目前發展的無鉛銲錫以錫(Sn)為基底元素，添加銅(Cu)、銀(Ag)、鉍(Bi)、鋅(Zn)等微量元素之合金。其中以銀-錫-銅三元合金為一大主流，成分以Sn-3.0Ag-0.5Cu (in wt %)最被廣泛使用。金屬銅除了在銲錫被添加使用外，在電子業中更是最常被使用的基材材料，因此銅在電子產業佔有舉足輕重的地位；另外於金屬銅添加鋅元素的黃銅合金，因具有較佳的延展性及良好的加工性質，用於製造精密儀器、端子及電子零組件，亦是被常使用的基材材料。本研究主要針對以五種無鉛銲錫Sn、Sn-3.0wt % Ag-0.5wt % Cu (SAC)、Sn-0.7wt % Cu (SC)、Sn-58wt % Bi (SB)、Sn-9wt % Zn (SZ)與金屬表面處理Au/Pd/Ni/Cu和Au/Pd/Ni/Brass兩種基材，於反應溫度240、255、270℃下，反應時間為20分鐘、1、2、4、8、20小時，以反應偶形式進行液/固反應，探討其界面反應行為。

實驗結果顯示，在基材Au/Pd/Ni/Cu方面，與純Sn的界面反應中，界面處的介金屬相由(Ni,Cu)3Sn4相，轉變生成為(Cu,Ni)6Sn5相與Cu3Sn相。SAC/Au/Pd/Ni/Cu及SC/Au/Pd/Ni/Cu反應偶中，界面處的介金屬相主要為(Cu,Ni)6Sn5相與Cu3Sn相共存。SB/Au/Pd/Ni/Cu反應偶中，界面處的鍍層Ni依然保留完整阻障，其生成相為Ni3Sn4相。SZ/Au/Pd/Ni/Cu反應偶中，鍍層Ni亦是保留完整阻障，反應初期界面處可觀察到Pd2Zn9相與NiZn相生成；當反應時間延長至4小時，除了Pd2Zn9相外，還會有NiZn相與Ni5Zn21相共存於界面處。

在基材Au/Pd/Ni/Brass方面，與銲錫Sn、SAC、SC的界面反應中，於較短時間20分鐘時，雖然有大部分鍍層Ni未完全消耗，但是界面處的介金屬相主要為(Cu,Ni)6Sn5相與CuZn相。隨著反應時間拉長及反應溫度上升，(Cu,Ni)6Sn5相逐漸成長粗大且有逐漸往銲錫中脫離之現象，CuZn相則由不連續狀趨於連續狀成長。SB/Au/Pd/Ni/Brass反應偶中，反應前期鍍層Ni依然保留完整阻障，界面生成物主要為Ni3Sn4相。當反應時間增加至8小時，大部分Ni鍍層逐漸消耗被破壞，界面生成物主要以(Ni,Cu)3Sn4、(Cu,Ni)6Sn5、CuZn三種介金屬相存在。當反應時間增加至20小時，界面處的(Ni,Cu)3Sn4相消失，留下(Cu,Ni)6Sn5相與CuZn相共存。SZ/Au/Pd/Ni/Brass反應偶中，反應前期鍍層Ni亦是保留完整阻障，界面生成物主要為Pd2Zn9相與Ni5Zn21相。當反應時間增加至8小時，鍍層Ni完全被消耗，界面生成物依然為Pd2Zn9相與Ni5Zn21相。當反應時間增加至20小時，界面處的生成相則轉變為CuZn5、Pd2Zn9、Ni5Zn21、Cu5Zn8四種介金屬相共存。

Pb-free solders have attracted much attention to replace the conventional Sn-Pb solders owing to an environmental issue. Popular lead-free solders are Sn, Sn-3.0Ag-0.5Cu, Sn-0.7Cu, Sn-58Bi and Sn-9Zn (in wt %). Multilayer structures of Au/Pd/Ni/Cu and Au/Pd/Ni/Brass are commonly used in printed circuit boards. This study investigates the interfacial reaction between Pb-free solders and two different kinds of substrates (Au/Pd/Ni/Cu and Au/Pd/Ni/Brass). The reflow temperature was at 240, 255 and 270℃, while the reflow time was varied between 20 minutes and 20 hours. The surface morphology and IMC formation are examined as well.

