Lithographic apparatus and device manufacturing method

摘要

An apparatus and a method to detect a defect or particle on a surface that involves combining an object radiation beam redirected by the surface with a reference radiation beam having a plurality of intensities lower than the object radiation beam, to produce a plurality of patterns detected by a detector in order to detect the defect or particle on the surface from the patterns.

主权项

1. A method to detect a defect or particle on a surface comprising:
combining an object radiation beam redirected by the surface, after the object radiation beam was redirected by the surface, with a reference radiation beam having a plurality of different intensities lower than the object beam and having a different intensity distribution than the redirected object radiation beam, to produce a plurality of patterns detected by a detector, the plurality of patterns comprising at least one interference pattern resulting from the combining of the object radiation beam and the reference radiation beam; and mathematically processing one or more of the detected patterns to restore an image of the surface from the one or more detected patterns, in order to detect the defect or particle on the surface from the image.