臺灣博碩士論文加值系統

化學-機械拋光法在積體電路多層金屬內連接線平坦化製程中扮演重要角色；而銅的導電性佳，抵抗電子遷移的能力好，使得銅成為半導體製程中取代鋁的新一代導電材料。影響銅的平坦化的因素以及平坦化的機制，乃成為熱門的研究課題。
本研究中則主要針對化學-機械拋光過程中電化學反應加以研究，特別是以銅在含不同氧化劑的研磨液中之電化學行為作為研究的重點。為了模擬研磨液在化學機械拋光過程中流動的特性，以銅旋轉電極為工作電極，來探討氧化劑種類、濃度及轉速對銅在0.0078 M檸檬酸水溶液中之電化學性質的影響。實驗結果顯示，在靜止狀態下，以雙氧水為氧化劑時，腐蝕電位隨著雙氧水濃度的增加而上升，其溶解速率在含6 vol. %雙氧水之0.0078 M檸檬酸水溶液中有極大值。且以雙氧水為氧化劑時，氧化銅及氫氧化銅會在銅表面生成；若以硝酸鐵為氧化劑時，腐蝕電位及溶解速率皆會隨著硝酸鐵濃度的增加而上升。另由表面型態觀察可知，在0.0078 M檸檬酸水溶液中表面呈現高低相間規則而平行之波浪狀；而在含雙氧水的0.0078 M檸檬酸水溶液中，表面形狀變為平滑；若在添加硝酸鐵之0.0078 M檸檬酸水溶液中，表面高低相間的規則狀消失，並可發現凹洞存在。
旋轉狀態下，以雙氧水為氧化劑時，腐蝕電位隨著轉速的增加而呈下降的趨勢，而溶解速率在添加雙氧水濃度為2 vol. % 時會有極大值。另由表面分析結果可知，含雙氧水之0.0078 M檸檬酸水溶液中，在三種轉速條件下( 100、1000、3000 rpm )，氧化銅及氫氧化銅仍然會在銅的表面附著。當以硝酸鐵為氧化劑時，腐蝕電位及溶解速率皆隨著轉速的增加而上升。

Chemical mechanical polishing (CMP) is one of the crucial techniques under intensive investigation for Ultra-Large-Scale- Integration (ULSI). Owing to the low electrical resistivity and high electromigration resistance, copper has emerged as alternative choice for aluminum in the applications of the interconnect in the future.
In this study, the electrochemical properties of copper in citric acid were investigated, with special emphasis on the effect of oxidizing agent. In order to simulate the flow condition of slurry during chemical mechanical polishing, a rotating electrode was employed. The effects of rotation, types and concentrations of oxidizing agent on the electrochemical behavior of copper were investigated. The oxidizing agents used were hydrogen peroxide and iron nitrate. The rotating speed was controlled in the range of 0~3000 rpm.
Under static condition, the corrosion potential of copper increased with increasing concentration, and the dissolution rate increased with the concentration of hydrogen peroxide in the range of 0~6 vol.%, while it decreased beyond 6 vol. %. With iron nitrate as the oxidizing agent, both the corrosion potential and the dissolution rate were increased with its concentration in the range of 0~0.2 M. Examination of surface morphology using atomic force microscope (AFM) revealed that the addition of hydrogen peroxide and iron nitrate could cause the morphology of copper become more smooth in 0.0078 M citric acid.
Under rotating condition, the corrosion potential of copper decreased with increasing in 0.0078 M citric acid solution with hydrogen peroxide addition. The dissolution rate was found to increase with increasing rotating speed in 0.0078 M citric acid solution added with hydrogen peroxide. However, with iron nitrate addition, both of the corrosion potential and the dissolution rate of copper increased with the rotating speed in 0.0078 M citric acid

總目錄
摘要 Ⅰ
Abstract Ⅱ
總目錄 Ⅲ
表目錄 Ⅴ
圖目錄 Ⅵ
第一章、前言 1
第二章、相關文獻及理論 3
2-1 以化學變因為主的銅CMP相關研究 3
2-2 金屬腐蝕之熱力學 4
2-3 電化學技術的應用 6
2-4 旋轉電極之理論和應用 7
第三章、實驗方法與步驟 9
3-1材料 9
3-1裝置 9
3-3 溶液的配製 10
3-4 極化曲線測試 10
3-5 溶解速率量測 11
3-6 電化學交流阻抗 12
3-7 表面性質 12
第四章、結果與討論 14
4-1雙氧水的影響 14
4-1-1 雙氧水濃度對極化行為之影響 14
4-1-2 雙氧水濃度對溶解速率之影響 15
4-1-3 表面分析 16
4-1-4 雙氧水濃度對交流阻抗之影響 18
4-1-5 雙氧水濃度對表面型態之影響 19
4-2硝酸鐵的影響 20
4-1-1 硝酸鐵濃度對極化行為之影響 20
4-1-2 硝酸鐵濃度對溶解速率之影響 21
4-1-3 硝酸鐵濃度對表面組成及交流阻抗之影響 22
4-1-4 硝酸鐵對表面型態之影響 22
4-2轉速的影響 23
4-3-1 以雙氧水為氧化劑 23
4-3-2 以硝酸鐵為氧化劑 27
4-4 綜合討論 28
第五章、結論 32
第六章、參考文獻 34
表目錄