According to experimental results, the IMCs changed from (Ni,Cu)3Sn4 to (Cu,Ni)6Sn5 and Cu3Sn at the interface of Sn/Au/Pd/Ni/Cu couple. In the Sn-3.0Ag-0.5Cu/Au/Pd/Ni/Cu and Sn-0.7Cu/Au/Pd/Ni/Cu couples, there were two IMCs such as (Cu,Ni)6Sn5 and Cu3Sn at the interface. In the Sn-58Bi/Au/Pd/Ni/Cu couple, only a Ni3Sn4 IMC was observed between the solder and Ni layer. In the Sn-9Zn/Au/Pd/Ni/Cu couple, the Pd2Zn9 and NiZn phases were formed at the interface. After reflow for 4 hours, the Pd2Zn9, NiZn, and Ni5Zn21 phases were formed at the interface.

On the other hand, there were two IMCs such as (Cu,Ni)6Sn5 and CuZn at the interface which are in the Sn/Au/Pd/Ni/Brass, Sn-3.0Ag-0.5Cu/Au/Pd/Ni/Brass, and Sn-0.7Cu/Au/Pd/Ni/Brass couples respectively. In the Sn-58Bi/Au/Pd/Ni/Brass couple, only a Ni3Sn4 IMC was observed between the solder and Ni layer. Until the reaction time of 8 hours, the (Ni,Cu)3Sn4, (Cu,Ni)6Sn5, and CuZn phases were formed at the interface. In the Sn-9Zn/Au/Pd/Ni/Brass couple, the Pd2Zn9 and Ni5Zn21 phases were formed at the interface. After reflow for 20 hours, the CuZn5, Pd2Zn9, Ni5Zn21, and Cu5Zn8 phases were formed at the interface.

1. C. H. Wang, S. W Chen, “Sn-0.7 wt.% Cu/Ni interfacial reactions at 250℃”, Acta Materialia, vol. 54, pp. 247-253 (2006)
2. S. W. Chen and Y. W. Yen, “Interfacial reactions in Ag-Sn/Cu couples”, Journal of Electronic Materials, vol. 28, pp. 1203-1208 (1999)
3. J. W. Yoon, S. B. Jung, “Interfacial reactions between Sn-0.4Cu solder and Cu substrate with or without ENIG plating layer during reflow reaction”, Journal of Alloys and Compounds, vol. 396, pp. 122-127 (2005)
4. J. W. Yoon, S. B. Jung, “Investigation of interfacial reactions between Sn-5Bi solder and Cu substrate”, Journal of Alloys and Compounds, vol. 359, pp. 202-208 (2003)
5. J. W. Yoon, S. W. Kim, S. B. Jung, “Effect of reflow time on interfacial reaction and shear strength of Sn-0.7Cu solder Cu and electroless Ni-P BGA joints” , Journal of Alloys and Compounds, vol. 385, pp. 192-198 (2004)
6. J. W. Yoon, S. W. Kim, S. B. Jung, “IMC morphology, interfacial reaction and joint reliability of Pb-free Sn-Ag-Cu solder on electrolytic Ni BGA substrate”, Journal of Alloys and Compounds, vol. 392, pp. 247-252 (2005)
7. C. Y. Lee, J. W. Yoon, Y. J. Kim, S. B. Jung, “Interfacial reactions and joint reliability of Sn-9Zn solder on Cu or electrolytic Au/Ni/Cu BGA substrate” , Microelectronic Engineering , vol. 82, pp. 561-568 (2005)
8. J. W. Yoon, S. W. Kim, S. B. Jung, “Effects of reflow and cooling conditions on interfacial reaction and IMC morphology of Sn-Cu/Ni solder joint”, Journal of Alloys and Compounds, vol. 415, pp. 56-61 (2006)
9. W. H. Tao, C. Chen, C. E. Ho, W. T. Chen, C. R. Kao, “Selective Interfacial Reaction between Ni and Eutectic BiSn Lead-Free Solder”, Chemical Materials, vol. 13, pp. 1051-1056 (2001)
10. 劉雨雯，“RoSH綠色指令：全球環境規範&無鉛銲接技術”，龍璟文化 (2005)
