Method for patterning narrow gate lines

摘要

Patterning of a gate line is terminated prior to etching completely through the conductive layer from which it is patterned. Surfaces of the conductive layer are then reacted in a reactive atmosphere, and the reacted surfaces are removed, creating a narrow gate line. The protection provided by the remaining portion of the conductive layer during reaction protects the lower corners of the patterned feature from undercutting growth of reacted material. Alternatively, a gate line is patterned from a multi-layered conductive structure that includes a lower conductive layer and an upper conductive layer that exhibits higher reactivity in a reactive atmosphere than the lower layer. The upper layer is patterned and then the structure is reacted in the reactive atmosphere. Reacted portions of the upper layer are then removed and the lower layer is patterned in a self-aligned manner to complete the formation of a gate line and gate insulator.