Simulation of Effect of Current Stressing on Reliability of Solder Joints with Cu-Pillar Bumps
The mechanism behind the electromigration and
thermomigration failure in flip-chip solder joints with Cu-pillar bumps
was investigated in this paper through using finite element method.
Hot spot and the current crowding occurrs in the upper corner of
copper column instead of solders of the common solder ball. The
simulation results show that the change in thermal gradient is
noticeable, which might greatly affect the reliability of solder joints
with Cu-pillar bumps under current stressing. When the average
applied current density is increased from 1×104 A/cm2 to 3×104 A/cm2
in solders, the thermal gradient would increase from 74 K/cm to 901
K/cm at an ambient temperature of 25°C. The force from thermal
gradient of 901 K/cm can nearly induce thermomigration by itself.
With the increase in applied current, the thermal gradient is growing. It
is proposed that thermomigration likely causes a serious reliability
issue for Cu column based interconnects.
[1] J. H. Lau, Flip Chip Technology , New York: McGraw-Hill, 1995, pp. 28.
[2] J. W. Nah, J. O. Suh, and K. N. Tu, "Electromigration in flip chip solder
joints having a thick Cu column bumpand a shallow solder interconnect,"
J. Appl. Phys., 2006, 100: 123513.
[3] C. Y. Liu, C. Chen, and K. N. Tu, "Electromigration in Sn-Pb solder strips
as a function of alloy composition," J. Appl. Phys., 2000, 88: 5703.
[4] C. Chen, and S. W. Liang, "Electromigration issues in lead-free solder
joints, J. Mater. Sci. - Mater Electron.," 2007, 18: 259-268.
[5] B. Y. Wu, Y. C. Chan, and H. W. Zhong, "Study of the thermal stress in a
Pb-free half-bump solder jointunder current stressing," Appl. Phys. Lett.,
2007, 90: 232112.
[6] S. H. Chiu, T. L. Shao, and C. Chen, "Infrared microscopy of hot spots
induced by Joule heating in flip-chip SnAg solder joints under accelerated
electromigration", Appl. Phys. Lett., 2006, 88: 022110.
[7] S.W. Liang, T. L. Shao, C. Chen, E. C. C. Yeh, and K. N. Tu, "Relieving
current crowding effect in flip-chip solder joints during current stressing,"
J. Mater. Res., 2006, 21(1): 137-146.
[8] P. G. Shewmon, Diffusion in Solids, Warrendale, PA: TMS, 1989, Chap.
7.
[9] D. V. Ragone, Thermodynamics of Materials, New York: Wiley,
1995,Vol. 2, Chap. 8.
[10] F. Y. Ouyang, K. N. Tu, Y. S. Lai, and A. M. Gusak, "Effect of entropy
production on microstructure change in eutectic SnPb flip chip soider
joints by thermigration," Appl. Phys. Lett., 2006, 89: 221906 .
[11] Y. C. Hsu, T. L. Shao, C. J. Yang, and C. Chen, "Electromigration study
in SnAg3.8 Cu0.7 solder joints on Ti/Cr-Cu/Cu under-bump
metallization," J. Electron. Mater, 2003, 132: 1222.
[12] B. Y. Wu, and Y. C. Chan, "Electric current effect on microstructure of
ball grid array solder joint," J. Alloys Compd. , 2005, 39: 237.
[1] J. H. Lau, Flip Chip Technology , New York: McGraw-Hill, 1995, pp. 28.
[2] J. W. Nah, J. O. Suh, and K. N. Tu, "Electromigration in flip chip solder
joints having a thick Cu column bumpand a shallow solder interconnect,"
J. Appl. Phys., 2006, 100: 123513.
[3] C. Y. Liu, C. Chen, and K. N. Tu, "Electromigration in Sn-Pb solder strips
as a function of alloy composition," J. Appl. Phys., 2000, 88: 5703.
[4] C. Chen, and S. W. Liang, "Electromigration issues in lead-free solder
joints, J. Mater. Sci. - Mater Electron.," 2007, 18: 259-268.
[5] B. Y. Wu, Y. C. Chan, and H. W. Zhong, "Study of the thermal stress in a
Pb-free half-bump solder jointunder current stressing," Appl. Phys. Lett.,
2007, 90: 232112.
[6] S. H. Chiu, T. L. Shao, and C. Chen, "Infrared microscopy of hot spots
induced by Joule heating in flip-chip SnAg solder joints under accelerated
electromigration", Appl. Phys. Lett., 2006, 88: 022110.
[7] S.W. Liang, T. L. Shao, C. Chen, E. C. C. Yeh, and K. N. Tu, "Relieving
current crowding effect in flip-chip solder joints during current stressing,"
J. Mater. Res., 2006, 21(1): 137-146.
[8] P. G. Shewmon, Diffusion in Solids, Warrendale, PA: TMS, 1989, Chap.
7.
[9] D. V. Ragone, Thermodynamics of Materials, New York: Wiley,
1995,Vol. 2, Chap. 8.
[10] F. Y. Ouyang, K. N. Tu, Y. S. Lai, and A. M. Gusak, "Effect of entropy
production on microstructure change in eutectic SnPb flip chip soider
joints by thermigration," Appl. Phys. Lett., 2006, 89: 221906 .
[11] Y. C. Hsu, T. L. Shao, C. J. Yang, and C. Chen, "Electromigration study
in SnAg3.8 Cu0.7 solder joints on Ti/Cr-Cu/Cu under-bump
metallization," J. Electron. Mater, 2003, 132: 1222.
[12] B. Y. Wu, and Y. C. Chan, "Electric current effect on microstructure of
ball grid array solder joint," J. Alloys Compd. , 2005, 39: 237.
@article{"International Journal of Mechanical, Industrial and Aerospace Sciences:55818", author = "Y. Li and Q. S. Zhang and H. Z. Huang and B. Y. Wu", title = "Simulation of Effect of Current Stressing on Reliability of Solder Joints with Cu-Pillar Bumps", abstract = "The mechanism behind the electromigration and
thermomigration failure in flip-chip solder joints with Cu-pillar bumps
was investigated in this paper through using finite element method.
Hot spot and the current crowding occurrs in the upper corner of
copper column instead of solders of the common solder ball. The
simulation results show that the change in thermal gradient is
noticeable, which might greatly affect the reliability of solder joints
with Cu-pillar bumps under current stressing. When the average
applied current density is increased from 1×104 A/cm2 to 3×104 A/cm2
in solders, the thermal gradient would increase from 74 K/cm to 901
K/cm at an ambient temperature of 25°C. The force from thermal
gradient of 901 K/cm can nearly induce thermomigration by itself.
With the increase in applied current, the thermal gradient is growing. It
is proposed that thermomigration likely causes a serious reliability
issue for Cu column based interconnects.", keywords = "Simulation, Cu-pillar bumps, Electromigration,Thermomigration.", volume = "4", number = "1", pages = "17-5", }