Apparatus and methods for real-time three-dimensional sem imaging and viewing of semiconductor wafers

An apparatus configured for real-time three-dimensional electron beam imaging of a substrate surface, the apparatus comprising:

• a source for generating a primary electron beam;
• scan deflectors configured to deflect the primary electron beam so as to scan the primary electron beam over the substrate surface causing electrons to be emitted from the substrate surface;
• a detection system configured for the simultaneous detection of emitted electrons using a plurality of at least two off-axis sensors so as to generate a plurality of image data frames, each image data frame being due to electrons emitted from the substrate surface at a different view angle;
• and
• an image data processing system configured to automatically process the plurality of image data frames to generate multiple views of a three-dimensional representation of the substrate surface, wherein the automatic processing performed by the image processing system includes aligning the three-dimensional representation to design data associated with the substrate surface being imaged and rectifying a surface height map of the three-dimensional representation using layer information in the design data.