2/O2 plasma discharge, with potential applications in the semiconductor industry.