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Research Papers

Effect of Joint Size on Microstructure and Growth Kinetics of Intermetallic Compounds in Solid-Liquid Interdiffusion Sn3.5Ag/Cu-Substrate Solder Joints

[+] Author and Article Information
Ousama M. Abdelhadi

e-mail: omabdelhadi@crimson.ua.edu

Leila Ladani

e-mail: lladani@eng.ua.edu
Mechanical Engineering Department,
University of Alabama,
Tuscaloosa, AL 35401

Contributed by the Electronic and Photonic Packaging Division of ASME for publication in the JOURNAL OF ELECTRONIC PACKAGING. Manuscript received July 11, 2012; final manuscript received February 19, 2013; published online March 28, 2013. Assoc. Editor: Jianmin Qu.

J. Electron. Packag 135(2), 021004 (Mar 28, 2013) (10 pages) Paper No: EP-12-1069; doi: 10.1115/1.4023846 History: Received July 11, 2012; Revised February 19, 2013

The effect of joint size on the interfacial reaction in the Sn3.5Ag/Cu-substrate soldering system was examined. An experiment was conducted in which parameters such as bonding time, temperature, and pressure were varied at multiple levels. The morphology and thickness of all intermetallic compounds (IMC) were analyzed using the scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) techniques. An examination of the microstructures of solder joints of different sizes revealed that the size of the solder joint has no effect on the type of IMCs formed during the process. It was found that the joint size significantly affected the thickness of the intermetallic layers. The Cu3Sn intermetallic layers formed in the smaller sized solder joints were found to be thicker than those in the larger sized solder joints. In all specimen sizes, the increase in the thickness of Cu3Sn intermetallic layers with soldering time was found to obey a parabolic relationship. Additionally, for the cases when eutectic solder is available in the joints, a similar soldering time and temperature dependency were found for the Cu6Sn5 IMC phase. The intermetallic growth of the Cu3Sn phase was under a volume-diffusion controlled mechanism. The growth rate constants and activation energies of intermetallic layers were also reported for different joint thicknesses. Furthermore, the growth rate constants of the Cu3Sn intermetallic layer were found to depend upon the size of the joints.

