近年來半導體產品線寬已躍入奈米級要求,意味其產品元件易受到環境品質所影響,一般在半導體工業潔淨室常見的環境污染以氣態分子污染物為主,已有不少案例證實其對晶圓缺陷有直接關聯,包含腐蝕、成形異常或電性異常等問題。潔淨室主要空氣來源為外氣空調箱(MAU)進氣口,其通常位於建築物屋頂或側牆,因此容易受到同樣位於建築物屋頂的煙囪所影響,當煙囪排出廢氣,經由大氣擴散及外氣空調箱的吸引力,重新導入潔淨室內產生二次污染。 本研究透過計算流體力學軟體進行分析,以廠區相關數據建立模型,針對不同天氣型態多種污染物擴散結果進行討論,並預測污染物對外氣空調箱進氣口影響情形。結果顯示,對新建廠外氣空調箱進氣口影響最大者為夏季盛行風,CUP棟則為影響最大者則為夏季靜風;外氣空調箱進氣口位置由外側改至內側,不一定有利於改善進氣口污染物濃度;將緊急電機煙囪位置從側牆改至屋頂時,外氣空調箱污染程度皆比原先位置嚴重。建議未來新建廠可利用模擬結果進行規劃、設計。
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. Result shows that in three different wind direction cases, the summer wind direction heavily affect the four MAU inlets on the newly build FAB roof. The result also shows when relocate the MAU inlets from outside to the inside, the inlet concentration change significantly. It is recommended to design the FAB layout by using the CFD technique as analysis tool in the future.