| 摘要 |
PROBLEM TO BE SOLVED: To provide a speckle reduction method and a system for EUV interferometry by which a wavefront quality measurement in an optical lithography tool is improved to be made even during wafer fabrication and exposure, without forcing the tool during measurement to be off-line. SOLUTION: The speckle reduction method and the system for EUV interferometry are constituted by a source of electromagnetic radiation, an imaging system that focuses the electromagnetic radiation at a target plane, a first grating that is positioned in the target plane and has a plurality of rulings with randomized height, a stage that moves the first grating parallel to the rulings, a projection optical system that projects an image of the first grating onto an image plane, a second grating at the image plane, and a detector that receives an interference fringe pattern produced by the second grating. COPYRIGHT: (C)2005,JPO&NCIPI |
