HNU-EBL: A Software Toolkit for Electron Beam Lithography Simulation and Optimization

This paper introduces a software toolkit, HNU-EBL, developed at Hunan University (HNU), to simulate and optimize electron beam lithography (EBL). The toolkit consists of three consecutive modules. Firstly, the electron trajectories in EBL resist and substrate layers are simulated by using Monte Carlo (MC), and point spread function (PSF) is obtained by fitting the electron trajectories. Secondly, using PSF, electron dose distribution is optimized using the fast Fourier transform (FFT), to efficiently correct the effects like proximity effect and fogging effect that may jeopardize the lithography resolution and pattern quality. Thirdly, based on the optimized electron dose distribution, the optimized pattern quality is evaluated based on metrics like the edge placement error (EPE). The HNU-EBL toolkit can simulate sub-10 nm EBL, and it has been successfully applied to optimize fabrication of nm-scale devices.