扇出型(Fan-out)晶圓級封裝因電性與封裝尺寸上的優勢，近年來成為封裝研究主要發展技術之一。在扇出型封裝結構中，為了滿足電性、製程與成本的考量，高分子材料被大量的使用。異質材料的整合，使扇出型封裝遇到諸多挑戰。由於材料間的密度與熱膨脹係數不同，在製造與使用過程中所產生的機械熱應力，會增加封裝體裂開與脫層的風險。另一方面，高分子材料具有吸濕性，水汽進入高分子材料會造成材料膨脹與特性上的改變，例如增塑效應、界面黏著力下降、翹曲行為改變、介電常數下降和斷裂強度下降等，皆有機會進一步造成封裝體的失效問題，因此了解水汽對高分子材料的影響有其必要性。其中聚醯亞胺薄膜常被用來當作重佈線層內介電薄膜的材料，此區域也是最常產生元件失效的區域，因此本文將針對聚醯亞胺薄膜材料進行水汽之相關研究。
本論文首先針對聚醯亞胺薄膜進行吸濕實驗、建立其雙階段吸濕擴散模型。並透過動態掃頻實驗分析溫度與濕度對於黏彈行為的影響，建立其溫度-濕度相依黏彈模型。接著進行熱膨脹係數的量測。最後以全域-局部有限元素方法建立扇出型封裝模型，模擬評估濕度敏感試驗中，封裝體內銅導線的應力變化與失效風險。

For investigating the influence of moisture on the reliability of fan-out wafer-level package (FOWLP), this study first considered the characterized the Polyimide (PI) thin film and developed the moisture diffusion model and the humidity dependent viscoelastic model. The models were implemented in finite element (FE) simulation to consider FOWLP under moisture sensitivity level (MSL) testing. In the diffusion characterization, a series of moisture absorption experiments were carried out by thermogravimetric analyzers (TGA). The material parameters for the dual-stage diffusion model were obtained by fitting. In the humidity-dependent viscoelastic model, results obtained from tensile dynamic mechanical analyses (DMA) were processed by following the time-temperature-moisture superposition principle to obtain the hygrothermal master curve. The vertical shift factor in the model can express the effect of humidity and improve the model accuracy in the low-temperature regime. From FE simulation results, it can be seen that the stress is reduced if the FOWLP is under hygroscopic swelling. However, to evaluate the moisture-induced failure, it is also required to consider factors such as degradation of interface adhesion due to moisture uptake.

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