11. W. T. Chen, C. E. Ho, C. R. Kao, “Effect of Cu concentration on the interfacial reactions between Ni and Sn-Cu solders”, Journal of Materials Research, vol. 17, pp. 263-266 (2002)
12. C. E. Ho, R. Y. Tsai, Y. L. Liu, C. R. Kao, “Effect of Cu concentration on the reactions between Sn-Ag-Cu solders and Ni”, Journal of Electronic Materials, vol. 31, pp. 584-590 (2002)
13. C. E. Ho, Y. W. Lin, S. C. Yang, C. R. Kao, “Effects of Limited Cu supply on Soldering Reactions Between SnAgCu and Ni”, vol. 35, pp. 1017-1024 (2006)
14. S. K. Kang, D. Y. Shih, K. Fogel, P. Lauro, M. J. Yim, G. Advocate, M. Griffin, C. Goldsmith, D. W. Henderson, T. Gosselin, D. King, J. Konrad, A. Sarkhel, K. J. Puttlitz, “Interfacial Reaction Studies on Lead (Pb)-Free Solder Alloys”, IEEE, vol. 25, pp. 155-160 (2002)
15. 陳娟娟，“綠色環保新趨勢”，台灣工銀投顧 (2005)
16. 黃育智、楊青峰、陳信文，“軟銲”，科學發展期刊，416期 (2007)
17. T. B. Massalski, Binary Alloy Phase Diagrams, William W. Scott, vol. 1, pp. 71 (1986)
18. I. Karakaya and W. T. Thompson, ASM Handbook vol. 3 Alloy Phase Diagrams, edited by H. Baker, ASM International, Materials Park, Ohio (1987)
19. S. Choi, J. G. Lee, F. Guo, T. R. Bieler, K. N. Subramanian, and J. P. Lucas, “Creep properties of Sn-Ag solder joints containing intermetallic particles”, Journal of Materials, vol. 53(6), pp. 22-26 (2001)
20. K. N. Tu, J. C. M. Li, “Spontaneous whisker growth on lead-free solder finishes”, Materials Chemistry and Physics, vol. 409, pp. 131-139 (2005)
21. M. O. Alam, Y. C. Chan, K. N. Tu, “Effect of 0.5wt.% Cu addition in Sn-3.5Ag solder on the dissolution rate of Cu metallization”, Journal of Applied Physics, vol. 94, pp. 7904-7909 (2003)
22. N. Saunders and A. P. Miodownik, ASM Handbook vol. 3 Alloy Phase Diagrams, edited by H. Baker, ASM International, Materials Park, Ohio (1990)
23. S. H. Huh, K. S. Kim, K. Suganuma, “Effect of Ag addition on the microstructural and mechanical properties of Sn-Cu eutectic solder”, Mater. Trans., vol. 42, pp. 739-744 (2001)
24. H. Okamoto, ASM Handbook vol. 3 Alloy Phase Diagrams, edited by H. Baker, ASM International, Materials Park, Ohio (1990)
25. P. L. Liu and J. K. Shang, “Interfacial segregation of bismuth in copper/tin-bismuth solder interconnect”, Scripta Mater., vol. 44, pp. 1019-1023 (2001)
26. Z. Moser, J. Dutkiewicz, W. Gasior, J. Salawa, ASM Handbook vol. 3 Alloy Phase Diagrams, edited by H. Baker, ASM International, Materials Park, Ohio (1985)
27. 余鐵城，“表面處理”，全華圖書 (1988)
28. A. G. Robert. and E.F. Morris, “Growth of η-phase scallops and whisker in liquid tin-solid copper reaction couples”, Journal of Materials, vol. 53, pp. 33-38 (2001)
29. K. N. Tu and R. D. Thompson, Acta Metall., vol. 30, pp. 947-952 (1981)
30. K. N. Tu, “Cu/Sn interfacial reactions: Thin-film case versus bulk case”, Materials Chemistry and Physics, v 46, p 217-223 (1996)
31. F. Bartels, J. W. Morris, Jr., G. Dalke, and W. Gust, “Intermetallic phase formation in thin solid-liquid diffusion couples”, Journal of Electronic Materials, vol. 23, p 787-790 (1994)
