Lam Research Corporation
Atomic layer etching and smoothing of refractory metals and other high surface binding energy materials

Abstract:

Etching a refractory metal or other high surface binding energy material on a substrate can maintain or increase the smoothness of the metal/high EO surface, in some cases produce extreme smoothing. A substrate having an exposed refractory metal/high EO surface is provided. The refractory metal/high EO surface is exposed to a modification gas to modify the surface and form a modified refractory metal/high EO surface. The modified refractory metal/high EO surface is exposed to an energetic particle to preferentially remove the modified refractory metal/high EO surface relative to an underlying unmodified refractory metal/high EO surface such that the exposed refractory metal/high EO surface after removing the modified refractory metal/high EO surface is as smooth or smoother than the substrate surface before exposing the substrate surface to the modification gas.