| 摘要 |
PROBLEM TO BE SOLVED: To measure the quality of the wave front in a photolithographic tool, without disassembling the photolithographic tool, while producing wafers and performing exposures. SOLUTION: A wave front measuring system comprises an electromagnetic radiation source; an illumination system for uniformly irradiating an objective plane with the electromagnetic radiation; a 1st grating, placed on the objective plane and adjusting the electromagnetic radiation; a projection optical system for projecting the image of the 1st grating onto a focal plane; a 2nd grating placed on the focal plane; and a detector, arranged behind the 2nd grating. The detector is constituted so as to receive an interference fringe pattern formed by the 2nd grating. COPYRIGHT: (C)2004,JPO&NCIPI
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