We have fabricated an ion beam mask having a narrow pattern with high aspect ratio for the application of ion-beam lithography. A conventional 40 keV electron beam microscope was used for the direct electron-beam writing, which is connected to a design computer by digital-to-analog converter. Polymethylmethacrylate with a thickness of about 400 nm was used as a resist material. To achieve the high aspect ratio and better interface quality, we have used multiple-pass electron beam writing technique with special design. As a result, we could obtain an electron beam writing pattern with a linewidth of about 60 nm and an aspect ratio of about 1:7.
2002 International Conference on Semiconductor (Aug. 29. 2002, Jeju, Korea)