本研究探討Sn-58Bi銲料於不同熱儲存溫度（60℃與110℃）及不同熱儲存時間（500 hrs、800 hrs與1100hrs）下進行熱儲存實驗，觀察銲料在微觀結構與硬度，以及透過循環腐蝕試驗(Cyclic Corrosion Test，CCT)，來模擬銲料經過熱儲存後之耐腐蝕性能變化，並探討銲料於高電流密度下進行長時間的實驗後，而導致微觀結構的變化與電性耐受性的影響。
研究結果顯示，Sn-58Bi銲料微觀結構由富Bi相與富Sn相所組成，隨著熱預算的增加，微觀結構中的富Bi相與富Sn中的初晶Bi相比例也隨之增加，介面金屬共化物(IMC，Intermetallic Compound) Cu6Sn5於迴銲時就已經產生，而Cu3Sn化合物在經過熱儲存110℃ 500hrs時才開始生成，且IMC層的厚度隨著熱預算的增加而增加。IMC層在生成初期呈現線性生長，當Cu6Sn5增加至一定厚度後，會作為Cu基板與Sn元素間的阻擋層，使Cu6Sn5生成速度減緩，且擴散反應較難以進行，因此Cu基板開始與Cu6Sn5中的Sn元素進行擴散反應，形成Cu3Sn，其活化能經過計算為36.52 kJ/mol·K。
由於Bi元素硬度較Sn元素高，因此經過熱儲存後，銲料中富Bi相與富Sn相中的初晶Bi相面積增加，而導致硬度隨著熱預算的增加而增加。
由動電位極化曲線結果顯示，隨著熱預算的增加，試件的腐蝕電位值下降，而腐蝕電流密度則上升，因此試件耐腐蝕性能會隨著熱預算的增加而降低。
試件於110℃下進行 500hrs、800hrs與1100hrs的熱儲存後，透過循環腐蝕試驗探討銲料之耐腐蝕性能，由於Sn元素活性較大，因此富Sn相較優先被腐蝕，而富Bi相受到富Sn相的保護，較慢開始受到腐蝕。未熱儲存試件經過1 cycle CCT後，於晶界處開始產生孔蝕，並隨著熱儲存時間的增加，逐漸往富Sn相腐蝕，由於熱儲存造成富Bi相面積增加，而富Sn相面積減少，使伽凡尼效應加劇。熱儲存條件110℃ 1100hrs的試件，於CCT 7 cycles後，富Bi相與富Sn相皆被腐蝕，在富Sn相皆被腐蝕後，生成顆粒特徵的腐蝕產物 SnO2，隨後初晶Bi相開始腐蝕，呈現花瓣狀特徵的腐蝕產物Bi2O3。
銲料於電流密度8000A/cm2下進行電性耐受性實驗，實驗初期電壓值與溫度值隨著實驗時間緩慢增加，於280hrs時電壓值與溫度增加幅度明顯上升。在微觀結構上觀察，富Bi相於陽極處聚集，並於銲料內部開始產生孔洞，使電壓值與焦耳熱增加，當實驗至340hrs時電壓值與溫度明顯上升，銲料內部產生更多的孔洞與裂紋，當電子流不斷衝擊原子，使原子產生位移而形成孔洞，孔洞逐漸增加將導致通道變得更加擁擠，且焦耳加熱更為嚴重，此時銲料已經明顯惡化，當隨著實驗的進行，電壓值與焦耳熱的增加將使銲料可靠性能降低。

This study investigates Sn-58Bi solder thermal storage experiments at temperatures (60 & 110) °C and thermal storage times (500, 800 & 1100) hours, evaluating the effect of Sn-58Bi solder on microstructure, hardness, and corrosion resistance after thermal storage, as well as long-term experiments to evaluate solder at high current density (8000A/cm2), effects on solder microstructure and Voltage value.
Grain coarsening appears under the observed microstructure, IMC Cu6Sn5 produced during within the reflow, and the thickness of the IMC layer increases with thermal budget, yielding IMC Cu3Sn compounds when thermally stored at 110°C for 500hrs.
Thermal storage increases Bi phase area in solder, thereby increasing the overall hardness of the solder.
