Patent ID: 7034401

Claim:
A packaging substrate comprising: (1) an interposer comprising: a semiconductor substrate having one or more through vias therein passing between a top surface of the semiconductor substrate and a bottom surface of the semiconductor substrate, the semiconductor substrate having a substantially planar bottom surface; a conductor in each of the through vias, each conductor providing a conductive path through the corresponding through via; wherein the interposer comprises one or more first conductive contact pads attachable to circuitry above the interposer but not attached to any circuitry, one or more second conductive contact pads attachable to circuitry below the interposer, and one or more conductive paths each of which comprises at least one of the conductors and connects at least one of the first contact pads to at least one of the second contact pads; (2) an intermediate substrate having a top surface facing the interposer and having a bottom surface attachable to a printed circuit board, the intermediate substrate comprising: a dielectric substrate or a plurality of dielectric substrates attached to each other; one or more first conductive contact pads attachable to circuitry above the intermediate substrate; one or more second conductive contact pads attachable to a printed circuit board below the intermediate substrate; one or more conductive paths each of which connects at least one first contact pad of the intermediate substrate to at least one second contact pad of the intermediate substrate; wherein at least one first contact pad of the intermediate substrate is attached to at least one second contact pad of the interposer; wherein the top surface of the interposer is not attached to any circuitry.