Novel electron optics for large sub-field electron beam projection lithography (EPL)

In Electron-beam Projection Lithography (EPL), achieving the requirements for the ITRS 45 nm roadmap node will require decreasing simultaneously both the beam blur from the Coulomb interaction effects and the geometrical aberrations from their present values. Because next generation lithography tools are required to have both high resolution and throughput, the Coulomb effect becomes more of an issue. In this paper, we propose a novel concept to effectively decrease the Coulomb effect. Based on this new concept we develop an EPL electron optical system in which not only the Coulomb effect but also the geometrical aberrations are greatly reduced. We report on the properties of this new EPL optical system.