電子元件在含溫度效應之動態負載下的可靠度研究

The Reliability Study for the Electronic Devices under Thermal and Dynamic Loading

蘇仁章(Ren-Jang Su)

指導教授 ： 陳永樹

元智大學/工程學院/機械工程學系/碩士(2004年)

摘要

本研究主要是針對FCBGA元件，進行四點彎曲測試，以瞭解其可承受之疲勞壽命。並經由實驗、有限元素分析與理論分析的相互配合，探討實驗測試過程中，元件失效與元件壽命之關連性。
實驗使用具有Daisy Chain之FCBGA元件，其將各錫球之電路串聯，並利用微材料試驗機(Micro Material Tester)，於不同環境溫度下，做電路板循環下壓之四點彎曲測試，用以觀察其Daisy Chain是否失效，並以有限元素分析之方法，來模擬真實受力情況下錫球接合處之應力大小，再與實驗所獲得的疲勞循環數相互配合對照。並以Weibull分佈之可靠度分析，配合疲勞壽命理論，估算錫球之疲勞壽命，並透過光學顯微鏡觀察錫球裂縫的產生。
研究結果發現，錫球之疲勞破壞位置在錫球與電路板接合界面上，與相關文獻中所述之破壞位置及實驗結果吻合。本研究對於電子系統元件之壽命分析，提供一個有效的可靠度驗證模式，利用此模式可檢驗並提高電子元件或系統的使用壽命，以達到提升可靠度的目的。

關鍵字

四點彎曲測試 ； 可靠度 ； 疲勞壽命

並列摘要

In this study, it is aimed to check the electronic component fatigue life with the four-point-bend test for FCBGA components. The resulting component life are determined by combining both the finite element analysis(FEA) technique and the theoretical calculation.

The experiment is conducted first by taking FCBGA components with the daisy chain circuits and mounted them on a PWB. The four-point bend test is performed on a micro material tester with different temperature settings. In the FEA, it uses the real displacements in the bending test as an input to the model. The resulting stresses of solder balls can be obtained. These stresses and the number of fatigue cycles as obtained in the bending test can then be plotted as the fatigue stress-cycle curve. Furthermore, the Weibull’s reliability analysis and fatigue theory are used to calculate the fatigue life.

The experimental results indicate that the failure cracks are located at the interface between solder balls and PWB. The procedures as described in the study provide an effective way in verifying the life of the electronic system. The method can be applied to the study of reducing the occurrence of unexpected component failure and also the improvement of their reliability in the electronic system design.

並列關鍵字

Four-Point Bend Test ； Fatigue Life ； FCBGA ； Daisy Chain ； Weibull

參考文獻

2.J. Schijvey, “A Normal Distribution or a Weibull Distribution for Fatigue Lives,” Fatigue & Fracture of Engineering Materials & Structures, Vol. 16, pp. 851-859, 1993.

3.S. Tanaka, M. Ichikawa, and S. Akita, “A Probabilistic Investigation of Fatigue Life and Cumulative Cycle Ratio,” Engineering Fracture Mechanics, Vol. 20, pp. 501-503, 1984.

4.C. Kanchanomai, Y. Miyashita, and Y. Mutoh, “Low-Cycle Fatigue and Mechanisms of A Lead-Free Solder 96.5Sn/3.5Ag,” Journal of Electronic Materials, Vol. 31, pp. 142-151, 2002.

5.C. Kanchanomai, and Y. Miyashita, “Low-Cycle Fatigue Behavior and Mechanical of A Eutectic Sn-Pb Solder 63Sn/37Pb,” International Journal of Fatigue, Vol. 24, pp. 671-683, 2002.

6.C. Kanchanomai, S. Yamamoto, Y. Miyashita, Y. Mutoh, and A. J. McEvily “Low-Cycle Fatigue Test for Solders Using Non-Contact Digital Image Measurement System,” International Journal of Fatigue, Vol. 24, pp. 57-67, 2002.