Development of new class of electronic packaging materials based on ternary systems of benzoxazine, epoxy, and phenolic resins

We have developed new polymeric systems based on the ternary mixture of benzoxazine, epoxy, and phenolic novolac resins. Low melt viscosity resins render void-free specimens with minimal processing steps. The material properties show a wide range of desirable reliability and processability, which are highly dependent on the composition of the monomers in the mixture. A glass transition temperature as high as 170 degrees C and considerable thermal stability at 5% weight loss up to 370 degrees C can be obtained from these systems. Phenolic novolac resin acts mainly as an initiator for these ternary systems while low melt viscosity, flexibility and improved crosslink density of the materials are attributed to the epoxy fraction. Polybenzoxazine imparts thermal curability, mechanical properties as well as low water uptake to the ternary systems. The materials exhibit promising characteristics suitable for application as underfilling encapsulation and other highly filled systems. (C) 2000 Elsevier Science Ltd. All rights reserved.