A method of testing integrated circuit chips. The method includes: attaching integrated circuit chips to an interposer of a temporary carrier, the carrier comprising: a substrate, a first interconnects on a bottom surface and a second array of interconnects on a top surface of the substrate, corresponding first and second interconnects electrically connected by wires in the substrate; the interposer, first pads on a top surface and a second pads on a bottom surface of the interposer, corresponding first and second pads electrically connected by wires in the interposer, and the second pads in physical and electrical contact with corresponding second interconnects; and the interposer including an interposer substrate comprising a same material as a substrate of the integrated circuit chip; connecting interconnects of the first array of interconnects to a tester; and testing the one or more integrated circuit chips.