Nuisance Event Reduction Using Sensitivity Control Layers (SCL) for Advanced Photomask Inspection

Conference: EMLC 2009 - 25th European Mask and Lithography Conference
01/12/2009 - 01/15/2009 at Dresden, Germany

Proceedings: EMLC 2009

Pages: 8Language: englishTyp: PDF

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Hedges, Shad; McMurran, Jeff (Phontronics nanoFab North America, Boise, ID, 83716)
Le, Chin; Simmons, Tim (Micron Technology, Boise, ID, 83707)
Eickhoff, Mark; Wylie, Mark; Vellanki, Venu (KLA-Tencor Corporation, San Jose, CA, 95134)

Conventional photomask inspection techniques utilize global sensitivity for all inspected area in the die; SRAF and OPC features become the sensitivity-limiters for advanced photomasks which can result in reduced sensitivity to defects of interest (DOI). We describe the implementation of Sensitivity Control Layer (SCL), a novel database inspection methodology for the KLA-Tencor TerascanHR platform to improve sensitivity and reduce nuisance detections. This methodology enables inspection at maximum sensitivity in critical die-areas via “layer definition” and reducing sensitivity to sub-resolution features during inspection which can dramatically improve false-rate. DRAM and FLASH inspection performance was improved through the use of up to 6-control layers to increase sensitivity in the active area while reducing false detections by as much as 100X. Post-inspection defect analysis, and improved disposition accuracy of the SCL-enabled inspections will also benefit cycle time and higher throughput. In all test cases, sensitivity parameters were increased in the regions of interest over baseline inspections run with typical, production-type inspection methodologies. SCL inspection-sensitivity management, and layer partitioning of OPC structures, SRAF’s, and other sub-resolution features is discussed in detail.