Etch rate modeling for ion-irradiated nitrocellulose

The self-developing mechanism of nitrocellulose when used as an ion beam resist is described by a model predicting the evolution of the etch rate versus irradiation time. Fundamentals of the model based on ion energy deposition dependent ablative development along with related mathematical derivations are given and briefly discussed. Comparison between theoretical results and experimental data available for protons at 20 keV and Ne+, Ar+, Kr+ ions at 150 keV is made and shows a good agreement. This result clearly does not conflict with our assumption that the nitrocellulose etch rate is dependent on the total ion deposited energy no matter how the energy is deposited