Abnormal accumulation of intermetallic compound at cathode in a SnAg3.0Cu0.5 lap joint during electromigration

Interfacial reactions in a SnAg3.0Cu0.5/Cu lap joint for naked and encompassed specimens were investigated contrastively under electric current stressing. After applying a constant direct current at 6.5?A for 144?h, an abnormal accumulation of bulk Cu6Sn5 intermetallic compound was found at the cathode for the naked specimen. But normal polarization phenomenon arose for the encompassed specimen at the same current density for 504?h. The abnormal accumulation phenomenon was explained by the mechanism that thermomigration and stress migration induced by temperature gradient dominated the migration process. A three-dimensional joint simulation model was designed to demonstrate how current crowding and temperature gradient can enhance the local atomic flux.

[1]  King-Ning Tu,et al.  Effect of current crowding on void propagation at the interface between intermetallic compound and solder in flip chip solder joints , 2006 .

[2]  K. Tu,et al.  Effect of electromigration-induced back stress gradient on nanoindentation marker movement in SnAgCu solder joints , 2006 .

[3]  Reiner Kirchheim,et al.  Stress and electromigration in Al-lines of integrated circuits , 1992 .

[4]  Paul A. Lauro,et al.  Effect of Sn grain orientation on electromigration degradation mechanism in high Sn-based Pb-free solders , 2008 .

[5]  Y. Lai,et al.  Electromigration induced high fraction of compound formation in SnAgCu flip chip solder joints with copper column , 2008 .

[6]  Sinn-wen Chen,et al.  Effects upon interfacial reactions by electric currents of reversing directions , 2003 .

[7]  K. Tu.  Recent advances on electromigration in very-large-scale-integration of interconnects , 2003 .

[8]  J. J. Clement,et al.  Modeling electromigration‐induced stress evolution in confined metal lines , 1995 .

[9]  King-Ning Tu,et al.  Current-crowding-induced electromigration failure in flip chip solder joints , 2002 .

[10]  C. A. Ross.  Stress and Electromigration in Thin Film Metallisation , 1991 .

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

[12]  Kuo-Ning Chiang,et al.  Current crowding-induced electromigration in SnAg3.0Cu0.5 microbumps , 2006 .

[13]  Cher Ming Tan,et al.  Investigation of the effect of temperature and stress gradients on accelerated EM test for Cu narrow interconnects , 2006 .

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

[15]  Tu.  Electromigration in stressed thin films. , 1992, Physical review. B, Condensed matter.

[16]  Y. Chan,et al.  Study of the thermal stress in a Pb-free half-bump solder joint under current stressing , 2007 .

[17]  King-Ning Tu,et al.  Interdiffusion and Reaction in Bimetallic Cu-Sn Thin Films , 1973 .

[18]  Sinn-wen Chen,et al.  Electromigration effect upon the Sn/Ag and Sn/Ni interfacial reactions at various temperatures , 2002 .

[19]  Cemal Basaran,et al.  Measurement of high electrical current density effects in solder joints , 2003, Microelectron. Reliab..

[20]  Paul S. Ho,et al.  Investigation of diffusion and electromigration parameters for Cu–Sn intermetallic compounds in Pb-free solders using simulated annealing , 2007 .

[21]  Y. C. Chuang,et al.  Thermomigration in eutectic SnPb alloy , 2006 .

[22]  Peng Su,et al.  Effect of contact metallization on electromigration reliability of Pb-free solder joints , 2006 .

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

[24]  Kazuaki Ano,et al.  Kirkendall void formation in eutectic SnPb solder joints on bare Cu and its effect on joint reliability , 2005 .

[25]  Sinn-wen Chen,et al.  Electric current effects on Sn/Ag interfacial reactions , 1999 .