Analysis of property of HSQ in electron beam lithography

Hydrogen silsesquioxane (HSQ) is a kind of inorganic negative-tone resist for electron beam lithography with high pattern resolution of about 5 nm. It is a kind of promising resist used in fabrication of nanostructures such as transmission grating (TG), dots array, and chiral structures. But the poor sensitivity limits the extensive application of HSQ. And the property of HSQ in electron beam lithography is also studied little before. In this paper, from the viewpoint of chemical structure the property of HSQ in electron beam lithography has been proposed and experiments have also been presented with the variety of the exposure dose and development conditions. It is proved by experiments not only the sensitivity and contrast of HSQ but also the influence of proximity effect can be modulated by changing the baking temperature and concentration of developer with the same exposure conditions. 100 nm lines at 200 nm pitch grating patterns with excellent vertical side-wall and line-edge roughness have been achieved in more than 450 nm thickness HSQ layer by increasing the concentration of developer and reducing the baking temperature in combination with optimization of exposure conditions.