錫鉛銲料在過去的數十年間於電子封裝產業扮演重要的角色。隨著積體電路之元件密度與功能迅速提升，封裝元件的操作溫度與電流密度亦持續攀升，進而對銲料接點的可靠度造成相當大的影響。本研究擬探討在電流作用下錫鉛銲料與銅膜反應，銲料內部微結構及銲料兩端先驅物所產生的變化。
首先以黃光微影製程製備實驗所需之圖形化銅膜試片，隨後將錫鉛銲料置於銅膜上，放在加熱平台再通入電流使銲料潤濕在銅薄膜上。研究結果顯示銲料兩端鉛析出相的分佈呈不對稱的情形，在陽極端有柱狀鉛析出，其生成長度與通入之電流密度及通電時間呈線性關係，而且柱狀鉛的成長方向與電流方向有密切關係。實驗結果顯示柱狀鉛成長之活化能約為165.1 KJ/mole。
在銲料先驅物研究方面，實驗結果顯示銲料的潤濕行為與流動特性受電流所影響，使得銲料兩端先驅物區生成之鉛析出相與介金屬相分佈有所不同。另外在銲料先驅物寬度量測方面發現其受銲料熔融潤濕時的溫度與助銲劑的影響較大，與施加的電流大小並無絕對的關係。

Lead-tin solder has played an important role in microelectronic packaging for the past few decades. The current density and the operation temperature in the packaged devices rise substantially with the increase in device density and functionality for integrated circuits, which may result in severe reliability problems of solder joints. In this study, the soldering reaction between eutectic lead-tin solders and copper thin films and the evolution of solder microstructure and wetting precursors under electric current stressing were investigated.
The patterned copper thin film samples were prepared by conventional photolithography techniques. The sample was placed on a preheated hotplate with a solder ball sitting on the center of the Cu strip. The solder melted and reacted with the Cu metallization after applying an electric current through the Cu strip. The results showed that there was an asymmetric distribution of Pb precipitates in the anode side and the cathode side of the solder. It was found that Pb precipitates aggregated and formed in columnar shape at the anode side, and the length of the Pb columnar precipitates increased proportionally with both the current density applied and the reaction time. The direction of the Pb columnar precipitates appeared to depend on the direction of the current applied. Besides, the activation energy for the growth of Pb columnar precipitates was measured to be 165.1 KJ/mole.
The effect of electric current on solder wetting behavior and solder precursor was also investigated. An asymmetric distribution of Pb precipitate and intermetallic compounds was observed in the precursor bands of both sides of the solder. It was also found that the width of the solder precursor band was mainly affected by the temperature and the flux applied on the samples during soldering reaction instead of the stressing electric current.

參考文獻:
1. M. L. Minges, “Packaging”, Electronic Materials Handbook, Vol.1, ASM International, Materials Park, Ohio (1898).
2. D. P. Seraphim, R. C. Lasky and C-Y. Li, “Principle of Electronic Package”, McGraw-Hill, New York (1993).
3. 蕭麗娟碩士論文，“SnAgCu無鉛銲料與BGA之Au/Ni墊層反應之研究”，國立中央大學化材所 (2002)。
4. 呂宗興，“電子構裝技術的發展歷程”，工業材料115期，p. 49 (1996)。
5. 魏仲廷碩士論文，“錫/銅薄膜界面反應之動力學研究”，國立清華大學材料所 (2004)。
6. R. J. Wassink, “Soldering in Electronics”, Electrochemical Pub. Ltd., p. 99 (1984).
7. T. Y. Lee, K. N. Tu, S. M. Kuo, D. R. Frear, “Electromigration of eutectic SnPb solder interconnects for flip chip technology”, J. Applied Physics, Vol. 89, No. 6, p. 3189 (2001).
8. D. R. Frear, S. N. Burchett, M. K. Neilsen, J. J. Stephens, “Microstructurally based finite-element simulation of solder joint behavior”, Soldering & Surface Mount Technology, Vol. 25, p. 39 (1997).
9. H. B. Huntington, “Diffusion in Solids : Recent Developement”, edited by A. S. Nowick and J. J. Burton, Academic Press, New York, p. 303 (1975).
10. Hua Ye, Cemal Basaran, Douglas Hopkins, “Thermomigration in Pb-Sn solder joints under joule heating during electric current stressing”, Appl. Phys. Lett. Vol. 82, No. 58, p. 1045 (2003).
11. Hua Ye, Cemal Basaran, Douglas Hopkins, “Pb phase coarsening in eutectic Pb/Sn flip chip solder joints under electric current stressing”, International Journal of Solids and Structures, Vol. 41, p. 2743 (2004).
