New EUV interference lithography tool at PSI: pushing the limits of resolution beyond hyper NA EUVL

An EUV interference lithography tool is under development at SLS 2.0, the Paul Scherrer Institute synchrotron in Switzerland and is expected to be operational in late 2025. The tool is designed to overcome the factors limiting the performance of the interference lithography method based on two decades of experience. We aim for better reproducibility, resolution, and throughput. We target to achieve subnanometer stability over a one-minute period – more than the duration of a typical exposure by mitigation of thermal and mechanical drifts and vibrations. The tool is designed for patterning on Si wafers up to 8 inch using interference lithography with transmissive diffraction gratings or mirrors and focused beams (direct writing with Fresnel zone plates or Bessel beams). The new endstation is expected to have a high impact on the EUV community pushing the resolution of photon-based lithography even further and enabling research towards and beyond hyper NA EUVL.