Hydrogen silsesquioxane

Hydrogen silsesquioxane (HSQ) is class of inorganic compounds with the chemical formula [HSiO_3/2]_n. Such clusters are specific representatives of the family of silsesquioxanes with the formula [RSiO_3/2]_n (R = alkyl, halide, alkoxide, etc.). The most widely studied member of the hydrogen silsesquioxanes is the cubic cluster H₈Si₈O₁₂.

HSQ has been used in photolithography and Electron-beam lithography due to the fine resolution achievable (~10 nm). Thickness of the coated resist has been reported to play a major role in the achievable resolution.

Cross-linking of the HSQ can is achieved through exposure to e-beam or EUV radiation with wavelengths shorter than 157 nm.