Comprehensive defect detection featuring die-to-database reflected light inspection

With ever shrinking k1 lithography, overall reticle quality is paramount to ensure high quality image transfer. State-of-the-art reticle inspection systems play two vital roles in reticle manufacturing: quality assurance and manufacturing process feedback. For quality assurance, the system must be capable of detecting all defects of interest to the end user - defects that repeatedly print on wafer, and also those that may reduce the lithography process window. For process monitoring and improvement, the system must be capable of detecting defects at or near the manufacturing limits of mask manufacturing. In order to meet both needs, an inspection system must detect all defect types including pattern errors and contaminates on all mask surfaces including chrome, quartz, and shifter materials. A new advanced inspection method compares both transmitted and reflected light images to the design database. This comprehensive inspection method detects numerous defects that would be missed in a transmitted or reflected only inspection tool. In this study we have tested a new method for detecting reticle defects. Inspection results will be shown from a programmed defect test vehicle as well as a production reticle.