本研究於Zn-25Sn合金中微量添加鈦元素，分析此系列銲錫合金與銅、鎳基板接合後，再經熱時效處理，對其界面反應與微結構的影響。Zn-25Sn與鎳基板經迴焊後，會在界面生成單層Ni5Zn21介金屬化合物，其界面反應為反應控制機制。微量添加鈦元素後，會使反應轉變為擴散控制機制，同時Ni5Zn21介金屬化合物的成長活化能會由63.24 kJ/mol下降至37.74 kJ/mol。而Ni5Zn21依據其晶粒形貌可大致分為三個區域，分別為凝核區、柱狀晶區，以及由等軸晶與柱狀晶共同組成的混合區域，在時效過程中，Ni5Zn21的厚度成長主要來自柱狀晶區晶粒的成長。Zn-25Sn與銅基板經迴焊後，則會在界面生成CuZn5及Cu5Zn8介金屬化合物。Cu5Zn8與總體介金屬化合物(CuZn5 + Cu5Zn8)的成長活化能，經過微量鈦元素添加後，也與鎳接點呈現類似趨勢，分別從39.74 kJ/mol及48.91 kJ/mol略微下降至35.91 kJ/mol及44.92 kJ/mol。迴焊試片界面分為由細晶粒所構成的CuZn5與晶粒較為粗大的Cu5Zn8，經時效處理後，可以發現在原先粗大Cu5Zn8 晶粒與銅基板之間生成了一層由細小Cu5Zn8 晶粒所構成的組織，而其界面介金屬化合物的成長，主要就來自這層細小Cu5Zn8晶粒在數量上的成長。

This study investigated the effects of minor addition of Ti on the interfacial reactions and microstructure variation of Ni/25Sn-xTi/Ni, Cu/Zn-25Sn-xTi/Cu solder joints during thermal aging. IMC formed between Zn-25Sn-xTi solder and Ni substrate was identified as Ni5Zn21. The interfacial Ni5Zn21 growth was controlled by the chemical reaction at first. After the addition of Ti, the activation energy of Ni5Zn21 growth decreased from 63.24 kJ/mol to 37.74 kJ/mol and the rate-controlling step changed to the volume diffusion. According to the grain morphology, Ni5Zn21 could be divided into three different zones: nucleation zone, columnar zone and mixed zone. Ni5Zn21 grains in columnar zone grew significantly after aging treatment. The interfacial IMCs formed between Zn-25Sn and Cu substrates were CuZn5 and Cu5Zn8. CuZn5 phase transformed to Cu5Zn8 after aging at 250℃ for 36h in this study. The activation energy of Cu5Zn8 and total IMC (CuZn5 + Cu5Zn8) growth changed from 39.74 to 35.91 kJ/mol and 48.91 to 44.92 kJ/mol, respectively. Ti addition slightly lowered the activation energy of Cu-Zn IMC growth. CuZn5 consisted of extremely fine grains while Cu5Zn8 was comprised of coarser grains. The total IMC growth during aging processes was mainly ascribed to the increase in the number of the newly-formed finer Cu5Zn8 grains between the original Cu5Zn8 IMC and Cu substrate.

[1] S. E. Thompson and S. Parthasarathy, "Moore's law: the future of Si microelectronics," Materials today, vol. 9, no. 6, 20-25, 2006.
[2] K. Suganuma, S.-J. Kim, and K.-S. Kim, "High-temperature lead-free solders: Properties and possibilities," JOM Journal of the Minerals, Metals and Materials Society, vol. 61, no. 1, p. 64, 2009.
[3] L. Meng, J. Gao, Y. Zhong, Z. Wang, K. Chen, and Z. Guo, "Supergravity separation for recovering Pb and Sn from electronic waste," Separation and Purification Technology, vol. 191, 375-383, 2018.
[4] S. Menon, E. George, M. Osterman, and M. Pecht, "High lead solder (over 85%) solder in the electronics industry: RoHS exemptions and alternatives," Journal of Materials Science: Materials in Electronics, vol. 26, no. 6, 4021-4030, 2015.
[5] K.-N. Tu, A. M. Gusak, and M. Li, "Physics and materials challenges for lead-free solders," Journal of applied Physics, vol. 93, no. 3, 1335-1353, 2003.
