A method of making an integrated circuit package, such as a ball grid array, includes providing a flexible tape that has first and second sets of bond pads on respective first and second surfaces thereof. A carrier is attached to the first surface of the flexible tape. Then conductive pillars are formed on the second set of bond pads and an intermediate layer of polymeric compound is deposited on the second surface of the flexible tape. After the compound has cured, a surface of the intermediate layer is ground to expose ends of the conductive pillars to form a sub-assembly comprising the flexible tape and the intermediate layer. Then the carrier is removed from the sub-assembly, thereby creating an interposer. The interposer is attached to a substrate and at least one die is attached to the interposer.