Curing kinetics study of thermosetting resin material with ultra-low dielectric loss for advanced electronic packaging

Ultra-low-loss resin materials are widely utilized in the novel electronic packaging. In this study, we have investigated the curing reaction kinetics of ultra-low-loss thermosetting resin systems represented by thermosetting polyphenylene oxide/small molecule crosslinking agent triallyl isocyanurate/macromolecular crosslinking agent 1,2-polybutadiene. Their curing process is very different from the commonly used epoxy resin. First, the curing reaction of such resin systems is decelerating, unlike typical auto-accelerating systems. Due to the high reaction temperature, the initiator concentration rapidly declines during curing, resulting in dead-end polymerization. Therefore, calculating the activation energy with conversion by the isoconversional method is not completely applicable. However, the calculation results are helpful for further analysis of the reaction mechanism and fitting of the reaction rate. More importantly, samples with high initiator content suffer from diffusion-controlled reactions, leading to a rapid increase in dielectric loss. This phenomenon has a great impact on materials requiring ultra-low dielectric loss. The use of higher reaction temperature initiators, especially carbon-carbon initiators, can mitigate the excessive and increasing dielectric loss. These research findings have great reference value for developing new resin materials with ultra-low loss.