Hot electron emission lithography

We discuss the applicability of a patterned hot electron emission mask in Hot Electron Emission Lithography (HEEL). This method holds the promise of printing entire circuits with exposure times of a few seconds and a resolution of at least 0.1 microns. The hot electron emission mask consists of a silicon wafer with a patterned oxide of two discrete thicknesses and a thin gate electrode. Under positive gate bias, electrons tunnel through the thin oxide regions and are accelerated by the oxide field. Some of these electrons are emitted through the thin gate into vacuum where they are projected onto a second, resist coated wafer by parallel E and B fields. We present experimental data on the mask properties, including energy distribution, angular distribution, electron efficiency and measurements on the mask reliability. We demonstrate 160 nm resolution in a 1:1 projection system and we anticipate that it will be capable of printing feature sizes of 50 nm.