Performance of a combined focused ion and electron beam system

Abstract

In order to characterize electron and ion beam induced etching and deposition parameters in a single system a combined focused ion beam (FIB) and electron beam (EB) column has been developed. This system has both an electron gun and a FIB gun with a gallium liquid metal ion (LMI) source integrated on an objective lens and deflector assembly shared by both sources. A cylindrical electrostatic prism was used to position the electron beam on the final lens axis. We have optimized the EB crossover location to minimize chromatic blurring induced by the prism. In addition, the system was configured with a common retarding lens below the objective lens to permit low energy ion and electron beam experimentation. This lens provided the system with an energy range from 1 to 25 keV. The theoretical minimum probe diameters at 1 keV are 20 and 300 nm, respectively, for the electron and focused ion final beam diameters. We will present the experimental scanning electron microscopy (SEM) mode and scanning ion microscopy (SIM) mode image results which compare well to the theoretical predictions at 1 keV.