| Summary: | 碩士 === 國立清華大學 === 化學工程學系 === 103 === We are using a wide range of electronic products in our daily life, and we can hardly live without them. Due to our requirements for modern electronic product - lighter, slimmer , shorter, and smaller, the smaller dimensional specification is expected to fit under the evolution of continuous process. On the other hand, under the highly competitive environment and the pressure of time-to-market, how to provide qualified modern electronic products is a new challenge for the associated package process. Specifically, one of the important defects is non-uniform property result from un-even filler particle distribution, temperature profile, and local gelation change during the package process.To catch the phenomena, CAE simulation is commonly applied. However, most CAE simulations assume the material property is homogeneous, and this assumption will be far from the situation in reality such as regarding to shear-induced migration and particle settling.
In this study, a three-dimensional simulation model of non-colloidal filler suspension is proposed to predict the filler concentration in microchips. Firstly, the proposed model is validated using two-dimensional channel and axisymmetrical circular pipe geometry model. Results showed that the trend of filler distribution is in a good agreement. Furthermore, there are various factors caused the inhomogeneity of fillers during the encapsulation of transfer molding processes. Therefore, it's important to figure out what the driving forces or causes are. Study shows there are two main reasons in the processes induce distinct filler concentration distributions after molding - settling and shear migration. We focus on the transfer molding processes in this study, and we discuss different conditions such as transfer time, mold temperrature, resin temperature, which affect the filler distribution. The results show that the transfer time may be the major factor than the others, and they will provide a comprehensive understanding uneven filler concentration after encapsulation. By using the integrated analysis, filler concentration under deferent working condition during encapsulation can be easily predicted, so as to efficiently reduce manufacturing cost and design cycle time.
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