Simulation-based photomask qualification using i-Virtual Stepper™

摘要

Mask manufacturers and mask users continue to pursue improvements in mask inspection and qualification processes driving standards to guarantee the highest performance of advanced photomasks while maintaining a high degree of predictability of turn-around-time. Simulation based defect analysis and dispositioning has become an area of much interest for both mask manufacturers and mask users. Repairing only the defects that impact wafer level performance (lithographically significant) improves both mask cycle time and eliminates unnecessary and costly repairs. Mask maker and mask users can utilize defect simulation as a common standard by which to benchmark the quality of results. We report in this paper the results of a joint evaluation of the i-Virtual Stepper system (i-VSS) the automated simulation based defect dispositioning software solution in an advanced photomask qualification flow. Results discussed include the optimization and automation of the mask inspection flow using i-VSS, simulation accuracy comparisons of i-VSS versus AIMS versus wafer printability for binary and phase shifting masks at 130nm, 90nm, and 65nm technology nodes, and a comparison of the iVirtual Stepper system's automated defect severity scoring (ADSS) versus manual defect dispositioning.