Open Access

ARTICLE

Study of the Underfill Effect on the Thermal Fatigue Life of WLCSP-Experiments and Finite Element Simulations

Shaw-Jyh Shin¹, Chen-Hung Huang², Y.C. Shiah³

1 Dept. of Communications Eng., Feng Chia University, R.O.C.
2 Dept. of Aerospace and Systems Eng., Feng Chia University, R.O.C.
3 Corresponding Author. Dept. of Aerospace and Systems Eng., Feng Chia University, R.O.C., Email: ycshiah@fcu.edu.tw

Computer Modeling in Engineering & Sciences 2009, 40(1), 83-104. https://doi.org/10.3970/cmes.2009.040.083

Abstract

Owing to the CTE (Coefficient of Thermal Expansion) mismatch among solder joints, IC (Integrated Circuit) chip, and PCB (Printed Circuit Board), electronic packages shall experience fatigue failure after going though a period of thermal cycling. As a major means to enhance the reliability of the solder joints, underfill is often dispensed to fill the gap between the die and the substrate. This study aims at investigating how the underfill may affect the thermal fatigue life of WLCSP (Wafer Level Chip Scale Package) by means of FEA (finite element analysis). In this study, the thermal fatigue life of the WLCSP was simulated using full-model. For comparison with the FEA simulations, experiments were also conducted for a few WLCSP with/without underfill.

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Keywords

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