Mold Flow Simulation Analysis of Molded Underfill in an Ultra-thin High-Density Package

The consumer electronics devices continue to develop towards ultra-thin, high-density and miniaturization. Advanced mold flow simulation analysis before the actual experiment will help to predict and understand the potential risks of Epoxy Molding Compound (EMC) filling and then effectively promote mold design and material selection. However, the contribution of mold flow simulation to EMC material evaluation is still insufficient. One of the main reasons is that mold flow simulation requires a large number of material parameters, so it is difficult to analyze the material by traditional design of experiment (DOE) methods. In this paper, we investigate a structure for an ultra-thin and fine-pitch package, and uses one commercial EMC material to study its mold flow filling process in Modex3D software. The changing of temperature, shear rate, curing degree and viscosity during the filling process are analyzed in detail. In addition, based on detailed analysis of the viscosity equations and curve, the influences of temperature, filling time, viscosity, gel point and curing kinetics parameters on filling state are discussed in depth. This research is expected to provide theoretical guidance for improving the filling state in ultra-thin fine-pitch devices in terms of material design and process control.