Reflective optical system
AssigneeNova Measuring Instruments Ltd.
InventorsDavid SCHEINER, Michael Winik, Yakov Lyubchik
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Abstract
A lens arrangement is presented. The lens arrangement comprises a first element having a concave reflective surface and defining an optical axis of the lens arrangement, and a second substantially flat and at least partially reflective element spaced-apart from the first element along the optical axis. The second element is configured to allow light passage therethrough and is oriented with respect to the optical axis and the first element such that at a predetermined angle of incidence of an input light beam onto the second element, the input light beam is reflected onto the reflective surface of the first element and reflected therefrom to pass through the second element.
Claims20
An optical system for use in measurement/inspection of an article, the optical system comprising an illuminator arrangement, and a light directing unit configured for focusing incident light beam from said illuminator arrangement onto an article under measurement/inspection at substantially normal incidence and for collecting light from the article, said light directing unit comprising an objective arrangement comprising a first reflective element having a concave reflective surface and defining an optical axis of the incident light propagation towards the article, and a second substantially flat and at least partially reflective element spaced-apart from said first reflective element along said optical axis, the second element being configured to allow light passage therethrough and being oriented with respect to the optical axis and the first element such that at a predetermined angle of incidence of the incident light beam from said illuminator arrangement onto the second element, said incident light beam is reflected onto the reflective surface of the first element and further reflected therefrom to pass through the second element and focus on the article.
An on-axis optical system for use in measurement/inspection of an substantially planar article such as a semiconductor wafer, reticle or flat panel display, the on-axis optical system comprising an illuminator arrangement with a light source assembly and an aperture assembly, a light directing unit configured for focusing incident light beam from said illuminator arrangement onto said article under measurement/inspection at substantially normal incidence and for collecting light from the article, said light directing unit comprising an objective arrangement comprising a first element having a concave reflective surface and defining an optical axis of incident light propagation, and a second substantially flat and at least partially reflective element spaced-apart from the first element along the optical axis, the second element being configured to allow light passage therethrough and being oriented with respect to the optical axis and the first element such that at a predetermined angle of incidence of the incident light beam from said illuminator arrangement onto the second element, said light beam is reflected onto the reflective surface of the first element and further reflected therefrom to pass through the second element and focus on the article, said aperture of the illuminator arrangement and said second element being located in conjugate planes.
Dependencies are inferred from the claim text.