Predicting the structure of ultra shallow EUV gratings fabricated via ion irradiation
Year: 2026
Type: article
Abstract: The controlled and precise fabrication of ultra-shallow structures for gratings operating near-normal incidence in the extreme ultraviolet and soft X-ray range is an important step towards compact tabletop devices. For this purpose, ion irradiation induced swelling has emerged as alternative to conventional etching processes for the precise fabrication of gratings with heights in the nanometre range. Here, we expand on this by presenting a model to predict the structure shape for gratings fabricated with a variety of ion species. Our model applies a Gaussian approximation in a convolution approach to calculate the point spread function of the resulting swelling. This approach is suitable to model the swelling caused by the irradiation of silicon with molecular nitrogen ions at 20keV, and helium ions at 10keV and 30keV, respectively. We verified the model by the deconvolution solution via Fourier transformation and experiments at smaller pitch sizes. By predicting structure shapes for pitch sizes between 250nm and 2µm the model extends the range of applications both in the EUV and soft X-ray range. This enables the prediction of structure shapes from masks with arbitrary pitch size and duty cycle from the morphology of the mask measured from focussed ion beam cross sections.
Source: Applied Surface Science
Authors: Johannes Kaufmann, Thomas Siefke, Uwe Zeitner
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,930
Award: G8083470581
OpenAlex ID: W7124982268