[6] V. Chidambaram, J. Hattel, and J. Hald, "Design of lead-free candidate alloys for high-temperature soldering based on the Au–Sn system," Materials & Design, vol. 31, no. 10, 4638-4645, 2010.
[7] G. Zeng, S. McDonald, and K. Nogita, "Development of high-temperature solders," Microelectronics Reliability, vol. 52, no. 7, 1306-1322, 2012.
[8] A. He and D. Ivey, "Electrodeposition of Au-Sn alloys for lead-free solders: Au-rich eutectic and Sn-rich eutectic compositions," in 2013 IEEE International Symposium on Advanced Packaging Materials, 2013: IEEE, 52-68.
[9] D. Ivey, "Microstructural characterization of Au/Sn solder for packaging in optoelectronic applications," Micron, vol. 29, no. 4, 281-287, 1998.
[10] Q. Wang, S.-H. Choa, W. Kim, J. Hwang, S. Ham, and C. Moon, "Application of Au-Sn eutectic bonding in hermetic radio-frequency microelectromechanical system wafer level packaging," Journal of electronic materials, vol. 35, no. 3, 425-432, 2006.
[11] I. Karakaya and W. Thompson, "The Ag-Bi (silver-bismuth) system," Journal of phase equilibria, vol. 14, no. 4, 525-530, 1993.
[12] J.-M. Song, H.-Y. Chuang, and T.-X. Wen, "Thermal and tensile properties of Bi-Ag alloys," Metallurgical and Materials Transactions A, vol. 38, no. 6, 1371-1375, 2007.
[13] J.-M. Song, H.-Y. Chuang, and Z.-M. Wu, "Interfacial reactions between Bi-Ag high-temperature solders and metallic substrates," Journal of electronic materials, vol. 35, no. 5, 1041-1049, 2006.
[14] J.-M. Song, H.-Y. Chuang, and Z.-M. Wu, "Substrate dissolution and shear properties of the joints between Bi-Ag alloys and Cu substrates for high-temperature soldering applications," Journal of Electronic Materials, vol. 36, no. 11, 1516-1523, 2007.
[15] M. Shimoda, T. Yamakawa, K. Shiokawa, H. Nishikawa, and T. Takemoto, "Effects of Ag content on the mechanical properties of Bi-Ag alloys substitutable for Pb based solder," Transactions of JWRI, vol. 41, no. 2, 51-54, 2012.
[16] S. Masaru, O. Kaoru, O. Kohei, T. Yoshihiro, M. Shigeyuki, and F. Hidetoshi, "Dissimilar spot welding of aluminium alloy and galvannealed steel by metal flow-application of friction anchor welding to aluminium alloy and Zn-coated steel," Welding International, vol. 32, no. 6, 377-389, 2018.
[17] S.-J. Kim, K.-S. Kim, S.-S. Kim, C.-Y. Kang, and K. Suganuma, "Characteristics of Zn-Al-Cu alloys for high temperature solder application," Materials transactions, vol. 49, no. 7, 1531-1536, 2008.
[18] N. Kang, H. S. Na, S. J. Kim, and C. Y. Kang, "Alloy design of Zn–Al–Cu solder for ultra high temperatures," Journal of Alloys and compounds, vol. 467, no. 1-2, 246-250, 2009.
[19] T. Shimizu, H. Ishikawa, I. Ohnuma, and K. Ishida, "Zn-Al-Mg-Ga alloys as Pb-free solder for die-attaching use," Journal of electronic materials, vol. 28, no. 11, 1172-1175, 1999.
[20] T. Gancarz, J. Pstruś, P. Fima, and S. Mosińska, "Thermal properties and wetting behavior of high temperature Zn-Al-In solders," Journal of materials engineering and performance, vol. 21, no. 5, 599-605, 2012.
[21] X. Wei, H. Huang, L. Zhou, M. Zhang, and X. Liu, "On the advantages of using a hypoeutectic Sn–Zn as lead-free solder material," Materials letters, vol. 61, no. 3, 655-658, 2007.
[22] J.-E. Lee, K.-S. Kim, K. Suganuma, J. Takenaka, and K. Hagio, "Interfacial properties of Zn–Sn alloys as high temperature lead-free solder on Cu substrate," Materials Transactions, vol. 46, no. 11, 2413-2418, 2005.
