An increased cooling rate following reflow produced a decrease in the microstructure size including the size of the colonies, the Pb-rich dendrites and the eutectic phases. The decrease in microstructure size gave an increased creep rate at room temperature and a decrease in the creep stress exponent. Also, thermo-mechanical fatigue crack growth rate decreased and fatigue life increased with the decrease in microstructure size. These effects of the increased cooling rate were attributed to an increase in boundary sliding which could occur from the increase in boundary area with decrease in microstructure size.

Issue Section:
Technical Papers
Topics:
Deformation, Fatigue, Solder joints, Thermomechanics, Cooling, Creep, Fatigue cracks, Fatigue life, Stress, Temperature
1.
Guo, Z., and Conrad, H., “Computer Modeling of Isothermal Low-Cycle Fatigue of Pb-Sn Solder Joints,” Proc. 43rd Electronics Components Tech. Conf., ECTC, CHMT IEEE, Buena Vista Palance, Orlando FL, June 1–4, 1993, pp. 831–838.
2.
Guo, Z., and Conrad, H., “Fatigue Cracking Kinetics and Lifetime Prediction of Electronic Solder Joints,” Proc. ASME/JSME/IEEE Inter Pack’95, Westin Maui, Hawaii, March 26–30, Advances in Electronic Packages, ASME, EEP, V.10–2, 1995, NY, pp. 1129–1141.
3.
Bae, K., Guo, Z., Sprecher, A. F., Jung, D., and Conrad, H., “Effect of Compliance on the Fatigue of Solder Joints in Surface-Mounted Electronic Packages,” Proc. Int. Symp. Test. Failure Analysis, ISTFA, 1988, ASM, Metals Park, OH, pp. 53–61.
4.
Guo
Z.
, and
Conrad
H.
, “
Fatigue Crack Growth Rate in 63Sn37Pb Solder Joints
,”
ASME JOURNAL OF ELECTRONIC PACKAGING
, Vol.
115
, June
1993
, pp.
159
–
164
.
5.
Hacke, P. L., Sprecher, A. F., and Conrad, H., “Thermomechanical Fatigue of 63Sn–37Pb Solder Joints,” Thermal Stress and Strain in Microelectronics Packaging, ed., J. H. Lau, Van Nostrand Reinhold, New York, 1993, pp. 467–499.
6.
Guo
Z.
,
Sprecher
A. F.
, and
Conrad
H.
, “
Plastic Deformation Kinetics of Eutectic Pb-Sn Solder Joints in Monotonic Loading and Low-Cycle Fatigue
,”
ASME JOURNAL OF ELECTRONIC PACKAGING
, Vol.
114
, June
1992
, pp.
112
–
117
.
7.
Solomon, H. D., “Creep, Strain Rate Sensitivity and Low-Cycle Fatigue of 60/40 Solder,” Brazing and Soldering, No. 11 Autumn 1986, pp. 68–75.
8.
Askill, J., Tracer Diffusion Data, Plenum, New York, N.Y., 1970.
9.
Guo, Z., Sprecher, A. F., and Conrad, H., “Effect of Sn Content on Crack Growth Rate in Low Cycle Fatigue of Pb-Sn Solder Joints,” Proc. ASM 5th Electronic Packaging Congress: Materials and Processes to Reduce Package Cycle Time and Improve Reliability, Cambridge, MA, Aug. 24–27, 1992, pp. 209–216.
10.
Shine, M. C., and Fox, L. R., “Fatigue of Solder Joints in Surface Mount Devices,” Low Cycle Fatigue, ASTM STP 942, ed. by H. D. Solomon, ASTM, Philadelphia, 1988, pp. 588–610.
11.
Knecht, S., and Fox, L., “Integrated Matrix Creep Application to Accelerated Testing and Lifetime Prediction,” Solder Joints Reliability-Theory and Application, ed. by L. H. Lau, Van Nostrand Reinhold, New York, 1991, pp. 508–544.
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