Contact level probing and transistor characterization - a new fault isolation technique - for identifying leakage fails

This paper describes how contact level probing and transistor characterization-a new fault isolation technique-helped to identify subtle defects in very large multifinger n-channel transistors. The defects caused leakage fails (0.5 μA to 3 μA) in 95nm technology DRAM devices. After deprocessing the die to contact level, DC probe pads were placed at the contact level by focused ion beam, which avoids having to use expensive nanoprobing tools, such as atomic force probing, to touch the very small contacts.