本研究係探討錫銀系無鉛銲錫與Cu、Au電極結合後於電遷移環境下之界面反應、介金屬化合物之成長動力學以及表面形貌變化。實驗共分為兩部份，第一部份為將Au以薄膜(Thin Film)方式濺鍍於Cu與銲錫之間以製作Cu/Au/Sn4Ag0.5Cu/Cu薄膜試片，藉以探討當Au原子為有限制供應時，其於1.0×103 A/cm2、2.0×103 A/cm2電流密度通電下之移動行為與界面反應；第二部份為將Au以塊材(Bulk)方式與Cu、銲錫接合形成Cu/Sn3.5Ag/Au三明治結構，藉以探討當Cu、Au原子皆無限供應時，其於2.6×103 A/cm2，100℃通電環境下的遷移行為、表面結構變化以及界面生成介金屬化合物之種類。
第一部份結果顯示以Au為陰極通電後Au原子朝陽極方向遷移，經短時間通電後Au固溶於銲錫中之Cu6Sn5內以形成(Cu,Au)6Sn5。長時間通電後則因(Cu,Au)6Sn5中的Au達飽和濃度，因此過多的Au則和Sn形成AuSn4析出附著於(Cu,Au)6Sn5/solder界面上。以Au為陽極通電後因銲錫中的Sn原子朝陽極遷移的結果造成大量AuSn4生成於陽極界面上，但因(Cu,Au)6Sn5為熱力學上穩定之介金屬化合物，因此長時間通電後半穩態的AuSn4將分解並釋放Au原子朝逆電流方向固溶至Cu6Sn5中以形成(Cu,Au)6Sn5。
以Cu為陰或陽極通電後界面上只形成Cu6Sn5，且因Cu原子朝陽極遷移之緣故，陰極產生Cu6Sn5的同時也伴隨大量孔洞生成於Cu/Cu6Sn5界面上。Cu為陰極時，其電遷移造成之Cu消耗率、Cu6Sn5成長速率、Cu6Sn5成長指數及其成長係數於1.0×103 A/cm2電流密度通電下分別為2.24×10-7 μm/s、6.33×10-7 μm/s、n=0.65及5.72×10-9 cm2/s；於2.0×103 A/cm2通電下則為5.17×10-7 μm/s、7.72×10-7 μm/s、n=0.63以及1.41×10-8 cm2/s。同時，電遷移誘發之陰極Cu原子幾乎完全形成界面Cu6Sn5，且不同電流密度造成之擴散通量( )及DZ＊分別為2.50×1012 atom/cm2.s、5.26×10-10 cm2/s(1.0×103 A/cm2)和5.88×1012 atom/cm2.s、6.18×10-10 cm2/s(2.0×103 A/cm2)。本研究之電遷移效應使得Cu原子於Cu6Sn5中之擴散速度高於其熱時效速度達1000倍，且其擴散係數於1.0×103 A/cm2、2.0×103 A/cm2下分別為2.02×10-11 cm2/s和2.38×10-11 cm2/s。
第二部份結果顯示Au於迴焊過程中快速溶解於液態銲錫，造成迴焊後銲錫內佈滿針棒狀AuSn4。銲錫接點通電後Sn原子往陽極遷移受大晶粒AuSn4阻礙後導致壓縮應力累積，造成表面AuSn4扭轉及破裂。AuSn4扭轉提供另一個壓縮應力來源，使得鄰近未反應之銲錫受擠壓後以Sn whisker方式生成於表面上以釋放過多的壓縮應力。HR-TEM觀察Sn whisker內部結構後發現差排生成於Sn whisker中，推測Sn whisker形成過程可能歷經些微碰撞及擾動。
以Cu為陰極長時間通電後因Sn往陽極遷移的結果造成裂縫產生於(Cu,Au)6Sn5/solder界面上，而Cu往陽極遷移的結果則造成Cu電極波浪狀消耗現象。以Cu為陽極時，(Cu,Au)6Sn5之成長指數為n=0.88，接近反應控制，而時效則為n=0.43，屬於擴散控制。電遷移加速Au、Sn原子於Au5Sn中之擴散速度，使其克服動力學上之生成限制，因此陰、陽極Au電極上之介金屬化合物依序為AuSn4/AuSn2/AuSn/Au5Sn，而時效反應則為AuSn4/AuSn2/AuSn。通電後大孔洞於陰極Au電極AuSn4中及AuSn4/solder界面生成是由於Sn原子往陽極遷移之結果，而小孔洞於陰、陽極AuSn中產生則是因為相轉變後Sn原子消耗造成之結果。

In this study, the interfacial reactions, kinetics of intermetallic compound (IMC) formation and change of morphology of lead-free SnAg based solders with Cu and Au electrodes under electromigration (EM) were investigated. The present results include two sections, one is with limited supply of deposited thin Au film on solder to form a Cu/Au/Sn4Ag0.5Cu/Cu specimen under 1.0×103 A/cm2、2.0×103 A/cm2 of current stressing, the other is with unlimited supply of Cu and Au in a Cu/Sn3.5Ag/Au sandwich solder joint under 2.6×103 A/cm2, 100℃ of current stressing.
