Reliability of Flip Chip Package with Underfills under Thermal Shock
The thermal fatigue properties of the solder joints with various underfills were evaluated by thermal shock test. Flip chip package with electroless nickel-immersion gold plated on Cu pad of FR-4 substrate and the Sn-37Pb solder ball was used. The thermal fatigue crack initiated at the edges of interface between solder and silicon die. The fatigue property of package with underfill, which has a higher glass transition temperature (Tg) and lower coefficient of thermal expansion (CTE) value was better than that of package with underfill having a lower Tg and higher CTE.
Seung-Seok Lee, Joon Hyun Lee, Ik Keun Park, Sung-Jin Song, Man Yong Choi
B. I. Noh and S. B. Jung, "Reliability of Flip Chip Package with Underfills under Thermal Shock", Key Engineering Materials, Vols. 321-323, pp. 1719-1722, 2006