Figure 5: Velocity vectors (ft/min) on a plane 12 cm from the FOUP center toward the center of the minienvironment (a) for case 2 (no nitrogen curtain, FOUP inlet port purge flow rate of 60 L/min); and (b) for case 8 (nitrogen curtain, plenum velocity of 140 ft/min, FOUP inlet port purge flow rate of 60 L/min).