Plasma etch method for forming uniform linewidth residue free patterned composite silicon containing dielectric layer/silicon stack layer

Abstract

A method for forming a patterned composite stack layer within a microelectronics fabrication. There is first provided a substrate. There is then formed over the substrate a blanket silicon layer. There is then formed upon the blanket silicon layer a blanket silicon containing dielectric layer. There is then formed upon the blanket silicon containing dielectric layer a patterned photoresist layer. Finally, there is etched sequentially while employing the patterned photoresist layer as a photoresist etch mask the blanket silicon containing dielectric layer and the blanket silicon layer to form a patterned composite stack layer comprising a patterned silicon containing dielectric layer coextensive with a patterned silicon layer, where the sequential etching is undertaken employing in situ in a single plasma reactor chamber or cluster of adjoining chambers a sequential plasma etch method employing a sequence of etching gas compositions which upon plasma activation perform the etching reactions with uniform linewidth dimensions and attenuated polymer residue formation and defect levels.