A Schottky-Emitter Electron Source for Wide Range Lithography Applications

A new 3-lens electron optical column using a Schottky emitter has been designed to perform very high-resolution lithography and also to produce reticles with good throughput. The theoretical performance has been computed from the source and lens characteristics and stochastic beam broadening. Measurements have shown excellent stability off the beam position and current. The measured current in a given spot-size is not as great as the theory predicts and further investigation is required. Examples are given of nanostructures formed by gold lift-off and of a DRAM reticle. The column is in use by research workers in the Technical University of Delft and examples of masks for Josephson junctions are shown.