In situ observation of thermomigration of Sn atoms to the hot end of 96.5Sn-3Ag-0.5Cu flip chip solder joints

In this study, we investigated the phenomenon of thermomigration in 96.5Sn-3Ag-0.5Cu flip chip solder joints at an ambient temperature of 150 °C. We observed mass protrusion on the chip side (hot end), indicating that Sn atoms moved to the hot end, and void formation on the substrate side (cold end). The diffusion markers also moved to the substrate side, in the same direction of the vacancy flux, indicating that the latter played a dominant role during the thermomigration process. The molar heat of transport (Q*) of the Sn atoms was 3.38 kJ/mol.

[1]  K. N. Tu,et al.  Reliability challenges in 3D IC packaging technology , 2011, Microelectron. Reliab..

[2]  Y. Chan,et al.  Thermomigration and electromigration in Sn58Bi solder joints , 2009 .

[3]  Hsiang-Yao Hsiao,et al.  Thermomigration in Pb-free SnAg solder joint under alternating current stressing , 2009 .

[4]  Chih Chen,et al.  In-situ observation of the failure induced by thermomigration of interstitial Cu in Pb-free flip chip solder joints , 2008, 2009 59th Electronic Components and Technology Conference.

[5]  Yi-Shao Lai,et al.  Effect of current crowding on whisker growth at the anode in flip chip solder joints , 2007 .

[6]  Y. Lai,et al.  Effect of entropy production on microstructure change in eutectic SnPb flip chip solder joints by thermomigration , 2006 .

[7]  Yi-Shao Lai,et al.  Electrothermal coupling analysis of current crowding and Joule heating in flip-chip packages , 2006, Microelectron. Reliab..

[8]  S. W. Liang,et al.  Effect of Al-trace dimension on Joule heating and current crowding in flip-chip solder joints under accelerated electromigration , 2006 .

[9]  Mahendra K. Sunkara,et al.  Near-infrared semiconductor subwavelength-wire lasers , 2006 .

[10]  Yi-Shao Lai,et al.  Thermomigration in SnPb composite flip chip solder joints , 2006 .

[11]  J. O. Suh,et al.  Effect of current crowding and Joule heating on electromigration-induced failure in flip chip composite solder joints tested at room temperature , 2005 .

[12]  King-Ning Tu,et al.  Polarity effect of electromigration on kinetics of intermetallic compound formation in Pb-free solder V-groove samples , 2005 .

[13]  Zhong Chen,et al.  Solid state interfacial reaction of Sn–37Pb and Sn–3.5Ag solders with Ni–P under bump metallization , 2004 .

[14]  J. O. Suh,et al.  Mechanism of electromigration-induced failure in the 97Pb-3Sn and 37Pb-63Sn composite solder joints , 2003 .

[15]  Hua Ye,et al.  Thermomigration in Pb–Sn solder joints under joule heating during electric current stressing , 2003 .

[16]  D. R. Frear,et al.  Electromigration of eutectic SnPb and SnAg3.8Cu0.7 flip chip solder bumps and under-bump metallization , 2001 .

[17]  D. R. Frear,et al.  Electromigration of eutectic SnPb solder interconnects for flip chip technology , 2001 .

[18]  King-Ning Tu,et al.  Electromigration in Sn-Pb solder strips as a function of alloy composition , 2000 .

[19]  K. Tu,et al.  Microstructure-electromigration correlation in a thin stripe of eutectic SnPb solder stressed between Cu electrodes , 1999 .

[20]  Milton Ohring,et al.  Tracer self‐diffusion and electromigration in thin tin films , 1976 .