Polarization curve measurement results display, solder corrosion resistance declines as thermal budget increases, and the specimens without thermal storage have better corrosion resistance.
Sn-58Bi solder was tested in 1 & 7 cycles of corrosion test, in the early stage of corrosion, pitting corrosion occurs at the grain boundaries and diffuses into the Sn-rich phase, and the increase in thermal budget makes the corrosion more serious, formation of granular SnO2 and petal-shaped Bi2O3 corrosion products. Electrical endurance tests were performed for 280 and 340 hours, respectively, with the increase of test time, the temperature and Voltage value increase, holes and cracks are created inside the solder, and the Bi-rich phase aggregates at the anode to form a Bi-rich layer.
After the Electrical endurance test for 340 hours, solder reliability is reduced because the solder is severely deteriorated by increased Joule heating.

[1] K. Suganuma, "Advances in lead-free electronics soldering," Curr. Opin. Solid State Mat. Sci., Review vol. 5, no. 1, pp. 55-64, Jan 2001.
[2] J. Chriastel'ova and M. Ozvold, "Properties of solders with low melting point," J. Alloy. Compd., Article vol. 457, no. 1-2, pp. 323-328, Jun 2008.
[3] L. R. Garcia, W. R. Osorio, L. C. Peixoto, and A. Garcia, "Wetting Behavior and Mechanical Properties of Sn-Zn and Sn-Pb Solder Alloys," J. Electron. Mater., Article vol. 38, no. 11, pp. 2405-2414, Nov 2009.
[4] E. P. Wood and K. L. Nimmo, "IN SEARCH OF NEW LEAD-FREE ELECTRONIC SOLDERS," J. Electron. Mater., Article; Proceedings Paper vol. 23, no. 8, pp. 709-713, Aug 1994.
[5] K. G. Scheckel et al., "AMENDING SOILS WITH PHOSPHATE AS MEANS TO MITIGATE SOIL LEAD HAZARD: A CRITICAL REVIEW OF THE STATE OF THE SCIENCE," J. Toxicol. Env. Health-Pt b-Crit. Rev., Review vol. 16, no. 6, pp. 337-380, Aug 2013.
[6] M. Oguchi, H. Sakanakura, and A. Terazono, "Toxic metals in WEEE: Characterization and substance flow analysis in waste treatment processes," Sci. Total Environ., Article vol. 463, pp. 1124-1132, Oct 2013.
[7] S. H. Wang, T. S. Chin, C. F. Yang, S. W. Chen, and C. T. Chuang, "Pb-free solder-alloy based on Sn-Zn-Bi with the addition of germanium," J. Alloy. Compd., Article vol. 497, no. 1-2, pp. 428-431, May 2010.
[8] Y. Liu and K. N. Tu, "Low melting point solders based on Sn, Bi, and In elements," Mater. Today Adv., vol. 8, p. 100115, 2020.
[9] O. R. Adetunji, R. A. Ashimolowo, P. O. Aiyedun, O. M. Adesusi, H. O. Adeyemi, and O. R. Oloyede, "Tensile, hardness and microstructural properties of Sn-Pb solder alloys," Materials Today: Proceedings, vol. 44, pp. 321-325, 2021.
[10] S. H. Jin, "DEVELOPING LEAD-FREE SOLDERS - A CHALLENGE AND OPPORTUNITY," JOM-J. Miner. Met. Mater. Soc., Editorial Material vol. 45, no. 7, pp. 13-13, Jul 1993.
[11] L. J. Turbini, "Chemical Changes for Lead-Free Soldering and Their Effect on Reliability," Lead‐Free Solders: Materials Reliability for Electronics, pp. 179-194, 2012.
[12] M. Ooida, F. Taniguchi, T. Iwasaki, A. Ono, Y. Asano, and Y. Hiruta, "Advanced packaging technologies supporting new semiconductor application," in 2016 IEEE CPMT Symposium Japan (ICSJ), pp. 125-128, 7-9 Nov, 2016.
[13] F. X. Huang, J. S. Ma, H. L. Ning, Y. W. Cao, and Z. T. Geng, "Precipitation in Cu-Ni-Si-Zn alloy for lead frame," Mater. Lett., Article vol. 57, no. 13-14, pp. 2135-2139, Apr 2003.
