Novel mask inspection flow using Sensitivity Control Layers (SCL) onthe TeraScanHR-587 Platform

摘要

Conventional photomask inspection techniques utilize global sensitivity for all inspected area in the die; SRAF and OPCfeatures become the sensitivity-limiters, which can result in reduced visibility to defects of interest (DOI). We describethe implementation of Sensitivity Control Layer (SCL), a novel database inspection methodology for the KLA-TencorTerascanHR platform. This methodology enables inspection at maximum sensitivity in critical die-areas via "layerdefinition" during job set-up and sensitivity management of the layers during inspection. Memory device inspectionperformance was improved through the use of up to six control layers to increase sensitivity in the active area whilereducing nuisance detections by as much as 100X. The corresponding inspection time was reduced by 30%, illustratingthe potential for substantial throughput advantage using SCL. Post-inspection analysis and improved dispositionaccuracy of the SCL-enabled inspections will also benefit cycle time and higher throughput. In all test cases, sensitivityparameters were increased in the regions of interest over baseline inspections run with typical production-usemethodologies. SCL inspection management and application on OPC structures, SRAFs, and MRC violations (slivers)are discussed in detail.