An integrated circuit package comprises a package substrate, an application specific integrated circuit (ASIC) having a first area and formed on a first wafer made from a select semiconductor material, a second wafer of the select semiconductor material, and a supplemental-integrated circuit. The supplemental-integrated circuit has a second area different from the first area. The first wafer includes a through-wafer via to couple the ASIC to the package substrate. An active surface of the ASIC is coupled to the second wafer. The second wafer is arranged with a window there through that is sized to closely receive and align one or more bonding interfaces of the supplemental-integrated circuit to respective bonding interfaces of the ASIC. A corresponding method for assembling a die-stacked integrated circuit package is disclosed.