Multi-column e-beam inspection system for advanced EUV reticles

With continued design shrinks enabled by EUV lithography, there is a greater need for high sensitivity reticle inspections to minimize defectivity during reticle manufacturing. While laser-illumination based inspection systems have been the workhorses in reticle quality control so far, electron-beam based inspection systems have fundamentally been expected to provide the highest resolution needed for the most critical layers. To address this EUV inspection need at the 3x nm pitch and beyond, KLA has developed a multi-column e-beam inspection system. This new e-beam inspector provides the industry's highest sensitivity die-to-database inspection system and is based on a unique multi-column e-beam architecture for HVM-worthy throughput. With multiple systems shipped to address gap layers at leading-edge mask shops, this new system has demonstrated significant sensitivity advantages while overcoming the long-standing e-beam limitation of throughput gap vs. optical systems. This paper covers the technology that combines advantages of e-beam resolution with KLA's database inspection algorithms. Additionally, recent inspection results are reviewed, highlighting the sensitivity results.