化學機械拋光是半導體製程中可達到全域性平坦化的一項重要技術，但是化學機械研磨應用於銅導線與以Low-k材料為主的介電層之多層導線架構平坦化製程時，易造成殘留應力、刮痕與平坦化後後續清洗等都是需要克服的問題。電化學機械拋光的製程控制方式可分為電流控制與電壓控制兩類，本研究使用自行建立的無磨料電化學機械拋光(Abrasive Free Electrochemical Mechanical Polishing, AF-ECMP)系統，透過動電位極化曲線(Potentiodynamic Polarization Curve, PD Curve)掃描與X-ray光電子能譜儀，分析KOH Based以及H3PO4 Based電解液在不同偏壓下銅膜表面產生的氧化物，結果使用H3PO4 Based電解液移除率比使用KOH Based電解液大，判斷是氧化物Cu2O所造成的差異。使用恆電位儀(Potentiostat/Galvanostat)所擷取的電流訊號，探討在接觸與非接觸模式下所造成的實際材料移除率與法拉第定律所估算的移除率，說明試片於AF-ECMP製程時，不接觸狀態下移除率會相當低。使用AF-ECMP加工後之試片，經原子力顯微鏡(Atomic Force Microscopy ,AFM)檢測表面粗糙度檢測結果，粗糙度Ra可改善至1.274 nm。最後比較經一般Cu-CMP與AF-ECMP製程後的薄膜殘留應力，說明Cu-CMP因透過磨料加工，因此容易產生殘留應力，但經AF-ECMP製程研磨後薄膜表面品質受到拋光墊與電解液的影響，使用軟拋光墊能有效減少殘留應力產生。未來可透過電解液與拋光墊的研究與開發，提升表面研磨品質與材料移除率。

Chemical mechanical planarization (CMP) process is an important technology to achieve overall planarization in integrated circuit (IC) fabrication process. However, there are some problems including residual stress, scratch and post CMP-cleaning in the manufacturing of multi-layer interconnect that containing copper metal and low-k dielectric should be solved. The electrochemical mechanical polishing (ECMP) has been proposed and it can be controlled with current control and voltage control. In this study, an abrasive free electrochemical mechanical polishing system (AF-ECMP) has been developed with voltage control mode. The potentiodynamic polarization curve (PD Curve) has been measured by potentiodynamic scan and X-ray photoelectron spectroscope is used to analyze the oxide layer on copper surface after different electrolyte (KOH based and H3PO4 based) and difference bias voltage. It shows the material removal rate (MRR) in H3PO4 based electrolyte is higher than that in KOH base electrolyte because the existence of copper oxide (Cu2O). The MRR is calculated based on the Faraday’s law as the workpiece contacts or noncontacts with pad. The MRR is observed to be very low when the workpiece noncontacts with pad. The surface roughness Ra of copper film is 1.274 nm measured by atomic force microscopy (AFM) after AF-ECMP process. Moreover the residual stress of copper film after Cu-CMP and AF-ECMP process have been investigated and the residual stress of copper film after AF-ECMP process with politex pad is lower than that of Cu-CMP. Future study can focus on the effects of pad design and slurry for AF-ECMP of copper film.

[1] 林春宏, 吳清吉, 李金揚, 張加強, “電解拋光技術於半導體製程上的應用”, 機械工業雜誌 246期, 光電與半導體設備技術專輯, 223-232.
[2] 謝耀儀, “薄膜應力與拋光應力對銅化學機械拋光行為影響之研究”, 國立中興大學機械工程學系碩士論文, 2002.
[3] 張鼎張,鄭晃忠,楊正杰,“銅金屬化製程簡介”, 國家奈米元件實驗室, 奈米通訊 第五卷第三期, 1998.
[4] C. JIN, S. LIN, J.T. WETZEL,“Evaluation of Ultra-Low-k Dielectric Materials for Advanced Interconnects”,Journal of Electronic Materials, Vol. 30, NO. 4, 2001.
[5] F. W. Preston, “The Theory and Design of Plate Glass Polishing Machine”, Journal of the Society of Glass Technology, Vol. 11, 214, 1927.
[6] S. V. Babu, Y. Li, A. Jindal, “Chemical Mechanical Planarization of Cu and Ta: Role of different slurry Constituents”, Journal of Materials, Vol. 53, No. 6, 50, 2001.
