本文主要探討高膜厚(以純鋁6000Å為基礎的多層結構)，在等向性濕式蝕刻的反應下，觀察SEM側蝕角度的變化。第一部分，採用半蝕刻(half etching)(蝕刻時間縮短)的實驗方式。從等向性蝕刻行為，首先觀察到最上層結構鉬的突出(overhang)，主要因為鋁(陽極)與鉬(陰極)(表面積鋁:鉬=∞:1)明顯的電位差，陽極鋁解離出大量電子，電子回到陰極端的鉬持續被還原保護住。到EPD(蝕刻反應終點)時，因鋁鉬(表面積鋁:鉬=10:1)電位差相近，故回到蝕刻率(E/R 鋁:鉬=1:3)，鉬被快速蝕刻反應，故overhang現象消失，最終側蝕角度形成。
第二部分，研究高膜厚結構在目前的CD loss與Over Etching規格下，所形成側蝕角度異常的現象，實驗確認其成因，以流體力學流經狹縫的行為說明解釋之，並進行佐證與解決。再套用解決方案，說明所面臨挑戰與執行不易的原因。故後續從鍍膜條件，利用田口方法，由實驗設計的結果，找出控制因子中的重要因子，並執行確認實驗，最終選擇一組製程配方，使異常變異因素的干擾降低至最小，來達到強健製程(robust process)。

Due to the fast development of thin film transistors and liquid crystal displays manufactured in China in recent years, the whole industry is facing the challenge of different designs and has to solve a lot of new process questions.
In this study, the over etching of a thicker MoNAlMoN structure is less than 60%; however, there is an abnormal angle which will affect the subsequent dry etching and ITO deposition processes. In the etching process, half etching is used to explore the isotropic behavior. By comparing the results of different etching time, different angles due to side etching can be observed which can be explained by hydrodynamics. Even though the design of experiment can be applied, it is limited by photo exposure process capability.
Thus, the phenomenon is further investigated by Taguchi Methods to optimize the associated process. Process parameters include top MoN thickness, top MoN N2 flow, Al materials, Al deposition methods, bottom MoN thickness, and bottom MoN N2 flow. The results show that both thicker Al and top MoN N2 flow are the most significant factor on the abnormal angle; top MoN thickness is the control factor to adjust the taper angle. The effect of Al deposition methods is insignificant. Thicker process parameters are also optimized by the Taguchi methods.

[1]呂文雄."鋁在磷酸溶液中之電化學行為及其蝕刻之研究." 臺灣大學化學工程學系碩士論文,1-24 (2005).
[2]陳漢邦."鋁/鉬/銅在酸性溶液之蝕刻研究." 臺灣大學化學工程學系碩士論文, 1-72 (2006).
[3]王怡珍."鋁和鉬/鋁在磷酸-硝酸溶液的蝕刻研究與鎳鈦合金表面陽極處理改質." 臺灣大學化學工程系碩士論文,24-48(2012).
[4]李文斌. "混酸中添加鉬酸銨對鋁陽極氧化之研究." 大同大學化學工程學系碩士論文(2002)
[5]曹琳翔. "TFT LCD製程之鉬鋁薄膜蝕刻輪廓控制." 交通大學工學院精密與自動化工程學系碩士論文(2015).
[6] 洪大偉. "鋁釹與鉬鈮雙層閘極結構在蝕刻機制之邊緣輪廓及傾斜角研究. " 臺北科技大學化學工程學系碩士論文.(2005)
[7] S. Metz, A. Bertsch, P. Renaud. Partial release and detachment of microfabricated metal and polymer structures by anodic metal dissolution. Journal of Microelectromechanical Systems ( Volume: 14, Issue: 2, April 2005), 83-391 (2005).
[8] Hsiang-Yu Chan, Chisa Fukuda, Dogukan Yildirim, G. P. Li, Mark Bachman, Low Cost, High Density Interposers in Aluminum Oxide Films. IEEE 66th Electronic Components and Technology Conference (2016).
[9] Xifeng Li, Leyong Zhu, Yana Gao, Jianhua Zhang. Solution-Processed Low-Operating-Voltage Thin-Film Transistors with Bottom-Gate Top-Contact Structure, IEEE Transactions on Electron Devices ( Volume: 62, Issue: 3, March 2015), 875-881 (2015).
