Issues on the Size and Outline of Killer Defects and their Influence on Yield Modeling

Yield prediction models and critical area calculations base on defects modeled as circular disks. But, the observation of real defects provides mostly irregular defect outlines. For this reason, we investigate the influence of real defect outlines on determining defect size distributions for yield prediction. To collect data on defects, checkerboard test structures were manufactured that enable a precise localization of defects inside large chip areas. Furthermore, we introduce a methodology to calculate a general defect size distribution that includes variety of real defect outlines. So, this realistic size distribution will be compared to defect size distributions based on known yield models to describe defect outlines.