Synthesis and characterization of Nano BaTiO3/epoxy composites for embedded capacitors

The miniaturization trend of integrated circuits (ICs) calls for replacing discrete passive components with embedded passives. Among the passive components, the embedded decoupling capacitors which are used for simultaneous switching noise suppression have drawn great attention. It is because decoupling capacitors should be placed as near as possible to a chip to reduce parasitic inductance. Important requirements for embedded capacitor materials are high dielectric constant, low capacitor tolerance, good processibility and low cost. BaTiO₃-filled epoxy composite is a promising material to meet the above requirements. It utilizes the high dielectric constant of ceramic powders and processibility of polymers. The dielectric behavior of the composite is influenced by the crystal phase type, grain size and dispersability of the BaTiO₃ particles distributing in it. In this study, nano-sized BaTiO₃ powders have been synthesized with a modified hydrothermal reaction method. The powers possess tetragonal crystal phase with a narrow size range around 50 nm. The dielectric constant of the epoxy filled with BaTiO₃ is 19.4 at the frequency of 10 kHz when the loading of BaTiO₃ was 50 vol% and the dielectric loss factor tandelta is about 0.02. It is believed that the high dielectric constant and low loss are attributed to the pure tetragonal phase and good dispersing of the nano particles.