[23] J.-E. Lee, K.-S. Kim, K. Suganuma, M. Inoue, and G. Izuta, "Thermal properties and phase stability of Zn-Sn and Zn-In alloys as high temperature lead-free solder," Materials transactions, vol. 48, no. 3, 584-593, 2007.
[24] S. Kim, K.-S. Kim, S.-S. Kim, and K. Suganuma, "Interfacial reaction and die attach properties of Zn-Sn high-temperature solders," Journal of Electronic Materials, vol. 38, no. 2, 266-272, 2009.
[25] R. Mahmudi and M. Eslami, "Shear strength of the Zn–Sn high-temperature lead-free solders," Journal of Materials Science: Materials in Electronics, vol. 22, no. 8, 1168-1172, 2011.
[26] R. Mahmudi and M. Eslami, "Impression creep behavior of Zn-Sn high-temperature lead-free solders," Journal of electronic materials, vol. 39, no. 11, 2495-2502, 2010.
[27] C.-h. Wang, H.-h. Chen, and P.-y. Li, "Interfacial reactions of high-temperature Zn–Sn solders with Ni substrate," Materials Chemistry and Physics, vol. 136, no. 2-3, 325-333, 2012.
[28] W.-C. Huang and K.-L. Lin, "Effect of Ti addition on early-stage wetting behavior between Zn-25Sn-xTi solder and Cu," Journal of Electronic Materials, vol. 45, no. 12, 6137-6142, 2016.
[29] X. Niu and K.-L. Lin, "Investigations of the wetting behaviors of Zn–25Sn, Zn–25Sn–XPr and Zn–25Sn–YAl high temperature lead free solders in air and Ar ambient," Journal of Alloys and Compounds, vol. 646, 852-858, 2015.
[30] X. Niu and K.-L. Lin, "The microstructure and mechanical properties of Zn-25Sn-XAl (X= 0–0.09 wt%) high temperature lead free solder," Materials Science and Engineering: A, vol. 677, 384-392, 2016.
[31] X. Niu and K.-L. Lin, "Effects of Al, Pr additions on the wettability and interfacial reaction of Zn–25Sn solder on Cu substrate," Journal of Materials Science: Materials in Electronics, vol. 28, no. 1, 105-113, 2017.
[32] A. Lis, M. S. Park, R. Arroyave, and C. Leinenbach, "Early stage growth characteristics of Ag3Sn intermetallic compounds during solid–solid and solid–liquid reactions in the Ag–Sn interlayer system: Experiments and simulations," Journal of alloys and compounds, vol. 617, 763-773, 2014.
[33] C.-h. Wang, H.-h. Chen, P.-y. Li, and P.-y. Chu, "Kinetic analysis of Ni5Zn21 growth at the interface between Sn–Zn solders and Ni," Intermetallics, vol. 22, 166-175, 2012.
[34] C. Hang, Y. Tian, R. Zhang, and D. Yang, "Phase transformation and grain orientation of Cu–Sn intermetallic compounds during low temperature bonding process," Journal of Materials Science: Materials in Electronics, vol. 24, no. 10, 3905-3913, 2013.
[35] L. Liu, W. Zhou, B. Li, and P. Wu, "Interfacial reactions between Sn–8Zn–3Bi–xNi lead-free solders and Cu substrate during isothermal aging," Materials Chemistry and Physics, vol. 123, no. 2-3, 629-633, 2010.
[36] J. Shen, Y. C. Chan, and S. Liu, "Growth mechanism of Ni3Sn4 in a Sn/Ni liquid/solid interfacial reaction," Acta Materialia, vol. 57, no. 17, 5196-5206, 2009.
[37] S. Fashu and R. Khan, "Recent work on electrochemical deposition of Zn-Ni (-X) alloys for corrosion protection of steel," Anti-Corrosion Methods and Materials, 2019.
[38] J.-M. Song, M.-J. Lin, K.-H. Hsieh, T.-Y. Pai, Y.-S. Lai, and Y.-T. Chiu, "Ball impact reliability of Zn-Sn high-temperature solder joints bonded with different substrates," Journal of electronic materials, vol. 42, no. 9, 2813-2821, 2013.
