近年來電子半導體產業的發展與技術十分快速，且潔淨度決定了微電子產品的最終特性與良率，因此，也提高了環境潔淨度的要求。由於微塵粒子很小，它的散佈與移動可以由流場的分佈來判定，所以，有關如何有效控制氣流場，使污染微粒順利排出，亦成為無塵室廠務設計的重點。本研究獲得的結果，不僅對無塵室設計有所助益，對於以CFX模擬程式分析無塵室內的流場變化，也能提供有用的資料。
本研究藉計算模擬程式CFX 4.2對無塵室進行分析，建立符合真實的無塵室尺寸大小及環境規範的模型。以穩態條件下，探討進風口排風的速度、風向，進風口的面積大小，機台設備形狀以及發熱源的熱通量的大小、位置，所造成的效應進行整個流場分析。亦以暫態條件下，針對當無塵室的跳電時，進風口停止送風而進口速度減小，和機台停止運轉而表面熱通量減小，分析整個流場的影響。在暫態分析過程中，利用CFX模擬程式的暫態分析模式以及使用者副程式協助設定，以分析整個流場對時間的變化。因此，暫態模式及使用者副程式的探討和使用亦為本研究所著重部分。

經模擬分析結果得知，當進風口速度及進風口面積越大時，其天花板非進風口處的渦漩區越大；若機台有突出尖角時，會造成機台側邊產生渦漩區；當機台上方的熱通量越大，其產生的渦漩區範圍和迴流速度越大。進風口風量改變時，原本已穩定的流場無法繼續維持，導致在機台側的渦漩區內的微塵粒子擴散開來，散佈整個無塵室，造成嚴重的污染。經由暫態分析得知，暫態到達穩定後的解與穩態分析的收斂解大致相同。

The technology development in semiconductor devices has been a fast growing business recently. The final performance of a device depends on how effective air cleanliness control is done in a clean room. Because the particle’s size is so tiny that it’s motion and diffusion can be directly determined by the airflow distribution. Therefore, the means of circulating air to remove these pollutant particles effectively is the major issue in clean room design. The results from the present thesis provide detail airflow field distributions that are important for a clean room design.
In the present thesis, we use the computational fluid dynamics code, CFX 4.2, to analyze airflow distributions in clean rooms. We build the model that is conformable to the size and environmental standard for a real clean room. Under steady state, we examine the effects of the inlet velocity, flow direction, inlet dimensions, machine platform shape, the quantity and location of heat flux. In the transient condition, we examine the effects of the inlet velocity and machine platform heat flux when they vary.

From our simulated results, we noticed that when the inlet velocity is large, the vortex region is wide in the non-inlet area. The vortex is produced at the machine platform side with a sharp corner. If the heat flux is large, the vortex region and velocity are large on top of the machine platform. Because the steady airflow field can’t hold when inlet velocity changes, the particles diffuse outward from the vortex region at the machine platform side. These transient analyses were investigated with user-supplied subroutines and we have successfully demonstrated the consistencies between transient and steady state cases.

參考文獻
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