Effective wafer inspection strategy for memory manufacturing foundries with inspiring HARI results

Yield monitoring has been and always will be one of the most important technologies in memory manufacturing foundries. The monitoring scheme is becoming drastically complicated. As the design rule surpasses the 90 nm regime, the types and sizes of defects are also getting extremely complex. New types of defects are discovered with emerging inspection technologies and a variety of defect inspection tools are available in the market today. However, the resolution cost for these tools are higher than the existing ones. To overcome the above problems, a new inspection scheme called combined inspection strategy is introduced. Defect review schemes were also studied to identify killer defect status more effectively. Potential benefits of the optimized monitoring strategy are detecting more excursions, obtaining meaningful information within a shorter period of time and reducing resolution costs