Direct electron-beam writing with high aspect ratio for fabricating ion-beam lithography mask

Abstract

An electron-beam lithography techniqe has been used to fabricate an ion-beam mask having a narrow pattern with a high aspect ratio for the application of ion-beam lithography. A conventional 40 kV electron-beam microscope was used for direct electron-beam writing, and was connected to a design computer by digital-to-analog converter. Polymethylmethacrylate with a thickness of 400 nm was used as a resist material. To achieve high aspect ratio and better interface quality, we used a multiple-pass electron-beam writing technique with a special design. As a result, we could obtain an electron-beam writing pattern with a linewidth of about 56 nm and an aspect ratio of about 1:7.