Effectiveness of a High-Velocity-Type Laminar Air Curtain Device for Moisture Isolation Under EFEM Airflow Deflection During FOUP Door Opening

Abstract

As semiconductor manufacturing advances toward the 3 nm node and beyond, wafer sensitivity to particulate and moisture contamination becomes increasingly critical. During front opening unified pod (FOUP) door opening, airflow disturbances and deflection from the equipment front-end module (EFEM) can lead to the intrusion of external moisture and airborne molecular contaminants (AMC), potentially degrading wafer surface integrity and process yield. To address this, a high-velocity-type laminar air curtain device (HV-LAC) was developed using a low-pressure-drop PTFE filter combined with an airflow deflector and perforated plate. This design overcomes deformation and particle-shedding issues seen in conventional ultra-high molecular weight polyethylene (UPE) panels under high flow rates, while improving flow uniformity and barrier stability. The HV-LAC achieved a maximum outlet velocity of 0.54 m/s, maintained velocity non-uniformity around 10% across all flow conditions, and met ISO Class 1 cleanliness. Performance evaluation was conducted under combinations of EFEM background velocities (0.3, 0.4, 0.5 m/s), airflow deflection angles (0°, 15°, 30°), and curtain velocities (0.35, 0.41, 0.54 m/s), with FOUP purge flow at 130 LPM. Experimental results confirmed that the HV-LAC effectively suppressed moisture intrusion, with FOUP internal relative humidity (RH) maintained below 5% in all conditions. The best isolation was observed when curtain velocity matched EFEM airflow, demonstrating that velocity matching is critical to maintaining barrier integrity. This study offers a quantitative design reference for enhancing FOUP micro-environmental control in advanced semiconductor processes.