| 摘要 |
<P>PROBLEM TO BE SOLVED: To detect particles and abnormality on a reticle having any pattern. <P>SOLUTION: A method and system for inspecting a reticle are provided. The method includes: coherently illuminating surfaces of an inspection reticle and a reference reticle; applying a Fourier transform to scattered light from the illuminated surfaces; shifting the phase of the transformed light from the reference reticle such that a phase difference between the transformed light from the inspection reticle and the transformed light from the reference reticle is 180 degrees; combining the transformed light as an image subtraction; applying an inverse Fourier transform to the combined light; and detecting the combined light at a detector. An optical path length difference between two optical paths from the illumination source to the detector is less than a coherence length of the illumination source. The image detected by the detector represents a difference in amplitude and phase distributions of the reticle, allowing foreign particles, defects or the like to be easily distinguished. <P>COPYRIGHT: (C)2010,JPO&INPIT |
