Design of plasma strip chamber for uniform gas supply with fluid flow simulation

Abstract

Within the domain of semiconductor fabrication, which entails progressively complex patterning steps, the significance of plasma stripping processes, particularly to achieve the effective stripping of photoresist (PR) without damaging the underlying substrates via uniform gas distribution across 300 mm wafers, cannot be overstated. The efficacy of plasma stripping is influenced by the design of the components of the process chamber, which is critical for advancing semiconductor manufacturing technologies. In this study, we elucidated the influence of the design of a process chamber, particularly the showerhead nozzle angles, on the plasma chemical reactions of radicals emanating from conventional PR equipment using computational fluid dynamics simulations. We assessed the impact of the showerhead design, which incorporated divergent or angled gas supply nozzles, on the distribution of the supply gas across the wafer within the process chamber. Five distinct angles of showerhead nozzles were investigated, and the uniformity of the oxygen mass fractions was optimized for nozzle angles of 45° and 60°. Additionally, the factors contributing to the low uniformity in a showerhead design were identified and design components were modified, resulting in a 16% improvement in uniformity. This study delineated the relationship between the nozzle position, mass fraction, and flow streamlines, thereby establishing the critical role of equipment design for enhancing the plasma stripping process. Furthermore, this principle transcends the realm of stripping equipment design; it is anticipated that incorporating flow dynamics simulations for designing process components will enhance the overall process performance.