For the Cu/Au/Sn4Ag0.5Cu/Cu specimen under EM, the microstructural evolution shows that the migration of Au atoms is from the cathode towards the anode. A small amount of Au atoms dissolved in Cu6Sn5 to form (Cu,Au)6Sn5 in early stage of current stressing. After long time of current stressing, AuSn4 was formed attaching to (Cu,Au)6Sn5 that is because of the supersaturation of Au in Cu6Sn5. The migration of Sn to the anode resulted in the formation of AuSn4 at the anodic Au side; nevertheless, for a long time of current stressing, metastable AuSn4 tended to dissolve to release Au atoms in Cu6Sn5 to form stable (Cu,Au)6Sn5 regardless of the direction of electric current.
When Cu acts as the cathode or anode, Cu6Sn5 was merely formed between Cu and solder. Due to the direction of EM is the same as concentration gradient of Cu at the cathodic Cu side, a large number of Cu6Sn5 was formed which also accompanied with voids formation at the Cu/Cu6Sn5 interface. For cathodic Cu side, EM induced consumption of Cu, growth rate of Cu6Sn5, n values of growth of Cu6Sn5 and growth constant (k) of Cu6Sn5 under various current densities were calculated, respectively, to be 2.24×10-7 μm/s, 6.33×10-7 μm/s, n=0.65 and 5.72×10-9 cm2/s for 1.0×103 A/cm2 while as 5.17×10-7 μm/s, 7.72×10-7 μm/s, n=0.63 and 1.41×10-8 cm2/s for 2.0×103 A/cm2. Meanwhile, migration of Cu induced by EM was nearly consumed to form interfacial Cu6Sn5. EM induced atomic flux of Cu ( ) and DZ＊ were calculated to be 2.50×1012 atom/cm2.s, 5.26×10-10 cm2/s for 1.0×103 A/cm2 while as 5.88×1012 atom/cm2.s, 6.18×10-10 cm2/s for 2.0×103 A/cm2. The migration of Cu in Cu6Sn5 enhanced by the present current densities was higher 1000 folds as that of thermal aging and the diffusivities of Cu in Cu6Sn5 were 2.02×10-11 cm2/s for 1.0×103 A/cm2 and 2.38×10-11 cm2/s for 2.0×103 A/cm2.
In the case of Cu/Sn3.5Ag/Au solder joint, rapid dissolution of Au in molten solder resulted in the formation of needle-like AuSn4 distributed inside the solder matrix after reflow. Sn atoms migrated from the cathode towards the anode, was blocked by large grains of AuSn4, accumulated at the grain boundary which induced compressive stress, resulted in the rotation and rupture of AuSn4. Rotation of AuSn4 itself provides another source of stress for neighboring unreacted solder and thus the Sn whisker was formed on the surface to relieve the compressive stress. Dislocations piled up in the Sn whisker, revealed by HR-TEM, suggests that the growth of Sn whisker may experience turbulence.
