近年來，因為國際上環保意識抬頭，各國開始禁止在電子產品中使用有毒物質，所以以無鉛焊錫取代含鉛焊錫成為必然之趨勢。但錫鉛焊錫的使用已經有一段很長的時間，因此對其材料行為有較充分的了解。相反地，因為對於無鉛焊錫材料相關的研究有限，所以其材料行為仍然無法完全掌握。
為了解無鉛焊錫在疲勞負載下的行為，本論文以實驗方法針對錫銀銅3807球閘陣列試件藉由恆溫下梯形波和三角波形式之循環負載來觀察材料的變形及損傷行為。實驗考慮的條件包含溫度、負載持平時間和負載峰值。從實驗結果觀察到，當材料處在負載升降的過程，即使所受到的負載峰值低於降伏點，仍然會有棘齒反應產生。另外，在材料處於峰值負載持平階段，會有暫態與穩態潛變反應發生。而且材料的潛變與棘齒反應會隨著溫度與最大負載的增加而增加。此外，本研究中發現，對於整體的負載對位移的遲滯迴圈，潛變行為造成之反應會大於棘齒反應。最後，利用有限元素法模擬恆溫條件下雙層剪力循環實驗，並以塑性應變能密度增量作為疲勞損傷評估的參數，與一上板之晶圓級封裝元件在加速熱循環試驗下之模擬結果作比較。期望藉由兩種實驗比較之結果，發展雙層剪力循環試驗與加速溫度循環之間疲勞壽命的加速因子。

For the purpose of considering the fatigue response of Pb-free SnAgCu solder joint, a cyclic double lap shear test consisting both ramp and dwell loading profiles under isothermal condition was investigated for ball grid array solder joints. Factors including test temperature, shearing load amplitude and load dwelling time were considered in the experiment for determining the damage accelerating effects. From the experiment it was observed that, during the cyclic shear load ramping stages, ratcheting would still occur even though the peak load is below the solder yielding point. Transient and steady-state creep responses were also observed during the dwelling stages of the loading profile. Both ratcheting and creep responses became more significant as temperature or peak load increases. An important finding of the experiment is that the contribution of creep to the overall load-displacement hysteresis is more significant than the contribution of ratcheting. The hysteresis and the corresponding inelastic energy dissipation under the cyclic double lap shear experiment were compared to those calculated numerically for a typical wafer-level package assembled on printed circuit board. The comparison can be used for developing acceleration factors between the cyclic shear and board-level temperature cycling tests.

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