Device for noncontact determination of edge profile at a thin disk-shaped object

摘要

A device for noncontact determination of the edge profile at a thin disk-shaped object helps determining the edge profile at semiconductor wafers in which exact image recording is not impaired by specular reflections of the edge profile. A plurality of light sources in the form of laser radiation sources each emitting a line-shaped light bundle are arranged so as to be coplanar in a common plane representing a measurement plane oriented orthogonal to a base plane of the object and are directed from different directions to a common intersection of the laser radiation sources in the edge region of the object. A light sheet is formed in the measurement plane and at least one base camera is directed in the base plane lateral to the measurement plane to capture scattered light proceeding from a light line generated by the light sheet when impinging the object edge region.

主权项

1. A device for noncontact determination of an edge profile at a disk-shaped object, the device comprising:
a turntable for rotating the disk-shaped object around an axis of rotation and a measuring arrangement for radial positioning of at least one light source for illuminating an edge region of the disk-shaped object in a virtually radial direction to the axis of rotation thereof; at least one camera for recording the illuminated edge region, the camera being arranged in a base plane extending parallely and medially between the plane faces of the disk-shaped object; a plurality of laser radiation light sources with a line-shaped beam profile, each laser radiation source emitting a line-shaped light bundle, the plurality of laser radiation sources forming line-shaped light bundles arranged to be coplanar in a common plane representing a measurement plane oriented orthogonal to a base plane, the line-shaped light bundles being directed from different directions to a common intersection in the illuminated edge region of the object; and a light sheet comprised of the line-shaped light bundles formed in the measurement plane; wherein the at least one camera serving as a base camera is directed to the base plane laterally to the measurement plane, so that the at least one camera records scattered light propagating from a light line illuminated by the light sheet in the edge region of the object.