| 摘要 |
<p>A flatness detecting apparatus of a wafer stage and a method thereof are provided to check the existence of particles in short time and to detect a damaged portion of a surface of the wafer stage by using a sensor unit. A flatness detecting apparatus includes a wafer stage(106) for loading a wafer, a sensor unit, and a control unit. The sensor unit(104) irradiates a laser beam onto a surface of the wafer stage and obtaining detection data from the laser beam reflected from the surface of the wafer stage. The control unit(102) receives the detection data from the sensor unit and discriminates the flatness of the surface of the wafer stage. The sensor unit obtains the detection data by checking the time difference between a laser beam irradiation point and a laser beam reflection point.</p> |
