Periodic sub-100nm structures fabricated by proximity i-line mask-aligner lithography (and self-aligned double patterning)

Diffractive mask-aligner lithography allows printing sub-micrometer resolution structures by using non-contact mode. For such a purpose, binary diffraction gratings are used as masks and are designed to transmit solely the ±1st diffraction orders. The high resolution interferogram is realized by the overlapping and the interference of the propagating beams. By applying the techniques known as Self-Aligned Double Patterning (SADP), it´s possible to decrease the period of the fabricated grating (350 nm) by a factor of two, and thus reaching the 90nm structure width. As application, metallic gratings have been fabricated operating as wire grid polarizer (WGP).