本論文主要針對目前應用於28奈米銅層化學機械研磨之鹼性清洗液中腐蝕抑制劑之失效程度對清洗後銅層生成表面鈍化層,對銅腐蝕抑制能力影響之探討。清潔液之pH值及腐蝕抑制劑濃度對清洗後銅表面研磨粒子殘留程度影響亦在此加以討論。
首先測量二氧化矽研磨粒及銅粉末在不同清潔液pH值下之界達電位(zeta potentials)及粒徑分布(particle size distribution ,PSD),發現研磨粒與銅表面在pH值約12時有較大的排斥作用力,而研磨粒也有較佳分散性,顯示較能完整清除表面殘留粒子。SEM及AFM圖像亦符合其實驗結果。 同時由界達電位看出腐蝕抑制劑濃度對於殘留粒子的移除無直接關係。由此找出清潔液的最佳化條件後,再以此條件探討腐蝕抑制劑的功效及失其失效機制。
由動態電位極化曲線(potentiodynamic curves)觀察表面鈍化層生成情形,在將清洗液靜置曝空氣數天後之實驗結果顯示,銅層在曝氣氧化後的清潔液中無法保留住氧化亞銅(Cu2O)鈍化層,並進一步生成氧化銅(CuO),推測其腐蝕抑制劑無法有效吸附在鈍化層上,並抑制氧化銅層之生成。由XPS圖譜可應證此推測結果。而由充氧惡化實驗中,證明其清潔液失效機制源自於氧化作用。
接下來將試著從XPS縱深分佈探討腐蝕抑制劑的添加及失效對銅層表面生成氧化(鈍化)層的厚度分析,以及鹼性清潔液中腐蝕抑制劑的添加與否對於銅腐蝕能力的改善證明。

The objective of our study is to investigate the influence of degradation of inhibitor employed in N28 node alkaline-based cleaning solution on the formation of copper oxide during post-Cu CMP cleaning. The effects of the pH and the inhibitor concentration of the cleaning solutions on adhesion force and removal of silica abrasive particles were also studied.
We measured the zeta potentials and particle size distribution (PSD) of silica abrasive and copper powder as a function of pH in order to find out the optimal condition of the cleaning solution. The results illustrate that pH around 12 induced strong repulsive force and very fine silica particles, resulting in improved particle removal efficiency. FESEM and AFM images also support the results. Based on this optimal condition, we investigated the effect of inhibitor degradation on copper oxide film formation.
In order to observe the formation of Cu oxide film, we did potentiodynamic studies on wafers under different in various air exposure times and found that the degraded cleaning solution failed to maintain the Cu2O passive layer, which resulted in the formation of CuO. XPS spectra also confirm the finding. The results of the XPS and potentiodynamic measurements of Cu wafers in the cleaning solution purged with oxygen indicated that the degradation can be attributed to the oxidative reaction.
In future works, we will continue to investigate the degradative mechanism of inhibitor by analyzing the depth profile of oxide film. In addition, we will check the ability of the inhibitor to corrosion inhibition.

[1] M. A. Fury, Solid State Technol., 38, 47 (1995).
[2] M. A. Martinez, Solid State Technol., 37, 26 (1994).
[3] M. Itano, T. Kezuka, M. Ishii, T. Unemoto, M. Kubo, and T. Ohmi, J. Electrochem. Soc., 142, 971(1995).
[4] P.L. Chen et al., Microelectronic Engineering, 75 (2004) 352–360.
[5] Gary T. Rochelle, the First National Conference on Carbon Sequestration, Washington, DC, May 14-17, 2001.
[6] Y. K. Hong, D. H. Eom, S. H. Lee, T. G. Kim, J. G. Park, A. A. Busnaina, J. Electrochem. Soc., 151 (11) G756-G761 (2004).
[7] R.H. Dennard et al., ”Design of Ion-Implanted MOSFET’s with Very Small Physical Dimensions”, IEEE Journal Solid-State Circuits, SC-9, pp. 256-268, 1974.
[8] P.k Chatterjee et al., “Trends for Deep Submicron VLSI and Their Implications for Reliability”, IRPS, pp.1-11, 1995.
[9] M. Bohr, “Interconnect Scaling – The Real Limiter to High Performance ULSI”, IEDM, pp. 241-244, 1995.
[10] M. Bohr, “Technology Development Strategies for the 21st Century”, Applied Surface Science, 100-101, pp.534-540, 1996.
[11] P.C. Wu, J.C. Lou, and M.S. Tsai, Master’s thesis, National Chaio Tung University, Department of Electronic Engineering, July 2005.
[12] D. Edelstein et al., “Full Copper Wiring in a Sub-0.25um CMOS ULSI Technology”, IEDM, pp. 773-776, 1997.
[13] T. Hashimoto et al., “A 0.2um-Bipolar-CMOS Technology on Bonded SOI with Copper Metallization for Ultra-High-Speed Processors”, IEDM, pp.209-212, 1998.