[39] D. Sarwono and K.-L. Lin, "Wetting and IMC Growth Behavior Between Cu Substrate and Zn-25Sn-xCu-yTi High-Temperature Solder Alloys," Journal of Electronic Materials, vol. 48, no. 1, 99-106, 2019.
[40] W. Chen, S. Xue, H. Wang, Y. Hu, and J. Wang, "Effects of rare earth Ce on properties of Sn–9Zn lead-free solder," Journal of Materials Science: Materials in Electronics, vol. 21, no. 7, 719-725, 2010.
[41] C. Wu, C. Law, D. Yu, and L. Wang, "The wettability and microstructure of Sn-Zn-RE alloys," Journal of Electronic Materials, vol. 32, no. 2, 63-69, 2003.
[42] C. L. Wu, D. Yu, C. Law, and L. Wang, "The properties of Sn-9Zn lead-free solder alloys doped with trace rare earth elements," Journal of electronic materials, vol. 31, no. 9, 921-927, 2002.
[43] A. L. Allred, "Electronegativity values from thermochemical data," Journal of inorganic and nuclear chemistry, vol. 17, no. 3-4, 215-221, 1961.
[44] Z. Ning, Y. He, and W. Gao, "Mechanical attrition enhanced Ni electroplating," Surface and Coatings Technology, vol. 202, no. 10, 2139-2146, 2008.
[45] Z.-H. Ning and Y.-D. He, "Rapid electroplating of Cu coatings by mechanical attrition method," Transactions of Nonferrous Metals Society of China, vol. 18, no. 5, 1100-1106, 2008.
[46] C. Grovenor, H. Hentzell, and D. Smith, "The development of grain structure during growth of metallic films," Acta Metallurgica, vol. 32, no. 5, 773-781, 1984.
[47] R. E. Reed-Hill, R. Abbaschian, and R. Abbaschian, Physical metallurgy principles. Van Nostrand New York, 1973.
[48] C. V. Thompson, "Structure evolution during processing of polycrystalline films," Annual review of materials science, vol. 30, no. 1, 159-190, 2000.
[49] J. Mittal and K.-L. Lin, "Diffusion of elements during reflow ageing of Sn-Zn solder in liquid state on Ni/Cu substrate–theoretical and experimental study," Soldering & Surface Mount Technology, 2018.
[50] A. H. Sulaymon, S. Mohammed, and A. H. Abbar, "Characterization and electrochemical preparation of thin films of binary heavy metals (Cu-Pb, Cu-Cd, Cu-Zn) from simulated chloride wastewaters," Int J Electrochem Sci, vol. 9, 6328-6351, 2014.
[51] C.-m. Chen and C.-h. Chen, "Interfacial reactions between eutectic SnZn solder and bulk or thin-film Cu substrates," Journal of electronic materials, vol. 36, no. 10, 1363-1371, 2007.
[52] F. Xing, J. Yao, J. Liang, and X. Qiu, "Influence of intermetallic growth on the mechanical properties of Zn–Sn–Cu–Bi/Cu solder joints," Journal of Alloys and Compounds, vol. 649, 1053-1059, 2015.
[53] N.-S. Liu and K.-L. Lin, "Evolution of interfacial morphology of Sn–8.5 Zn–0.5 Ag–0.1 Al–xGa/Cu system during isothermal aging," Journal of alloys and compounds, vol. 456, no. 1-2, 466-473, 2008.
[54] J. Pstruś, "Early stages of wetting of copper by Sn–Zn eutectic alloy," Journal of Materials Science: Materials in Electronics, vol. 29, no. 24, 20531-20545, 2018.
[55] C.-y. Chou and S.-w. Chen, "Phase equilibria of the Sn–Zn–Cu ternary system," Acta Materialia, vol. 54, no. 9, 2393-2400, 2006.
[56] R. Mayappan and Z. A. Ahmad, "Effect of Bi addition on the activation energy for the growth of Cu5Zn8 intermetallic in the Sn–Zn lead-free solder," Intermetallics, vol. 18, no. 4, 730-735, 2010.
[57] H. Ma, L. An, L. Qu, J. Wang, L. Gu, and M. Huang, "Interfacial reaction between Sn-9Zn/Sn double layers solder and Cu," in 2012 13th International Conference on Electronic Packaging Technology & High Density Packaging, 2012: IEEE, 393-397.