3D simulation of filler concentration in semiconductor processing

Due to the tighter and tighter requirement for modern electronic product, the smaller dimensional specification is expected to fit under the evolution of continuous process. On the other hand, under the pressure of time-to-market, how to provide qualified modern electronic products is more and more 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. This assumption will be far from the situation in reality, for example regarding to shear-induced migration and particle settling. In this study, a three-dimensional simulation model of noncolloidal 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, transfer molding process is utilized to study the inhomogeneity of fillers due to settling and shear migration. Particularly, there are three different experimental factors discussed to see the effect that induce distinct filler concentration distributions after molding. The results will provide a comprehensive understanding the driving force for filler concentration. By using the integrated analysis, filler concentration during encapsulation can be easily detected to efficiently reduce manufacturing cost and design cycle time.