某彩色濾光片廠濕式蝕刻區硝酸氣體污染改善研究

Abstract

本研究目的在於改善彩色濾光片廠濕式蝕刻區之硝酸氣體逸散污染情形。首先藉由區域採樣分析找出硝酸氣體產生源--蝕刻液恆溫貯槽，然後在貯槽上方加裝抽氣通風管線以改善污染，最後再經由作業環境測定確認改善情形。研究結果發現經加裝抽氣管改善通風後、且在作業區出入門關閉時，作業區之硝酸濃度可由最高的129.9 ppbv 降至37.0 ~ 41.7 ppbv的濃度，改善幅度可達68 ~ 72 ％左右，顯示花費不大的抽氣管路的裝設對於作業環境的改善助益很大。 本研究進一步研究蝕刻作業區出入門的開啟是否可以進一步降低硝酸的濃度。結果發現出入門開啟時最大硝酸氣體濃度為32.5 ~41.6 ppbv，與關閉時的37.0 ~41.7 ppbv並無太大差異。由此可證明，作業區域出入門的開啟並無法再降低硝酸氣體濃度，藥液恆溫貯槽的通風改善才能達到預期的改善效果。

The purpose of this study is to reduce the pollution of nitric acid gas in the wet etching area of a color filter plant. First, area sampling and analysis was conducted to find out the source of nitric acid pollution--constant temperature etching liquid storage tank. Then a ventilation duct was installed at the top of the storage tank to reduce the pollution. The improvement was confirmed by workplace sampling and analysis again. It was found that the maximum nitric acid gas concentration was reduced from 129.9 to 37.0 ~ 41.7 ppbv, or a 68-75 % reduction when the access door to the etching area was closed. That is, the installation of the ventilation duct is effective for the reduction of the nitric concentration at a nominal cost. To study whether the opening of the access door to the etching area was effective to reduce the nitric acid concentration further, sampling and analysis was conducted again. It was found that the nitric acid concentration ranged from 32.5 ~ 41.6 ppbv when the access door was opened. This value is not too different from the concentration of 37.0 ~ 41.7 ppbv when the door was closed. This further indicates that the reduction of nitric acid pollution is mainly achieved by the ventilation improvement of the liquid storage tank.