Realization of embedded capacitors using polymer matrix composites with barium titanate as high-k-active filler

Polymer matrix composites (PMC) with barium titanate as high-k-active filler have high potential in embedded capacitors within a printing circuit board (PCB) enabling high permittivity values and low loss factors. These PMCs allows for the use of established polymer processing techniques like screen printing and curing, which are compatible to the established PCB-materials and shaping processes. In this work a process chain, starting with a material optimization of the nano-sized barium titanate, dispersed in an unsaturated polyester-styrene reactive resin, and a further specific process development, will be presented. With respect to the optimization of the individual process steps the flow behaviour of the uncured composite, the polymerization process and the dielectric properties were characterized comprehensively. Using a composite with a barium titanate filler load of 74 wt% allows for a dielectric layer formation by a modified screen printing technique. After capacitor mounting and composite curing an initial capacity density of 13.3 pF/mm² could be achieved.