[14] O. Brand and H. Achour, "Packaging," in Reference Module in Materials Science and Materials Engineering: Elsevier, 2016.
[15] J. X. Hu, B. Jing, Z. J. Sheng, F. Lu, Y. J. Chen, and Y. L. Zhang, "Failure and failure characterization of QFP package interconnect structure under random vibration condition," Microelectron. Reliab., Article vol. 91, pp. 120-127, Dec 2018.
[16] C. Liu, J. Wang, A. Zhang, and H. Ding, "Research on the fault diagnosis technology of intermittent connection failure belonging to FPGA solder-joints in BGA package," Optik, vol. 125, no. 2, pp. 737-740, 2014.
[17] V. Kiran Sanipini, B. Rakesh, A. Jyothi Chamanthula, N. Santoshi, A. Arunkumar Gudivada, and A. Kumar Panigrahy, "Thermal management in TSV based 3D IC Integration: A survey," Materials Today: Proceedings, vol. 45, pp. 1742-1746, 2021.
[18] K. N. Tu and Y. X. Liu, "Recent advances on kinetic analysis of solder joint reactions in 3D IC packaging technology," Mater. Sci. Eng. R-Rep., Review vol. 136, pp. 1-12, Apr 2019.
[19] L. E. Felton, C. H. Raeder, and D. B. Knorr, "THE PROPERTIES OF TIN-BISMUTH ALLOY SOLDERS," JOM-J. Miner. Met. Mater. Soc., Article vol. 45, no. 7, pp. 28-32, Jul 1993.
[20] W. J. Tomlinson and I. Collier, "THE MECHANICAL-PROPERTIES AND MICROSTRUCTURES OF COPPER AND BRASS JOINTS SOLDERED WITH EUTECTIC TIN BISMUTH SOLDER," J. Mater. Sci., Article vol. 22, no. 5, pp. 1835-1839, May 1987.
[21] S. Abdelaziz, H. Zahran, and D. A. Abd El-Rehim, "Microstructure and mechanical properties of tin-bismuth solder alloy reinforced by antimony oxide nanoparticles," International Journal of Advances in Engineering & Technology, vol. 10, pp. 73-83, 2017.
[22] B.-G. Park, W.-R. Myung, C.-J. Lee, and S.-B. Jung, "Mechanical, electrical, and thermal reliability of Sn-58wt.%Bi solder joints with Ag-decorated MWCNT for LED package component during aging treatment," Composites Part B: Engineering, vol. 182, p. 107617, 2020.
[23] C. H. Raeder, L. E. Felton, V. A. Tanzi, and D. B. Knorr, "THE EFFECT OF AGING ON MICROSTRUCTURE, ROOM-TEMPERATURE DEFORMATION, AND FRACTURE OF SN-BI/CU SOLDER JOINTS," J. Electron. Mater., Article; Proceedings Paper vol. 23, no. 7, pp. 611-617, Jul 1994.
[24] Z. Mei and J. W. Morris, "CHARACTERIZATION OF EUTECTIC SN-BI SOLDER JOINTS," J. Electron. Mater., Article vol. 21, no. 6, pp. 599-607, Jun 1992.
[25] Y. Goh, A. Haseeb, and M. F. M. Sabri, "Effects of hydroquinone and gelatin on the electrodeposition of Sn-Bi low temperature Pb-free solder," Electrochim. Acta, Article vol. 90, pp. 265-273, Feb 2013.
[26] Z. Hou et al., "Alloying regulation mechanism toward microstructure evolution of Sn-bi-based solder joint under current stress," Materials Characterization, p. 112094, 2022.
[27] C. M. Chen and C. C. Huang, "Effects of silver doping on electromigration of eutectic SnBi solder," J. Alloy. Compd., Article vol. 461, no. 1-2, pp. 235-241, Aug 2008.
[28] F. Q. Hu, Q. K. Zhang, J. J. Jiang, and Z. L. Song, "Influences of Ag addition to Sn-58Bi solder on SnBi/Cu interfacial reaction," Mater. Lett., Article vol. 214, pp. 142-145, Mar 2018.