For cathodic Cu electrode, both Sn and Cu atoms migrated from cathode to anode, these phenomena also accompanied with the crack formation at (Cu,Au)6Sn5/solder interface and consumption of wavy shape of Cu. For anodic Cu electrode, n value of growth of (Cu,Au)6Sn5 was 0.88 which demonstrates that the growth of IMC was close to reaction controlled mechanism while as 0.43 for thermal aging specimen reveals that the growth of IMC was under diffusion controlled regime. EM effect increases the diffusivities of Au and Sn in Au5Sn and makes the formation of Au5Sn become possible kinetically. Consequently, the sequence of IMC formed upon EM is AuSn4/AuSn2/AuSn/Au5Sn and for aging is AuSn4/AuSn2/AuSn. Large voids were found in AuSn4 or at AuSn4/solder interface at cathodic Au side that is because Sn atoms migrated towards the anode. Small voids were found on both cathodic and anodic AuSn that is due to the occurrence of Sn consumed by transformation of AuSn into Au5Sn.

1. William D. Callister, Jr., Materials Science and Engineering： An Introduction. 4th edition, John Wiley＆Sons, 1996.
2. M. Abtew and G. Selvaduray, ”Lead-Free Solders in Microelectronics”, Materials Science and Engineering R, Vol. 27, 2000, pp. 95~141.
3. K. Zeng and K. N. Tu, “Six Cases of Reliability Study of Pb-Free Solder Joints in Electronic Packaging Technology”, Materials Science and Engineering R, Vol. 38, 2002, pp. 55~105.
4. Y. Li, K. S. Moon and C. P. Wong, “Electronics Without Lead”, Science, Vol. 308, No. 3, 2005, pp. 1419~1420.
5. T. B. Massalski, Binary Alloy Phase Diagrams, ASM International, Materials Park, Ohio, Volume 1, 1986, p. 965.
6. D. S. Dunn, T. F. Marinis, W. M. Sherry and C. J. Williams, “Dependence of Cu/Sn and Cu/60Sn40Pb Solder Joint Strength on Diffusion Controlled Growth of Cu3Sn and Cu6Sn5”, MRS Symposium Proceedings, Vol. 40, 1984, pp.129~138.
7. T. B. Massalski, Binary Alloy Phase Diagrams, ASM International, Materials Park, Ohio, Volume 1, 1986, p. 498.
8. T. B. Massalski, Binary Alloy Phase Diagrams, ASM International, Materials Park, Ohio, Volume 1, 1986, p. 926.
9. T. B. Massalski, Binary Alloy Phase Diagrams, ASM International, Materials Park, Ohio, Volume 1, 1986, p. 981.
10. T. B. Massalski, Binary Alloy Phase Diagrams, ASM International, Materials Park, Ohio, Volume 1, 1986, p. 19.
11. K. N. Tu, “Cu/Sn Interfacial Reactions：Thin-Film Case versus Bulk Case”, Materials Chemistry and Physics, Vol. 46, No. 2-3, 1996, pp. 217~223.
12. K. N. Tu, “Interdiffusion and Reaction in Bimetallic Cu-Sn Thin Films”, Acta Metallurgica, Vol. 21, No. 4, 1973, pp. 347~354.
13. K. N. Tu and R. D. Thompson, “Kinetics of Interfacial Reaction in Bimetallic Cu-Sn Thin Films”, Acta Metallurgica, Vol. 30, No. 5, 1982, pp. 947~952.
14. P. T. Vianco, K. L. Erickson and P. L. Hopkins, “Solid State Intermetallic Compound Growth between Copper and High Temperature”, Tin-Rich Solders—Part I：Experimental Analysis”, Journal of Electronic Materials, Vol. 23, No. 8, 1994, pp. 721~727.
15. P. T. Vianco, P. F. Hlava and A. C. Kilgo, “Intermetallic Compound Layer Formation between Copper and Hot-Dipped 100In, 50In-50Sn, 100Sn, and 63Sn-37Pb Coatings”, Journal of Electronic Materials, Vol. 23, No. 7, 1994, pp. 583~594.
16. S. Bader, W. Gust and H. Hieber, “Rapid Formation of Intermetallic Compounds by Interdiffusion in the Cu-Sn and Ni-Sn Systems”, Acta Metallurgica et Materialia, Vol. 43, No. 1, 1995, pp. 329~337.
17. S. K. Kang, R. S. Rai and S. Purushothaman, “Interfacial Reactions During Soldering with Lead-Tin Eutectic and Lead(Pb)-Free, Tin-Rich Solders”, Journal of Electronic Materials, Vol. 25, No. 7, 1996, pp. 1113~1120.
