Investigating the Influence of Different Diverter Pipes on the Humidity for FOUP by Using Computational Fluid Dynamics

Maintaining a controlled environment is essential for preserving wafer quality and manufacturing yield, as humidity, oxygen, and airborne contaminants can degrade wafer surfaces during fabrication and storage. Computational fluid dynamics (CFD) simulations based on the k–ε turbulence model were applied to reduce relative humidity inside a front opening unified pod (FOUP) using clean dry air (CDA) purging. A guiding duct was designed to enhance CDA circulation between wafer layers, and the influences of duct geometry and perforation configuration on flow distribution and dehumidification performance were systematically evaluated. The results indicate that increasing the number of perforations improves gas intake, while enlarging the duct diameter increases flow rate and suppresses jet effects, leading to improved flow uniformity and moisture removal. An optimized configuration combining an expanded duct with a 25-hole design achieves an average internal humidity of 3.2%, approximately 5% lower than that of a conventional cylindrical duct. These findings provide a clear direction for future FOUP design optimization and support humidity control strategies that can reduce average internal moisture levels, thereby improving process yield and enhancing production capacity in semiconductor manufacturing.