Fault Localization Using Dynamic Optical-beam Induced Current Variation Mapping

In this paper, we report a new dynamic laser stimulation technique based on optical beam-induced current (OBIC) variation mapping for global fault localization. A production tester exercised the chip dynamically whilst a 1064 nm wavelength laser rasters the region of interest through the silicon substrate. The OBIC variation with test cycles is recorded for every scanned pixel and translated into a current profile for pattern matching to determine the suspected defect location. Unlike laser-assisted device-alteration (LADA) which uses the same laser, this technique applies to hard defects. Four case studies successfully demonstrated the feasibility of this technique.