Investigation of the complex 3D flow structure within a front opening unified pod (FOUP) semiconductor wafer carrier*

Minimizing moisture infiltration into a front opening unified pod (FOUP), which is a semiconductor wafer carrier, is crucial in suppressing surface defects. Moisture reacts with airborne molecular contaminants (AMCs) on the wafer surface, creating residual particles that cause defects. Wafers are transported between various processes by the FOUP and enter through the equipment front end module (EFEM). During this procedure when the door is open, the FOUP is inevitably exposed to moist air coming from the EFEM. Thus, nitrogen gas is used to purge the FOUP to reduce humidity and AMCs. To enhance purge performance, it is essential to understand the complex flow structures within the FOUP-EFEM system. This study analyzes the 3D flow structure within the FOUP-EFEM system using magnetic resonance velocimetry (MRV). Additionally, we conducted a parametric study for various flow conditions using computational fluid dynamic (CFD) simulations. As a result, this study provides a deeper understanding of the purge flow structure and identifies effective methods for defect prevention.