Die-to-database inspection of 256-Mb DRAM reticles

256 Mbit DRAM devices pose a great challenge to the mask manufacturers. Shrinking kne widths, tighter CD requirements, new lithography enhancement techniques, dense data bases, and higher sensitMty to half-tone defects require advanced process and inspection systems. The improvements and changes in mask manufacturing are translated into three main characteristics of a dietodatabase inspection system: Image quality, reference data injection and defect detection. In order to meet the challenge of inspecting 256 Mbit DRAM masks various enhancements need to be implemented in die.. to-database inspection systems which bring the above characteristics to the required level and supply the mask maker with a highly reliable and sensitive tool.