The Effectiveness of Bismuth Addition to Retard the Intermetallic Compound Formation
The aim of this paper is to study the effectiveness of bismuth addition in the solder alloy to retard the intermetallic compound formation and growth. In this study, three categories of solders such as Sn-4Ag-xCu (x = 0.5, 0.7, 1.0) and Sn-4Ag-0.5Cu-xBi (x = 0.1, 0.2, 0.4) were used. Ni/Au surface finish substrates were dipped into the molten solder at a temperature of 180-190 oC and allowed to cool at room temperature. The intermetallic compound (IMCs) were subjected to the characterization in terms of composition and morphology. The IMC phases were identified by energy dispersive x-ray (EDX), whereas the optical microscope and scanning electron microscopy (SEM) were used to observe microstructure evolution of the solder joint. The results clearly showed that copper concentration dependency was high during the reflow stage. Besides, only Ni3Sn4 and Ni3Sn2 were detected for all copper concentrations. The addition of Bi was found to have no significant effect on the type of IMCs formed, but yet the grain became further refined.
Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1124873Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF
 Amin, N. A. A. M., Shnawah, D. A., Said, S. M., Sabri, M. F. M., and Arof, H., "Effect of Ag content and the minor alloying element Fe on the electrical resistivity of Sn–Ag–Cu solder alloy," Journal of Alloys and Compounds, vol. 599, pp. 114-120, 6/25/ 2014.
 Dongxia, X., Xusheng, L., Caiqin, W., and Bin, X., "Study on wettability and corrosivity of a new no-clean flux for lead-free solder paste in electronic packaging technology," in Mechanic Automation and Control Engineering (MACE), 2011 Second International Conference on, 2011, pp. 1706-1708.
 Zeng, G., Xue, S., Zhang, L., and Gao, L., "Recent advances on Sn–Cu solders with alloying elements: review," Journal of Materials Science: Materials in Electronics, vol. 22, pp. 565-578, 2011/06/01 2011.
 Tulman, S., "Tin base lead-free solder composition containing bismuth, silver and antimony," ed: Google Patents, 1989.
 Mahdavifard, M. H., Sabri, M. F. M., Shnawah, D. A., Said, S. M., Badruddin, I. A., and Rozali, S., "The effect of iron and bismuth addition on the microstructural, mechanical, and thermal properties of Sn–1Ag–0.5Cu solder alloy," Microelectronics Reliability, vol. 55, pp. 1886-1890, 8// 2015.
 Saliza Azlina, O., Ourdjini, A., and Siti Rabiatull Aisha, I., "Effect of nickel doping on interfacial reaction between lead-free solder and Ni-P substrate," vol. 488-489, ed, 2012, pp. 1375-1379.
 Zhao, G.-j., Sheng, G.-m., Wu, L.-l., and Yuan, X.-j., "Interfacial characteristics and microstructural evolution of Sn–6.5Zn solder/Cu substrate joints during aging," Transactions of Nonferrous Metals Society of China, vol. 22, pp. 1954-1960, 8// 2012.
 Liu, J.-C., Zhang, G., Ma, J.-S., and Suganuma, K., "Ti addition to enhance corrosion resistance of Sn–Zn solder alloy by tailoring microstructure," Journal of Alloys and Compounds, vol. 644, pp. 113-118, 9/25/ 2015.
 Billah, M. M., Shorowordi, K. M., and Sharif, A., "Effect of micron size Ni particle addition in Sn–8Zn–3Bi lead-free solder alloy on the microstructure, thermal and mechanical properties," Journal of Alloys and Compounds, vol. 585, pp. 32-39, 2/5/ 2014.
 Haseeb, A. S. M. A. and Leng, T. S., "Effects of Co nanoparticle addition to Sn–3.8Ag–0.7Cu solder on interfacial structure after reflow and ageing," Intermetallics, vol. 19, pp. 707-712, 5// 2011.
 Chavali, S., Singh, Y., Subbarayan, G., Bansal, A., and Ahmad, M., "Effect of pad surface finish and reflow cooling rate on the microstructure and the mechanical behavior of SnAgCu solder alloys," Microelectronics Reliability, vol. 53, pp. 892-898, 6// 2013.
 Chen, C. H., Wong, W., Lo, J. C. C., Fubin, S., and Lee, S. W. R., "Characterization and Comparison of Five SAC-based Solder Pastes for Pb-free Reflow Soldering," in High Density packaging and Microsystem Integration, 2007. HDP '07. International Symposium on, 2007, pp. 1-8.
 Wu, F., Hu, Y., Wu, Y., An, B., and Zhang, J., "The growth behavior of intermetallic compound layer at solder/Cu joint interface during soldering," in Electronic Packaging Technology, 2005 6th International Conference on, 2005, pp. 355-359.
 Hu, X., Li, Y., Liu, Y., and Min, Z., "Developments of high strength Bi-containing Sn0.7Cu lead-free solder alloys prepared by directional solidification," Journal of Alloys and Compounds, vol. 625, pp. 241-250, 3/15/ 2015.