全氟化物因為具有穩定、安全、不自燃、低毒性以及常溫下不易起化學反應等優點，自從1930年代發明以來，被廣泛應用於工業生產，尤其是半導體製程。但是全氟化物中的氟原子與碳、氮、硫之間的分子鍵有很強的紅外光吸收能力，會造成溫室效應的日益嚴重。因此，如何有效控制溫室效應氣體的排放以減緩地球暖化趨勢，已成為世界各國之科學家努力研究的目標。 以半導體業來說，他們面對PFCs的排放控制有幾個策略，包括採用替代的化學物、回收再利用以及破壞削減等方法。而相較於替代化學物之開發不易，回收再利用的高成本，破壞削減是現階段比較可行的方向。而破壞削減的方式有燃燒破壞、觸媒熱裂解以及電漿破壞。本研究選擇具有高溫(中心溫度可達3,000℃以上)且低耗能(相對於燃燒法)等特點的電漿技術，再結合有降低活化能特質的觸媒技術，期能獲得高效能且省能源的解決途徑。 研究結果顯示在300 ℃下，Ni觸媒以及Pd觸媒分別在氧氣添加量為9.5%以及不加氧氣的條件下，對於轉化NF3都有良好的轉化率，如併用電漿，效果可再提升20 %以上；除此之外，加上電漿可以減緩觸媒經過時間轉化率下降的趨勢。能量效率方面，在此粗略估計實際應用在反應器的能量若能佔整個系統能量的18 %以上，電漿結合觸媒就會比單純使用觸媒具有競爭力。 產物方面，無論是電漿破壞或者是觸媒轉化，主要產物皆為NO、NO2以及N2O，對照最終產物以及反應速率常數，大致推測NF3的氧化途徑，但是因為氟化物監測上的困難，所以不甚完整，仍待後續研究深入探討。 Due to their stability, safety and low toxicity, PFCs are widely used in industrial production, especially semiconductor manufacturing processes. But molecular bonds between F and C、N、S have strong capacities on infrared rays absorption, they will aggravate global warming once emitted into the atmosphere. Thus, how to effectively control PFC emissions to alleviate the increasingly deteriorated phenomenon has become the focus of scientific researches. In addition to increasing the efficiency of utilizing PFCs, the semiconductor industry applies alternative chemicals, recovery/recycle systems and abatement techniques. Owing to the difficulty in development of alternative chemicals and high cost in recovery/recycle systems, the abatement techniques have become the primary way to control PFC emissions at present stage. This study investigates the effectiveness of plasma technology which has high temperature (central temperature 3,000 ℃ up) and low energy consumption (compare to burning), combined with catalysis technology which can lower activation energy for NF3 removal. Results of the study indicate that both Ni and Pd catalyst are good at destroying and removing NF3 in 300 ℃. Destruction and removal efficiency of NF3 can be enhanced by more than 20 % if combined with plasma. Besides, poison of the catalysts can be alleviated with plasma on. As for the energy efficiency, if more than 18 % of the input energy is devoted to the reactor, plasma combined with catalyst has a higher energy efficiency compared with catalyst-only cases. Major products detected in this study include are NO、NO2 and N2O for both plasma and catalysis destruction of NF3. Due to the difficulty of fluoride measurement, products analysis is not complete in this investigation, further studies are needed to better understand the reaction mechanisms.
