Polymer-Ceramic Nanocomposites Based on New Concepts for Embedded Capacitor

Abstract

A rapid growth of mixed-signal integrated circuits is driving the needs of multifunction and miniaturization of the component in electronics applications. Polymer-ceramic composites have been of great interest as embedded capacitor materials because they enabled companies to combine the processability of polymers with the high dielectric constant of ceramics. Polymer-ceramic nanocomposites based on new concepts were developed for embedded capacitor applications. The dielectric constant was above 80 at 1 MHz and the specific capacitance was successfully achieved 8 nF/cm2. By use of this nanocomposites, multilayer printed wiring boards with embedded passive components were fabricated for prototypes. The following technologies are reported in this paper. Firstly, based on the investigation of barium titanium oxide (BaTiO3) crystallites, various particles with the sizes from 17 nm to 100 nm were prepared by the 2-step thermal decomposition method from barium titanyl oxalate (BaTiO(C2O4)2·4H2O). It was clarified that BaTiO3 particles with a size of around 70 nm exhibited a maximum dielectric constant of over 15,000 by FEM analysis from the measured dielectric constants of BaTiO3 suspensions. Secondary, the BaTiO3 surface modification based on a new concept was applied to improve the affinity between BaTiO3 particles and polymer matrix. Thirdly, the blend polymer of an aromatic polyamide (PA) and an aromatic bismaleimide (BMI) was employed as the matrix from a view-point of both the processabilty during fabricating the substrates with embedded passive components and the thermal stability during assembling LSI chips. Finally, these technologies were combined and optimized for embedded capacitor materials.