Investigation of Significant Parameter and Interaction of Plastic Transfer Molding Parameters for 3D Dual In-Line IC Package Encapsulation

Abstract

Control of plastic transfer molding process parameters is critical to ensure high yield and part reliability in advanced semiconductor packaging. This paper investigates the parameters influencing air bubble formation and shear stress in the 3D Dual In-Line Package (DIP) encapsulation. To separate out these effects, Mold-flow® simulation was conducted at different processing parameters, namely mold temperature, melt temperature, curing time and injection pressure. The experiment also differentiated the material formula between unfilled and 80% silica-filled epoxy molding compound (EMC). ANOVA-based response surface methodology (RSM) was used to assess the significance and interactions of these parameters. The results indicate that process sensitivity is tightly dependent on the silica filler content (F > 900, p < 0.0001). The unfilled EMC exhibited steady performance, with minimal variation of defects regardless of processing modifications. However, the trend in highly filled EMC is triply diphasic, with the dip as its highest is driven by high viscosity. Among the factors that could be controlled the most, there is the melt temperature that is the most effective way to reduce the air traps and shear stresses (p < 0.0001). The contribution of a mold temperature to a predictable, synergistic, secondary effect was noted. Based on this analysis, a process window was designed for the processing of high filler EMC with high melt and mold temperature and sufficient injection pressure. The developed statistical models have been shown to be highly predictive (R² > 0.96, adequate precision > 37). By elucidating these material–process–defect relationships, this work presents a clear-cut dual-defect mitigation technique for enhanced yield, reduced rework and reliable high-density electronic system outcomes.