Nanolithography with coherent extreme ultraviolet light

Extreme ultraviolet interference lithography (EUV-IL) is a newly developed technique for the production of periodic nano-structures with resolution below 20 nm. The technique is based on coherent radiation that is obtained from undulators at synchrotron radiation laboratories. The high resolution is afforded by small wavelength and practical absence of the proximity effect at this energy. The throughput of this parallel exposing method is much higher than that of the serial electron-beam lithography. Interference schemes based on both reflection (mirrors) and diffraction (gratings) optics have been realized. Both one- dimensional and two-dimensional patterns such as arrays of dots have been achieved. Achromatic interference schemes have been developed to make efficient use of the beam power available from the wideband sources in the extreme ultraviolet region. EUV-IL is used in a growing number of applications; examples include fabrication of self-assembly templates, magnetic nanodot arrays and nano-optical components.