Projection exposure apparatus including an illumination optical system that forms a secondary light source with a particular intensity distribution
Patent 6128068 Issued on October 3, 2000. Estimated Expiration Date: 
October 3, 2017. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
October 3, 2017. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3729252 3776633 3887816 Light illumination device Exposure apparatus Exposure apparatus Illumination optical arrangement Optical apparatus using polarized light Observation apparatus with selective light diffusion Projection exposure apparatus InventorsAssigneeApplicationNo. 467149 filed on 06/06/1995US Classes:355/53Step and repeatExaminersPrimary: Braun, Fred L.Attorney, Agent or FirmForeign Patent References
International ClassG03B 027/42Foreign Application Priority Data1991-02-22 JPAbstractAn exposure apparatus for forming an image of a fine pattern having linear features extending in orthogonal first and second directions. The apparatus includes an illumination optical system for illuminating the pattern, the illumination optical system including a device for forming a secondary light source having decreased intensity portions at a center thereof and on first and second axes defined to intersect with each other at the center and defined along the first and second directions, respectively, wherein the secondary light source includes four sections being distributed in four quadrants defined by the center and the first and second axes, a projection optical system for projecting, on an image plane, an image of the pattern illuminated with light from the secondary light source, and a quartered detector, having four detector sections, for detecting a light quantity distribution of the secondary light source. Each of the four detector sections of the quartered detector independently detects a light quantity of a corresponding one of the four sections of the secondary light source.Other References
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