半導體廠維修作業勞工有害氣體溢散調查

The Evaluation of Hazardous Gases Emission from the Preventive Maintenance Procedure in Semiconductor Factory

本研究主要是進行半導體廠內有害氣體之偵測¸以霍氏紅外光譜偵測儀進行的量測顯示，每間隔一段時間，會有一濃度尖峰值出現。經進一步調查後得知¸金屬蝕刻機台進行預防保養時¸當作業人員以去離子水或異丙醇擦拭機台之反應腔時¸即會產生高濃度之氯化氫蒸氣，如製程中使用含氮原子的氣體進行反應，在進行預防保養擦拭時¸則會產生氰化氫¸兩者之最高瞬間濃度可能超過法定最高容許濃度。其發生主要原因為金屬蝕刻時利用電漿加速氯與鋁結合¸而產生三氯化鋁¸在進行預防保養時遇水即會產生氯化氫﹔氰化氫的產生則是氮與碳受到電漿的影響而結合產生氰化物¸遇酸性環境而產生氰化氫。

This study presents an exposure survey of toxic gases in semiconductor wafer manufacturing plants. Periodical peak exposures were detected by FTIR in metal etching operation. Further investigation showed that high exposure of hydrogen chloride was found in preventive maintenance of metal etching when de-ionized water or isopropyl alcohol was used to clean up the reaction chamber. When nitrogen gas existed, hydrogen cyanide gas was detected. In both situations, the peak exposures were higher than the Permissible Exposure Limits-Ceiling. It was believed that plasma accelerated the chemical reaction of chloride and aluminum. The aluminum chloride produced, then further reacted with water to generate hydrogen chloride. Through the similar mechanism, plasma accelerated the reaction of carbon and nitrogen, then got the cyanide compound. The cyanide compounds then reacted with acid to generate hydrogen cyanide.