High resolution electron-beam lithography on thin films

Abstract
The influence of electron scattering on the resolution of electron-beam lithography has been studied. Theoretically, we have used two different Monte-Carlo approaches to study the spatial extent of energy dissipation in a thin film of electron sensitive polymer film coated on various thicknesses of silicon substrates. The two Monte-Carlo approaches are the conventional continuous-slowing-down approximation approach and the direct simulation approach in which individual inelastic scattering is taken into account. Experimentally, we have exposed lithographic patterns on the structures mentioned above. Agreement between both Monte-Carlo approaches and experiment is satisfactory. Results show that higher resolution in electron beam lithography can be achieved by using thin electron sensitive resist layers and thin substrates. Improvement in proximity effect is also obtained for thin structures.