Boehmite filled hybrid sol–gel system as directly writable hard etching mask for pattern transfer

Abstract

We discuss some preliminary results on the development of a new kind of positive tone resist whose peculiarity is an extreme dry etch resistance. This profitable property is obtained by loading and compatibilizing with ceramic nano particles a radiation sensitive sol–gel silica based hybrid organic/inorganic system. With an appropriate choice of the nano particles, the investigated approach is suitable to be adapted and optimized for achieving high selectivity in plasma etching processes of different materials. Here, we specifically demonstrate how the filling with boehmite nano particles (aluminum hydroxide, y-AlO(OH)) confers a much higher selectivity (>60) to the radiation sensitive silica based system when used for the etching of silicon, that show a selectivity <2 if unloaded. The patterning of the new resist was carried out by X-ray lithography while the dry etching tests were made with a fluorine-based chemistry.