Supercritical drying for high aspect-ratio HSQ nano-structures

The benefits of supercritical resist drying (SRD) technique using carbon dioxide (CO2) are investigated with respect to the resolution of dense patterns and the aspect ratio (AR) of nano-structures in rather thick HSQ layers. For double lines separated by a distance of 50 nm the maximum achievable AR is trebled using SRD processes compared to conventional nitrogen blow. The mechanical stability of resist structures is significantly improved by using SRD.