32. Y. W. Yen, PhD. Thesis, “Phase Equilibria of the ternary Ag-Sn-Cu and Ag-Sn-Au systems, and interfacial reactions in Ag-Sn/Cu and Ag-Sn/Au couples”, National Tsing-Hua University (2002)
33. H. Oikawa and A. Hosoi, “High-temperature creep mechanisms in alpha-iron and an Fe_Mo alloy determined by stress-relaxation tests”, Scripta Metallurgica, vol. 9, pp. 823-828 (1975)
34. C. M. Chuang, K. L. Lin, “Effect of Microelements Addition on the Interfacial Reaction between Sn-Ag-Cu Solders and the Cu Substrate”, Journal of Electronic Materials, vol. 32, pp. 1426-1431 (2003)
35. S. W. Shin, J. Yu, “Creep deformation of Sn-3.5Ag-xCu and Sn-3.5Ag-xBi solder joints”, Journal of Electronic Materials, vol. 34, pp. 188-195 (2005)
36. M. J. Rizvi, Y. C. Chan, C. Bailey , H. Lu, M. N. Islam, “Effect of adding 1 wt% Bi into the Sn-2.8Ag-0.5Cu solder alloy on the intermetallic formations with Cu-substrate during soldering and isothermal aging”, Journal of Alloys and Compounds, vol. 407, pp. 208-214 (2006)
37. H. Nishikawa, “Interfacial reaction between Sn-0.7Cu(-Ni) solder and Cu substrate”, Journal of Electronic Materials, vol. 35, pp. 1127-1132 (2006)
38. A. Hayashi, C. R. Kao, and Y. A. Chang, “Reactions of solid copper with pure liquid tin and liquid tin saturated with copper”, Scripta Materialia, vol. 37, pp. 393-398 (1997)
39. D. P. He, D. Q. Yu, W. Lai, C. M. Lawrence, ”Effect of Cu content on IMC between Sn-Cu solder and Cu and Ni substrates”, Zhongguo Youse Jinshu Xuebao/Chinese Journal of Nonferrous Metals, vol. 16, pp. 701-708 (2006)
40. P. T. Vianco, A. C. Kilgo, and R. Grant, “Intermetallic compound layer growth by solid state reactions between 58Bi-42Sn solder and copper”, Journal of Electronic Materials, vol. 24, pp. 1493-1505 (1995)
41. C. Y. Chou, PhD. Thesis, “Interfacial Stabilities in the Thermal Inkjet Printing System”, National Tsing-Hua University (2006)
42. D. Q. Yu, H. P. Xie, L. Wang, “Investigation of interfacial microstructure and wetting property of newly developed Sn-Zn-Cu solders with Cu substrate”, Journal of Alloys and Compounds, vol. 385, pp. 119-125 (2004)
43. C. Y. Chou, S. W. Chen, Y. S. Chang, ”Interfacial reactions in the Sn-9Zn-(xCu)/Cu and Sn-9Zn-(xCu)/Ni couples”, Journal of Materials Research, vol. 21, pp. 1849-1856 (2006)
44. L. Wang, H. T. Ma, H. P. Xie, D. Q. Yu, “Interfacial reaction and shear strength of Sn-Zn-Cu/Cu joints”, Dalian Ligong Daxue Xuebao/Journal of Dalian University of Technology, vol. 45, pp. 663-667 (2005)
45. P. Nash and A. Nash, ASM Handbook vol. 3 Alloy Phase Diagrams, edited by H. Baker, ASM International, Materials Park, Ohio (1991)
46. T. Laurila, V. Vuorinen, and J.K. Kivilahti, “Interfacial reactions between lead-free solders and common base materials”, Materials Science and Engineering, Review 49, pp. 1-60 (2005)
47. S. Bader, W. Gust, H. Hieber, “Rapid formation of intermetallic compounds by interdiffusion in the Cu-Sn and Ni-Sn systems”, Acta. Metall. Mater., vol. 43, pp. 329-337 (1995)
