High dielectric constant polymer-ceramic (epoxy varnish-barium titanate) nanocomposites at moderate filler loadings for embedded capacitors

Polymer-ceramic nanocomposites are the major candidate dielectrics for embedded capacitors. Due to the poor adhesion and poor thermal stress reliability at high filler loadings, commercially available polymer-ceramic composites can only achieve a maximum dielectric constant of similar to 30. However, a high dielectric constant of similar to 50-200 is required to make the layout area small enough for embedding applications. In this work, we systematically studied the material formulations in order to obtain a high dielectric constant (kappa > 50) at the lowest ceramic filler loading. It was found that material design and processing were critical. By modifying the epoxy matrix with a chelating agent and using bimodal fillers and a proper amount of dispersing agent, dielectric constants >50 were obtained at moderate filler loadings.