Abstract
Slow cooling of Sn-Ag-Cu and Sn-Ag-Cu-X (X = Fe, Co) solder-joint specimens made by hand soldering simulated reflow in surface-mount assembly to achieve similar as-solidified joint microstructures for realistic shearstrength testing, using Sn-3.5Ag (wt.%) as a baseline. Minor substitutions of either cobalt or iron for copper in Sn-3.7Ag-0.9Cu refined the joint matrix microstructure, modified the Cu6Sn5 intermetallic phase at the copper substrate/solder interface, and increased the shear strength. At elevated (150°C) temperature, no significant difference in shear strength was found in all of the alloys studied. Ambient temperature shear strength was reduced by largescale tin dendrites in the joint microstructure, especially by the coarse dendrites in solute poor Sn-Ag-Cu.
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W.J. Plumbridge, C.R. Gagg, and S. Peters, “ The Creep of Lead-free Solders at Elevated Temperatures,”J. Electronic Materials, 30 (9) (2001), pp. 1178–1183.
“ What Else is in the Refrigerator?”Consumer Reports (February 1994), p. 100.
C.M. Miller, “ Development of a new Pb-free solder: Sn-Ag-Cu” (Master of Science Thesis, Iowa State University, 1994).
Challenges and Efforts Toward Commercialization of Lead-free Solder-Road Map 2000 for Commercialization of Lead-free Solder, ver. 1.2 (The Japan Electronic Industry Development Association, Leadfree Soldering R&D Project Committee, February 2000);www.jeida.or.jp/english/information/pbfree/ roadmap.html.
J. Bath, C. Handweker, and E. Bradley, “ Research Update: Lead-free Solder Alternatives,”Circuits Assembly (May 2000), pp. 31–40.
C.M. Miller, I.E. Anderson, and J.F. Smith, “ A Viable Tin-Lead Solder Substitute: Sn-Ag-Cu,”J. Electronic Materials, 23 (7) (1994), pp. 595–601.
I.E. Anderson et al., “ Alloying Effects in Near-Eutectic Sn-Ag-Cu Solder Alloys for Improved Microstructural Stability,”J. Electronic Materials, 30 (9) (2001), pp. 1050–1059.
I.E. Anderson, K. Kirkland, and W. Willenberg, “Implementing Pb-free Soldering,”Surface Mount Technology, 14 (11) (2000), pp. 78–81.
K.-W. Moon et al., “ Experimental and Thermodynamic Assessment of Sn-Ag-Cu Solder Alloys,”J. Electronic Materials, 29 (10) (2000), pp. 1122–1136.
C.A. Drewien, F.G. Yost, S. J.Sackinger, J. Kern, and M.W. Weiser, “ Progress Report: High Temperature Solder Alloys for Underhood Applications,” Sandia Report, SAND95-0196.UC-704, February 1995.
M. McCormack and S. Jin, “ Progress in the Design of New Lead-free Solder Alloys,”JOM, 45 (7) (1993), pp. 36–40.
I.E. Anderson et al., “ Pb-free Sn-Ag-Cu Ternary Eutectic Solder,” U.S. patent 5,527,628 (18 June 1996).
I.E. Anderson et al., “ Development of Eutectic and Near-eutectic Sn-Ag-Cu Solder Alloys for Lead-free Electronic Assemblies,”Proceedings of IPC Works ’99 IPC (1999), paper No. S-03-5.
I.E. Anderson and R.L. Terpstra, “ Pb-free Solder,” U.S. patent 6,231,691 B1 (15 May 2001).
C.M. Liu et al., “ Reflow Soldering and Isothermal Solid-State Aging of Sn-Ag Eutectic Solder on Au/Ni Surface Finish,”J. Electronic Materials, 30 (9) (2001), pp. 1152–1156.
O. Unal et al., “ Application of Asymmetrical Four Point Bend Shear Test to Solder Joints,”J. Electronic Materials, 30 (9) (2001), pp. 1206–1213.
I.E. Anderson et al., “ Microstructural Modifications and Properties of Sn-Ag-Cu Solder Joints Induced by Alloying,”J. Electronic Materials, submitted (2002).
I.E. Anderson et al., “ Development of Eutectic and Near-eutectic Tin-Silver-Cu Solder Alloys for Lead-free Joining Applications,”Advanced Brazing and Soldering Technologies, ed. P.T. Vianco and M. Singh (Miami, FL: American Welding Society, 2000), pp. 575–586.
D.P. Woodruff,The Solid-Liquid Interface, ISBN: 0 521 20123 3 (New York: Cambridge University Press, 1973).
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Anderson, I.E., Cook, B.A., Harringa, J.L. et al. Sn-Ag-Cu solders and solder joints: Alloy development, microstructure, and properties. JOM 54, 26–29 (2002). https://doi.org/10.1007/BF02701845
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DOI: https://doi.org/10.1007/BF02701845