Developments at SSRF in soft X-ray interference lithography

The soft X-ray interference lithography （XIL） branch beamline at Shanghai Synchrotron Radiation Facility （SSRF） is briefly introduced in this article. It is designed for obtaining 1D （line/space） and 2D （dot/hole） periodic nanostructures by using two or more coherent extreme ultraviolet （EUV） beams from an undulator source. A transmission-diffraction-grating type of interferometer is used at the end station. Initial results reveal high performance of the beamline, with 50 nm half-pitch 1D and 2D patterns from a single exposure area of 400 μm × 400 μm. XIL is used in a growing number of areas, such as EUV resist test, surface enhanced Raman scattering （SERS） and color filter plasmonic devices. By using highly coherent EUV beam, broadband coherent diffractive imaging can be performed on the XIL beamline. Well reconstructed pinhole of Ф20 μm has been realized.