18. J. O. G. Parent, D. D. L. Chung and I. M. Bernstein, “Effects of Intermetallic Formation at the Interface between Copper and Lead-Tin Solder”, Journal of Materials Science, Vol. 23, No. 7, 1988, pp. 2564~2572.
19. H. K. Kim and K. N. Tu, “Rate of Consumption of Cu in Soldering Accompanied by Ripening”, Applied Physics Letters, Vol. 67, No. 14, 1995, pp. 2002~2004.
20. T. B. Massalski, Binary Alloy Phase Diagrams, ASM International, Materials Park, Ohio, Volume 2, 1986, p. 1759.
21. T. Laurila, V. Vuorinen and J. K. Kivilahti, “Interfacial Reactions between Lead-Free Solders and Common Base Materials”, Materials Science and Engineering R, Vol. 49, 2005, pp. 1~60.
22. T. B. Massalski, Binary Alloy Phase Diagrams, ASM International, Materials Park, Ohio, Volume 1, 1986, p. 316.
23. V. B. Fiks, “On the Mechanism of the Mobility of Ions in Metals”, Soviet Physics, Solid State, Vol. 1, 1959, pp. 14~28.
24. H. B. Huntington and A. R. Grone, “Current-Induced Marker Motion in Gold Wires”, Journal of Physics and Chemistry of Solids, Vol. 20, 1961, pp. 76~87.
25. J. R. Black, “Electromigration-A Brief Survey and Some Recent Results”, IEEE Transactions on Electron Devices, Vol. ED-16, No. 4, 1969, pp. 338~347.
26. I. A. Blech, “Electromigration in Thin Aluminum Films on Titanium Nitride”, Journal of Applied Physics, Vol. 47, No. 4, 1976, pp. 1203~1208.
27. I. A. Blech and C. Herring, “Stress Generation by Electromigration”, Applied Physics Letters, Vol. 29, No. 3, 1976, pp. 131~133.
28. I. A. Blech and K. L. Tai, “Measurement of Stress Gradients Generated by Electromigration”, Applied Physics Letters, Vol. 30, No. 8, 1977, pp. 387~389.
29. J. V. Ek and A. Lodder, “Electromigration of Hydrogen in Metals：Theory and Experiment”, Defect and Diffusion Forum, Vol. 115-116, 1994, pp. 1~38.
30. G. A. Rinne, “Issues in Accelerated Electromigration of Solder Bumps”, Microelectronics Reliability, Vol. 43, 2003, pp. 1975~1980.
31. C. M. Tan and A. Roy, “Electromigration in ULSI Interconnects”, Materials Science and Engineering R, Vol. 58, 2007, pp. 1~75.
32. G. T. T. Sheng, C. F. Hu, W. J. Choi, K. N. Tu, Y. Y. Bong and L. Nguyen, “Tin Whiskers Studies by Focused Ion Beam Imaging and Transmission Electron Microscopy”, Journal of Applied Physics, Vol. 92, No. 1, 2002, pp. 64~69.
33. K. N. Tu and J. C. M. Li, “Spontaneous Whisker Growth on Lead-Free Solder Finishes”, Materials Science and Engineering A, Vol. 409, 2005, pp. 131~139.
34. K. N. Tu, “Irreversible Processes of Spontaneous Whisker Growth in Bimetallic Cu-Sn Thin-Film Reactions”, Physical Review B, Vol. 49, No. 3, 1994, pp. 2030~2034.
35. C. C. Wei, P. C. Liu, C. Chen, J. C. B. Lee and I. P. Wang, “Relieving Sn Whisker Growth Driven by Oxidation on Cu Leadframe by Annealing and Reflowing Treatments”, Journal of Applied Physics, Vol. 102, 2007, pp. 043521-1~043521-7.
36. E. Chason, N. Jadhav, W. L. Chan, L. Reinbold and K. S. Kumar, “Whisker Formation in Sn and Pb-Sn Coatings：Role of Intermetallic Growth, Stress Evolution, and Plastic Deformation Processes”, Applied Physics Letters, Vol. 92, 2008, pp. 171901-1~171901-3.