[29] D. Susan, J. Rejent, P. Hlava, and P. Vianco, "Very long-term aging of 52In–48Sn (at.%) solder joints on Cu-plated stainless steel substrates," Journal of Materials Science - J MATER SCI, vol. 44, pp. 545-555, 2009.
[30] K. Shimizu, T. Nakanishi, K. Karasawa, K. Hashimoto, and K. Niwa, "Solder joint reliability of indium-alloy interconnection," J. Electron. Mater., vol. 24, no. 1, pp. 39-45, 1995.
[31] N. Z. Blagojevic, R. M. Zejnilovic, A. R. Despic, and Z. Blecic, "Determination of the zinc and cadmium contents in low-alloyed tin," J. Serb. Chem. Soc., Article vol. 64, no. 11, pp. 707-719, 1999.
[32] J. M. Song and K. L. Lin, "Double peritectic behavior of Ag-Zn intermetallics in Sn-Zn-Ag solder alloys," J. Mater. Res., Article vol. 19, no. 9, pp. 2719-2724, Sep 2004.
[33] C. Geng et al., "Mechanical properties and oxidation resistance of Sn-Zn-xCu (2.3 <= x <= 20.2) solder alloys prepared by high-throughput strategy," Manuf. Lett., Article vol. 27, pp. 47-52, Jan 2021.
[34] K. L. Lin and Y. C. Wang, "Wetting interaction of Pb-free Sn-Zn-Al solders on metal plated substrate," J. Electron. Mater., Article; Proceedings Paper vol. 27, no. 11, pp. 1205-1210, Nov 1998.
[35] A. A. El-Daly, Y. Swilem, M. H. Makled, M. G. El-Shaarawy, and A. M. Abdraboh, "Thermal and mechanical properties of Sn–Zn–Bi lead-free solder alloys," J. Alloy. Compd., vol. 484, no. 1, pp. 134-142, 2009.
[36] V. Baheti and A. Paul, "Diffusion–controlled growth of phases in metal–tin systems related to microelectronics packaging," 2017.
[37] J. Glazer, "Metallurgy of low temperature Pb-free solders for electronic assembly," International Materials Reviews, vol. 40, no. 2, pp. 65-93, 1995.
[38] J. Li, P. Agyakwa, and M. Johnson, "Suitable Thicknesses of Base Metal and Interlayer, and Evolution of Phases for Ag/Sn/Ag Transient liquid-phase Joints Used for Power Die Attachment," J. Electron. Mater., vol. 43, 03/31 2014.
[39] W. Yang, L. E. Felton, and R. W. Messler, "The effect of soldering process variables on the microstructure and mechanical properties of eutectic Sn-Ag/Cu solder joints," Journal of Electronic Materials, vol. 24, no. 10, pp. 1465-1472, 1995.
[40] F. Ochoa, J. J. Williams, and N. Chawla, "The effects of cooling rate on microstructure and mechanical behavior of Sn-3.5Ag solder," JOM-J. Miner. Met. Mater. Soc., Article vol. 55, no. 6, pp. 56-60, Jun 2003.
[41] J. S. Lee, K. M. Chu, R. Patzelt, D. Manessis, A. Ostmann, and D. Y. Jeon, "Effects of Co addition in eutectic Sn-3.5Ag solder on shear strength and microstructural development," Microelectron. Eng., Article vol. 85, no. 7, pp. 1577-1583, Jul 2008.
[42] R. W. Cahn, "Binary Alloy Phase Diagrams–Second edition. T. B. Massalski, Editor-in-Chief; H. Okamoto, P. R. Subramanian, L. Kacprzak, Editors. ASM International, Materials Park, Ohio, USA. December 1990. xxii, 3589 pp., 3 vol., hard- back. $995.00 the set," Advanced Materials, vol. 3, no. 12, pp. 628-629, 1991.
[43] X. Wang, L. Zhang, and M.-l. Li, "Microstructure and properties of Sn-Ag and Sn-Sb lead-free solders in electronics packaging: a review," Journal of Materials Science: Materials in Electronics, vol. 33, no. 5, pp. 2259-2292, 2022.
