使用數值分析探討半導體廠房製程排氣汙染物排放情形

Numerical Investigation of Dispersion of Pollutant Plumes from Process Exhaust Systems in a Semiconductor Fabrication Plant

李俊儀(Jyun-Yi Lee)

指導教授 ： 胡石政

國立臺北科技大學/機電學院/能源與冷凍空調工程系碩士班/碩士(2012年)

摘要

近年來半導體工業的產品元件線寬已進入奈米等級要求，產品必須仰賴高精密的設計與製造。而製程排氣大多經由屋頂的排氣煙囪排至戶外，然而對潔淨室相當重要的外氣空調箱吸入口，也位於接近屋頂處，容易形成煙囪排出的廢氣經由外氣空調箱吸入口，再引入潔淨室內產生二次汙染。本研究利用計算流體力學套裝軟體進行相關分析，針對此廠之各種不同的條件下，來預測外氣空調箱吸入口汙染物分佈的情形，並對汙染物擴散結果來加以做分析討論。結果顯示，在八種不同風向下的外氣空調箱吸入濃度，以西風的平均濃度為最高，北風的平均濃度為最低。當外氣空調箱吸入口與風向平行，所吸入的汙染物濃度會較小，而吸入口在背風面時汙染物濃度會較高。大氣風速較高之區域，可降低汙染物對其外氣空調箱吸入口的影響與減少對周邊區域的影響，而增加煙囪高度可以有效的減少汙染物進入外氣空調箱吸入口，高度越高汙染物吸入越少。建議新建廠區依此模式建立起合理的製程排氣煙囪高度。

關鍵字

計算流體力學 ； 外氣空調箱 ； 排氣煙囪 ； 汙染物排放

並列摘要

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.

並列關鍵字

Computational Fluid Dynamics ； Make-up Air Unit ； Exhaustion Chimney ； Pollution Exhaust.

參考文獻

[5]ASHRAE STANDARD 62.1-2004, "Ventilation for Acceptable Indoor Air Quality".

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[3]“Cleanrooms and associated controlled environments,” ISO14644-1 First Edition, 1999.

[6]ACGIH (American Conference of Governmental Industrial Hygienists