表1-1 各種低電阻係數金屬的特性比較 37
表4-1 銅在0.0078 M檸檬酸水溶液中浸泡後，以XPS分析Cu之光譜圖可能出現的化合物 38
表4-2 銅在添加雙氧水之0.0078 M檸檬酸水溶液中以電化學交流阻抗分析之極化阻抗值 39
表4-3 應用於Reynold數和Sherwood數計算之係數值 40


圖目錄

圖2-1 Cu-H2O之波貝斯圖 41
圖3-1 實驗流程圖 42
圖3-2 裝置示意圖 43
圖4-1 靜止狀態下，銅在含不同雙氧水濃度(0、2、4、6、12 vol %)之0.0078 M 檸檬酸水溶液中之動電位極化曲線 44
圖4-2 雙氧水濃度對銅在0.0078 M 檸檬酸水溶液中腐蝕電位之影響 45
圖4-3 靜止狀態下，銅在含不同雙氧水濃度(0、2、4、6、12 vol % )之0.0078 M 檸檬酸水溶液中之開路電位曲線 46
圖4-4 雙氧水濃度對銅在0.0078 M 檸檬酸水溶液中溶解速率之影響 47
圖4-5 銅在商用研磨液中，雙氧水濃度對溶解速率的影響 48
圖4-6 銅在含雙氧水之0.0078 M 檸檬酸水溶液中的混合電位示意圖 49
圖4-7 銅在含不同的雙氧水濃度之0.0078 M 檸檬酸水溶液中AES分析 50
圖4-8 銅在含不同的雙氧水濃度(0、2、4、6、12 vol % )之0.0078 M 檸檬酸水溶液中浸泡1小時後，經XPS分析所得之銅的光譜圖 51
圖4-9 銅在(a) 0.0078 M Citric Acid、(b) 0.0078 M Citric Acid + 2 vol. % H2O2水溶液中浸泡1小時後，經XPS分析所得之Cu ( 2p 3/2 ) 的光譜圖 52
圖4-10 靜止狀態下，銅在含不同的雙氧水濃度( 0、2、4、6、12 vol. % )之0.0078 M 檸檬酸水溶液中的電化學交流阻抗測試之Nyquist圖 53
圖4-11 靜止狀態下，銅在含不同的雙氧水濃度(0、2、4、6、12 vol. % )之0.0078 M 檸檬酸水溶液中之Bode圖 54
圖4-12 銅在含雙氧水之0.0078 M 檸檬酸水溶液中電化學特性等效電路圖 55
圖4-13 雙氧水濃度對銅在0.0078 M 檸檬酸水溶液中極化阻抗值之影響 56
圖4-14 利用AFM觀察表面型態，(a)以#2000砂紙研磨後的表面型態、(b)浸泡在0.0078 M Citric Acid、(c)浸泡在0.0078 M Citric Acid + 2 vol. % H2O2 水溶液中，(d)浸泡在0.0078 M Citric Acid + 6 vol. % H2O2 、(e)浸泡在0.0078 M Citric Acid + 12 vol. % H2O2 水溶液中之表面型態。 57
圖4-15 銅在含不同硝酸鐵濃度( 0、0.01、0.1、0.2 M )之0.0078 M 檸檬酸水溶液中的動電位極化曲線 59
圖4-16 硝酸鐵濃度對銅在0.0078 M 檸檬酸水溶液中溶解速率之影響 60
圖4-17 銅在含硝酸鐵之0.0078 M 檸檬酸水溶液中的混合電位示意圖 61
圖4-18 銅在含不同硝酸鐵濃度( 0、0.1、0.2 M )之0.0078 M 檸檬酸水溶液中浸泡1小時後，經分析XPS所得之銅的的光譜圖 62
