Method and device for inspecting a disk-shaped object

In order to improve the detectability of defects in structures incorporated beneath the surface of a wafer, it is suggested to acquire an IR subimage of the illuminated wafer with an IR image acquisition device and a VIS subimage with a VIS image acquisition device. The acquisition is performed simultaneously and is controlled such that the same area of the wafer is imaged sharply by both image acquisition devices. An image processor is used to determine whether a detected defect is attributable to a defect on the surface or to a defect of the structures located beneath the surface.