Prepreg Layers

Prepreg layers are composite materials consisting of woven or non-woven fiberglass reinforcement impregnated with a partially cured thermosetting resin system, typically epoxy. They serve as insulating dielectric layers between copper layers in multilayer PCBs, providing electrical isolation, mechanical support, and thermal management. During PCB lamination, heat and pressure cause the resin to fully cure, bonding adjacent layers together to form a solid, monolithic structure.

Prepreg layers function as adhesive dielectric materials that bond copper layers together during the PCB lamination process. When subjected to heat (typically 180-200°C) and pressure (200-400 psi), the partially cured resin flows, fills voids, and fully polymerizes, creating strong mechanical bonds and uniform dielectric properties throughout the PCB stack-up.