圖4-19 銅在含硝酸鐵的0.0078 M 檸檬酸水溶液中電化學交流阻抗測試之Nyquist圖 63
圖4-20 銅在含硝酸鐵的0.0078 M 檸檬酸水溶液中電化學交流阻抗測試之Bode圖 64
圖4-21 利用AFM觀察表面型態，(a)以#2000砂紙研磨後、(b)浸泡在0.0078 M Citric Acid、(c)浸泡在0.0078 M Citric Acid + 0.1 M硝酸鐵水溶液中之表面型態。 65
圖4-22 銅在轉速100 rpm時，添加不同雙氧水濃度(0、2、4、6、12 vol % )之0.0078 M 檸檬酸水溶液中，其動電位極化曲線圖 66
圖4-23 銅在轉速1000 rpm時，添加不同雙氧水濃度(0、2、4、6、12 vol % )之0.0078 M 檸檬酸水溶液中，其動電位極化曲線圖 67
圖4-24 銅在轉速3000 rpm時，添加不同雙氧水濃度(0、2、4、6、12 vol % )之0.0078 M 檸檬酸水溶液中，其動電位極化曲線圖 68
圖4-25 銅在不同雙氧水濃度( 0、2、4、6、12 vol. % )之0.0078 M檸檬酸水溶液中，腐蝕電位與雙氧水濃度、轉速變因間之關係圖 69
圖4-26 銅在不同雙氧水濃度中電位隨時間變化圖 70
圖4-27 銅在不同雙氧水濃度( 0、2、4、6、12 vol. % )之0.0078 M檸檬酸水溶液中雙氧水濃度與轉速對溶解速率影響之關係圖 71
圖4-28 轉速對銅在含雙氧水之0.0078 M檸檬酸水溶液中浸泡1小時後之XPS光譜圖的影響(a) 0.0078 M CA + 2 vol. % H2O2 、(b) 0.0078 M CA + 2 vol. % H2O2 72
圖4-29 不同轉速對銅在含6 vol. % 雙氧水的檸檬酸水溶液中浸泡1小時後，經XPS分析所得之銅的光譜圖影響(a) static、(b) 100 rpm、(c) 3000 rpm 73
圖4-30 銅在轉速100 rpm時，在添加不同的硝酸鐵濃度(0、0.01、0.1、0.2 M )之0.0078 M 檸檬酸水溶液中，其動電位極化曲線圖 74
圖4-31 銅在轉速1000 rpm時，在添加不同的硝酸鐵濃度(0、0.01、0.1、0.2 M )之0.0078 M 檸檬酸水溶液中，其動電位極化曲線圖 75
圖4-32 硝酸鐵濃度與轉速對銅在0.0078 M檸檬酸水溶液中腐蝕電位影響之關係圖 76
圖4-33 硝酸鐵濃度與轉速對銅在0.0078 M檸檬酸水溶液中溶解速率影響之關係圖 77
圖4-34 不同轉速對銅在含0.1M硝酸鐵之0.0078 M檸檬酸水溶液中浸泡1小時後的XPS光譜圖之影響 (a) static、(b) 100 rpm 、(c) 1000 rpm 78
圖4-35 銅在含不同氧化劑之0.0078 M 檸檬酸水溶液中之動電位極化曲線圖 79
圖4-36 銅在含不同氧化劑之0.0078 M 檸檬酸水溶液中(a)電位和pH值變化圖、(b)長時間(24h)靜置後電位和pH值變化示意圖。 80
圖4-37 轉速對銅在含不同氧化劑之0.0078 M 檸檬酸水溶液中的溶解速率影響 81
圖4-38 銅在含不同氧化劑之0.0078 M 檸檬酸水溶液中的Re數-Sh數關係圖 82
致謝 83
自述 84
聲明書85

