Reactive Ion Etching of Silicon using F-based chemistry - Exploring the Limits

Abstract: Dry Etching is widely used in nanoprocessing as a method of pattern transfer onto a hard substrate, like silicon. Improving the resolution of this etch process is an important step in reducing the feature size in, for instance, computer microchips, or Nanoimprint Lithography stamps. TheReactiveIonEtcheratLundUniversityhasrecentlybeenupgradedwithaturbo molecular pump. This allows for lower pressure ranges with any given gas flow in the working chamber. Therefore, a sufficient process window had to be established for the upgraded system, where a plasma can be generated and sustained in a stable manner. The study shows that the process window for the system appears to be large, with power, pressure and flow rates not hindering plasma generation outside of hardware limitations. A recipe for anisotropic etching was developed and, although limited in etch rates and mask selectivity, the process shows promise as anisotropic structures as small as 30 nm were successfully etched with anisotropic features.