Patent ID: 6549290
Filing Date: 2003-04-15
Classification: G01N,G02B

Abstract:
An apparatus for aligning a target object, comprising:an objective lens for magnifying an image of the target object; focusing means including a laser source for irradiating the target object through the objective lens and a focus detecting light-receiving section for receiving light reflected from the target object, the focusing means being used for detecting a defocus from a detection result of the focus detecting light-receiving section to execute focusing; displacing means for changing a relative positional relationship between the target object and the objective lens such that a laser beam is emitted from the laser source of the focusing means to at least three points of a periphery of the target object; a rotary table for holding the target object; edge detecting means for detecting edge positions corresponding to at least three points excluding an orientation flat or a notch in the periphery of the target object, using the laser beam emitted from the laser source of the focusing means; and operating means for calculating a displacement of a central position of the target object from an axis-of-rotation position of the rotary table based on the edge positions detected by the edge detecting means.