Analyzing the Impact of Inclined Airflow Within the EFEM on the Lateral Flow Around the FOUP Using Flow Visualization Techniques

With rapid advancements in technology, Taiwan has become a global leader in semiconductor manufacturing. Over the past decade, process technologies have continually advanced, reaching the latest 1.2 nm node. However, as feature sizes shrink, the complexity of processes increases, leading to more stringent requirements for the stability of the manufacturing environment. Cleanroom environments have become increasingly critical in semiconductor manufacturing, significantly impacting production capacity and yield. In the equipment front-end module (EFEM), we observed that when the front opening unified pod (FOUP) door is opened, internal pressure differentials can cause air ingress into the microenvironment. This ingested air may carry moisture and oxygen, which, upon entering the FOUP, can damage the wafers, leading to decreased yield. In real-world scenarios, we found that despite the use of laminar air curtain devices, wafer box yields remained unstable due to the influence of inclined airflow. To simulate this situation, our experiment utilized flow field visualization to observe the effects of different air curtain flow rates (0.3 m/s,0.4 m/s and 0.5 m/s) and environmental wind speeds (0.3 m/s and 0.5 m/s) on inclined airflows (7°, 15°, and 30°) when the FOUP door is opened. While flow field visualization provided clear images of airflow directions, it could not determine whether the ingested air contained contaminants harmful to the wafers. Therefore, we supplemented our experiment with relative humidity monitoring data to identify whether the ingested air originated from the external environment or the air curtain device itself, providing effective recommendations based on the findings.