Control critical dimensions in optical imaging processes for semiconductor fabrication by extracting aberrations based on imaging plant-specific intensity measurements and simulations

摘要

A method comprising: imaging a lithography mask (110) into an image plane (140) through an imaging optic of an imager using lithography mask (110), the lithography mask (110) having a pattern of mask features (111) representing a pattern of device features of a semiconductor product that are included in measuring an average intensity value (146) for each at least a plurality of image subregions (141A, 141B) of an image of the lithography mask (110) formed in the image plane (140), wherein a lateral size of each of a plurality of image subregions (141A, 141B) ranging from several 10 μm to several 100 μm; generating a simulated averaged intensity value (155) for imaging at least some of the image subregions (141A, 141B); andgenerating correction data (106) by comparing the measured averaged intensity values (146) and the simulated averaged intensity values (155); wherein measuring the averaged intensity value (146) for each of the plurality of image subregions (141A, 141B) comprises: obtaining electrical data from one A radiation sensor disposed in the image plane (140), wherein obtaining the electrical data comprises: positioning a radiation-sensitive sensor area in the image plane (140) and scanning the radiation-sensitive sensor area over the image such that at least the plurality of partial areas (141A, 141B) are covered wherein the radiation-sensitive sensor area is scanned stepwise with a step size that is equal to or greater than the lateral size of the radiation-sensitive sensor area.