Patent ID: 6344896
Filing Date: 2002-02-05
Classification: G01M,G03F

Abstract:
A distortion measuring method comprising the steps of:forming a mask having at least a first diffraction grating pattern having an array of a plurality of large patterns and a second diffraction grating pattern having arrays of a plurality of micropatterns spaced apart from the first diffraction grating pattern by a predetermined interval, the plurality of micropatterns being arrayed in a direction perpendicular to an array direction of the second diffraction grating pattern at a predetermined pitch; projecting at least the first and second diffraction grating patterns formed on the mask on a photosensitive substrate through a lens; and measuring a positional shift component of an image point by distortion and a positional shift component of the image point by aberration of the lens by scanning the photosensitive substrate using coherent light having a diffractable wavelength and by measuring an interval between at least the first and second diffraction grating patterns.