膜過濾法回收切割液以及改良沉降單元分離矽和碳化矽

Recovery of cutting liquid by membrane filtration and separation of silicon and silicon carbide using a modified settling unit

何昇陽(Sheng-Yang Ho)

指導教授 ： 蔡子萱

國立臺北科技大學/工程學院/資源工程研究所/碩士(2012年)

摘要

矽晶圓製造過程中，切割步驟造成大量廢棄物的產生及原物料的浪費，因此回收切割廢料中之有價物質，將有助於製程減廢與降低成本。本研究利用薄膜過濾回收切割液，以及改良沉降單元促進矽和碳化矽之分離。由膜過濾實驗結果發現，降低進料固含量對過濾通量提升最為重要。以134ml/min進料速度、切割廢料含水量為50％、過濾壓差為105KPa下，回收效率較佳，其切割液回收率為81.69％，且回收之切割液品質與原切割液相近。改良沉降單元分離矽與碳化矽之實驗結果顯示，於pH值7、離子強度0.01M及加入磁力作用下，其回收後之碳化矽粉含量提升至95 wt.％；所回收富矽粉體之碳化矽含量降至9 wt.％，且原粉體中金屬含量降至2636ppm。本研究成功地以膜過濾法回收切割液，且改良之沉降單元更可縮短分離矽和碳化矽之時間及一併去除52.07％之金屬雜質。

關鍵字

矽 ； 碳化矽 ； 切割液 ； 膜過濾 ； 分離 ； 沉降

並列摘要

In silicon wafer manufacturing, a large amount of slurry waste is produced and feedstock is wasted during cutting process. Recovery of silicon carbide, cutting liquid and kerf silicon will be a good solution to reduce waste and costs. This study investigated recovery of cutting liquid from the silicon slurry waste by membrane filtration, and separation of silicon and silicon carbide using a modified settling unit. The experimental results show that the solid content in the feed is the most important factor for increase the filtration flux. It was found the input rate 134ml/min for slurry waste with 50wt%water at 105KPa resulted in good separation performance. Its recovery yield reached 81.69%. In addition, the important properties of the recovered liquid are similar as the original cutting liquid. The experimental results for the separation of silicon and silicon carbide show at pH 7 and the ionic strength 0.01M, the SiC content of the recovered silicon carbide could increase to 95wt.% using settling unit CM-U, the SiC content of the recovered silicon decreased to 9wt.％, and the metal content of the recovered silicon decreased to 2636ppm. Moreover, the recovery of silicon and silicon carbide with our modified settling unit (C) can save time, and iron were removed 52.07% at the same time.

並列關鍵字

Silicon ； Silicon carbide ； Cutting liquid ； Membrane filtration ； Separation ； Settling

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