Alignment mark optimization to reduce tool and wafer induced shift for XRA-1000

Summary form only given. As the most critical semiconductor device geometry shrinks down to 100 nm order, requirements for overlay accuracy also become increasingly critical in the actual semiconductor manufacturing process. Factors in overlay error (especially, alignment error) originate in the interaction of processes and tools. It is therefore necessary to improve alignment accuracy from both the process and the tool sides. The alignment errors can be separated into Tool Induced Shift (TIS), Wafer Induced Shift (WIS), and TIS-WIS interaction. The authors consider the optimization of the alignment mark in order to reduce not only TIS, but also WIS for the XRA-1000, which is the volume production stepper of proximity X-ray lithography.