Automated SEM Offset using programmed defects

Defect inspection plays a large role in the development and manufacture of semiconductor technologies. Defects detected in today's inspections tools are generally a fraction of a micron and require SEM review to analyze and justify corrective measures. It is very important that the review SEM drives to the exact location of the defects as a FoV (Field of View) of 2μm is necessary to provide the resolution needed for defect redetection without the inefficiencies associated with repeated zooming of the image. A methodology which allows quick and accurate alignment of the review SEM to the defects in the results file is presented. This methodology uses a special structure containing programmed defects. The methodology is illustrated using the challenging example of PWQ wafers. © 2011 IEEE.