A materials science based damage metric is presented for solders in electronic packaging. The damage metric characterizes the damage state when solders are subjected to cyclic thermal strain due to mismatch of the coefficient of thermal expansion (CTE). The damage metric is derived through a micromechanics approach, and its relationship to the damage parameters is assumed to follow power law. A unified creep and plasticity constitutive model with damage incorporation showed reasonable agreement with the experimental results for two solders under a one-dimensional strain controlled fatigue test.
1. Mavoori, H. (1996). Mechanical Properties and Fatigue Lifetime Prediction of Solders for Electronic Applications: Tin–Silver and Tin–Zinc Eutectics, Ph.D. Dissertation, Northwestern University, Evanston, IL.
2.
2. Stolkarts, V., Keer, L.M. and Fine, M.E. (1999). J. Mech. Phys. Solids, 47: 2451–2468.
3.
3. Mura, T. and Nakasone, Y. (1990). J. Appl. Mech.-Trans. ASME, 57: 1–6.
4.
4. Fine, M.E. (2000). Scripta mater., 42: 1007–1012.
5.
5. Wen, S. and Keer, L.M. (2001). J. Appl. Mech. -T. ASME, 69: 1–10.
6.
6. Wen, S. (2001). Thermomechanical Fatigue Life Prediction For Several Solders, Ph.D. Dissertation, Northwestern University, Evanston, IL.
7.
7. Stauffer, D. and Aharony, A. (1992). Introduction to Percolation Theory, 2nd Edn.Taylor & Francis, Washington DC.
8.
8. Krajcinovic, D. (1996). Damage Mechanics, Elsevier, Amsterdam; New York.
9.
9. Heiduschke, K. (1998). Int. J. Numer. Methods Eng.41: 211–231.
10.
10. Chandaroy, R. and Basaran, C. (1999). J. Electron. Packag., 121: 61–68.
11.
11. Zhang, X., Lee, S.-W.R. and Pao, Y.-H. (2000). J. Electron. Packag., 122: 200–206.
12.
12. McDowell, D.L., Miller, M.P. and Brooks, D.C. (1994). A Unified Creep-Plasticity Theory for Solder Alloys. In: Schroeder, S.A. and Mitchell, M.R. (eds.) Fatigue of Electronic Materials, ASTM STP 1153, American Society for Testing and Materials, Philadelphia.
13.
13. Simo, J.C. and Ju, J.W. (1987). Int. J. Solids Struct., 23: 821–840.
14.
14. Chow, C.L. and Yu, L.G. (1997). A Unified Approach to Metal Fatigue Based on the Theory of Damage Mechnaics. In: McDowell, D.L. (ed.), Applications of Continuum Damage Mechanics to Fatigue and Fracture, ASTM STP 1315, ASTM.
15.
15. Qi, W.D. and Bertram, A. (1999). Int. J. Plast., 15: 1197–1215.
16.
16. Wen, S., Keer, L.M. and Mavoori, H. (2001). J. Electron. Mater., 30: 1190–1196.
17.
17. Budiansky, B. and O’Connell, R.J. (1976). Int. J. Solids Struct., 12: 81–97.
18.
18. Wen, S., Keer, L.M., Vaynman, S. and Lawson, L.R. (2001). IEEE T Compon. Pack. Tech., 25: 23–31.
19.
19. Mavoori, H. (2001). Fatigue Tests on Sn–3.5Ag Solders, Personal communication, January 2001.
20.
20. Lawson, L.R. (2000). Thermomechanical Fatigue Experiment of 97Pb–3.5Sn, Personal communication, June–August 2000.
