Full size x-ray grating fabrication using large area nanoimprint

We developed a process for fabrication of ultra-precise blazed diffraction gratings for high resolution x-ray spectroscopy. The process based on nanofabrication techniques provides high fidelity for groove placement, high groove density, and perfect saw-tooth profile of grating grooves. A grating pattern is recorded on a quartz plate by use of e-beam lithography with a nanometer scale accuracy over the grating size. The pattern is transferred to a grating substrate by large area nanoimprint and then a hard Cr mask is formed via a lift-off process. Fidelity of the transfer step in terms of groove placement accuracy was investigated by differential wavefront interferometry. Anisotropic wet etch was applied to the patterned Si single crystal substrate to shape triangular grooves. Fabrication of a blazed grating of area 120 mm × 30 mm with groove density of 2000 lines/mm was demonstrated.