1.Shyam P. Murarka, “Multilevel interconnections for ULSI and GSI era”, Materials Science and Engineering, pp. 87-151 (1997).
2.R. Carpio, J. Farkas, and R. Jairath, "Initial Study on Copper CMP Slurry Chemistries", Thin Solid Film, 266, pp. 238-244 (1995).
3.R. Gutmann, J. Steigerwald, L. You, D. Price, J. Neirynck, D. Duqutte, and S. Murarka, “Chemical-Mechanical Polishing of copper with oxide and polymer inter-level dielectrics”, Thin Solid Film 270, pp. 596-600 (1995).
4.M. Pourbaix, Atlas of Electrochemical Equilibria in Aqueous Solutions, NACE, Houston, TX (1975).
5.H. Hirabayashi, M. Higuchi, M. Kinoshita, H. Hagasaka, K. Mase, J. Oshima, “Proceedings of the 1st International VMIC Specialty Conference on CMP Planarization ”, Santa Clara, CA, Feb., p. 119 (1996).
6.J. M. Steigerwald, S. P. Murarka, R. J. Gutmann, in “Chemical Mechanical Planarization of Microelectronic Materials”, John & Wiley Sons, Inc., NY (1997).
7.D. Zeidler, Z. Stavreva, M. Plotner, K. Drescher, “Characterization of Cu chemical-mechanical polishing by electrochemical investigations”, Microelectronic Engineering, 33, pp. 259-265 (1997).
8.Stavreva, Z. Zeidler, M., and Drescher, "Characteristic in Chemical -Mechanical Polish of Copper: Comparison of Polishing Pads" Applied Surface Science, 108, pp. 39-44 (1997).
9.Stavreva, Z. Zeidler, D. Plotner, M., and Drescher, “Influence of Process Parameters on Chemical-Mechanical Polish of Copper”, Microelectronic Engineering, 37 / 38, pp. 143-149 (1997).
10.Stavreva, Z. Zeidler, D. Plotner, M., Grasshoff, and Drescher, "Chemical-Mechanical Polish of Copper for Interconnect Formation" Microelectronic Engineering, 33, pp. 247-259 (1997).
11.Fayolle, M. and Romagna, F., "Copper CMP Evaluation: Planarization issues", Microelectronic Engineering, 37 / 38, pp. 135-141 (1997).
12.Fayolle, M., Sicurani, E., and Morand, Y., "W CMP Process Integration: Consumables Evaluation-Electrical Results and End Point Detection", Microelectronic Engineering, 37 / 38, pp. 347-352 (1997).
13.Q. Luo, D. R. Campbell, S. V. Babu, “Proceedings of the 1st International VMIC Specialty Conference on CMP Planarization, Santa Clara, CA, Feb., p. 145 (1996).
14.Seiichi Kondo, Noriyuki Sakuma, Yoshio Homma and Naofumi Ohashi, “Chemical Mechanical Polishing of Copper Using Silica Slurry”, Electrochemical Society Processing Vol. 98-6m, p.195 (1998).
15.V. Nguyen, H. VanKranenburg, P. Woerlee, “Dependency of dishing on polish time and slurry chemistry in Cu CMP, ” Microelectronic Engineering 50, pp. 403-410 (2000).
16.K. Osseo-Asare Kamal K. Mishra, “Solution Chemical Contraints in the Chemical Mechanical Polishing of Copper: Aqueous Stability Diagrams for the Cu-H2O and Cu-NH3-H2O Systems”, Journal of Electronic Materials, Vol. 25, No.10, p. 1599 (1996).
17.R. J. Gutmann, J. Steigerwald, D. J. Duquette, S. P. Maraka, Journal of the Electrochemical Society, Vol. 142, No. 7, p. 2379 (1995).
18.R. Gutmann, J. Steigerwald, L. You, D. Price, J. Neirynck, D. Duqutte, and S. Murarka, “Chemical-Mechanical Polishing of copper with oxide and polymer inter-level dielectrics”, Thin Solid Film, Vol. 270, pp. 596-600 (1995).
19.A. E. Bolzan, I. B. Wakenge, R. C. Salvarezza, A. J. Arvia, “The behavior of copper in aqueous thiourea-containing sulphuric acid solution”, Journal of Electroanalytical Chemistry, Vol. 501, pp. 241-252 (2001).
20.E. Stupnisek, N. Galic, and R. Gasparac, ”Corrosion Inhibition of Copper in Hydrochloric Acid Under Flow Conditions”, Corrosion, Vol. 56, No.11, pp. 1105-1111 (2000).
21.M. E. Folquer, S. B. Ribotta, S. G. Real, and L. M. Gassa “Study of Copper Dissolution and Passivation Processes by Electrochemical Impedance Spectroscopy ”, Corrosion Science, Vol. 58, No.3, pp. 240-247 (2002).
22.S. Zhou, M. M. Stack and R. C. Newman, “Electrochemical Studies of Anodic Dissolution of Mild Steel in a Carbonate-Bicarbonate Buffer Under Erosion-Corrosion Conditions”, Corrosion Science, Vol. 38, No.7, pp. 1071-1084 (1996).
23.M. Eisenberg, C. W. Tobias and C. R. Wilke, Journal of the Electrochemical Society, Vol. 101, p306 (1954).
24.Practical Surface Analysis, second editon, John &Wiley (1994).
25.Jun Itoh, Taeshi Sasaki, Toshiaki Ohtsuka, “The Influence of oxide layers on initial corrosion behavior of copper in air containing water vapor and sulfur dioxide”, Corrosion Science, pp. 1539-1551 (2000).
26.F. B. Kaufman, et al., “Chemical-Mechanical Polishing for Fabricating Patterned W Metal Features as Chip Interconnects”, Journal of the Electrochemical Society, Inc., No.11, Nov., p.3460 (1991).
27.I. D. Zaytsev, G. G. Aseyev, Properties of Aqueous Solutions of Electrolytes (1998)