Development of high-k inorganic/organic composite material for embedded capacitors

The particle size distribution control and the dispersion agent were investigated, and a higher than 79 vol.% BaTiO3 filler loading to epoxy resin was implemented with suppressing the porosity increment. The dielectric constant of 10 mum thick film at 1 MHz was 115, which corresponded to a capacitance density of larger than 10 nF/cm(2). The dielectric constant obtained a results of 100 at 10 GHz when evaluated from 45 MHz - 10 GHz. The chemical state evaluation of the surface of the filler, which was performed by FT-IR spectroscopic analysis, revealed that the surface absorption water of the filler increased the dielectric loss. After the dispersant was added and the composition of the resin and cure condition was optimized, the dielectric loss of the composite was 0.02 at 1 MHz. The temperature dependence of the dielectric constant was evaluated and showed to be small. Laser via formation process of the composite material was also examined. It was confirmed that a 100 mum diameter via hole into a 10 mum thick layer could be formed. The in-plane coefficient of thermal expansion of the composite material was 17 ppm/degreesC, as the obtained by the stress measurement of the film. This value is coincident with the coefficient of thermal expansion of Cu. The elastic modulus was measured and found to be 18 GPa at 75 vol.% of the filler.