To improve the fatigue life of electronic packages, it is necessary to clarify thermal fatigue characteristics of underfill resin materials. In this study, a new setup for measuring thermal fatigue crack growth was developed, and the effects of thermal cycle conditions and silica filler contents on fatigue crack propagation were investigated. The results show that the likelihood of crack initiation increased with the filler content and the temperature of the thermal cycles. Comparing the results with those from mechanical fatigue tests, crack initiation and propagation occurred at lower ΔK and the crack growth rates were higher for thermal fatigue. Observations of the fracture surface revealed that the cracks propagated inside the underfill resin, which resulted in smaller crack growth resistance than that in mechanical fatigue. The addition of fillers introduced a crack propagation path at the interface between fillers and resins and enhanced the crack propagation resistance in thermal fatigue.
|ジャーナル||Fatigue and Fracture of Engineering Materials and Structures|
|出版ステータス||Published - 2022 5月|
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