In-situ sequential silicon containing hard mask layer/silicon layer

Abstract

A method for etching a silicon layer within a microelectronics fabrication. There is first provided a substrate employed within a microelectronics fabrication. There is then formed over the substrate a blanket silicon layer. There is then formed upon the blanket silicon layer a blanket silicon containing hard mask layer, where the blanket silicon containing hard mask layer is formed from a silicon containing material chosen from the group of silicon containing materials consisting of silicon oxide materials, silicon nitride materials, silicon oxynitride materials and composites of silicon oxide materials, silicon nitride materials and silicon oxynitride materials. There is then formed upon the blanket silicon containing hard mask layer a patterned photoresist layer. There is then etched through a first plasma etch method the blanket silicon containing hard mask layer to form a patterned silicon containing hard mask layer while employing the patterned photoresist layer as a first etch mask layer. The first plasma etch method employs a first etchant gas composition comprising a first fluorine and carbon containing etchant source gas and a first bromine containing etchant source gas. Finally, there is then etched in-situ through a second plasma etch method the blanket silicon layer to form an at least partially etched silicon layer while employing the patterned photoresist layer and the patterned silicon containing hard mask layer as a second etch mask. The second plasma etch method employs a second etchant gas composition comprising a second fluorine and carbon containing etchant source gas, a second bromine containing etchant source gas and a chlorine containing etchant source gas.