迷你環境潔淨室內空氣流場及微粒濃度控制分析

Abstract

對於現今高科技包含半導體、光電等工業生產環境的嚴格要求，封閉製程空間概念為另一種值得考量可行的方法。基於此種概念的迷你環境潔淨室，不但比一般傳統潔淨室更節省能源，且可提供更為妥善的製程環境，極具彈性和省去不少操作和成本的花費。 本文利用STAR-CD套裝軟體，來研究不同外型輪廓迷你環境潔淨室內的流場和微塵粒子控制。採用有限容積法，探討三維空間的迷你環境潔淨室，並求出空氣速度、溫度場分佈、濃度場分佈和粒子軌跡等結果，以做為新設計改變的依據。期望使新的迷你環境潔淨室設計，能夠具有增強潔淨效率的氣流。特別是能避免製程中會聚集粒子的迴流區域產生，且可常保持與外界正壓差的狀態，以預防污染物的進入。 研究結果顯示，迷你環境潔淨室可藉由進口氣流速度值的強弱及進口面積之大小，控制危險氣體之污染區域範圍。及改變進口氣流強弱，亦可以解決在需室內擺設發熱設備機台的問題，以減少室內因自然對流現象造成之迴流區的發生。而不同大小的微塵粒子在相同流場中之運動軌跡也不同，採用適當進口氣流分佈，可以解決在室內會堆積微塵粒子的問題

The application of mini-environment clean room for the reduction and control of particulate contamination level has progressed from the development and evaluation stages to its current status as a preferred alternative for new high technology manufacturing facilities. Yield improvement, reduced operating cost, efficient use of floor space, reduced gowning cost, and great productivity are some of benefits derived from this technology. The objective of this research is to study the flow field and airborne particles control in non-rectangular mini-environment clean room by the computer software STAR-CD. The three-dimensional code used to predict the air velocity, concentration distribution and the particle traces based on a finite volume approach. The results prompted a design change. The new design is shown to have a desirable airflow for a more effective performance in mini-environment clean room. The traces of particles with different sizes are different in the same turbulent flow. And particular attention was paid to air re-circulation zones that could potentially trap particles generated during the process.