CERAMIC SUBSTRATES WITH HIGHLY CONDUCTIVE METAL VIAS

摘要

A ceramic substrate (11) is provided with filled via holes (14) for electrical or thermal feedthrough to or from an electronic device, each via hole (14) having at least one dimension from about 4 to 50 mils. The via holes (14) are filled with cooper, silver or gold for high conductivity and the filling is without visible voids at a magnification of 1000 diameters. The filling (18) is preferably hermetic and is achieved by first electrodepositing metal into the holes and extending therefrom as dumbbell shaped plugs and then heating the substrate to the melting point of the metal so that metal from the dumbbell ends enters the connecting portion within the via hole to seal any aperture therein.