Abstract: An assembly of intercoupled integrated circuit die comprises: a substrate having a plurality of holes which extend through the substrate; each hole is of a size that is suitable to receive an integrated circuit die; a plurality of independent subassemblies are also provided; each subassembly includes an integrated circuit die and a heat sink which is attached to the back of the die and extends beyond it; each subassembly is aligned with a respective hole in the substrate such that the die lies in the hole and the heat sink extends beyond the hole and attaches to the substrate; subassemblies are interconnected by printed conductors on the substrate and discrete wires that are bonded from the front of the die to the conductors; and the die and heat sink have similar thermal expansion coefficients, while the substrate has a substantially different thermal expansion coefficient.