APPARATUS AND MEASUREMENT PROCEDURE FOR THE FAST, QUANTITATIVE, NON-CONTACT TOPOGRAPHIC INVESTIGATION OF SEMICONDUCTOR WAFERS AND OTHER MIRROR LIKE SURFACES

摘要

The subject of the present invention is, on one hand, a measurement set-up for the fast, quantitative, non-contact topographic investigation of semiconductor wafers and other mirror like surfaces which, contains a point source (1), a collimating concave mirror (4) producting a parallel beam and directing the beam to the sample to be investigated, a structured mask (3) located between the point source and the concave mirror, and an image sensor (6) taking the beam reflected from the sample and the concave mirror. The image sensor is connected through a suitable interface (7) to a computer (8), that, on one hand shows the image taken by the image sensor on a display (9) connected to the computer and, on the other hand, determines the position of the image of the individual mask elements by means of a suitable algorithm. On the other hand, the subject of the invention is a measurement procedure that by means of the above set-up and a suitable algorithm, provides a fast, quantitative, non-contact topographic investigation of semiconductor wafers and other mirror like surfaces. The substance of the invention is that the relative positions of the mask and the sensor to the other elements of the set-up are chosen to provide an essentially sharp image of the mask on the sensor. The advantage of the patent is the increased lateral resolution, accuracy and dynamic range.