Device for determining focus of optical system on substrate, has detector, which comprises four-quadrant diode, and individual quadrants of four-quadrant diode are interconnected in pairs such that two two-quadrant diodes are formed

摘要

The device (100) has a detector (54), which comprises a four-quadrant diode. The individual quadrants of the four-quadrant diode are interconnected in pairs such that two two-quadrant diodes are formed. An auxiliary light beam (50) meets on the substrate such that it lies on a line, which is not parallel to the x-coordinate direction and y-coordinate direction. An independent claim is included for a method for determining the focus of an optical system on a substrate.