Printed wiring board structure with integral metal matrix composite core

Abstract

A printed wiring board structure having at least one chip-carrying layer adjacent a core fabricated of a metal matrix having disposed therein continuous pitch based graphite fibers. The chip carrying layers and the core have an interface therebetween and are integrally connected to each other through vias plated with an electrically and thermally conductive material to thereby provide a plurality of connection sites along this interface. The matrix is preferably fabricated of aluminum. Preferred fibers are fabricated of pitch based graphite. A substantial weight savings over a common molybdenum core printed wiring board is realized due to the significant reduction in density of the core material. A typically preferred present printed wiring board structure has several circuit layers and two chip-carrying layers each on opposite sides of the core, with each of the layers and the core having respective interfaces therebetween wherein each layer is integrally connected to the core at a plurality of connection sites, as required by circuit design, along the respective interfaces. Because of the plurality of connection sites along respective interfaces, superior thermal conductivity occurs from the layers to the core since heat travels through these connection sites to effectuate extremely efficient heat transfer and ultimate heat dissipation from the entire printed wiring board structure.