晶圓重組 (wafer reconstitution) 必須經歷一系列壓模、後熟化、卸除載盤等製程，其中壓模速度、壓力、溫度以及時間等參數設定，對製程良率維持而言是極為關鍵的因素。若未能妥善地設定這些參數，將可能造成重組後晶圓在外觀上明顯可見的缺陷，如晶圓翹曲 (wafer warpage) 以及晶粒偏移 (die shift) 等直接降低製程良率的現象。所謂晶粒偏移是由製程中的模流因素負載和各材料間熱膨脹係數 (coefficient of thermal expansion；CTE) 差異所致之熱應力，與封膠固化收縮時所產生之殘留應力，以及長時間處於高溫時封膠所產生之黏彈效應等固力因素交互作用所致，而本論文主要評估這些模流因素與固力因素對製程所造成的缺陷。論文中我們利用自行研發的演算法，求得封膠 (Epoxy molding compound ; EMC) 的材料參數和固化程度，轉換成製程時封膠的黏度；並將黏度做為分析模型的材料參數，透過三維CFD模型中，評估出模流因素造成的晶粒偏移。固力因素的分析，主要利用固化收縮與熱膨脹關係，去計算每段製程的晶圓半徑大小，進而估算出一個晶粒偏移的等效伸縮率。在經過晶粒偏移的模擬與實驗驗證後，模型的準確率高達90%以上，最後我們試著提出對於晶粒偏移之改善方案，以降低前述各項缺陷在產線上實際發生之機率，進而達成改善製程良率之終極目標。

SUMMARY
In advanced packaging technologies, there are many important parameters in the wafer reconstitution process, such as molding velocity, pressure, temperature and duration of each process. Without proper tuning of these parameters, some serious defects typically appear after wafer reconstitution, such as die shift and wafer warpage. These defects clearly may decrease the yield. In this thesis, we utilize 3D CFD simulation and curing shrinkage analysis to determine both the fluid and solid effects on die-shift defects. Then it turns out that die shift mainly is caused by the interaction of fluid force loading, material thermal expansion, shrinkage of molding compound and viscoelastic effects. Following previous research, we use experimentally determined values for material parameters in our simulations. In the meantime, we also estimate the extent of curing of molding compound by analyzing experimental data of viscosity tests. After finishing those experiments, we then input these material parameters into our 3D CFD model to simulate the real molding process. Calculating the shear force loading on tape, we can predict die shift made by the fluid effect. It is much smaller than the actual die shift measured in the factory. On the other hand, we use thermal and shrinkage formulation to estimate die shift caused by solid effect. Comparing actual and prediction of die shift, finally, we find out that the curing shrinkage and coefficient of thermal expansion are key factors of the die shift defect. To sum up, this thesis predicts the amount of die shift accurately, comparing the measurement in production lines. With this successful prediction, we can give displacement compensation to dies before the reconstitution process. After wafer reconstitution process, dies will locate at the desired target position.

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