Various structures of a programmable semiconductor interposer for electronic packaging are described. An array of semiconductor devices having various values is formed in said interposer. A user can program said interposer and form a “virtual” device having a desired value by selectively connecting various one of the array of devices to contact pads formed on the surface of said interposer. An inventive electronic package structure includes a standard interposer having an array of unconnected devices of various values and a device selection unit, which selectively connects various one of the array of devices in said standard interposer to an integrated circuit die encapsulated in said electronic package. Methods of forming said programmable semiconductor interposer and said electronic package are also illustrated.