New Strategies for Improvement and Implementation of the Digital Electrostatic e-beam Array Lithography (DEAL) Concept

The digital electrostatically focused e-beam array direct-write lithography (DEAL) concept incorporates a digitally addressable field-emission array (DAFEA) and an integrated dose control circuit to function as the write head for an e-beam lithography tool. Typically, DEAL devices have been fabricated using vertically aligned carbon nanofibers as the field emitter. To further improve device performance and patterning resolution, tungsten nanofibers formed by electron-beam-induced deposition (EBID) were used. Auger electron spectroscopy (AES) and transmission electron microscopy (TEM) characterization results have shown that high purity, single crystal beta-W nanofibers with sharp tips can be deterministically grown and used for field emission. Additional design modifications have been implemented in an attempt to further improve lithography results. These include the introduction of an integrated, 500-nm diameter, beam-forming aperture in an effort to increase the depth of focus and minimize beam divergence as well as to function as a focusing electrode. Fabrication and operation details will be discussed, as well as modeling results which predict the anticipated performance improvements