37. M. Sobiech, U. Welzel, E. J. Mittemeijer, W. Hugel and A. Seekamp, “Driving Force for Sn Whisker Growth in the System Cu-Sn”, Applied Physics Letters, Vol. 93, 2008, pp. 011906-1~011906-3.
38. S. H. Liu, C. Chen, P. C. Liu and T. Chou, “Tin Whisker Growth Driven by Electrical Currents”, Journal of Applied Physics, Vol. 95, No. 12, 2004, pp. 7742~7747.
39. C. Y. Liu, C. Chen and K. N. Tu, “Electromigration in Sn-Pb Solder Strips as a Function of Alloy Composition”, Journal of Applied Physics, Vol. 88, No. 10, 2000, pp. 5703~5709.
40. C. Y. Liu, C. Chen, C. N. Liao and K. N. Tu, “Microstructure Electromigration Correlation in a Thin Stripe of Eutectic SnPb Solder Stressed between Cu Electrodes”, Applied Physics Letters, Vol. 75, No. 1, 1999, pp. 58~60.
41. C. C. Wei, P. C. Liu, C. Chen and K. N. Tu, “Electromigration-Induced Pb and Sn Whisker Growth in SnPb Solder Stripes”, Journal of Materials Research, Vol. 23, No. 7, 2008, pp. 2017~2022.
42. F. Y. Ouyang, K. Chen, K. N. Tu and Y. S. Lai, “Effect of Current Crowding on Whisker Growth at the Anode in Flip Chip Solder Joints”, Applied Physics Letters, Vol. 91, 2007, pp. 231919-1~231919-3.
43. Y. M. Hung and C. M. Chen, “Electromigration of Sn-9wt.％Zn Solder”, Journal of Electronic Materials, Vol. 37, No. 6, 2008, pp. 887~893.
44. P. Shewmon, Diffusion in Solids. 2nd edition, Warrendale, Pennsylvania, The Minerals Metals＆Materials Society, 1989, p. 229.
45. B. F. Dyson, T. R. Anthony and D. Turnbull, “Interstitial Diffusion of Copper in Tin”, Journal of Applied Physics, Vol. 38, 1967, pp. 3408~3408.
46. Z. Mei, A. J. Sunwoo and J. W. Morris, Jr., “Analysis of Low-Temperature Intermetallic Growth in Copper-Tin Diffusion Couples”, Metallurgical Transactions A, Vol. 23A, 1992, pp. 857~864.
47. B. F. Dyson, “Diffusion of Gold and Silver in Tin Single Crystals”, Journal of Applied Physics, Vol. 37, No. 6, 1966, pp. 2375~2377.
48. T. Y. Lee, K. N. Tu, S. M. Kuo and D. R. Frear, “Electromigration of Eutectic SnPb Solder Interconnects for Flip Chip Technology”, Journal of Applied Physics, Vol. 89, No. 6, 2001, pp. 3189~3194.
49. T. Y. Lee, K. N. Tu and D. R. Frear, “Electromigration of Eutectic SnPb and SnAg3.8Cu0.7 Flip Chip Solder Bumps and Under-Bump Metallization”, Journal of Applied Physics, Vol. 90, No. 9, 2001, pp. 4502~4508.
50. F. Ren, J. W. Nah, K. N. Tu, B. Xiong, L. Xu and H. L. Pang, “Electromigration Induced Ductile-to-Brittle Transition in Lead-Free Solder Joints”, Applied Physics Letters, Vol. 89, 2006, pp. 141914-1~141914-3.
51. C. Y. Liu, J. T. Chen, Y. C. Chuang, L. Ke and S. J. Wang, “Electromigration-Induced Kirkendall Voids at the Cu/Cu3Sn Interface in Flip-Chip Cu/Sn/Cu Joints”, Applied Physics Letters, Vol. 90, 2007, pp. 112114-1~112114-3.
52. S. W. Chen and Y. W. Yen, “Interfacial Reactions in the Sn-Ag/Au Couples”, Journal of Electronic Materials, Vol. 30, No. 9, 2001, pp. 1133~1137.
