A module includes a substrate having a plurality of contact regions, and a spacer-chip assembly. The spacer-chip assembly in turn includes at least first and second semiconductor dies, each having a plurality of electrical interconnect pillars and a plurality of contact pads, and a spacer wafer. The at least first and second semiconductor dies are secured to the spacer wafer, and the spacer wafer includes at least first and second semiconductor circuit features coupled to a first portion of the contact pads of the at least first and second semiconductor dies. The spacer wafer includes wiring electrically coupling the at least first and second semiconductor dies via a second portion of the contact pads. The spacer wafer has a plurality of holes formed therethrough. The plurality of electrical interconnect pillars extend through the holes and are secured to the contact regions on the substrate.