Direct ArF laser photopatterning of metal oxide nanostructures prepared by the sol-gel route.

We developed specific negative tone resists suitable for preparing periodic inorganic nanostructures by ArF photolithography. This approach is based on the sol-gel chemistry of modified metal alkoxides followed by DUV laser irradiation. Patterning at the nanoscale was demonstrated by using an achromatic interferometer operating at 193 nm. In a second step, thermal treatment could be used to obtain metal oxide nanostructures (ZrO(2), TiO(2)). Such thermal treatment did not affect the integrity of the nanostructures. The DUV-induced modifications of the physico-chemical properties of the sol-gel thin film were followed by ellipsometry, XPS and AFM. The crystalline structure of the material after thermal treatment was proved by DRX analysis. Examples of periodic nanostructures are given in order to illustrate the possibilities opened by this new route that provides a convenient method to create transparent, robust, high refractive index nanostructures compatible with a wide variety of substrates.