The scanning laser-SQUID microscope can detect electrical defects in a chip without requiring electrical contacts to the chip. Using our new system, we can get magnetic flux images of a 300mmɸ wafer in air. Experiments with 256Mbit-DRAM chips showed that IDDS testing results are correlated well with laser-SQUID images, and that the spatial resolution is 0.59 µm in an intensity image, and 0.54 µm in a phase image. We have also succeeded in localizing the open site in a whole chip area of a 90nm-node logic IC chip.