Chemorheology of Epoxy/Nickel Conductive Adhesives During Processing and Cure

Epoxy/nickel adhesives can be used as integrated circuit (IC) packaging material due to their lower cost than epoxy/silver adhesives with acceptable electrical conductivity. In this work, chemorheological behaviors of Epon 830/Ni/diethylenetriamine (DETA) adhesives were investigated during processing and cure, as a function of shear rate, resin conversion, Ni volume fraction and temperature. A strongly nonlinear characteristic of filled epoxy/Ni systems was revealed, and a steady shear had to be employed for chemorheological analyses. A strongly non-Newtonian flow behavior was observed for epoxy/Ni adhesives also during cure. The power-law model, Castro–Macosko model, Liu model and the Arrhenius model adequately describe, respectively, the effects of shear rate, resin conversion, filler volume fraction and temperature on chemoviscosity. A comprehensive model combining these individual models predicts the isothermal chemoviscosity data well and the nonisothermal data reasonably. A modified comprehensive model was also proposed in this work to improve the model fit to nonisothermal experimental data.