12. D. Gupta, K. Vieregge, W. Gust, “Interface diffusion in eutectic Pb-Sn solder”, Acta Mater., Vol. 47, No. 1, p. 5 (1999).
13. G. A. Rinne, “Issues in accelerated electromigration of solder bumps”, Microelectronics Reliability, Vol. 43, p. 1975 (2003).
14. G. A. Rinne, “Electromigration in SnPb and Pb-Free solder Bumps”, Proceedings of Electronic Components and Technology Conference, p. 974 (2004).
15. J. W. Morris, Jr., D. Tribula, T. S. E. Summers, D. Grivas, “The role of microstructure in thermal fatigue of Pb-Sn solder joints”, Solder Joint Reliability, p. 225 (1991).
16. D. A. Porter, “Phase transformations in metals and alloys”, Chapman & Hall, New York, p. 45 (1992).
17. 簡朝和，“Kinetic Processes in Materials”, 材料動力學課程講義，國立清華大學材料所 (2004)。
18. K. N. Tu, R. D. Thompson, “Kinetics of interfacial reaction in bimetallic Cu-Sn thin films”, Acta Metall, Vol. 30, p. 947 (1982).
19. K. N. Tu, “Interdiffusion and Reaction in Bimetallic Cu-Sn Thin Films”, Acta Metall., Vol. 21, p. 347 (1973).
20. K. N. Tu, “Cu/Sn interfacial Reactions: Thin-Film Case Versus Bulk Case”, Mat. Chem. And Phys., Vol. 46, p. 217 (1996).
21. Y. C. Chan, Alex C. K. So, J. K. L. Lai, “Growth kinetic studies of Cu-Sn intermetallic compound and its effect on shear strength of LCCC SMT solder joints”, Material Science and Engineering B, Vol. 55, p.5(1998).
22. K. N. Tu, T. Y. Lee, J. W. Jang, L. Li, D. R. Frear, K. Zeng, J. K. Kivilahti, “Wetting reaction versus solid state aging of eutectic SnPb on Cu”, J. Appl. Phys., Vol. 89, No. 9, p. 4843 (2001).
23. A. Liu, H. K. Kim, K. N. Tu, Paul A. Totta, “Spalling of Cu6Sn5 spheroids in the soldering reaction of eutectic SnPb on Cr/Cu/Au thin fuls”, J. Appl. Phys., Vol. 80, No. 5, p. 2774 (1996).
24. H. K. Kim, H. K. Liou, K. N. Tu, “Three-dimensional morphology of a very rough interface formed in the soldering reaction between eutectic SnPb and Cu”, Appl. Phys. Lett. Vol. 66(18), p. 2337 (1995).
25. H. K. Kim, K. N. Tu, “Rate of consumption of Cu in soldering accompanied by ripening”, Appl. Phys. Lett. 67(14), p. 2002 (1995).
26. Ahmed Sharif, Y. C. Chan, “Dissolution kinetics of BGA Sn-Pb and Sn-Ag solders with Cu substrates during reflow”, Materials Science and Engineering B, Vol. 106, p.126 (2004).
27. G. Ghosh, “Kinetics of Interfacial Reaction Between Eutectic Sn-Pb Solder and Cu/Ni/Pd Metallizations”, Journal of Electronic Materials, Vol.28, No. 11, p.1238 (1999).
28. W. H. Muller, “Morphology changes in solder joints-experimental evidence and physical understanding”, Microelectronics Reliability 44, p.1901 (2004).
29. L. J. van der Pauw, “A method of measuring specific resistivity and Hall coefficient on lamellae of arbitrary shape”, Philips Technical Review, Vol. 20, p. 220 (1958).
30. Timothy J. Singler, James A. Clum, Edward R. Prack, “Dynamics of Soldering Reactions: Microscopic Observations”, Microscopy Research and Technique, Vol. 25, p. 509 (1993).
31. Q. T. Huynh, C. Y. Liu, Chih Chen, K. N. Tu, “Electromigration in eutectic SnPb solder lines”, J. Appl. Phys., Vol. 89, No. 8, p. 4332 (1996).
32. Handbook of Chemistry and Physics, 55th ed. (CRC, Cleveland, 1974).
33. K. N. Tu, James W. Mayer, Leonard C. Feldman, Electronic Thin Film Science For Electrical Engineers and Materials Scientists, p. 360 (Macmillan Publishing Company, New York, 1992).
34. M. M. Mostafa, “Steady state creep characteristics of the eutectic Pb-Sn alloy”, Physica B, Vol. 349, p. 56 (2004).