Patent attributes
The invention may be embodied in a time delay integration (TDI) based sensor wafer inspection system that introduces controlled blur into the sampled image to suppress high spectral frequencies and thereby mitigate the occurrence of aliasing in the sampled image. Image blur may be introduced in the scan direction by desynchronizing the image motion (scan rate) from the charge transfer rate within the TDI sensor (sample clock rate). The scan rate may be desynchronized from the TDI sample clock rate by altering the speed of wafer movement, the sample clock rate, or the magnification of the imaging optics. Image blur may be introduced in the cross-scan direction by imparting a small alignment difference between the direction of image motion (image scan direction) and the direction that charges transfer within the TDI sensor (sensor direction).
