某印刷電路板濕式蝕刻區酸性氣體污染改善研究

Abstract

本研究針對某一印刷電路板濕式蝕刻區裝設的空氣洗滌設備Air Washer，研究其對濕式蝕刻作業區內無機酸性HCl氣體濃度之降低是否有效，並研究Air Washer洗滌液之pH值，對氣體濃度的改善效率之影響。研究結果發現純水洗滌液的pH值在6以上時，HCl氣體的濃度可由Air Washer設備裝設前的最高114.79 ppb下降到裝設後的15.86 ppb，濃度改善效率可達50 % 以上；但當洗滌液的pH值降至5以下，則濃度的改善效率會降低至20 % 以下。另外本研究也發現於純水洗滌液中加入3 % 的NaOH調整洗滌液的pH值在7 ~ 9之間時，HCl氣體的濃度改善效率為90 ~ 95 % ，且濕式蝕刻作業區的HCl氣體濃度可控制在10 ppb以內。由研究結果顯示Air Washer空氣洗滌設備的裝設對無機酸性氣體的去除具有一定的成效，但需維持洗滌液的pH值在7 ~ 9時，才可達到最好的HCl濃度改善效率。

This research was to confirm the effectiveness of reducing the acidic HCl gas concentration in the working environment of the wet etching area of a printed circuit board plant by using an Air Washer equipment. The effect of the pH value of the scrubbing liquid of the Air Washer on the control efficiency of HCl gas concentration was also investigated. The experiment results show when the pH value of the DI water used in the Air Washer is greater than 6, HCl concentration in the wet etching area can be lowered from the maximum value of 114.79 ppb to 15.86 ppb by using the Air Washer. The control efficiency of HCl gas concentration in the etching area is over 50 %. However when the pH value of Air Washer DI water is under 5, the control efficiency of HCl gas concentration is lower than 20 %. When the pH value of Air Washer liquid is maintained between 7 and 9 by adding 3 % of NaOH, HCl gas concentration in the wet etching area can be controlled under 10 ppb and the control efficiency of HCl gas concentration is found between 90 % and 95 %. This research shows that the Air washer equipment can effectively eliminate acidic gas pollution in the etching area, the best control efficiency of acidic HCl gas concentration is obtained when the pH value of the Air Washer scrubbing liquid is kept between 7 to 9.