台灣地區晶圓製造廠超純水系統各單元之生命週期評估

Abstract

本研究依據 ISO 14040/44 生命週期評估方法，運用 SimaPro 9.6.0.1 與 CML IA Baseline 2000 方法，研究台灣地區晶圓製造廠超純水系統（Ultrapure Water, UPW），並透過文獻及資料庫收集投入產出數據，評估各處理單元對環境之衝擊。系統邊界涵蓋前處理（砂濾、活性碳、軟水）、一次處理（逆滲透、陰陽離子脫氣塔）、電去離子與二次處理（UV185/254、超濾），功能單位定義為 1 m³ 產出水。利用特徵化數據評估各處理單元內投入產出對環境之衝擊，並利用標準化數據比較各單元間之環境衝擊。 結果顯示，11 項中點指標中以海水生態毒性（METP）貢獻最高，單元比較中，以RO系統、軟水系統、2B3T系統之環境衝擊較高，並且電力使用為所有單元環境衝擊之主要貢獻。化學品使用對於再生能源枯竭類別影響較大，軟水系統之化學品使用占比為79.04 %、2B3T系統為45.82 %、RO系統為62.85 %、UF系統為77.49 %。 敏感度分析顯示，電力相較於化學品，在各單元間較為敏感。當電力消耗變動 ±50 % 時，RO系統、軟水系統、2B3T系統之敏感度分別為79.53 %、71.59 % 及81.01 %，相比之下，化學品僅為9.96 %、18.59 % 及11.07 %。

This study applied the ISO 14040/44 Life Cycle Assessment（LCA）framework, using SimaPro 9.6.0.1 and the CML IA Baseline 2000 method, to evaluate ultrapure water system units for wafer fabrication plants in Taiwan. Input and output data were gathered from literature sources and databases. The system boundary encompassed pretreatment（sand filtration, granular activated carbon, and water softening）, primary treatment（RO, 2B3T, and EDI）, and secondary treatment（UV 185/254 nm and ultrafiltration）. The functional unit was defined as 1 m³ of product water. Characterized results were used to evaluate the impacts of individual units, and normalized results were used to compare impacts across units. Among the eleven midpoint impact categories, METP dominated overall impacts. Unit comparisons showed that the RO, softening, and 2B3T had the higher impacts, respectively with electricity use emerging as the major contributor across all units. Chemical consumption strongly affected the abiotic resource depletion, accounting for 79.04 % of the impact in the softening, 45.82 % in 2B3T, 62.85 % in RO, and 77.49 % in UF. Sensitivity analysis revealed that electricity used is more influential than chemical used. ±50 % variation in electricity produced sensitivities of 79.53 %, 71.59 %, and 81.01 % for the RO, softening, and 2B3T, respectively, whereas the corresponding sensitivities for chemical use were only 9.96 %, 18.59 %, and 11.07 %.