APPARATUSES, METHODS AND COMPUTER PROGRAMS FOR ARTIFICIAL RESOLUTION ENHANCEMENT IN OPTICAL SYSTEMS

In a method for measuring lithographic features on a surface with an optical system, a laser beam is scanned over lithographic features on the surface and the laser beam is reflected or transmitted. An image of the lithographic features is formed by the reflected or transmitted laser beam. The image is filtered using a filter, which is an inverse convolution based on a kernel representing the optical system. The filtering provides a threshold that is equal for all line widths and provides the same relative difference from the nominal critical dimension for all line widths. The surface is a wafer or a work piece.