Patent
Bifocal wave zone plate interference microscopic-inspection apparatus for detecting flat mask defect
Gao Zhishan,Jiantai Dou,Ruoyan Wang,Song Huaqing,Yang Zhongming,Wang Shuai,Cheng Jinlong,Wang Kailiang,Wei Wang,Jingfei Ye,Yuan Qun +10 more
TLDR
In this article, a bifocal wave zone plate interference microscopic-inspection apparatus for detecting flat mask defect is presented, where light passes through the aperture diaphragm to form a spot light source, and then passes through a positive lens to form parallel light, parallel light passes along the semi-reflecting and semi-transmitting spectroscope and realizes incidence on the Bifocal Wave Zone plate, 0-grade diffracted light satisfies a refraction principle.Abstract:
The invention discloses a bifocal wave zone plate interference microscopic-inspection apparatus for detecting flat mask defect. According to the apparatus, a light source, an aperture diaphragm, a positive lens, a semi-reflecting and semi-transmitting spectroscope, a bifocal wave zone plate, a flat mask to be detected, light passes through the aperture diaphragm to form a spot light source, and then passes through a positive lens to form parallel light, parallel light passes through the semi-reflecting and semi-transmitting spectroscope and realizes incidence on the bifocal wave zone plate, 0-grade diffracted light satisfies a refraction principle, +1 grade diffracted light realizes converge under regulation and control of a bifocal wave zone plate phase function, and light having the phase information of the surface of the flat mask to be detected is reflected to form a return light path. By employing a bifocal wave zone plate interference system of reference light and test light common path, bifocal wave zone plate realizes diffraction condition of coexistence focal length and no focal length, Compared with a several sheets lens transmission group system, quantity of the lens transmission groups can be reduced, The bifocal wave zone plate interference microscopic system realizes synchronous detection function of amplitude-type defect and phase-type defect.read more
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Patent
Reflective lithography mask inspection tool based on achromatic fresnel optics
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