[7] M. Hariharaputhiran, Y. Li, S. Ramarajan, S. V. Babu, “Chemical Mechanical Polishing of Ta”, Electrochemical Solid-State Letters, Vol. 3, No. 2, 2000.
[8] J. Lu, J. E. Garland, C. M. Petite, S. D. Babu, V. Roy, “Electrochemical Studies of Copper Chemical Mechanical Polishing Mechanism: Effects of Oxidizer Concentration”, Materials Material Research Society Symposium Proceeding, Vol. 767, F6.4.1, 2003.
[9] Jui-Chin Chen, Shiou-Ru Lin, Wen-Ta Tsai, “Effects of oxidizing agent and hydrodynamic condition on copper dissolution in chemical mechanical polishing electrolytes”, Applied Surface Science, 233, 80-90, 2004.
[10] D. Zeidler, Z. Stavreva, M. Plotner, K. Drescher, “Characterization of Cu chemical mechanical polishing by electrochemical investigations”, Microelectronic Engineering, 33, 259-265, 1997.
[11] 林永成, “晶圓銅膜無磨粒化學機械拋光機制研究”, 國立中興大學機械工程學系碩士論文, 2005.
[12] 許厲生, “矽晶圓薄化與平坦化加工研究”, 國立台灣科技大學機械工程學系博士論文, 2007.
[13] 高進峯, “奈米級磨粒粒徑對晶圓銅膜化學機械拋光效應之實驗探討”, 國立中興大學機械工程學系碩士論文, 2004.
[14] 朱英仁, “化學反應與機械拋光對晶圓銅膜化學機械拋光影響之實驗探討”, 國立中興大學機械工程學系碩士論文, 2004.
[15] Serdar Aksu, Fiona M. Doyle, “The Role of Glycine in the Chemical Mechanical Planarization of Copper”, Journal of The Electrochemical Society, 149 (6) G352-G361, 2002.
[16] 王忠祥, “強制對流於電解拋光中的影響”, 元智大學機械工程研究所碩士論文, 2003.
[17] 黃志昌, “ULSI嵌入式銅導線之電解拋光平坦化研究”, 國立交通大學材料科學與工程學系碩士論文, 2002.
[18] 施博中, “脈衝電流對電解拋光之影響”, 元智大學機械工程研究所碩士論文, 2004.
[19] 方政煜, 蔡明蒔, 戴寶通, 馮明憲, “無磨粒銅製程化學機械研磨平坦化技術”, 毫微米通訊第九卷第一期, 12-16, 2002.
[20] P.C. Goonetilleke, D. Roy, “Voltage pulse-modulated electrochemical removal of copper surface layer using citric acid as a complexing agent”, Materials Letters, 61, 380-383, 2007.
[21] 林春宏, 吳清吉, 李金揚, 張加強, “電解拋光技術於半導體
製程上的應用”, 機械工業雜誌 第246期, 223-232, 2003.
[22] Sue-Hong Liu, Jia-Min Shieh, Chih Chen, Karl Hensen, and Shih-Song Cheng, “Roles of Additives in Damascene Copper Electropolishing”, Journal of The Electrochemical Society, 153 (6) C428-C433, 2006.
[23] Sukhoon Jeong, Sukbae Joo, Hojun Lee, Boumyoung Park, Hyoungjae Kim and Haedo Jeong, “Two-Step planarization of ECMP and CMP for MEMS Copper Patterns”, Materials Science Forum Vol. 569, 117-120, 2008.
[24] M. Mellier, T. Berger, R. Duru, M. Zaleski, M. C. Luche, M. Rivoire, C. Goldberg, G. Wyborn, K-L Chang, Y. Wang, V. Ripoche, S. Tsai, M. Thothadri, W-Y. Hsu, L. Chen, “Full Copper Electrochemical Mechanical Planarization (ECMP) as a Technology Enabler for the 45 and 32 nm Nodes”, 1-4244-1070-3/07, IEEE, 2007.
[25] Yuan-Long Chen, Shu-Min Zhu, Shuo-Jen Lee, Jong C. Wang, “The technology combined electrochemical mechanical polishing”, Journal of Materials Processing Technology, 140, 203-205, 2003.
[26] Antoine Manens, Paul Miller, Eashwer Kollata, Alain Duboust, “Advanced process control extends: ECMP process consistency”, Solid State Technology, February, 2006.
