New dynamic FIB-SEM fusion model for controllable high-precision nanofabrication with high-energy synchronous FIB-SEM beams

Abstract

With the advantages of high-resolution fabrication of FIB and real-time imaging of SEM, the FIB-SEM synchronous system has been widely used in in-situ nanofabrication of semiconductors, life science, new energy, etc. Its machining accuracy and quality can be improved by controlling ion neutralization and sample charge accumulation with the electron beam (EB). In this paper, a new dynamic FIB-SEM fusion beam was developed for a 30 kV gallium FIB-SEM system by considering the SEM regulation on interionic Coulomb force and the modulation of sample surface potential on FIB. Based on three-dimension (3D) FIB/SEM beam current density distributions, the fusion model was complemented by GPU-accelerated algorithm for solving the multi-particle dynamics in the coupled ion-electron system, and verified by sputtering experiments on Si and PMMA. Results show that the machining accuracy on Si can be improved up to 17 % for FIB of 30 pA wtih a 5 keV EB of 1.6 nA, and it will be ∼30 % on PMMA for FIB of 80 pA with a 3 keV EB of 170 pA. The model will provide guidance for controllable high-precision FIB-SEM nanofabrication in both conductive and insulating materials.