晶圓廠濕蝕刻機台排水分流系統與氟系廢水處理設施效能評估研究

Abstract

本研究目的是評估半導體廠含氟廢水處理設施及濕蝕刻機台排水分流之效能，並選定科學園區某半導體廠進行評估，依評估內容進行改善建議，究內容包括，採樣分析半導體廠部濕蝕刻機台的排放水水質變化與各中間槽之水質，氟濃度偵測值差異原因探討，現場操作效能儀器評估。 根據濕蝕刻機台的排放水與各中間槽之水質分析結果分析，在處理氟系廢水時需考量硫酸根離子的影響，磷酸根的影響則是相對較小，依檢測結果可建議進行改管排至酸鹼系廢水、流體化床處理或維持原狀排入混凝處理之氟系中間槽。 根據實驗結果以鹼性條件處理效果較佳，若從第一槽開始將pH提高可維持所有反應槽皆為偏鹼之條件，建議氟系第一槽僅需進行pH調整，而不要加氯化鈣，因為進流水若pH太低的時候，加液鹼調整pH會反應不及，此時加入氯化鈣，效果並不佳，建議第二槽才加氯化鈣。 針對出流水端採用線上氟電極偵測出流水氟濃度，和科管局調查方法所測定濃度有所差異，經由實驗結果，需做一校正。除了校正之外，放流水中之氫氧根離子(OH-)，會逐漸消耗氟離子電極內的LaF3，使得氟離子電極效能及壽命逐漸下降，需定期比對檢測數據及汰換氟離子電極。

This study goal is appraised the semiconductor fabrication the fluoride containing wastewater to process the facility and potency of the etching tools draining water divergence, and designated the science park some semiconductor fabrication carries on the appraisal, carries on the improvement suggestion according to the appraisal content. This study Effluents from production lines representing semiconductor manufacture, and investigates causes for effluent fluoride concentration differences between values detected by fluoride electrode and values monitored by Science Industrial Park Administration (SIPA). as well as effluents from intermediate units, were analyzed on-site by instrumental methods. The impact of sulfate concentration needs to be taken into consideration, with less impact of phosphates. Based on water quality monitoring, effluents could be diverted to acid-alkaline wastewater treatment trains, to fluidized bed or to remain being directed into fluorine intermediate units. Alkaline treatments lead to better removal based on experiments. Increasing pH from the first unit can maintain system pH as alkaline. Hence, sole pH adjustment is recommended for first fluorine unit, without calcium fluoride addition. Insignificant removals by adding calcium fluoride occurred with low influent pH, while pH adjustments couldn’t complete in the first unit. Calcium fluoride addition is recommended starting at the second unit. Effluent fluoride concentration differences between values detected by online fluoride electrode and values monitored by Science Industrial Park Administration (SIPA) were investigated. Calibration is required. In addition to calibration, hydroxyl (OH-) ions in effluents were found to gradually consume LaF3 in online fluoride electrodes and to damage efficiency and service life of electrodes. Values monitored by electrodes needed to be checked regularly, and fluoride electrodes needed to be routinely replaced.