One embodiment relates to a method of classifying defects on a substrate surface. The method includes scanning a primary electron beam across a target area comprising a defect on a substrate surface to cause secondary electrons to be emitted therefrom. In order to generate a plurality of image frames of the target area, secondary electrons are detected from the target area using a plurality of at least two off-axis sensors, and each image frame of the target area is detected from a different off- Data. A plurality of image data frames are processed to produce a surface height map of the target area, and a surface height property is determined for the defect. The surface height property for the defect is input as the defect finer. Other embodiments, aspects and features are also disclosed.
展开▼
