場發射顯示器之電化學蝕刻製程溶劑性能研究

Abstract

場發射顯示器 (Field Emission Display) 是藉由背面基板的尖端陰極放電，放出電子到前板的螢光層上激發螢光體發光。其顯示器的特性有自發光、低耗電、高亮度，廣視角，反應速度快等。所以在FED的基板蝕刻製程中，形成陰極發射的尖端(Tip)也成為相當重要的一環。 在Cathode(陰極板)的製程中，Halo Etchant中所使用的電解溶液為DMSO(二甲基硫)。製程中DMSO(二甲基硫)會隨著基板進入H2O槽並排至有機廢水處理槽。由於DMSO經有機廢水處理後會轉化為臭味物—DMS而影響週遭氣味，環保單位與渴望園區已進行DMSO溶液與氣味監測計畫，並定期採樣抽測，除了暫時將DMSO廢液及廢水做收集外，仍須找尋可取代的溶劑，避免產生環保問題。故研究Halo Etchant的電解蝕刻溶液之替代劑，並比較其性能差異，將成為FED在台灣發展重要的項目之一。 本研究利用QC七大手法中的層別法，篩選可行性的溶劑，並設計一小型電化學槽進行實驗。再以QC七大手法中的直方圖(Histogram)，來進行小型電化學槽的製程能力檢核(Cpk)，並利用田口實驗法將最具影響蝕刻率的最強因子找出；以該因子作實驗基準，最後以電子顯微鏡及EDX去判斷反應完成的玻璃試片其蝕刻速率、深度、表面殘留物質是否與使用DMSO溶液相近並收集實驗相關數據。最終達到取代DMSO溶液的目地。 研究結果顯示，乙二醇(EG)溶液可取代DMSO溶液。經由蝕刻速率，蝕刻深度，臨界電壓區間，安全性之特性驗證，均符合規格需求。

Through the discharge of cathode tip from the backside of substrate, FED emits electrons to excite phosphor to the fluorescent layer of the front panel. The characteristics of FED are self-luminous, low power consumption, high brightness, wild viewing angle, and fast response. Therefore, in the process of using electrolytic solution to the substrate layer to form the tip of cathode has become an important procedure. In the process of Cathode tip, the electrolytic solution in Halo Etchant is DMSO. During the halo etching process, DMSO with the substrate will be immersed into the organic wastewater treatment tank. Because the treatment of organic wastewater will generate DMS compound, which has smelly cloves. The environmental protection agency and has been planning the monitoring and regular sample of test. In addition to temporary collect the waste liquid and wastewater of DMS, it is necessary to find out the solvent that can replace DMSO in order to avoid environmental problems. Research for the electrolytic etching solution replacement of Halo Etchant, and achieve the performance will become one of the most important FED developments in Taiwan. In the study, we use stratification of QC Seven Techniques to select the replacement solvent and design a basic electrochemical cell experiments to verify process capability index (Cpk).The Taguchi method is used to identify the most influential factor in etching rate. Based on this factor and by carrying out the experiment, electron microscopy and EDX are used to determine the glass specimen reaction of the etching rate, depth and surface residual substance. The performance of replacement solvent one compare with DMSO solution. The result shows that the solution of EG could replace the solution of DMSO. Through the etching rate, depth, and the threshold of voltage range, the verification result meets the specification requirements.