53. C. W. Chang, Q. P. Lee, C. E. Ho and C. R. Kao, “Cross-Interaction between Au and Cu in Au/Sn/Cu Ternary Diffusion Couples”, Journal of Electronic Materials, Vol. 35, No. 2, 2006, pp. 366~371.
54. S. M. Kuo and K. L. Lin, “Microstructure Evolution during Electromigration between Sn-9Zn Solder and Cu”, Journal of Materials Research, Vol. 22, No. 5, 2007, pp. 1240~1249.
55. Y. C. Hu, Y. H. Lin, C. R. Kao and K. N. Tu, “Electromigration Failure in Flip Chip Solder Joints due to Rapid Dissolution of Copper”, Journal of Materials Research, Vol. 18, No. 11, 2003, pp. 2544~2548.
56. B. Chao, S. H. Chae, X. Zhang, K. H. Lu, M. Ding, J. Im and P. S. Ho, “Electromigration Enhanced Intermetallic Growth and Void Formation in Pb-Free Solder Joints”, Journal of Applied Physics, Vol. 100, 2006, pp. 084909-1~084909-10.
57. B. J. Lee, N. M. Hwang and H. M. Lee, “Prediction of Interface Reaction Products between Cu and Various Solder Alloys by Thermodynamic Calculation”, Acta Materialia, Vol. 45, No. 5, 1997, pp. 1867~1874.
58. C. Y. Liu, L. Ke, Y. C. Chuang and S. J. Wang, “Study of Electromigration-Induced Cu Consumption in the Flip-Chip Sn/Cu Solder Bumps”, Journal of Applied Physics, Vol. 100, 2006, pp. 083702-1~083702-8.
59. B. Chao, S. H. Chae, X. Zhang, K. H. Lu, J. Im and P. S. Ho, “Investigation of Diffusion and Electromigration Parameters for Cu-Sn Intermetallic Compounds in Pb-Free Solders using Simulated Annealing”, Acta Materialia, Vol. 55, 2007, pp. 2805~2814.
60. H. Gan and K. N. Tu, “Polarity Effect of Electromigration on Kinetics of Intermetallic Compound Formation in Pb-Free Solder V-Groove Samples”, Journal of Applied Physics, Vol. 97, 2005, pp. 063514-1~063514-10.
61. V. I. Dybkov, Reaction Diffusion and Solid State Chemical Kinetics, Kyiv, The IPMS Publications, 2002.
62. C. M. Chen, L. T. Chen and Y. S. Lin, “Electromigration-Induced Bi Segregation in Eutectic SnBi Solder Joint”, Journal of Electronic Materials, Vol. 36, No. 2, 2007, pp. 168~172.
63. Y. C. Hsu, C. K. Chou, P. C. Liu, C. Chen, D. J. Yao, T. Chou and K. N. Tu, “Electromigration in Pb-Free SnAg3.8Cu0.7 Solder Stripes”, Journal of Applied Physics, Vol. 98, 2005, pp. 033523-1~033523-6.
64. C. C. Wei and C. Y. Liu, “Electromigration Studies of Sn(Cu) and Sn(Ni) Alloy Stripes”, Journal of Materials Research, Vol. 20, No. 8, 2005, pp. 2072~2079.
65. C. M. Tsai, Y. S. Lai, Y. L. Lin, C. W. Chang and C. R. Kao, “In-Situ Observation of Material Migration in Flip-Chip Solder Joints under Current Stressing”, Journal of Electronic Materials, Vol. 35, No. 10, 2006, pp. 1781~1786.
66. H. Y. Hsiao and C. Chen, “Thermomigration in Flip-Chip SnPb Solder Joints under Alternating Current Stressing”, Applied Physics Letters, Vol. 90, 2007, pp. 152105-1~152105-3.
67. F. Y. Ouyang, K. N. Tu, Y. S. Lai and A. M. Gusak, “Effect of Entropy Production on Microstructure Change in Eutectic SnPb Flip Chip Solder Joints by Thermomigration”, Applied Physics Letters, Vol. 89, 2006, pp. 221906-1~221906-3.
68. D. Yang, B. Y. Wu, Y. C. Chan and K. N. Tu, “Microstructural Evolution and Atomic Transport by Thermomigration in Eutectic Tin-Lead Flip Chip Solder Joints”, Journal of Applied Physics, Vol. 102, 2007, pp. 043502-1~043502-6.
