Fabrication of nanometer-scale patterns is of critical importance for many new applications such as patterned magnetic media, crossbar electronics, sub-wavelength optics and x-ray optics. Extreme ultraviolet interference lithography (EUV-IL) has recently emerged as a viable tool for the creation of periodic nano-patterns. Dense line/space patterns with half-pitch as small as 12.5 nm have been achieved by this method. EUV-IL is also capable of creating other patterns of interest such as circular structures and 2D dot arrays.
The achievement of high resolution in EUV-IL is made possible by the short wavelength and the practical absence of the proximity effect. Recent advances in photoresists such as calixarene and HSQ and processing techniques have been critical in realizing the high-resolution potential of EUV-IL. With continued progress in EUV-IL tools and photoresist materials we expect to approach the ultimate resolution available from this technique, which is equal to half of the wavelength in terms of the pattern period. This outstanding potential for resolution well below 10 nm marks, for the first time, the emergence of a photolithography method that rivals conventional e-beam lithography for the creation of sub-50 nm patterns. Being a parallel exposure technique EUV-IL has higher throughput than e-beam lithography.