[44] Y. Toyama and I. Shohji, "Effect of strain rate on tensile properties of miniature size lead-free alloys," in 2012 35th IEEE/CPMT International Electronics Manufacturing Technology Conference (IEMT), pp. 1-5, 6-8 Nov. 2012.
[45] T. Kobayashi, K. Kobayashi, K. Mitsui, and I. Shohji, "Comparison of Sn-5Sb and Sn-10Sb Alloys in Tensile and Fatigue Properties Using Miniature Size Specimens," Adv. Mater. Sci. Eng., Article vol. 2018, p. 9, 2018.
[46] 謝喻丞, "Ni添加對Sn-1.5Ag-0.7Cu低銀無鉛銲料顯微組織與機械性質影響之研究," 碩士, 機械工程學系, 國立成功大學, 台南市, 2016.
[47] N. Saunders and A. P. Miodownik, "The Cu-Sn (Copper-Tin) system," Bulletin of Alloy Phase Diagrams, vol. 11, no. 3, pp. 278-287, 1990.
[48] S. Sakuyama, T. Akamatsu, K. Uenishi, and T. Sato, "Effects of a Third Element on Microstructure and Mechanical Properties of Eutectic Sn&ndash;Bi Solder," Transactions of The Japan Institute of Electronics Packaging, vol. 2, no. 1, pp. 98-103, 2009.
[49] W. R. Myung, M. K. Ko, Y. Kim, and S. B. Jung, "Effects of Ag content on the reliability of LED package component with Sn-Bi-Ag solder," J. Mater. Sci.-Mater. Electron., Article vol. 26, no. 11, pp. 8707-8713, Nov 2015.
[50] L. Zhang, L. Sun, and Y.-h. Guo, "Microstructures and properties of Sn58Bi, Sn35Bi0.3Ag, Sn35Bi1.0Ag solder and solder joints," Journal of Materials Science: Materials in Electronics, vol. 26, no. 10, pp. 7629-7634, 2015.
[51] F. Hua, M. Zequn, and J. Glazer, "Eutectic Sn-Bi as an alternative to Pb-free solders," in 1998 Proceedings. 48th Electronic Components and Technology Conference (Cat. No.98CH36206), pp. 277-283, May 1998.
[52] L. Zhang, L. Sun, and Y. H. Guo, "Microstructures and properties of Sn58Bi, Sn35Bi0.3Ag, Sn35Bi1.0Ag solder and solder joints," J. Mater. Sci.-Mater. Electron., Article vol. 26, no. 10, pp. 7629-7634, Oct 2015.
[53] A. Yamauchi and M. Kurose, "Effect of Sb and Zn Addition on the Microstructures and Tensile Properties of Sn-Bi-Based Alloys," Materials, Article vol. 15, no. 3, p. 11, Feb 2022.
[54] C. Zhang, S. D. Liu, G. T. Qian, J. Zhou, and F. Xue, "Effect of Sb content on properties of Sn-Bi solders," Trans. Nonferrous Met. Soc. China, Article vol. 24, no. 1, pp. 184-191, Jan 2014.
[55] j. Xu, h.-j. He, f.-w. Zhang, z.-h. Zhao, and q. Hu, "Study of Sn-Bi-Cu Lead-free Solder," in 2008 10th Electronics Packaging Technology Conference, pp. 1375-1380, Dec 2008.
[56] H. W. Miao and J. G. Duh, "Microstructure evolution in Sn-Bi and Sn-Bi-Cu solder joints under thermal aging," Mater. Chem. Phys., Article vol. 71, no. 3, pp. 255-271, Sep 2001.
[57] X. L. Wu et al., "Microstructure and mechanical behavior of Sn-40Bi-xCu alloy," J. Mater. Sci.-Mater. Electron., Article vol. 28, no. 20, pp. 15708-15717, Oct 2017.
[58] B. L. Silva, A. Garcia, and J. E. Spinelli, "Complex eutectic growth and Bi precipitation in ternary Sn-Bi-Cu and Sn-Bi-Ag alloys," J. Alloy. Compd., Article vol. 691, pp. 600-605, Jan 2017.
