以WIO-EIO探討半導體業的氫氟酸廢液循環經濟策略對溫室氣體排放之影響

Abstract

台灣半導體業對於台灣經濟體、對於全球半導體製造非常重要，而半導體製程目前仍無法替代氫氟酸的使用，同時氫氟酸的供應、廢棄物處置存在風險。過去，台灣半導體業已經建立氫氟酸廢液的再利用，以人造螢石、鋼鐵業酸洗液、水泥生料的進行再利用。目前半導體製造廠台積電預計設立大型氫氟酸廢液再生合成冰晶石系統，主要目標是處理廢棄物問題。半導體製造廠三星嘗試建立氫氟酸回收廠內重複使用，主要目標是處理供應不穩定的問題。 本研究以廢棄物投入產出-環境投入產出(WIO-EIO)模型，使用產業關聯表、廢棄物生成量、廢棄物處理量、事業溫室氣體排放量，模擬現況(R8b)、再生電子級氫氟酸(R8a)、再生合成冰晶石（國內使用）(R8b)、再生合成冰晶石（國內、出口）(R8b)四種情境。研究結果呈現溫室氣體排放量變化、經濟影響，並輔以資源循環率討論。並討論同品質回收(R8a)、降品質回收(R8b)是否會影響資源循環度，是否符合循環經濟對於經濟效益、環境效益的假設。 結果顯示以台灣範圍進行分析時，再生電子級氫氟酸回用，氟原子的回用比例增加，並可以降低台灣整體經濟的碳排放密集度、增加台灣整體經濟的附加價值率。以再生合成冰晶石（國內使用）回用，則是附加價值率下降、碳排放密集度下降。以再生合成冰晶石（出口）回用，提高附加價值、增加碳排放密集度。結果說明，氫氟酸廢液回收策略從R8b改為R8a，確實使台灣經濟更接近循環經濟，從R8b改為另一種R8b，則不能同時改善環境與經濟。 然而本研究中的進口產品無計算溫室氣體排放，出口再生產品替代國際上的原生產品也沒有計算替代效果。因此結果討論僅限於台灣範圍，後續研究可以增加進出口產品碳排放計算以了解此決策是否助於推動全世界循環經濟。

Taiwan’s semiconductor industry is very important to both the economy of Taiwan and global semiconductor foundry capacity, and semiconductor manufacturing still cannot replace the use of hydrofluoric acid while there are risks of hydrofluoric acid supply and disposal. In the past, Taiwan’s semiconductor industry has established hydrofluoric acid waste recycling as artificial fluorite, pickle liquor of steel industry, cement raw meal. Taiwan Semiconductor Manufacturing Company is planning to build a large-scale hydrofluoric acid waste-cryolite regeneration system, which aims at solving the issue of hydrofluoric acid waste disposal. Samsung is trying to establish hydrofluoric acid regeneration factory, which aims at solving the issue of hydrofluoric acid supply. This research simulates the existing circumstances, electronic hydrofluoric acid regeneration, synthetic cryolite regeneration (domestic), synthetic cryolite regeneration (domestic & export) four scenarios with Waste Input-Output – Environmental Input-Output (WIO-EIO) Model by importing Input-Output Table, waste generation, value of activity of waste treatment, industrial Greenhouse Gas (GHG) emissions. The results include the difference of GHG emissions and economic impact, which are compared with material circularity. This research aims to decide whether same-grade recycling (R8a) is more circular than low-grade recycling (R8b), whether circularity really contributes to economic prosperity and improves environmental quality. In the electronic hydrofluoric acid regeneration scenario, the result reveals that ratio of recycled Fluorine is higher, carbon intensity of overall economy is lower, Value-added Rate of overall economy is higher within Taiwan. In the synthetic cryolite regeneration (domestic) scenario, Value-added Rate and carbon intensity of overall economy are both lower within Taiwan. In the synthetic cryolite regeneration (domestic & export) scenario, Value-added Rate and carbon intensity of overall economy are both higher within Taiwan. In conclusion, if the recycle strategy of hydrofluoric acid shifts from R8b to R8a, the economy of Taiwan will be more circular. Furthermore, if the recycle strategy of hydrofluoric acid shifts from one R8b to another, economic prosperity and environmental quality improvement cannot be achieved at the same time. However, this study does not calculate GHG emissions of the imported goods, the replacement effects on GHG emissions of exporting regeneration goods. Thus, the results only indicate the impact within Taiwan. Further research may interface Taiwan’s economy with the world economy and assess the GHG emissions of the imports and exports to solve this issue.