A device for measuring the performance of high speed integrated circuits (ICs) while in wafer form consists of one or more miniature coaxial transmission lines for carrying the test signals to and from test instruments. Each of the miniature coaxial cables has a standard connector at one end for connection to testing instruments. The other end of each cable has its center conductor extended beyond the shield of the cable and formed into a conical point for connection to test pads on the IC. One or more miniature leaf springs are attached to the shield. The leaf springs are adapted so that during a probing operation they contact the test pads first and thereafter flex to allow the center conductors to make contact to other test pads. The miniature coaxial transmission lines also flex to limit forces which could otherwise damage center conductors or the test pads.
