Optimisation of Reflow Profile of Surface Mount Assembly Using Taguchi Design of Experiments
Volume 3, Issue 4, August 2015, Pages: 150-169
Received: May 25, 2015;
Accepted: Jun. 16, 2015;
Published: Jul. 2, 2015
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Gabriel Takyi, Department of Mechanical Engineering, Kwame Nkrumah University of Science & Technology, Kumasi, Ghana
Peter Kojo Bernasko, Electronics Manufacturing Engineering Research Group, School of Engineering, University of Greenwich, Chatham Maritime, Kent, UK
A major source of concern in the electronic manufacturing industry is the reliability of solder joints produced by lead-free solders pastes. Research has shown that solder joint produced with a thin layer of intermetallic compounds (IMC) during the reflow process has a higher reliability. The focus of this paper is on the development of a deeper understanding of the lead-free reflow soldering process and to optimise the reflow profile using Taguchi Design of Experiments (DOE). The optimum parameters are those that yield lower IMC layers. The experiment was designed to consider the effect of the following reflow soldering parameters: soak temperature, time above liquidus, soak time and time to peak temperature. The eight (8) reflow profiles studied were derived from the Taguchi DOE which also included three factorial interactions. A stencil with three (3) holes of diameters 3.1 mm, 3.7 mm and 4.3 mm was used in the solder printing process, after which the samples were reflowed. The samples were then thermal cycled, cross-sectioned and finally the IMC image captured and analysed using an optical electron microscope. The analysis of variance (ANOVA) carried out on the results indicate the soak time to be the most significant factor in achieving a solder joint with a thin IMC layer. The next most significant factor was the time above liquidus, and the most significant interaction was found to be the interaction between the soak temperature and time above liquidus. The results indicate a soak time of 60 seconds and time above liquidus of 60 seconds is preferred to achieve a thin IMC layer. The recommended time to peak temperature is 240 seconds and the soak temperature is 150°C. The results can be very useful to researchers and scientists in the surface mount technology (SMT) field, providing an understanding of the effect of the four reflow parameters studied. In addition, the DOE methodology used in this research can be adopted by other process improvement engineers or scientists involved in the optimisation of a process or product.
Peter Kojo Bernasko,
Optimisation of Reflow Profile of Surface Mount Assembly Using Taguchi Design of Experiments, Science Research.
Vol. 3, No. 4,
2015, pp. 150-169.
J. Pan, B. Toleno, T. Chou, and W. Dee (2006) “The effect of reflow profile on SnPb and SnAgCu solder joint shear strength”, Soldering & Surface Mount Technology, Vol. 18 No. 4, pp. 48 -56
B. Salam, C. Vireseda, H. Da, N.N Ekere, (2004) “Reflow profile study of the Sn-Ag-Cu solder”, Soldering and Surface Mount Technology, Vol. 16 No. 1, pp. 27 – 34.
Salam, B., Ekere, N.N., Rajkumar, D. (2001) “Study of the interface microstructure of SnAgCu lead free solder and the effect of solder volume on intermetallic layer formation”, Proceedings of the Electronics Components and Technology Conference, IEEE 16 No. 1.
A. Haseeb, T.S Leng, (2011), Effects of Co nanoparticle addition to Sn-3.8Ag-0.7Cu solder on interfacial structure after reflow and ageing, Intermetallics, vol. 19, iss. 5, pp, 707–712, Elsevier.
S. Na, T. Hwang, J. Park, J.Y Kim, (2011), “Characterization of IMC growth in Cu wire ball bonding on Al pad metallization”, 61st IEEE Electronic components and technology conference, ECTC, Lake Buena Vista FL. pp. 1740-1745.
P. Bernasko, M. Sabuj, N. Ekere, G. Takyi, (2011), “Evaluating the effect of pad sizes on the inter-metallic layer formation and growth for Sn-Cu-Ag solders on Cu metallization”, international conference on electronics packaging (ICEP), Japan,
G. Takyi, P.K Bernasko, (2014), The Effects of reflow profile parameters on Sn-Ag-Cu solder bumps and Cu substrate using full factorial design, Journal of surface mount technology, (SMT), vol. 27, iss. 4, pp 13-22
J. Gao, Y. Wu, H. Ding, N. Wan, (2008) “Thermal profiling: a reflow process based on the heating factor”, Soldering & Surface Mount Technology, vol. 20 no. 4, pp 20 – 27.
D.C Whalley, (2004) “A simplified reflow soldering process model”, Journals of Materials processing Technology, Vol.150, pp. 134 – 144.
R. Pandler, N. Jodhan, R. Raut, M. Liberatore, (2010), Electronics head in-pillow defect- role of solder ball alloy, 12th electronics packaging technology conference.
N. Lee, (2001), “Reflow soldering processes and troubleshooting: SM, BGA, CSP, and flip chip technologies”, Boston: Newnes, ISBN-13: 978-0-7506-7218-4
J. Gao, Y. Wu, H. Ding, (2007) “Optimization of the reflow profile based on the heating factor”, Soldering and Surface Mount Technology, Vol. 19 No. 1, pp 28 – 33.
B. Yuvaraj, (2012), Application of Taguchi Method for Design of Experiment in Turning Gray Cast Iron, International Journal of Engineering Research and Applications Vol. 2, Issue 3, pp.1391-1397.
R.K Roy, (2001) “Design of experiments using the Taguchi approach: 16 steps to product and process improvement”. New York: Wiley.
D. Montgomery, (2005) “Design and Analysis of Experiments”, 6th Edition, Wiley: New York, ISBN:0-471-66159-7.