Performance improvement through CFD and field measurement in a unidirectional airflow cleanroom for wafer manufacture

In wafer grinding processes, maintaining strict contamination control in Class 1 cleanrooms is essential to prevent defects and ensure high product quality. However, achieving optimal unidirectional airflow remains a challenge, necessitating further research to improve cleanroom performance. This study investigates airflow performance and unidirectional airflow optimization in a cleanroom equipped with Ultra-Low Particulate Air (ULPA) filters. To ensure compliance with standards, Testing, Adjusting, and Balancing (TAB) were performed before conducting field measurements. The study explores the impact of varying Fan Filter Unit (FFU) air velocities, perforated floor porosities, and raised floor heights on airflow characteristics and turbulence within the cleanroom. Using Computational Fluid Dynamics (CFD) simulations and field measurements, we assessed FFU air velocities from 0.30 to 0.50 m/s, floor porosities of 17 %, 25 %, and 50 %, and raised floor heights of 400 mm, 600 mm, and 900 mm. The results demonstrated that decreasing FFU air velocity generally improved airflow uniformity and reduced turbulent kinetic energy (TKE), with notable enhancements at lower velocities. Perforated floor porosity had minimal impact on airflow distribution, whereas raised floor height significantly influenced turbulent intensity and airflow patterns. Higher raised floor heights led to smoother airflow and reduced turbulence. These findings underscore the importance of optimizing FFU air velocity and raised floor height to achieve effective cleanroom performance.