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References

Puttlitz, K. J., and StalterK. A., 2004, Handbook of Lead-Free Solder Technology for Microelectronic Assemblies, Marcel Dekker AG, Basel, Switzerland.
Blackwell, G. R., 2000, The Electronic Packaging Handbook, Chemical Rubber, Boca Raton, FL.
Arzt, E., 1998, “Overview No. 130, Size Effects in Materials Due to Microstructural and Dimensional Constraints: A Comparative Review,” Acta Mater., 46(16), pp. 5611–5626. [CrossRef]
Huang, Z., Conway, P. P., and Qin, R., 2008, “Modeling of Interfacial Intermetallic Compounds in the Application of Very Fine Lead-Free Solder Interconnections,” J. Microsyst. Technol. (Special Issue on Micro-Nano-Reliability), 15(1), pp. 101–107. [CrossRef]
Abdelhadi, O. M., Ladani, L., and Razmi, J., 2011, “Fracture Toughness of Bonds Using Interfacial Stresses in Four-Point Bending Test,” J. Mech. Mater., 43(12), pp. 885–900. [CrossRef]
Bernstein, L., 1966, “Semiconductor Joining by the Solid-Liquid-Interdiffusion (SLID) Process,” J. Electrochem. Soc., 113(12), pp. 1282–1288. [CrossRef]
Bernstein, L., and Batholomew, H., 1966, “Application of Solid-Liquid Interdiffusion (SLID) Bonding in Integrated-Circuit Fabrication,” Trans. Metall. Soc. AIME, 236(3), pp. 405–412.
Roman, J. W., and Eagar, T. W., 1992, “Low Stress Die Attach by Low Temperature Transient Liquid Phase Bonding,” Proceeding of the 1992 International Symposium on Microelectronics, San Francisco, CA, October 19–21, pp. 1–6.
Li, J. F., Agyakwa, P. A., and Johnson, C. M., 2011, “Interfacial Reaction in Cu/Sn/Cu System During the Transient Liquid Phase Soldering Process,” Acta Mater., 59(3), pp. 1198–1211. [CrossRef]
Li, J. F., Agyakwa, P. A., and Johnson, C. M., 2010, “Kinetics of Ag3Sn Growth in Ag-Sn-Ag System During Transient Liquid Phase Soldering Process,” Acta Mater., 58(9), pp. 3429–3443. [CrossRef]
Li, J. F., Mannan, S. H., Clode, M. P., Whalley, D. C., and Hutt, D. A., 2006, “Interfacial Reaction Between Molten Sn-Bi-X Solders and Cu Substrates for Liquid Solder Interconnects,” Acta Mater., 54(11), pp. 2907–2922. [CrossRef]
Ladani, L. J., Razmi, J., and Bentley, J., 2010, “Microstructural and Mechanical Strength of Snag-Based Solid Liquid Inter-Diffusion Bonds for 3 Dimensional Integrated Circuits,” Thin Solid Films, 518(17), pp. 4948–4954. [CrossRef]
Ladani, L. J. and Razmi, J., 2009 “Bonding Strength and Microstructure of SnAg-Based Solid Liquid Inter-Diffusion Bonds,” ASME Conference Proceedings, IMCE2009, Lake Buena Vista, FL, November 13–19, ASME Paper No. IMECE2009-11454, pp. 107–111. [CrossRef]
Bartels, F., Morris, J. W., and Gust, W., 1994, “Intermetallic Phase Formation in Thin Solid-Liquid Diffusion Couples,” J. Electron. Mater., 23(8), pp. 787–790. [CrossRef]
Wu, F., Wang, B., Du, B., An, B., and Wu, Y., 2009, “Effect of Stand-Off Height on Microstructure and Tensile Strength of the Cu/Sn9Zn/Cu Solder Joint,” J. Electron. Mater., 38(6), pp. 860–865. [CrossRef]
Wiese, S., and Wolter, K. J., 2004, “Microstructure and Creep Behavior of Eutectic SnAg and SnAgCu Solders,” Microelectron. Reliab., 44(12), pp. 1923–1931. [CrossRef]
Wiese, S., Roellig, M., and Wolter, K. J., 2008, “The Effect of Downscaling the Dimensions of Solder Interconnects on Their Creep Properties,” Microelectronics Reliability, 48(6), pp. 843– 850. [CrossRef]
Zimprich, P., Kotas, A., Khatibi, G., Weiss, B., and Ipser, H., 2008, “Size Effects in Small Scaled Lead-Free Solder Joints,” J. Mater. Sci.: Mater. Electron., 19(4), pp. 383–388. [CrossRef]
Zimprich, P., Saeed, U., Betzwar-Kotas, A., Weiss, B., and Ipser, H., 2007 “Mechanical Size Effects in Miniaturized Lead-Free Solder Joints,” J. Electron. Mater., 37(1), pp. 102–109. [CrossRef]
Zimprich, P., Saeed, U., Weiss, B., and Ipser, H., 2009, “Constraining Effects of Lead-Free Solder Joints During Stress Relaxation,” J. Electron. Mater., 38(3), pp. 392–399. [CrossRef]
Huang, Y. C., Wu, K. S., and Chen, S. W., 2009, “Size and Substrate Effects Upon Undercooling of Pb-Free Solder,” 4th International Microsystems, Packaging, Assembly and Circuits Technology Conference (IMPACT 2009), Taipei, China, October 21–23, pp. 662–665.
Huang, Y. C., and Chen, S. W., 2010, “Co Alloying and Size Effects on Solidification and Interfacial Reactions in the Sn-Zn-(Co)/Cu Couples,” Mater. Res., 25(12), pp. 2430–2438. [CrossRef]
Kinyanjui, R., Lehman, L. P., Zavalij, L., and Cotts, E., 2005, “Effect of Sample Size on the Solidification Temperature and Microstructure of SnAgCu Near Eutectic Alloys,” J. Mater. Res. Soc., 20(11), pp. 2914–2918. [CrossRef]
Cho, M. G., Kang, S. K., and Lee, H. M., 2008, “Undercooling and Microhardness of Pb-Free Solders on Various Under Bump Metallurgies,” Mater. Res., 23(4), pp. 1147–1154. [CrossRef]
