Patent ID: 8451440
Filing Date: 2013-05-28
Classification: G01N

Abstract:
1. An apparatus for optical inspection of wafers, comprising: an assembly unit carrying optical elements of at least one illumination path for bright field illumination, optical elements of at least one illumination path for dark field illumination, and several optical elements of at least a first detection path and a second detection path; a plurality of corresponding light sources providing the bright field illumination and/or the dark field illumination; an imaging optical element of the at least one illumination path for the bright field illumination; and a plurality of imaging optical elements of the at least one illumination path for the dark field illumination, wherein the imaging optical elements of the at least one illumination path for the dark field illumination are set into a respective casing, and to each casing corresponds a tilted mirror as an optical element directing the dark field illumination onto a surface of a wafer at a defined angle, each tilted mirror extending below a bottom of a first board of the assembly unit, and a plurality of imaging optical elements of the at least one first detection path and second detection path, wherein the imaging optical element of the at least one illumination path for the bright field illumination, the plurality of imaging optical elements of the at least one illumination path for the dark field illumination, and the plurality of imaging optical elements of the at least one first detection path and second detection path are designed so that all illumination paths and all detection paths are telecentric.