Development of a multi-electron-beam source for sub-10nm electron beam induced deposition

Abstract

A multibeam electron beam induced deposition (EBID) system is presented that aims at the fabrication of sub-10nm structures with EBID. This system consists of a multibeam source (MBS) module, delivering 100 virtual sources and a standard scanning electron microscope column to image the 100 sources onto a wafer. In this paper, the concept for the MBS is presented: starting with a single Schottky field emission gun, its broad beam is divided into 100 individually focused sub-beams. This is accomplished with an aperture plate with small current-limiting apertures on the side irradiated by the beam and larger holes on the other side, acting as aperture lenses due to the presence of a macroelectrode in front of it. With this concept, in addition to the miniature aperture lenses, a negative macrolens effect is established that can serve to compensate for both the third-order geometric and first-order chromatic aberration of the collimator lens in front of the aperture plate. A simple aberration model is presented to illustrate this, and first results are shown of a prototype MBS.