Inspection Method and Apparatus

Abstract

A method and apparatus is used for inspection of devices to detect processing faults on semiconductor wafers. Illuminating a strip of a die along a scan path with a moving measurement spot. Detecting scattered radiation to obtain an angle-resolved spectrum that is spatially integrated over the strip. Comparing the scattering data with a library of reference spectra, obtained by measurement or calculation. Based on the comparison, determining the presence of a fault of the die at the strip. The measurement spot is scanned across the wafer in a scan path trajectory comprising large (constant) velocity portions and the acquisition of the angle-resolved spectrum is taken, and comparisons are done, at full scan speed. If a long acquisition is performed along a strip across the die in the Y direction, then variation in the acquired spectrum resulting from position variation will primarily depend on the X position of the spot. Spot position variation will occur because no alignment of the spot to the wafer is performed along the high-speed scan path trajectory. A library of reference spectra are obtained for a range of scan paths at respective X-positions on the die to allow for variation in the X position of the high-speed measurement spot.

Dependencies are inferred from the claim text.