Novel Flip-Chip Probing Methodology Using Electron Beam Probing

The measurement of timing and voltage signals inside integrated circuits (IC) is critical to debugging new devices, to failure analysis of advanced devices, validating new IP (intellectual property) in new silicon, etc. E-beam probing (EBP) has been very useful for front side devices for over two decades. For measuring signals below the top metal layers, probe pads are made using a focused ion beam (FIB) where lower metal was accessible. Increasing migration of ICs to flip chip packaging has necessitated the need for a new tool set or methodology for design debug and failure analysis. This paper introduces data taken from a flip chip using an IDS 10K+ E-beam Prober (EBPr). The samples are thinned using an Allied HiTech polishing wheel and the Credence OptiFIB. The investigation utilized the capability of the EBPr to acquire both repeating (clocks) and non-repeating signals at various: supply voltages, loop lengths frequencies.