| Summary: | 碩士 === 國立臺北科技大學 === 能源與冷凍空調工程系碩士班 === 100 === As the semiconductor technology has shrunk the half-pitch (hp) node into nanometer scales, more attention has been directed toward the yield-affecting influences from the air quality of manufacturing environment. Re-entrainment of potential pollutants into the supply air, which released from the process exhaust system, through the make-up air unit can cause the secondary pollution in the semiconductor fab. In this study, the computational fluid dynamics (CFD) software-FLUENT was applied to investigate the impacts of varying atmospheric wind speeds and directions on the dispersion of pollutant plumes from process exhaust systems in a semiconductor fabrication plant, and the subsequent impacts on the potential of re-entrainment of pollutants into the supply air for semiconductor fab through the make-up air unit. Based on the numerical investigations with eight varying prevailing wind directions, the results showed that the west wind and north wind contribute to the highest and lowest averaged concentration of pollutants at the inlet of make-up air unit, respectively. Besides, it is found that the concentration of re-entrained pollutants into the make-up air unit is relatively lower when the inlet of make-up air unit is setup in parallel to the wind direction. However, the concentration of re-entrained pollutants into the make-up air unit is found relatively higher when the inlet of make-up air unit is installed on the leeward side. The results also demonstrated that the higher atmospheric wind speed helps reducing the dispersion of pollutant plumes to the adjacent regions and the concentration of pollutants at the inlet of make-up air unit. Meanwhile, increasing the height of process exhaust chimney can effectively minimize both the concentration and potential of re-entrainment of pollutants through the make-up air unit. This numerical investigation serves as good references for establishing the reasonable height of process exhaust chimneys for the construction of new fab buildings in adjacent areas to the existing semiconductor fabrication plant.
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