Nanolithography in microelectronics: A review

The current status of basic photolithographic techniques allowing researchers to achieve results that seemed to be unrealistic even a short time ago is reviewed. For example, advanced DUV photolithography makes it possible to exactly reproduce IC elements 25 times smaller in size than the wavelength of an excimer laser used as a lithographic tool. Approaches owing to which optical lithography has pushed far beyond the Rayleigh-Abbe diffraction limit are considered. Among them are optical proximity correction, introduction of an artificial phase shift, immersion, double exposure, double patterning, and others. The prospects for further advancement of photolithography into the nanometer range are analyzed, and the capabilities of photolithography are compared with those of electronolithography, EUV lithography, and soft X-ray lithography