Technology for fabrication of packaging interface substrate wafers with fully metallized vias through the substrate wafer

The invention is the technology of providing a packaging intermediate product that can serve as an interface substrate that is to be positioned between different circuitry types where the dimensions are approaching the sub 100 micrometer range. The invention involves a dielectric wafer structure where the first and second area surfaces of the wafer are separated by a distance that is of the order of the electrical via design length, and an array of spaced vias through the wafer arranged with each via filled with metal surrounded by a chemical metal deposition promoting layer with each via terminating flush with a wafer surface. The wafer structure is achieved by forming an array of blind via openings through the first surface of the dielectric wafer to a depth approaching the via design length, lining the walls for adhesion enhancement, filling the blind via openings completely with a chemically deposited metal, removing material at the first wafer surface thereby planarizing the filled vias, and removing material at the second wafer surface thereby exposing the vias at the design length.