Castro de, W. B., Maia, M.de, L., Kiminami, C. S., and Bolfarini, C., 2001, “Microstructure of Undercooled Pb-Sn Alloys,” Mater. Res., 4(2), pp. 83–86. [CrossRef]
Yang, S., Rian, Y., and Wang, C., 2010, “Investigation on Sn Grain Number and Crystal Orientation in the Sn-Ag–Cu/Cu Solder Joints of Different Sizes,” J. Mater. Sci.: Mater. Electron., 21(11), pp. 1174–1180. [CrossRef]
Gong, J., Liu, C., Conway, P. P., and Siberschmidt, V. V., 2007, “Micromechanical Modeling of SnAgCu Solder Joint Under Cyclic Loading: Effect of Grain Orientation,” J. Comput. Mater. Sci., 39(1), pp. 187–197. [CrossRef]
Chi, Z., 2008, Nanofabrication: Principles, Capabilities, and Limits, Springer, Didcot, UK.
Abdelhadi, O. M. and Ladani, L., 2012, “Intermetallic Compound Growth of Tin-3.5 wt. % Silver/Copper System: Combined Chemical Reaction and Diffusion Mechanisms,” J. Alloys Compd., 537, pp. 87–99. [CrossRef]
Lee, C. C., Wang, P. J., and Kim, J. S., 2007, “Are Intermetallics in Solder Joints Really Brittle?,” Proceeding of the 57th Electronic Components and Technology Conference (ECTC 07), Irvine, CA May 29–June 1, pp. 648–652.
Larche, F. C., and Cahn, J. W., 1982, “Overview 25: The Effect of Self-Stress on Diffusion in Solids,” Acta Mater., 30(10), pp. 1835–1845. [CrossRef]
Aziz, M., 1998, “Pressure and Stress Effects on Diffusion in Si,” Defect Diffus. Forum, 153–155, pp. 1–10. [CrossRef]
Abdelhadi, O. M., and Ladani, L., 2012, “Mechanical Characterization of Intermetallic Compounds in Sn-3.5Ag/Cu-Substrate Soldering System,” IEEE Trans. Compon. Packag. Manuf. Technol. (submitted).
Kim, Y. M., Roh, H. R., and Kim, S., 2010, “Kinetics of Intermetallic Compound Formation at the Interface Between Sn-3.0Ag-0.5Cu Solder and Cu-Zn Alloy Substrates,” J. Electron. Mater., 39(12), pp. 2504–2512. [CrossRef]
Yoon, J. W., Lee, C. B., Kim, D. U., and Jung, S. B., 2003, “Reaction Diffusions of Cu6Sn5 and Cu3Sn Intermetallic Compound in the Couple of Sn-3.5Ag Eutectic Solder and Copper Substrate,” Met. Mater. Int., 9(2), pp. 193–199. [CrossRef]
Yu, D. Q., Wu, C. M. L., Law, C. M. T., Wang, L., and Lai, J. K. L., 2005, “Intermetallic Compounds Growth Between Sn-3.5Ag Lead-Free Solder and Cu Substrate by Dipping Method,” J. Alloys Compd., 392(1–2), pp. 192–199. [CrossRef]
Ladani, L., and Razmi, J., 2010, “IMC Growth in Solid-Liquid Interdiffusion Bonds,” Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm), 2010 12th IEEE Intersociety Conference, Las Vegas, NV, June 2–5, pp. 1–5.
Dybkov, V. I., 2002, “Reaction Diffusion and Solid State Chemical Kinetics,” IPMS, Kiev.
Dybkov, V. I., 2001, “Reaction Diffusion in Binary Solid-Solid, Solid-Liquid and Solid-Gas Systems: Common and Distinctive Features,” Defect Diffus. Forum, 194–199, pp. 1503–1522. [CrossRef]
Dybkov, V. I., Khoruzha, V. G., Sidorko, V. R., Meleshevich, K. A., Samelyuk, A. V., Berry, D. C., and Barmak, K., 2009, “Interfacial Interaction of Solid Cobalt With Liquid Pb-Free Sn-Bi-In-Zn-Sb Soldering Alloys,” J. Mater. Sci., 44(22), pp. 5960–5979. [CrossRef]
Wang, C. H., and Kuo, C., 2011, “Interfacial Reactions Between Eutectic Sn-Pb Solder and Co Substrate,” J. Mater. Sci., 46(8), pp. 2654–2661. [CrossRef]
Chada, S., Fournelle, R. A., Laub, W., and Shangguan, D., 2000, “Copper Substrate Dissolution in Eutectic Sn-Ag Solder and Its Effect on Microstructure,” J. Electron. Mater., 29(10), pp. 1214–1221. [CrossRef]

Figures

Grahic Jump Location
Fig. 1

(a) Actual specimen design (top) and schematic drawing (bottom) of the SS specimen. (b) Actual specimen design (top) and a schematic drawing (bottom) of the LS specimen. Dimensions are in mm.

Grahic Jump Location
Fig. 2

SEM backscattered electron images illustrating the microstructure of Sn-3.5Ag/Cu solder joints of the SS2 specimen (25 μm-thick) fabricated at different temperatures for various soldering times

Grahic Jump Location
Fig. 3

SEM backscattered electron images illustrating the microstructure of Sn-3.5Ag/Cu solder joints of the LS specimen (450 μm-thick) fabricated at different temperatures for various times

Grahic Jump Location
Fig. 4

EDX analysis indicating the presence of (a) Cu3Sn (b) Cu6Sn5, and (c) Ag3Sn IMCs in the Sn-3.5Ag/Cu solder joints

Grahic Jump Location
Fig. 5

Comparison of the IMC growth behavior in different specimen sizes at different soldering temperatures

Grahic Jump Location
Fig. 6

Log-log plot of the growth rate constant versus the reciprocal of temperature: (a) for the Cu6Sn5 IMC layer and (b) for the Cu3Sn IMC layer in different specimen sizes

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