Fabrication by Tri-Level Electron Beam Lithography of X-Ray Masks with 50nm Linewidths, and Replication by X-Ray Nanolithography

摘要

Scanning-electron-beam lithography is an essential tool for producing patterns of arbitrary geometry with linewidths of 100nm or less. In those applications where large areas of fine-linewidth features are needed, the e-beam writing time can become extremely long. A process has been developed to produce x-ray nanolithography masks containing fine linewidth patterns generated by scanning-electron-beam lithography. This technology allows researchers to combine the high resolution, arbitrary-pattern-generation capability of electron-beam lithography with the parallel replication, high contrast, and large process-latitude of x-ray nanolithography. A tri-level structure was used which consisted of Polymethyl methacrylate (PMMA) as the electron-sensitive material, titanium as the middle, masking layer, and polymide as the buffer layer on top of a gold plating base. After electron-beam exposure and development, the pattern is transferred to the Ti layer by Dichlorodifluoro Methane RIE, and then a polyimide mold is produced by Oxygen RIE. Gold is then electroplated into this mold to form the x-ray absorber. X-ray masks with 100-nm-period gratings and electronic device patterns of approx 100nm linewidths were fabricated by this process and replicated. Reprints. (JES)