Abstract: An apparatus includes an input probe configured to be placed on a first cluster of u-bumps disposed on a semiconductor die, output probes configured to be respectively placed on multiple clusters of u-bumps disposed on the semiconductor die, the multiple clusters being separately connected to the first cluster. The apparatus further includes a space transformer and printed circuit board (PCB) portion including a current source configured to supply a current to the input probe placed on the first cluster, resistors having a same resistance and being connected to ground, and tester channels at which voltages are respectively measured, the tester channels being respectively connected to ends of the output probes respectively placed on the multiple clusters and being respectively connected to the resistors. The apparatus further includes a processor configured to determine whether the input probe is properly aligned with the first cluster, based on the measured voltages.