48. D. Gur and M. Bamberger, “Reactive isothermal solidification in the Ni-Sn system ”, Acta Materialia, vol. 46, pp. 4917-4923 (1998)
49. W. J. Tomlinson and H. G. Rhodes, “Kinnetics of intermetallic compound growth between nickel, electroless Ni-P, electroless Ni-B and tin at 453 to 493 K”, Journal of Materials Science, vol. 22(5), pp. 1769-1772 (1987)
50. S. W. Chen, C. M. Chen and W. C. Liu, “The electric current effects upon the Sn/Cu and Sn/Ni interfacial reactions”, Journal of Electronic Materials, vol. 27(11), pp. 1193-1198 (1998)
51. J. Haimovich, “Intermetallic compound growth in tin and tin-lead platings over nickel and its effects on solderability”, Welding Research Supplement, vol. 68(3), pp. 102-111 (1989)
52. S. K. Kang and V. Ramachandran , “Growth kinetics of intermetallic phases at the liquid Sn and solid Ni interface”, Scripta Metall., vol. 14, pp. 421-424 (1980)
53. J. A. Van Beek, S. A. Stolk, and F. J. Jvan Loo, Zeitschrift Fur Meatalkunde, vol. 73(7), pp. 439-444 (1982)
54. C. M. Liu, M. S. Thesis, National Central University, Taiwan (2000)
55. L. Y. Hsiao, S. T. Kao and J. G. Duh, “Characterizing metallurgical reaction of Sn3.0Ag0.5Cu composite solder by mechanical alloying with electro-less Ni-P/Cu under-bump metallization after various reflow cycles”, Journal of Electronic Materials, vol. 35, pp. 81-88 (2006)
56. J. W. Yoon, S. W. Kim, J. A. M. Koo, D. G. Kim, S. B. Jung, “Reliability investigation and interfacial reaction of ball-grid-array packages using the lead-free Sn-Cu solder”, Journal of Electronic Materials, vol. 33, pp. 1190-1199 (2004)
57. D. Q Yu., C.M. Lawrence, D. P. He, N. Zhao, Wang Lai, J. K. Lin, “Effects of Cu contents in Sn-Cu solder on the composition and morphology of intermetallic compounds at a solder/Ni interface”, Journal of Materials Research, vol. 20, pp. 2205-2212 (2005)
58. J. Wang, H.S. Liu, L.B. Liu, and Z.P. Jin, “Interfacial Reaction between Sn-Bi Alloy and Ni Substrate”, Journal of Electronic Materials, vol. 35, pp. 1842-1847 (2006)
59. P. Nash, and Y. Y. Pan, ASM Handbook vol. 3 Alloy Phase Diagrams, edited by H. Baker, ASM International, Materials Park, Ohio (1991)
60. T. Shimozaki and M. Onishi, “Frame of reference and intrinsic diffusion coefficients for binary interdiffusion”, Journal of the Japan Institute of Metals, vol. 45, pp. 1221-1222 (1981)
61. Y. W. Yen, W. K. Liou, “Effect of Cu Addition on Interfacial Reaction between Sn-9Zn Lead-Free Solder and Ni Substrate”, Journal of Materials Research, vol. 22 (2007)
62. C. H. Lin, S. W. Chen, C. H. Wang, J. Electron. Mater., vol. 31, pp. 907-915 (2002)
63. H. Okamoto, ASM Handbook vol. 3 Alloy Phase Diagrams, edited by H. Baker, ASM International, Materials Park, Ohio (1990)
64. W. Hume-Rothery, J. W. Christian, and W. B. Pearson, “Metallurgical Equilibrium Diagrams”, The Institute of Physics, London, 1952
65. B. F. Dyson, T. R. Anthony and D. Turnbull, “Interstitial Diffusion of Copper in Tin”, Journal of Applied Physics, vol. 38, pp. 3408-3416 (1967)