Effect of plate thickness on particle deposition velocity onto a face-up flat plate situated parallel to an airflow

The effect of plate thickness on particle deposition velocity onto a face-up flat plate in a parallel airflow was examined both numerically and experimentally. Plate thickness was varied as 0.05, 0.925, 2.3, and 6.35 mm, by considering flat plates of negligible thickness, 450 mm wafers, 5 in photomasks, and 6 in EUVL photomasks, respectively. Statistical Lagrangian particle tracking (SLPT) model with the use of commercial codes was employed. The SLPT model was validated by comparing the numerically obtained particle deposition velocities with either the theoretically predicted or the experimentally determined particle deposition velocities, for the flat plates of various thicknesses. Then, the effect of plate thickness on particle deposition velocity onto the face-up flat plate in a parallel airflow was investigated by employing the SLPT model. It was found that the effect of plate thickness should be taken into account, when the particle deposition velocity onto a 5 in photomask (2.3 mm thick) or a 6 in EUVL photomask (6.35 mm thick) was considered. However, it was anticipated that the effect of plate thickness was insignificant, when the particle deposition velocity onto a 450 mm wafer was taken into consideration.