Apparatus for checking semiconductor wafers with complementary light sources and two cameras

摘要

One embodiment of an apparatus for checking semiconductor wafers includes a receiver for a semiconductor wafer to be checked. A light illuminates the wafer. A hemispherical hood has a surface and a hemispherical region defining an interior inside the hemispherical region. A further hood is disposed in the vicinity of the light. A camera is disposed at the hemispherical hood and has a lens looking into the interior inside the hemispherical hood. A evaluator is connected to the camera for controlling the camera and receiving, buffer-storing, processing and outputing data transmitted by the camera. Another embodiment includes a first light directly illuminates the wafer with light of a first color and a second light indirectly illuminates the wafer with light of a second color being complementary to the first color. A surface of the hood is of the second color. The further hood is opaque to incident light, permitting the wafer to be illuminated directly by the first light, and permitting the wafer to only be illuminated indirectly by the second light. A first camera has a filter admitting only light of the first color and a second camera has a filter admitting only light of the second color and being disposed at an angle greater than 0 DEG relative to a center point of the receiver for the semiconductor wafer to be checked.