A Novel Embedded Capacitor Insulating Composite Material Using Benzoxazine Resin as Polymeric Matrix

We report a novel polymer-ceramic composite of high dielectric constant for embedded capacitor application. The low cost polymeric matrix was benzoxazine resin and the high constant ceramic filler for the polymer composite was BaTiO₃. The benzoxazine/BaTiO₃ composite was prepared by the method of mixing. The dielectric constant, dissipation factor, volume resistivity and breakdown voltage of the composite were measured. Measurement results indicated that the particle size and the content of the BaTiO₃ were affected strongly to the dielectric properties of the composite. The dielectric constant and dissipation of the composite were increased as particle sizes of the BaTiO₃ powder were increased from 50nm to 1.8 mum. The volume resistivities and breakdown voltages of the composites were of comparative high as the particle sizes of the BaTiO₃ powders were in the range of nanometer, and they were declined quickly with the particle sizes increasing from 50nm to 0.8 mum. Volume resistivities of the composites were declined continuously while the breakdown voltages tended to be stable as the particle sizes increasing continuously. The relation of the dielectric constant between the composite and the components was accorded with Lichtenecker logarithmic law in mixing. Effective dielectric constant of the BaTiO₃ in the benzoxazine resin matrix was 283, lower than its intrinsic dielectric constant. A composite was prepared and it had good dielectric properties such as: high dielectric constant of 54, high volume resistivity of 10¹¹ Omega.m, high breakdown voltage of 8kV/mm and low dissipation factor of 0.027.And a high dielectric constant glass cloth laminate applied in embedded capacitor was prepared with the composite resin. The laminate had good dielectric properties such as: high dielectric constant of 20, high volume resistivity of 10 ¹¹ Omega.m, high breakdown voltage of 8.9kV/mm, a- nd low dissipation factor of 0.016.A new method of producing embedded capacitor with low cost industrially was explored