Various structures of a programmable semiconductor interposer for electronic packaging are described. An array of semiconductor devices having various values is formed in the interposer. A user can program the 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 the 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 the standard interposer to an integrated circuit die encapsulated in the electronic package. Methods of forming the programmable semiconductor interposer and the electronic package are also illustrated.