A stackable tier structure comprising one or more integrated circuit die and one or more feedthrough structures is disclosed. The I/O pads of the integrated circuit die are electrically rerouted using conductive traces from the first side of the tier structure to a feedthrough structure comprising one ore more conductive structures. The conductive structures electrically route the integrated die pads to predetermined locations on the second side of the tier structure. The predetermined locations, such as exposed conductive pads or conductive posts, in turn, may be interconnected to a second tier structure or other circuitry to permit the fabrication of a three-dimensional microelectronic module comprising one or more stacked tiers.