Method for highly anisotropic etching of titanium oxide spacer using selective top-deposition

Abstract

Methods are provided herein for forming spacers on a patterned substrate. A self-aligned multiple patterning (SAMP) process is utilized for patterning structures, spacers formed adjacent mandrels, on a substrate. In one embodiment, a novel approach of etching titanium oxide (TiO) spacers is provided. Highly anisotropic etching of the spacer along with a selective top deposition is provided. In one embodiment, an inductively coupled plasma (ICP) etch tool is utilized. The etching process may be achieved as a one-step etching process. More particularly, a protective layer may be selectively formed on the top of the spacer to protect the mandrel as well as minimize the difference of the etching rates of the spacer top and the spacer bottom. In one embodiment, the techniques may be utilized to etch TiOspacers formed along amorphous silicon mandrels using an ICP etch tool utilizing a one-step etch process.