Evaluation of the Effects of Geometric Degradation of the Showerhead Nozzle Exit on Process Characteristics in Etching Equipment: A Multiphysics Analysis Approach

Reactive Ion Etching (RIE) equipment widely employs showerhead-type structures to ensure plasma and etching uniformity; however, geometric degradation of the showerhead nozzle exit during prolonged operation may alter the internal chamber environment and thereby affect process performance. In this study, the effects of showerhead nozzle exit geometric degradation on process characteristics were evaluated for a 300 mm wafer-scale RIE system using a multiphysics numerical approach. A total of 16 analysis cases were constructed according to nozzle position and nozzle exit diameter, and Computational Fluid Dynamics (CFD), electrostatic analysis, and particle tracing analysis were performed sequentially using COMSOL Multiphysics. The results showed that increasing the showerhead nozzle exit diameter decreased both the pressure and velocity at the nozzle exit, while increasing the electric potential near the nozzle exit. These changes led to different wafer-level distributions of neutral and charged species. Neutral species were mainly affected by drag-based transport under the flow field, whereas charged species were influenced by both the flow field and the electric potential distribution. Cases with below-range neutral-species distributions occurred more frequently than cases with above-range distributions, and below-range charged-species distributions were concentrated in cases with larger diameter combinations. These findings indicate that geometric degradation of the showerhead nozzle exit can influence wafer-level reactive-species distributions through coupled fluidic and electrical pathways and may contribute to process non-uniformity.