Printed circuit board with inorganic insulating matrix

摘要

A printed circuit board has a base made from fibers (e.g., ceramic) and an inorganic coating (e.g., silicon carbide) covering the fibers to provide the base with inorganic properties. The base may have a particular coefficient of thermal expansion (CTE) as by providing the fibers with particular characteristics in the plane of, and perpendicular to, the base. The base may be isotropic thermally as by disposing the fibers in two adjacent transverse layers. An inorganic material (e.g. copper) on the base provides a radio frequency barrier. An inorganic material (e.g., silicon dioxide) on the RF barrier constitutes a dielectric insulator. An electrically conductive layer (eg. copper) partially covers the dielectric layer in a pattern defining an electrical circuit. A dielectric material (eg., silicon dioxide) fills the remaining space in this layer in a flush relationship with the conductive layer. Electrically conductive posts are added to coincide with the pads of an integrated circuit chip mounted on the board and having the particular CTE and an electrical continuity with the electrical circuit. A dielectric material fills the remaining space in flush relationship with the conductive layer. Alternatively, an electrically conductive layer defining a second printed circuit may be disposed on the first circuit and may communicate electrically with the first circuit via posts. A dielectric material may be disposed in the spaces between such circuits. The chip may then be disposed on the second circuit and may be electrically connected to the first and second circuits.