電子封裝中的環氧樹脂封膠和介電層皆為高分子複合材料，此類材料具有明顯的黏彈性行為，且隨著溫度與時效的作用會產生硬化、化學老化與物理老化等行為，而材料長期暴露於大氣中也會產生吸濕老化的現象。當溫度低於玻璃轉換溫度時，材料的機械行為尤其會受物理老化影響，例如隨著時間增長，材料自由體積會下降、密度增加、產生鬆弛或潛變行為等。隨著模擬方法的演進與預測產品行為的準確度需求提升，正確的描述封裝體上材料的本構行為是必須的，且應將物理老化的效應納入考量。本文針對已有物理老化條件的封膠材料進行黏彈性行為量測，接著建立材料之本構模型，發現動態恆溫掃頻實驗無法準確量得無物理老化之材料模數，並證實短時間的製程條件中，降溫速率造成的物理老化差異會影響封膠材料的熱膨脹係數與熱應力累積行為。本文也探討封膠中水分的吸濕與再吸濕行為，並建立水分擴散模型與水分造成的體積變化關係。由於製程當中材料特性受老化行為影響甚深，本文利用模擬方法來預測與控制封裝體在短期熱製程的結構變化。將封膠搭配矽晶等材料模型套入有限元素軟體中，預測重構晶圓在非均勻溫度改變下的翹曲變化，觀察不同熱處理條件造成的影響，由模擬結果發現表面溫度最大值的調整具有較佳的重構晶圓翹曲調整效果。

Epoxy molding compound (EMC) used in semiconductor package exhibit strong viscoelastic behavior under typical processing conditions. Their behaviors change with time and temperature, including hardening, chemical aging and physical aging. EMC properties are also affected by moisture. Moisture absorption usually induces swelling of the polymer compound. As the requirement of simulation accuracy becomes higher, the effects of aging on the stress and strain responses should be included in the analysis. Physical aging starts when the temperature of amorphous polymer drops below its glass transition temperature (Tg). The process may cause changes to the molecular structure and a reduction in the free volume. In this study, the EMC under various aging conditions were investigated. Both tensile and torsional dynamic mechanical analyses (DMA), thermal mechanical analysis (TMA) and quasi-static tensile tests were conducted to measure the thermoviscoelastic behavior of an EMC. It was shown that physical aging affected the viscoelastic behavior, and the faster cooling from above-Tg temperature leads to lesser dimension change. The EMC mass increase due to moisture uptake was also measured, and were used for establishing the diffusion model. As an application example taking advantage of the viscoelastic characteristics of the EMC, a heat treatment procedure for reconstituted-wafer warpage mitigation was investigated by using numerical simulation. Effects of the heat-treatment control variables including heat flux and process time on the warpage change were investigated.

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