An integrated circuit package system includes: providing a package substrate; mounting an interposer chip containing active circuitry over the package substrate; attaching a conductive bump stack having a base bump end and a stud bump end, the base bump end on the interposer chip; connecting a stack connector to the interposer chip and the package substrate; and applying a package encapsulant over the interposer chip, the stack connector, and the conductive bump stack with the stud bump end of the conductive bump stack substantially exposed.