Abstract: Extreme ultraviolet lithography technology represents one of the most advanced semiconductor manufacturing processes. However, during this process, hydrocarbon compounds and water vapor are generated through material outgassing and photo-induced physical-chemical reactions, which can infiltrate the projection chamber and result in carbon deposition on multilayer mirrors' surfaces. This phenomenon significantly impacts product quality while also increasing costs associated with component replacement and maintenance. The introduction of clean gas via a gas lock structure effectively mitigates the diffusion process of pollutants, thereby offering a viable technical solution. In this study, simulation and orthogonal experiments were conducted to investigate the flow rate and temperature of clean gas as well as pollutants under different gas lock structures. The suppression rate parameters for pollutants by gas locks under varying process conditions were determined. These research findings provide a numerical basis for designing gas lock structures, selecting parameters for process experiments, and offer valuable insights into controlling pollution sources within similar vacuum environments.