A modularized interposer includes a plurality of interposer units that are assembled to provide a complete set of electrical connections between two semiconductor chips. At least some of the plurality of interposer units can be replaced with other interposer units having an alternate configuration to enable selection of different functional parts of semiconductor chips to be connected through the modularized interposer. Bonding structures, connected to conductive metal pads located at peripheries of neighboring interposer units and an overlying or underlying portion of a semiconductor chip, can provide electrical connections between the neighboring interposer units. The interposer units can be provided by forming through-substrate vias (TSV's) in a substrate, forming patterned conductive structures on the substrate, and cutting the substrate into interposers.