Towards three-dimensional and multilayer rod-split-ring metamaterial structures by means of deep x-ray lithography

Presently existing THz electromagnetic metamaterials were mostly produced as planar single layer structures, either deposited on a substrate or embedded in a polymer matrix, and patterned by a primary pattern generator such as an electron beam writer or a laser writer. Some attempts to produce more voluminous structures were made using ultraviolet photolithography and a stacking process. We explore deep x-ray lithography and subsequent stacking of chips to fabricate, with good yield, substantial quantities of rod-split-ring structures that come closer to three dimensions than before. Samples were characterized layer-by-layer using Fourier transform interferometry in the far infrared.