| 摘要 |
<p>The present invention provides apparatus and methods for scanning a workpiece for defects with increased resolution and sensitivity relative to conventional workpiece inspection systems. Specifically, the apparatus and methods of the present invention repeatedly scan different portions of the workpiece with an optical beam that forms a scan region on the surface of the workpiece having in-scan and cross-scan dimensions. The in-scan dimension of the scan region is parallel to the direction with which the optical beam is scanned, and the cross-scan dimension is in a direction that is generally perpendicular to the direction in which the optical beam is scanned. The apparatus and methods of the present invention filter the signal reflected from the surface of the workpiece in the cross-scan direction using a cross-scan filter. As such, the method and apparatus of the present invention effectively remove a significant portion of the noise in the reflected signals used for detecting for defects in the workpiece. Further, in some embodiments, the apparatus and method also filter the reflected signal in the in-scan direction using an in-scan filter. By filtering the reflected signals in either a cross-scan or both a cross-scan and in-scan directions, the apparatus and methods of the present invention remove noise from the reflected signals, thereby increasing the sensitivity and resolution of the workpiece inspection device. <IMAGE></p> |
