Abstract: An image (30) of a disc-shaped object (100) is recorded, wherein the entire surface (100O) is captured with a plurality of fields (60). A difference image (31) is formed, by subtracting a reference from each field (60) of the surface (100O) of the disc-shaped object (100), and subject to a color transformation, wherein by a suitable choice of transformation signals in one channel are maximized, while at the same time undesired variations, caused by production, of the fields (60) are moved to a different channel. That combination of transformation and detection channel is chosen for which the largest number of pixels of a field (60) with the defect to be found are located outside the spread of the pixels of the respective field (60) on the surface (100O) of the respective disc-shaped object (100) from production and provide the largest signals for the defect.

Abstract: A method for optical inspection, detection and visualization of defects (9) on wafers (2) is disclosed, wherein at least one camera (5) acquires images of at least one portion (11) of the wafer (2) relative to a reference point (12) of the wafer (2), and the Cartesian coordinates of the image data associated with the at least one portion (11) of the wafer (2) are transformed into polar coordinates.

Abstract: A method for optical inspection, detection and visualization of defects (9) on wafers (2) is disclosed, wherein at least one camera (5) acquires images of at least one portion (11) of the wafer (2) relative to a reference point (12) of the wafer (2), and the Cartesian coordinates of the image data associated with the at least one portion (11) of the wafer (2) are transformed into polar coordinates.

Abstract: The invention relates to a method for detecting defects on the back side of a semiconductor wafer. The brightness distribution of the color values is essentially a normal distribution. An average value and surroundings can be defined using the determined normal distribution, which are criteria for the occurrence of a defect.

Abstract: A method of determining geometric parameters of a wafer (16) is disclosed. For this purpose, the wafer (16) is inserted in a wafer holder (30). The wafer holder (30) is equipped with at least three mechanical contacting elements (22). The wafer is in mechanical contact with the contacting elements (22). The contacting elements (22) are distributed on the wafer holder (30) in such a way that they define a geometric figure which is configured such that the center point (40) of the wafer (16) comes to lie within the geometric figure. The position of each contacting element (22) is determined. Each desired geometric parameter of the wafer (16) is then calculated from the position of the contacting elements (22).