A method of making a multilayered circuitized substrate assembly which includes bonding at least two circuitized substrates each including at least one layer of high temperature dielectric material, one of these layers in turn including at least one thru-hole therein having therein a quantity of a a low temperature conductive paste, the paste including an organic binder component and at least one metallic component. The flakes of the metallic component are sintered during the bonding to form a conductive path through the dielectric of one of the substrates.