X-ray lithography

X-ray lithography uses soft x-rays with a wavelength of 0.4-5.0 nm. An X-ray beam is passed through the template and exposes the resist layer. Optical elements of X-ray lithographic installations can be reflective mirrors (reflectors) based on nanoheterostructures with layers of Ni-C, Cr-C, Co-C, Mo-C, W-C and zone plates; thin (1 µm or less) metal membranes are used as templates. Multilayer X-ray mirrors provide Bragg reflection under the condition d = λ/(2sinΘ), where d is the period of the structure and Θ is the glancing angle. With perpendicular incidence of radiation Θ = 90° and period d = λ/2, so the thickness of each layer in the X-ray mirror is approximately λ/4 or 1 nm.

X-ray lithography, like optical lithography, is carried out by simultaneously exposing a large number of details in a pattern, but short-wavelength x-rays allow you to create a pattern with finer details and higher resolution.

Due to the short wavelength of X-ray radiation, X-ray lithography methods have a high resolution (~ 10 nm). Compared to electron-beam and ion-beam lithography, X-ray lithography has low radiation damage to formed structures and high productivity due to the possibility of simultaneous processing of large sample areas. X-ray lithography is characterized by a large depth of field and a small effect of the substrate material and its topography on the resolution.