EBM-8000: EB mask writer for product mask fabrication of 22-nm half-pitch generation and beyond

摘要

Many lithography candidates, such as ArF immersion lithography with double-patterning/double-exposure techniques, EUV lithography and nano-imprint lithography, show promising capability for 22-nm half-pitch generation lithography. ArF immersion lithography with double-patterning/double-exposure techniques remains the leading choice as other techniques still lack the conclusive evidence as the practical solution for actual production. Each of the prospective lithography techniques at 22-nm half-pitch generation requires masks with improved accuracy and increased complexity. We have developed a new electron beam mask writer, EBM-8000, as the tool for mask production of 22-nm half-pitch generation and for mask development of 16nm half-pitch generation, which is necessary for the practical application of these promising lithography technologies. The development of EBM-8000 was focused on increasing throughput and improving beam positioning accuracy. Three new major features of the tool are: new electron gun with higher brightness to achieve current density of 400 A/cm~2, high speed DAC amplifier to accurately position the beam with shorter settling time, and additional temperature control to reduce the beam drift. The improved image placement accuracy and repeatability, and higher throughput of EBM-8000 have been confirmed by actual writing tests with our in-house tool.