69. Y. C. Chuang and C. Y. Liu, “Thermomigration in Eutectic SnPb Alloy”, Applied Physics Letters, Vol. 88, 2006, pp. 174105-1~174105-3.
70. A. T. Huang, A. M. Gusak, K. N. Tu and Y. S. Lai, “Thermomigration in SnPb Composite Flip Chip Solder Joints”, Applied Physics Letters, Vol. 88, 2006, pp. 141911-1~141911-3.
71. H. P. R. Frederikse, R. J. Fields and A. Feldman, “Thermal and Electrical Properties of Copper-Tin and Nickel-Tin Intermetallics”, Journal of Applied Physics, Vol. 72, No. 7, 1992, pp. 2879~2882.
72. M. Onishi and H. Fujibuchi, “Reaction-Diffusion in the Cu-Sn System”, Transactions of the Japan Institute of Metals, Vol. 16, 1975, pp. 539~547.
73. L. Y. Hsiao, G. Y. Jang, K. J. Wang and J. G. Duh, “Inhibiting AuSn4 Formation by Controlling the Interfacial Reaction in Solder Joints”, Journal of Electronic Materials, Vol. 36, No. 11, 2007, pp. 1476~1482.
74. A. T. Wu, A. M. Gusak, K. N. Tu and C. R. Kao, “Electromigration-Induced Grain Rotation in Anisotropic Conducting Beta Tin”, Applied Physics Letters, Vol. 86, 2005, pp. 241902-1~241902-3.
75. S. M. Kuo and K. L. Lin, “The Hillock Formation in a Cu/Sn-9Zn/Cu Lamella upon Current Stressing”, Journal of Electronic Materials, Vol. 36, No. 10, 2007, pp. 1378~1382.
76. Y. W. Chang, S. W. Liang and C. Chen, “Study of Void Formation due to Electromigration in Flip-Chip Solder Joints using Kelvin Bump Probes”, Applied Physics Letters, Vol. 89, 2006, pp. 032103-1~032103-3.
77. J. W. Nah, K. W. Paik, J. O. Suh and K. N. Tu, “Mechanism of Electromigration-Induced Failure in the 97Pb-3Sn and 37Pb-63Sn Composite Solder Joints”, Journal of Applied Physics, Vol. 94, 2003, pp. 7560~7566.
78. W. H. Wu, H. L. Chung, C. N. Chen and C. E. Ho, “The Influence of Current Direction on the Cu-Ni Cross-Interaction in Cu/Sn/Ni Diffusion Couples”, Journal of Electronic Materials, Vol. 38, No. 12, 2009, pp. 2563~2572.
79. L. Zhang, S. Ou, J. Huang, K. N. Tu, S. Gee and L. Nguyen, “Effect of Current Crowding on Void Propagation at the Interface between Intermetallic Compound and Solder in Flip Chip Solder Joints”, Applied Physics Letters, Vol. 88, 2006, pp. 012106-1~012106-3.
80. A. Paul, A. A. Kodentsov and F. J. J. Van Loo, “Intermetallic Growth and Kirkendall Effect Manifestations in Cu/Sn and Au/Sn Diffusion Couples”, Zeitschrift fur Metallkunde, Vol. 95, No. 10, 2004, pp. 913~920.
81. S. Nakahara, R. J. Mccoy, L. Buene and J. M. Vandenberg, “Room Temperature Interdiffusion Studies of Au/Sn Thin Film Couples”, Thin Solid Films, Vol. 84, 1981, pp. 185~196.
82. D. Gregersen, L. Buene, T. Finstad, O. Lønsjø and T. Olsen, “A Diffusion Marker in Au/Sn Thin Films”, Thin Solid Films, Vol. 78, 1981, pp. 95~102.
83. W. Tang, A. He, Q. Liu and D. G. Ivey, “Room Temperature Interfacial Reactions in Electrodeposited Au/Sn Couples”, Acta Materialia, Vol. 56, 2008, pp. 5818~5827.
84. C. Ghosh, “Interdiffusion Study in Binary Gold-Tin System”, Intermetallics, Vol. 18, 2010, pp. 2178~2182.