本研究「Mold Underfill (MUF)覆晶封裝之填膠現象研究」其目的是要探討在考慮氣體因素影響之下FC BGA的結構下進行填膠而產生Voids的現象，而在分析前，亦針對特殊的環氧樹脂材料進行相關流變性質量測，例如:黏度分析、反應動力分析與材料玻璃轉化溫度量測…等等，並將量測結果輸入至模流分析軟體Moldex3D針對四分之一模型與二分之一模型分別進行膠體充填模擬分析，之後與實際案例短射實驗之流動波前做比較，探討模流分析的準確度與可靠度，並修正造成模擬分析不準確的因素，接著進行不同參數的設計與變更來觀察流動波前的情形以及Voids產生的位置，其中此次研究的設計的參數變更參數包含在模穴加入了預留區以及溢流區，並觀察設計變更設的整體流動波前差異性。另外此這次研究的另一個重點使考慮氣體對整體流動波前的影響性，以等溫過程的方式考慮了氣體以及熔融膠體兩項流體模穴中流動的相互情形，藉此模擬出更加貼切於實際情況的模流分析，藉由此研究可以藉由電腦輔助分析預測可能產生的Voids的區域以及確切位置、縫合線等封裝過程中可能產生問題的區域，在晶片設計時可避開這些區域進行設計，預期將可節省許多試模上財力與物力支出，可說是相當具有效率的開發方式，相信對於封裝技術的開發能有一定程度的幫助。

Air trap in a molded underfill package always exists. It is an annoying problem and needed further investigation. In this research, the mold filling phenomenon of molded underfill (MUF) was investigated through numerical method. The carrier was a flip chip BGA (FC BGA) package. Moldex3D software was used as the tool. The resin was modeled as a reaction fluid. Cure kinetics and viscosity was measured and modeled. Kamal’s model was used for the cure kinetics. Castro Macosko’s model was used for the viscosity model.
The simulation results were compared with the experiment results and were found the short shot results agreed well with the experiments. The simulation results also showed that the locations of the air trap for each package could be accurately predicted if the simulation was well setup. The size of trapped air voids could also be well predicted if Boyle's Law was used as the constitutive model for the compressed air and considered air vent effect. The simulation results could serve as a good reference for engineers to alleviate the MUF air trap problems.

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