Wet scandium etching for hard mask formation on a silicon substrate

Abstract

Nowadays, microelectronics requires the search for materials, including masks for creating structures. The intermediate hard mask strategy is one of the key issues in achieving a good balance between lithography and etching in microelectronics manufacturing. One of the interesting challenges in microelectronics and photovoltaics is the creation of interlayer, vertically oriented silicon arrays on Si substrate for semiconductor devices with multifunctional purposes. The fabrication of such structures is still a serious technological problem and requires searching for approaches and materials. In this work, we propose using scandium as a hard mask material over silicon due to its high resistance to plasma chemical etching and low sputtering coefficient. We have shown that a wet etching of the scandium layer with a thickness of several nanometers can be used to obtain pattern structures on silicon with a resolution of up to 4 µm, which is a good result for the wet etching approach. The scandium was found to be an excellent resistant mask over silicon with the lowest etch rate compared to other metal masks under the selected plasma etching conditions. Therefore, a scandium hard mask can open up possibilities for the formation of different microscale topographical patterns.