Abstract: A semiconductor assembly comprising first and second chips, each having an active surface including an integrated circuit and a plurality of input/output contact pads; an interposer of electrically insulating material having a plurality of electrically conductive paths extending through said interposer from the first surface to the second surface, forming electrical terminals on each of said surfaces; said interposer being disposed between said active surfaces of said first and second chips; connections between each of said contact pads of said first chip to selected terminals on said first interposer surface, respectively, and between each of said contact pads of said second chip to selected terminals on said second interposer surface, respectively; and said interposer further having electrical terminals for interconnecting said chips to other parts.