Patent attributes
When the electrode potential of a charge control electrode above a wafer is reduced, image brightness is reduced. A point of change in the image brightness is a switching point between a positively charged state of the image and a negatively charged state of the image, showing the weakly charged state of the image. By setting this point of change as an inspecting condition, the amount of electric charges on the surface of the wafer can be reduced, and stable wafer inspection can be performed. It is estimated that an applied voltage V1 in FIG. 14 corresponds to the point of the change and is roughly included in the voltage range of a region enclosed by a broken line in the vicinity of the applied voltage V1. Within this voltage range, the influence of charge on an inspection under the inspecting condition can be reduced.
