SIMULATION OF FILLING AND CURING PROCESSES IN EPOXY REACTIVE MOLDING

摘要

Numerical simulation of both filling and curing processes in electronic encapsulation with epoxy molding compound (EMC) is developed in this work. The resin is assumed here to be inelastic and Non-Newtonian in a non-isothermal temperature field. The governing equations are solved by employing the hybrid finite-element and finite-difference method (FEM/FDM). The 8-cavity IC package mold is used as the geometrical model. The predicted results provide useful information regarding the process variables, i.e., the pressure, temperature, shear rate and conversion profiles. A ladder-type pressure increase and an abrupt shear-rate change are observed during the filling stage. The conversion and reaction rate of this EMC material are insignificant during the filling and early curing stages. Additionally, the effects of mold temperature and reaction heat are also discussed. Productivity can be markedly enhanced for processing under a higher mold temperature. The curing time of 60 sec can be cut significantly short to 38 sec if the mold temperature increases from 178 to 188 degrees C. The demold time is 5 seconds longer with a 200 KJ/kg decrease of reaction heat, probably due to the addition of fillers. This work demonstrates its powerful capabilities in optimal mold design, processing condition setting, suitable EMC selection and cycle time calculation. [References: 20]