在覆晶接合(flip chip bonding)之銲錫接點(solder interconnect)技術中，銲材與凸塊下金屬層(under bump metallurgy)因化學擴散反應使得兩者介面間常產生一層極薄介金屬化合物(intermetallic compound)。此介金屬化合物之剪切強度通常較銲材低而會影響銲錫接點之抗掉落衝擊(drop impact)能力，且在熱機械負載下，當介金屬化合物厚度超過一定值時，易於其相鄰界面產生局部高應力，而導致裂紋生成及銲錫接點破壞。因此，介金屬化合物層之機械性質及行為探討，對銲錫接點可靠度之提昇，極為重要。
介金屬化合物之硬度及楊氏模數等機械性質目前雖可利用奈米壓痕試驗測得，但對其彈-塑性行為(如應變硬化指數與降伏應力等)，因受介金屬化合物奈微米試片製作及量測技術限制，常無法準確量測，而數值計算不失為一可行且可與實驗量測互補之方法。
Dao材料分析模型雖可針對楊氏模數範圍在10 ~ 210 GPa間材料之彈-塑性行為進行探討，但因探討之範圍較廣且建立分析模型時採用之數據不足，致使其預測之材料彈-塑性行為產生相當之誤差。
本論文主要以Dao材料分析模型為基礎進行修正，建立介金屬化合物材料性質(楊氏模數範圍在60~200GPa)與奈米壓痕試驗參數之關係式，進而對介金屬化合物之料彈-塑性行為進行探究。由實驗與數值計算結果發現，介金屬化合物之初始卸載勁度(initial unloading stiffness)與減化楊氏模數(reduced young’s modulus)之比值並不為常數，而會隨著材料的不同而有所改變。本論文成功建立此比值與奈米壓痕試驗參數間之關係式，使其能有效評估介金屬化合物之應變硬化指數與降伏應力。
最後，本論文利用所建立之修正型Dao材料分析模型，結合Coffin-Manson疲勞壽命經驗公式，進一步探討一高密度、超細微間距三維晶片對晶片(chip-on-chip)堆疊構裝，在加速熱循環負載(accelerated thermal cycling loading)下，其微接點介金屬化合物對錫銀銲料疲勞壽命之影響。結果顯示，當納入介金屬化合物彈-塑性行為分析時，確可提昇微接點錫銀銲料疲勞壽命預估之精準度。

In the solder interconnect technology of flip chip bonding, a thin intermetallic compound layer is likely to form at the interface between solder bump and under bump metallurgy due to the constitutional chemical diffusion. Generally, the shear strength of the intermetallic compound is less than that of the solder. This would influence the drop impact reliability of the solder bump. In addition, as the thickness of intermetallic compound is up to a certain value, a high local stress would commonly occurred at the interface between intermetallic compound layer and its neighborhood, thereby leading to the crack formation and solder bump failure. Thus, it is essential to explore the mechanical property and behavior of intermetallic compound for improving the reliability of the solder bump.
Up to date, though the mechanical properties, such as hardness and Young’s modulus, of the intermetallic compound can be measured through the nanoindentation, it is hard to accurately grasp the elasto-plastic behavior of intermetallic compound, i.e., strain hardening exponent and yield stress and, etc., due to the constrains of nano/micro samples fabrication of intermetallic compound and measurement technique. Therefore, the numerical calculation could be the alternative method, which is in replacement of experimental approach, to obtain the mechanical property and behavior of intermetallic compound.
Though the Dao model can yield the elasto-plastic behavior, i.e., strain hardening exponent and yielding strength, of the material, whose Young’s modulus is in the range of 10~210 GPa. Nevertheless, the range of the Young’s modulus of the material investigated in the Dao model is extremely extensive. It would result in a lack of the data regarding to development of the Dao model, thereby resulting in a substantially error for Dao model in prediction of elasto-plastic behavior.
This thesis constructed the material property and relationship of nanoindentation empiric parameter of the intermetallic compound (Young’s modulus is in the range of 60 ~ 200GPa) by mainly modifying the Dao model to further investigate the elasto-plastic behavior of intermetallic compound. According to the experimental and simulated results, the ratio of initial unloading stiffness and reduced young’s modulus of the intermetallic compound was not constant, and it would vary with different material. This thesis successfully established the relationship between the ratio and nanoindentation empiric parameter. Thus, the strain hardening exponent and yield stress of intermetallic compound were effectively evaluated.
Finally, this thesis applied the modified Dao’s material analysis model together with Coffin-Manson fatigue life empiric formula to further investigate the elasto-plastic behavior effect of intermetallic compound on the reliability of SnAg solder bump of the high-density and ultra-fine-pitch 3D chip-on-chip stacking packaging under accelerated thermal cycling loading. The calculated results reveal that the accuracy of prediction of solder bump reliability can be significantly enhanced as the elasto-plastic behavior of the intermetallic compound is taken into account.

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