[59] J. Shen, Y. Y. Pu, H. G. Yin, and Q. Tang, "Effects of Cu, Zn on the Wettability and Shear Mechanical Properties of Sn-Bi-Based Lead-Free Solders," J. Electron. Mater., Article vol. 44, no. 1, pp. 532-541, Jan 2015.
[60] T. Mousavi, C. Aksoy, C. R. M. Grovenor, and S. C. Speller, "Microstructure and superconducting properties of Sn–In and Sn–In–Bi alloys as Pb-free superconducting solders," Superconductor Science and Technology, vol. 29, no. 1, p. 015012, 2015.
[61] X. Chen, F. Xue, J. Zhou, and Y. Yao, "Effect of In on microstructure, thermodynamic characteristic and mechanical properties of Sn-Bi based lead-free solder," J. Alloy. Compd., Article vol. 633, pp. 377-383, Jun 2015.
[62] R. M. Shalaby, "Effect of silver and indium addition on mechanical properties and indentation creep behavior of rapidly solidified Bi-Sn based lead-free solder alloys," Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process., Article vol. 560, pp. 86-95, Jan 2013.
[63] O. Mokhtari and H. Nishikawa, "Effects of In and Ni Addition on Microstructure of Sn-58Bi Solder Joint," J. Electron. Mater., Article vol. 43, no. 11, pp. 4158-4170, Nov 2014.
[64] M. Li, Y. Tang, Z. Li, M. Zhu, and W. Wang, "Microstructure and mechanical properties of Sn–58Bi eutectic alloy with Cu/P addition," Materials Research Express, vol. 7, p. 116502, 2020.
[65] N. Zhao, Y. Zhong, M. L. Huang, H. T. Ma, and W. Dong, "Growth kinetics of Cu6Sn5 intermetallic compound at liquid-solid interfaces in Cu/Sn/Cu interconnects under temperature gradient," Scientific Reports, vol. 5, no. 1, p. 13491, 2015.
[66] M. H. Roh, J. P. Jung, and W. Kim, "Microstructure, shear strength, and nanoindentation property of electroplated Sn-Bi micro-bumps," Microelectron. Reliab., Article vol. 54, no. 1, pp. 265-271, Jan 2014.
[67] L. Veleva. Veleva L., “Soils and Corrosion” (Chapter 32), in Corrosion Tests and Standards: Application and Interpretation , 2nd Edition, R. Baboian Ed., ISBN: 0-8031-2058-3, ASTM International, OH, pp.387-404, 2005.
[68] I. Nakatsugawa and Y. Chino, "Effect of Area Ratio on the Galvanic Corrosion of AZX611 Magnesium Alloy/A6N01 Aluminum Alloy Joint," Mater. Trans., Article vol. 62, no. 12, pp. 1764-1770, 2021.
[69] J. E. C. Guerrero, D. H. Camacho, O. Mokhtari, and H. Nishikawa, "Corrosion and Leaching Behaviours of Sn-0.7Cu-0.05Ni Lead-Free Solder in 3.5 wt.% NaCl Solution," Int. J. Corros., Article vol, p. 11, 2018.
[70] H. W. He, H. Y. Zhao, F. Guo, and G. C. Xu, "Bi Layer Formation at the Anode Interface in Cu/Sn-58Bi/Cu Solder Joints with High Current Density," J. Mater. Sci. Technol., Article vol. 28, no. 1, pp. 46-52, Jan 2012.
[71] J. P. Daghfal and J. K. Shang, "Current-induced phase partitioning in eutectic indium-tin pb-free solder interconnect," J. Electron. Mater., Article vol. 36, no. 10, pp. 1372-1377, Oct 2007.
[72] P. Y. Zheng, R. P. Deng, and D. Gall, "Ni doping on Cu surfaces: Reduced copper resistivity," Applied Physics Letters, vol. 105, no. 13, p. 131603, 2014.
[73] S. Zhou et al., "Effects of Ti addition on the microstructure, mechanical properties and electrical resistivity of eutectic Sn58Bi alloy," Materials Science and Engineering: A, vol. 744, pp. 560-569, 2019.
[74] 林宗寬, "覆晶銲錫之電遷移研究: 溫度對破壞機制的影響與電阻曲線之分析," 博士, 材料科學與工程學系所, 國立交通大學, 新竹市, 2014.