彩色濾光片廠濺鍍機台清潔保養作業時的微粒逸散研究

Abstract

TFT-LCD已成為目前顯示技術之主流，而隨著產值逐漸攀升之際，因製程需要使用到大量的化學品、有毒物質，作業勞工之安全衛生議題也注漸受到大眾之關注，本研究針對TFT-LCD關鍵零組件之彩色濾光片濺鍍製程於進行清潔維護保養時進行採樣分析，探討該作業環境中之有害物質種類及其濃度分佈。本研究利用粉塵質量濃度即時監測儀TSI DustTrak監測背景值，並於濺鍍機台實施清潔維護保養時以旋風式個人採樣器進行採樣，藉以了解作業人員之粉塵暴露值，最後採集腔体上之粉體以微小粉末分散器(SSPD)將粉塵再揚起，並以掃瞄式電動度粒徑分析儀、氣動微粒分析儀及微孔均勻沉積衝擊器進行分析，藉以了解粉體之數目與質量濃度分佈。 本研究於濺鍍機台實施清潔維護保養時進行個人採樣，測得總粉塵平均濃度為0.057±0.038mg/m3，銦金屬平均濃度為0.034±0.015mg/m3，而可呼吸性粉塵測得之平均濃度分別為0.028±0.011 mg/m3。由實驗結果可知作業環境中粉塵濃度值皆能符合國內法規規範。實驗發現以空氣噴槍清潔腔体會導致測值超出SEMI所建議之暴露容許濃度，此清潔方式應該避免。 而以SSPD分散ITO粉體發現，微粒的數目濃度以次微米微粒為主，平均數目中間電動度直徑為180 nm；以質量分佈計，微粒大多為可呼吸性微粒，其質量中間氣動直徑為1080nm。

TFT-LCD (Thin Film Transistor Liquid Crystal Display) has been the mainstream color display technology since the beginning of this century. With rapidly growing market, large amount of chemicals and toxic substances are extensively used in the TFT-LCD industry during the manufacturing process, posing health threats to workers. Therefore, the occupational hygiene and safety problems of the workers deserve attention. The main objective of this study is to investigate fugitive aerosols during the preventive maintenance of the sputtering facility in a color-filter fab. The experiment in this study has three stages. In the first stage, a TSI DustTrak was used to monitor the background level of the particle mass concentration. In the second stage, IOSH (Institute for Occupational Safety and Health) cyclones were used to measure the exposure level of the sputtering workers. In the final stage, the SSPD (Small-Scale Powder Disperser) method was used to disperse the collected particles which were deposited on the wall of the sputter chamber. A TSI SMPS (Scanning Mobility Particle Sizer) and a TSI APS (Aerodynamic Particle Sizer) were used to measure the particle size distributions, and a MOUDI (Multiple-Orifice Uniform Deposit Impactor) was used to measure the mass distributions of the dispersed powders. The exposure level of the operators to the fugitive particles was studied during regular preventive maintenance of the sputtering facility. The average particle concentration was found to be 0.057±0.038mg/m3, and the metallic Indium concentration was 0.034±0.015mg/m3. In addition, the average respirable particle concentration was 0.028±0.011 mg/m3. The results clearly indicated that the aerosol concentration in the current working environment meets the domestic occupational health and safety regulation. However, it was found that using the air blow gun to clean the sputter chamber increased the aerosol concentration which might exceed the exposure threshold value suggested by SEMI. Such cleaning method should be avoided. It was found that particles emitted from the ITO powders were submicron in number distribution with the number median electric mobility diameter of 180nm. In terms of mass concentration, these particles were in the respirable size range with the mass median aerodynamic diameter of 1080 nm.