Three-Dimensional Flow Analysis and Humidity Level Evaluation for a FOUP During Open Door Operation Conditions

Controlling moisture content during silicon wafer fabrication is essential to maintain good product quality, minimize undesired defects, and improve the performance of the manufacturing process. This study investigated the 3D air flow patterns and relative humidity (RH) distribution within a Front Opening Unified Pod (FOUP) used in semiconductor manufacturing. Two purging techniques were evaluated: the diffuser purge method and the diffuser & laminar air curtain (LAC) purge method, to determine their effectiveness in moisture removal when the FOUP door is open under varying flow rates. Computational Fluid Dynamics (CFD) simulations using the Large Eddy Simulation (LES) model were conducted to analyze air flow behavior and RH levels, and the numerical results were validated through experimental measurements using humidity sensors embedded in dummy wafers. The findings demonstrate that the integrated diffuser and LAC purging strategy is a highly effective solution for maintaining low humidity levels in FOUPs, thereby enhancing cleanliness standards critical to semiconductor fabrication.