Application of IR-OBIRCH to the failure analysis of CMOS integrated circuits

IR-OBIRCH (Infra-Red Optical Beam Induced Resistance Change) is a revolutionary new method for the localization of leakage current paths and detection of abnormal resistance in interconnects of ULSI devices. Application of this technique to the actual failure analysis of 0.25 μm, 0.22 μm & 0.18 μm CMOS integrated circuits in volume production was demonstrated. It was found that IR-OBIRCH is a powerful fault isolation technique. Process defects detectable using this technique in our experience are: 1) Short circuits due to interconnect bridging. 2) Short circuits due to poly-gate bridging or poly-gate to source/drain bridging. 3) Resistive Vias due to the presence of micro-voids or residue at via/metal interface.