Enhancing nanoscale patterning on Ge–Sb–Sn–O inorganic resist film by introducing oxygen during blue laser-induced thermal lithography

This work describes a new inorganic resist material Ge–Sb–Sn–O (GSSO) for nanoscale patterning by thermal lithography in which a laser beam directly illuminates the resist film. The heat from the illuminating laser can change the phase of a resist material from amorphous to crystalline. During development, the contrast between the dissolution rates of these two states can cause the formation of nanoscale patterns. Experimental results demonstrate that nanoscale patterning on GSSO inorganic resist film can be improved by introducing oxygen into the film during blue laser-induced thermal lithography, and that the GSSO resist is positive. Additionally, when the numerical aperture is 0.65 and the wavelength is 405 nm, a minimum pattern width of 140 nm on the GSSO film and a height of 80 nm, far below the diffraction limit of 320 nm, can be obtained.