晶圓代工業混合處理氟類與機械研磨類廢水最適化條件與pH均勻性探討

Abstract

過去混合處理含氟類與機械研磨類的廢水，多數以人工混合並利用Jar-test求得最適化操作條件。由於Jar-test實驗與實廠運轉之反應槽體積差異甚大，故Jar-test所得最適化條件常常無法套用在實廠運轉上，此問題可能是因反應槽體積過大導致均勻度差所致。就此，本研究著重於測試及改善反應槽內均勻度問題，並以竹科某8吋晶圓代工廠廠內的廢水處理廠為實例，探討此廠現有混合處理含氟類與化學機械研磨類廢水系統，以實驗搭配統計軟體分析，求出最適化之操作條件，以利氟化鈣因混入機械研磨顆粒後而使粒徑被放大之效果。而在混合處理過程中，pH均勻性成為此流程最重要的操作關鍵之一，本研究宗旨在探討與改善pH對平面上的均勻性問題，並以多變量分析中的反應曲面法，搭配簡單的實驗設計，找出最適化的操作條件。研究結果顯示，氫氟酸廢水處理系統流量9.0 m3/hr、pH加藥啟動值6.0、及研磨廢水系統流量11.0 m3/hr時，實際測得水質的指標平均值分別為pH= 5.9、氟離子濃度= 8.0 mg/L及水中懸浮固體量= 5.0 mg/L，已達該廠預期之成效並符合竹科園區管理局納管標準。

In the past, the Jar-test was commonly used to determine the optimal operation condition for the treatment of mixed fluoride and chemical mechanism polishing wastewater. Because the actual volume of reaction tank is larger than the Jar-test with beaker, the result from Jar-test is however not applicable to the real wastewater treatment plant. The problem of uniformity between the Jar-test and wastewater plant might be due to the volume difference of the reaction tank. This focus of study is on improvement of uniformity in wastewater plant in a 8-inch semiconductor foundry at the Hsinchu Science Park. The multivariate statistical analysis along with the experiment design is used to determine optimal pH uniformity on coagulation procedure in the treatment plant. The optimal conditions of HFTS’s flow rate is set to 9.0 m3/hr and its pH is 6.0, and CMPRS’s flow rate is 11 m3/hr. The result from optimal condition is pH = 5.9、F－= 8.0 mg/L、SS = 5.0 mg/L. It meets the water quality requirement of wastewater discharge in Hsinchu Science Park.