Synchrotrons as a Source for Soft X-Ray Lithography

Abstract: To move to lower modes in extreme ultra-violet lithography (EUVL) technology (and keep up with Moore’s law), new sources of soft X-ray radiation must be developed. It is clear from previous studies that Free Electron Lasers (FELs) can easily meet the in-band power requirements at these lower wavelength modes, however detailed studies for insertion devices (undulators) as a soft X-ray lithography (SXL) source are due for a re-evaluation. Here we present the results of a systemic study to determine the undulator parameters to meet the required dosage, while meeting typical optical characteristics for wafer stages. To do this we resolved a large parameter set to find maximum in-band power at each wavelength mode. Using the resolved undulator parameters an accelerator lattice was developed to further realize the conceptual footprint of such a machine. Finally a cost-per-watt evaluation was made to estimate the total amount of power achievable per million euro. This showed that synchrotrons are an attractive and cost-effective source for SXL. However, a larger bandwidth and thus grazing incidence optics are required. Further developments of optical train feasibility will need to be performed.