彩色濾光片廠UV清洗機臭氧逸散調查及改善研究

Abstract

彩色濾光片(Color filter,CF)製程對Indium Tin Oxide (ITO)玻璃上之潔淨度要求非常高。玻璃清潔主要使用低污染、高時效之Ultraviolet (UV)清洗機進行，它係利用紫外光子對有機物質所起的光敏氧化作用以清洗黏附在玻璃表面上的有機化合物，但在清洗過程中會因光敏氧化作用而產生具刺激氣味之臭氧毒性氣體，並隨著UV清洗機反應腔出片過程逸散至潔淨室，造成勞工健康危害。本研究主要目的在研究彩色濾光片廠UV清洗機作業環境臭氧逸散濃度分佈情形，藉由煙霧可視化，調查臭氧逸散煙流走向，並以MDA毒性氣體偵測器(Scientific ChemKey TLD-1, Zellweger Analytics, England)搭配化學紙帶進行臭氧逸散濃度量測，量測點為勞工個人工作站之呼吸帶及UV清洗機台出片端。MDA毒性氣體偵測器偵測數值每分鐘有一筆數據，另外為調查勞工實際暴露八小時日時量平均濃度，並比對TLD-1毒性氣體偵測器偵測數值之差距，本實驗再採用美國勞工安全衛生處(Occupational Safety & Health Administration, OSHA)公告之採樣分析方法ID-214進行實驗。在UV清洗機作業環境之偵測結果顯示，不論是MDA TLD-1毒性氣體偵測器或OSHA ID-214採樣分析方法，作業勞工臭氧暴露濃度皆高於勞工作業環境空氣中有害物容許濃度標準-八小時日時量平均容許濃度的100ppb，且UV清洗機台出片端更遠高於此標準。本研究結果顯示，為減少作業環境下UV清洗機臭氧逸散濃度，若同時密閉兩台UV清洗機出片口之輸送機上方開孔，使其臭氧不直接逸散至作業環境，而直接經由UV清洗機反應腔排氣系統及無塵室迴風系統稀釋後排出，則可降低作業環境臭氧濃度34%~64%，至符合標準的40~88 ppb。

Process of Color Filter (CF) sets high standard for the cleanness of Indium Tin Oxide (ITO) Glass. Glass is cleaned mainly by low pollution, highly efficient Ultraviolet (UV) equipment. UV equipment makes use of photosensitive oxidation of organic matter on glass surface by ultraviolet light. During cleaning process, photosensitive oxidation produces ozone toxic gas, which is diffused into the Clean Room when the glass comes out from reacting cabin of UV equipment, posing health hazard to the operators. The main purpose of this study is to examine the concentration distribution of emitted ozone in the work environment of UV equipment in a Color Filter plant. A fogger was used to visualize the direction of ozone-laden air flow. MDA toxic gas detector (Scientific ChemKey TLD-1, Zellweger Analytics, England) with chemical paper was used to measure the emitted ozone concentration at the breathing zone of operators and the exit of the UV equipment. MDA toxic gas detector output data every minute. In addition, the sampling and analysis method of (Occupational Safety & Health Administration) ID-214 was used to measure the 8-h time-weighted average ozone concentration and compared with those measured by the MDA detector. This study showed that the workers’ exposure concentrations measured by the MDA detector or OSHA ID214 all exceeded the current exposure 8-h time-weighted limit of ozone, or 100 ppb. The exit of UV equipment far exceeded this limit value. If the top covers of the carriers at the exit of two UV cleaning equipments were closed, then ozone was forced to discharge into the exhaust system of the reacting cabin of the UV cleaning equipment and diluted by the recirculation air of the clean room. Ozone concentration in the working area was found to reduce by 34%~64%, and ranged from 40~88 ppb.