[14] J.M. Steigerwald et al., “Chemical Mechanical Planarization of Microelectronic Materials”, Wiley Interscience, New York, 1996, p.209.
[15] B.J. Howard and C. Steinbruchel, Appl. Phys. Lett., 59 (8), 914 (1999).
[16] H.P. Feng et al., Doctoral thesis, National Tsing Hua University, Department of Chemical Engineering, July 2008.
[17] Stephen A. Campbell, The Science and Engineering of Microelectronic Fabrication, Oxford University Press, Inc., 411 (1996).
[18] J.M. Steigerwald, S.P Murarka, R.J. Gutmann, Chemical Mechanical Planarization of Microelectronic Materials, John Wiley & Sons, Inc., New York, 1997, p.4.
[19] Stephen A. Campbell, The Science and Engineering of Microelectronic Fabrication, Oxford University Press, Inc., 1996, p.411.
[20] TSMC training material, “Introduction of CMP”, 2008.
[21] P.B. Zantye, A.Kumar, and A.K. Sikder, Mater. Sci. Eng., R.,45, 89(2004).
[22] S.V. Babu et al., Chemical-Mechanical Polishing 2001: Advances and Future Challenges, Materials Research Society, Warrendale, PA (2001).
[23] L. Zhang, S. Raghavan, and M. Weling, J. Vac. Sci. Technol. B, 17, 2248 (1999).
[24] F. Tardif, Semiconduct. Semimet., 63, 186 (2000).
[25] W.C. Chiou, Y.H.Chen, S.N.Lee, S.M. Jeng, S.M. Jang, and M.S.Liang, IEEE, 127 (2004).
[26] Y. K. Hong, D. H. Eom, S. H. Lee, T. G. Kim, J. G. Park, A. A. Busnaina, J. Electrochem. Soc., 151 (11) G756-G761 (2004).
[27] M. Eissa, S. Joshi, G. Shinn, S. Rafie, and B. Fraser, in Chemical Mechanical Planarization in IC Device Manufacturing Ⅲ, PV 99-37, pp.499-505, The Electrochemical Society Proceedings Series, Pennington, NJ (1999).
[28] S.Y. Lee, S.H. Lee, and J.G. Park, J. Electrochem. Soc., 150, G327 (2003).
[29] A.W. Adamson and A.P. Gast, Physical Chemistry of Surfaces, pp.250-276, John Wiley & Son, Inc., New York (1997).
[30] R.J. Strokes and D.F. Evans, Fundamentals of Interfacial Engineering, p. 145, Wiley-VCH, Inc., New York (1997).
[31] P.C. Hiemenz, Principles of Colloid and Surface Chemistry, p.645, Marcel Dekker, New York (1986).
[32] D.J. Shaw, Introduction to Colloid and Surface Chemistry, 4th ed., p.214, Butterworth-Heinemann, Woburn, MA (1992).
[33] H. Reerink and J.Th.G. Overbeek, Discuss Faraday Soc., 18, 77 (1954).
[34] J. Hernandez, P. Wrschka, and G.S. Orhriein, V. Brusic, M.A. Frisch, B.N. Eldridge, E.P. Novak, F.B. Kaufman, B.M. Rush, and G.S. Frankel, J. Electrochem. Soc., 148, G389 (2001).
[35] J. Isrealachvili, “Intermolecular and Surface Forces”, 2nd ed, Academic Press, 2004.
[36] J. Isrealachvili, “Intermolecular and Surface Forces”, 2nd ed, Academic Press, 1992.
[37] Po-Lin Chen et al., “Post-Cu CMP cleaning for colloidal silica abrasive removal”, Microelectronic Engineering, 75, pp.352-360, 2004.
[38] P.C. Wu, J.C. Lou, and M.S. Tsai, Master thesis, National Chaio Tung University, Department of Electronic Engineering, July 2005.
[39] Y. K. Hong, D. H. Eom, S. H. Lee, T. G. Kim, J. G. Park, A. A. Busnaina, J. Electrochem. Soc., 151 (11) G756-G761 (2004).
[40] J.M. Steigerwald et al, “Chemical Processes in the chemical mechanical polishing of copper”, Materials Chemistry and Physics , 41, pp. 217-228, March 1995.
[41] W. Stumm and J.J. Morgan, “Aquatic Chemistry: Chemical Equilibria and Rates in Natural Waters”, 3rd ed. John Wiley & Sons, 1996.
[42] Darryl W. Peters et al, “Incorporation of Cu Passivators in Post-CMP Cleaners”, 212th ECS Meeting, Abstract #1067.
[43] A. Mishra, M.L. Fischer, US Patent Application No. US 2005/0181961.
[44] S. Naghsineh, J. Barnes, E.B. Oldak, US Patent No. 6,723,691 B2.
