SIMULATION OF FILLING AND CURING PROCESSES IN EPOXY REACTIVE MOLDING

Numerical simulation of both filling and curing processes in electroni c 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 mode l. The predicted results provide useful information regarding the proc ess variables, i.e., the pressure, temperature, shear rate and convers ion profiles. A ladder-type pressure increase and an abrupt shear-rate change are observed during the filling stage. The conversion and reac tion rate of this EMC material are insignificant during the filling an d early curing stages. Additionally, the effects of mold temperature a nd reaction heat are also discussed. Productivity can be markedly enha nced for processing under a higher mold temperature. The curing time o f 60 sec can be cut significantly short to 38 sec if the mold temperat ure 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 se lection and cycle time calculation.