US Patent 7901761 Hermetic vias utilizing metal-metal oxides

The invention is a hermetic via in a ceramic substrate that is comprised of noble metal powder in a glass-free paste that contains an admixture of a particulate phase of niobium pentoxide. The electrically conductive platinum provides excellent electrical conductivity while the niobium pentoxide phase prevents shrinkage of the paste during thermal processing and binds to both the ceramic and the noble metal particulates in the via, thus maintaining a hermetic seal around the via.