[10] 呂仁雄. "銅/鉬酸性蝕刻液之研究. " 臺灣大學化學工程學系碩士論文 (2005).
[11] Takatoshi Tsujimura, Atsuya Makita. Molybdenum/aluminum stacked metal taper etching for high-resolution thin-film transistor liquid-crystal display. Journal of Vacuum Science & Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena (2002)
[12] 高銘聰." AlNx/Al雙層複合材料應用於TFT之可行性分析與鋁薄膜產生鋁尖凸特性研究." 國立成功大學機械工程學系博士論文 (2012).
[13] 戴亞翔. "Design and Operation of TFT-LCD Panels." 五南圖書出版公司 (2008).
[14] 陳連春."彩色液晶顯示器 原理與技術". 國立中央圖書館, 臺北市(2003).
[15] 陳志強."LTPS低溫複晶矽顯示器技術". 全華科技圖書股份有限公司, 臺北市 (2004).
[16] 王國賢. "利用非等向性濕蝕刻於絕緣層覆矽(SOI)上研製長週期波導光柵".成功大學微電子工程學系碩士論文(2013).
[17] 龍柏華. "濕蝕刻製程介紹暨機台原理簡介", 光連:光電產業與技術情報, 48期, pp.37-41 (2003).
[18] 陳耀茂. ”統計分析-Excel應用”. 鼎茂圖書出版有限公司 (2009).
[19] Mingxia Gu, Ph. D, http://www.personal.kent.edu/~mgu/LCD/tft.htm
[20] A. M. Miri, S. Mohajerzadeh, A. Nathan. A modified inverted-staggered TFT structure suitable for a fully wet etch fabrication process for high performance low and high voltage a-Si:H TFTs. Microelectronics, 2000. ICM 2000. Proceedings of the 12th International Conference on, IEEE (2000) .
[21] S. M. GadelRab, A. M. Miri, S. G. Chamberlain. A comparison of the performance and reliability of wet-etched and dry-etched a-Si:H TFTs. IEEE Transactions on Electron Devices (Volume: 45, Issue: 2, Feb 1998). pp. 560-563 (1998).
[22] Da Eun Kim, Sung Woon Cho, Sung Chan Kim, Won Jun Kang, Hyung Koun Cho. Corrosion Behavior and Metallization of Cu-Based Electrodes Using MoNi Alloy and Multilayer Structure for Back-Channel-Etched Oxide Thin-Film Transistor Circuit Integration. IEEE Transactions on Electron Devices (Volume: 64, Issue: 2, Feb. 2017). pp. 447-454 (2017)
[23] C. F. Liu, C. T. Pan, J. K. Tseng, Y. J. Chen. Wet processes for conductive layer of silver and insulating layer Al2O3 for thin-film transistor. pp. 297-300 IEEE (2011).
[24] W. Kang, J. Mao. Robust Control of lithographic process in semiconductor manufacturing, Proceedings of SPIE-The International Society for Optical Engineering, Vol. 5755, Data Analysis and Modeling for Process Control II, pp. 29-36 (2005).
[25] C. Yan, J. Stokes, S. Arias. Etch/metallization process sequence integration-impact of Al texture on Al etch performance. Interconnect Technology Conference, 1998. Proceedings of the IEEE 1998 International. IEEE (2002)
[26]簡儀禎. "超薄蝕刻阻劑在金的圖形製作表面之抗蝕刻機制研究. " 成功大學材料科學及工程學系碩士論文(2006)
[29] A. J. Bard, L. R. Faulkner. “Electrochemical Methods”, 2nd Ed., John Wiley & Sons, Inc., New York (2001)..
[29] D.H. Killeffer, Arthur Linz. “Molybdenum Compound”. Interscience Publishers, Inc., New York (1952).
[30]李輝煌. "田口方法-品質設計的原理與實務." 第四版 高立圖書有限公司,新北市(2017).
[31] BYU cleanroom, https://cleanroom.byu.edu/wet_etch
[32] Witsview, http://www.witsview.com/