[45] J. Barnes, P. Zhang, A. Miller, Mater. Res. Soc. Symp. Proc. 991 (2007) 71.
[46] M. Pourbaix, Atlas of Electrochemical Equilibria in Aqueous Solutions, NACE International, Houston (1974) 384.
[47] Lennon Ko et al, “Novel Post Alkaline Cleaning Solutions for Next Generation Cu CMP Application”, ECS Transactions, 27 (1) 619-624 (2010).
[48] T. M. Pan et al, “Comparison of Novel Cleaning Solutions With Various Chelating Agents for Post-CMP Cleaning on Poly-Si Film”, IEEE transactions on semiconductor manufacturing, vol. 14, No. 4, November 2001.
[49] J. Noguchi, N. Konishi, Y. Yamada, IEE T Electron Dev, 52 (2005) 934.
[50] T. M. Pan, T. F. Lei, F. H. Ko, T. S. Chao, T. H. Chiu, Y. H. Lee, C. P. Lu, IEEE Trans. Semicond. Manuf. 14(4) (2001) 365.
[51] W. H. Huang, S. Raghavan, Y. Fang, L. Zhang, Mat. Res. Soc. Symp. Proc. 566 (2000) 161.
[52] D.W. Peters, Mater. Res. Soc. Symp. Proc. 991 (2007) 215.
[53] W.C.Chiou, Y.H.Chen, S.N.Lee, S.M.Jeng, S.M.Jang, M.S.Liang, IEEE International Interconnect Technology Conf. (2004) 127.
[54] T. Y. Kwon et al, “Characterization of TMAH Based Cleaning Solution for Post Cu-CMP Application”, Microelectronic Engineering, Accepted manuscript, April 2012.
[55] P. G. Fox, G. Lewis, and P. J. Boden, “Some Aspects of the Corrosion Inhibition of Copper by Benzotriazole”, Corrosion Science, Vol. 19, pp. 457-467, Pergamon Press, Ltd. (1979).
[56] I. C. C. Ogle and G. W. Poling, “Corrosion Inhibition of Copper with Benzotriazole”, Canadian Metallurgical Quarterly, Vol. 14, pp. 37-46 (1975).
[57] R. F. Roberts, “X-Ray Photoelectron Spectroscopic Characterization of Copper Oxide Surfaces Treated with Benzotriazole”, Journal of Electron Spectroscopy and Related Phenomena, Vol. 4, pp. 273-291, Elsevier Scientific Publishing, Amsterdam (1974).
[58] A. R. Siedle, R. A. Velapoldi, and N. Erickson, “Surface Formation of Cuprous Benzotriazole”, Inorganic and Nuclear Chemistry Letters, Vol. 15, pp. 33-36, Pergamon Press, Ltd. (1979).
[59] C.F. Yeh, C.W. Hsiao, W.S. Lee, Appl. Surf. Sci., 216 (2003) 46.
[60] Y.K. Hong, D.H. Eom, S.H. Lee, T.G. Kim, J.G. Park, A. A. Busnaina, J. Electrochem. Soc., 151(11) (2004) G756.
[61] L. Zhang, S. Raghavan, M. Weling, J. Vac. Sci. Tech. B, 17 (1999) 2248.
[62] I. K. Kim et al, “Citric Acid and NaIO4 Based Alkaline Cleaning Solution for Particle Removal during Post-Ru CMP Cleaning”, Journal of The Electrochemical Society, 158 (10) H1052-H1056 (2011).
[63] Y.K. Hong et al, “The Effects of pH Adjustors in Post Cu CMP Cleaning Solutions on Particle Adhesion and Removal”, 208th ECS Meeting, Abstract #794.
[64] Gary T. Rochelle, the First National Conference on Carbon Sequestration, Washington, DC, May 14-17, 2001.
[65] PlanarClean function of components from ATMI material, 2010.04.12.
[66] NCTS Industrial Statistics Research Group Seminar, Tzu-Cheng Lin (2010)
[67] Faramarz S. Gard, Department of Physics, Sultan Qaboos University.
[68] Ninhydrin reaction mechanism, 28 January 2008, wikipedia web site.
[69] M. Pourbaix, Atlas of Electrochemical Equilibria in Aqueous Solutions, NACE, Houston, TX, 1975.
[70] H.E. Johnson, J. Leja, J. Electrochem. Soc. 112 (1965) 638.
[71] Tzu-Hsuan et al, Localized corrosion effects and modifications of acidic and alkaline slurries on copper chemical mechanical polishing, Applied Surface Science 210 (2003) 190-205.
[72] D.A. Jones, Principles and Prevention of Corrosion, seconded., Prentice Hall, Upper Saddle River, NJ, 1983.
[73] S.J. Vevelstad et al, “Degradation of MEA; a theoretical study”, Energy Procedia 4(2011), 1608–1615.