Sonnenschein, Nath & Rosenthal LLP
Mechanism and method for controlling focal point position of UV light and apparatus and method for inspection
A method and apparatus for controlling the focal position of the UV light for auto-focussing the converged UV light, and a method and apparatus and for inspecting a device, such as a semiconductor wafer or liquid crystal using the converged UV light, in which the UV light converged is to be auto-focussed accurately and speedily. The method includes an inspection stage 11 for supporting a semiconductor wafer, an objective lens for UV light 40 or converging a UV laser light for illuminating the laser light converged to the semiconductor wafer, a distance sensor 41 secured to this objective lens for UV light 40 to detect the distance to the semiconductor wafer and a controller for causing movement of the inspection stage 11 in a perpendicular direction. The controller causes the distance between the objective lens for UV light 40 and the semiconductor wafer to coincide with the target distance T based on the distance as detected by the distance sensor 41. 
Sony Corporation
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Masayuki Asahiko Hiroki
Morita Nogami Kikuchi