Automated Interpretation of SEM Images

An important part of quality control in the fabrication of integrated circuit wafers involves making three-dimen sional measurements of the wafer’s surface topography. We describe a method for obtaining a dense depth map of the wafer surface from a single Scanning Electron Microscope (SEM) image. The depth map gives a complete description of the surface topography, allowing the easy calculation of any measurement required in the quality control process. The technique presented here uses a novel scale space Shape From Shading algorithm. Results are shown for real SEM images and for a synthetic test image. We also de scribe how the method can be extended to use stereo images in order to achieve greater accuracy in the surface