ABSTRACT
We have improved the optical beam induced resistance change (OBIRCH) method so as to detect (1) a current path as small as 10–50 μA from the rear side of a chip, (2) current paths in silicide lines as narrow as 0.2 μm, (3) high-resistivity Ti-depleted polysilicon regions in 0.2 μm wide silicide lines, and (4) high-resistivity amorphous thin layers as thin as a few nanometers at the bottoms of vias. All detections were possible even in observation areas as wide as 5 mm × 5 mm. The physical causes of these detections were characterized by focused ion beam and transmission electron microscopy.
