Complete monitoring and matching strategy for multiple CD SEMs in advanced fab

In a multiple CD SEM fab, the CD matching and tool stability performance of CD SEM become more and more crucial for new technology generation. In this article, we first address the method to match tools, and also introduce the current monitoring system of linewidth for multiple tools. Next, a new design monitor wafer is introduced. This new design successfully reduces the carryover and it could be a potential standard to monitor the absolute linewidth and control the stability of CD SEM.