Numerical simulation study of the flow and diffusion characteristics of trace gas in a gas mixture based on the ellipsoidal statistical Bhatnagar–Gross–Krook model

Rarefied gas mixture flow is widely applied in aerospace, microelectronics, and vacuum technologies. Dynamic gas lock (DGL) technology introduces clean gas to effectively suppress the diffusion of pollutants into the optical region. It is typical flow of rarefied gas mixture, thereby achieving isolation and control of the pollutants. Previous DGL simulations commonly used the direct simulation Monte Carlo method, but its computational cost grows rapidly at high-flow rates; this study adopts the ellipsoidal statistical Bhatnagar–Gross–Krook method to efficiently simulate rarefied gas flow in DGL, addressing challenges under high mass flow conditions. The current work investigates the effects of different gas mass flow rates (0–1000 SCCM), DGL width, distance between the wafer and DGL, and DGL cone angle on the zero-flow pressure ratio, suppression ratio, and decompression ratio. The results indicate that increasing the mass flow rate of clean gas significantly enhances the pollutant suppression performance of the DGL and reduces pollutant intrusion. When the flow rate is increased by a factor of 20, the suppression rate improves by approximately 181 times. With a reduction of 2.2 mm in DGL width, the zero-flow pressure ratio increases by 50%, and the suppression rate improves by 49.46%. When the distance between the wafer and DGL is reduced by 6 mm, the zero-flow pressure ratio increases by 15%, and the suppression ratio increases significantly by 2712.4%. On the other hand, when the DGL cone angle is 22.62°, the zero-flow pressure ratio decreases by 42%, yet the suppression rate still increases by 3601.3%.