[27] Feng Q Liu, Tianbao Du, Alain Duboust, Stan Tsai, and Wei-Yung Hsu, “Cu Planarization in Electrochemical Mechanical Planarization”, Journal of The Electrochemical Society, 153 (6) C377-C381, 2006.
[28] Feng Q Liu, Liang Chen, Alain Duboust, Stan Tsai, Antoine Manens, Yan Wang, Wei-Yung Hsu, “Chemistry is Key to ECMP Efficiency”, Semiconductor International, 51-54, May 2007.
[29] Liang Chen, “Breakthrough technology for CMP”, Semiconductor FABTECH – 24TH Edition, 137-141, 2003.
[30] Youn-Jin Oh, Gyung-Soon Park, and Chan-Hwa Chung, “Planarization of Copper Layer for Damascene Interconnection by Electrochemical Polishing in Alkali-Based Solution”, Journal of The Electrochemical Society, 153 (7) G617-G621, 2006.
[31] P. Warrendable, “Residual Stress Measurement by X-Ray Diffraction”, SAE International, HS-784, 2003.
[32] U. Welzel, J. Ligot, P. Lamparter, A. C. Vermeulen, E. J. Mittemeijer, “Stress analysis of polycrystalline thin films and surface regions by X-ray diffraction”, Journal of Applied Crystallography, 38, 1-29, 2004.
[33] B. D. Cullity, S. R. Stock, “Elements of X-Ray Diffraction”, Prentice Hall, 2001.
[34] M. Birkholz, “Thin Film Analysis by X-Ray Scattering”, Wiley, 2006.
[35] 陳孟科, “應用GIXRD量測薄膜殘留應力與化學機械拋光的影響分析”, 國立台灣科技大學機械工程學系碩士論文, 2008.
[36] 柯賢文, “腐蝕及其防制”, 全華科技圖書股份有限公司, 1995.
[37] 鮮祺振, “金屬腐蝕及其控制”, 徐氏基金會出版, 1995.
[38] 楊藏越, 楊慶成,“電化學及應用-中國電機工程師手冊第二十二篇”, 中華電機工程學會 編行, 1992.
[39] 蔡子萱, 蕭資永, “添加聚乙二醇促進電化學平坦化鍍銅晶圓”, 北台學報 第29期 106-115.
[40] Kirsi Mansikkamaki, Christoffer Johans, and Kontturi, “The Effect of Oxygen on the Inhibition of Copper Corrosion with Benzotriazole”, Journal of The Electrochemical Society, 153 (1) B22-B24, 2006.
[41] 胡啟章, “電化學原理與方法”, 五南圖書出版公司, 2002.
[42] Ian Ivar Suni, Member, IEEE and Bing Du,“Cu Planarization for ULSI Processing by Electrochemical Methods：A Review”, IEEE Transactions on semiconductor manufacturing, Vol. 18, 3, August 2005.
[43] C. Y. Chang, S. M. Sze, ULSI Technology, the McGRAW-
HILL, P. 663, 1996.
[44] 汪建民, “材料科學叢書2-材料分析”, 中國材料科學學會, 1998.
[45] C.-C. A. Chen, Handout of Manufacturing Analysis, Department of Mechanical Engineering, National Taiwan University of Science and Technology, 2008.
[46] 張鼎張, 鄭晃忠, 楊正杰, “銅金屬化製程簡介”, 奈米通訊第五卷第三期.
[47] Chao-Chang A. Chen, Wei-En Fu, Meng-Ke Chen, “Residual
Stress Estimation of Tungsten Film by GIXRD”, Proc. of the International Conference Frontiers in Materials Science & Technology, Brisbane, Australia, March 26-28, 2008.
[48] Chen, C.-C. A, Ming-Hui Fang , C.Z. Feng,I-Peng Yao, Yung-Chang Hung, Kun-Cheng Tsai, “Analysis on Polishing Properties of CMP Pads”, Proc. of the International Conference on Planarization / Polishing Technology 2008, Hsinchu, Taiwan, November 11-13, 2008.
[49] Wei-En Fu, Tzeng-Yow Lin, Meng-ke Chen, Chao-Chang A. Chen, ”Surface qualities after chemical-mechanical polishing on thin films”, Journal of Thin Solid Films.
[50] Hsu, L-S, C.-C. A Chen, “A wafer Process Model for Chemical Mechanical Planarization”, Journal of Machine Tools and Manufacture, 2009.