SiN SPACER PROFILE PATTERNING

An etching method comprising:

• oxidizing an exposed nitride material surface on a semiconductor substrate within a processing region of a semiconductor processing chamber to produce a region of oxide;
• forming an inert plasma within the processing region of the semiconductor processing chamber;
• modifying at least a portion of the region of oxide with effluents of the inert plasma;
• contacting the modified oxide with plasma effluents of a fluorine-containing precursor;
• and
• etching the modified oxide, wherein the oxidizing, modifying, contacting, and etching are all performed in the semiconductor processing chamber.

An etching method comprising:

• forming an oxygen-containing plasma within a processing region of a semiconductor processing chamber;
• oxidizing an exposed silicon-containing surface on a semiconductor substrate within the processing region of the semiconductor processing chamber to form a region of silicon oxide;
• forming an inert plasma within the processing region of the semiconductor processing chamber, wherein the inert plasma comprises a hydrogen or helium plasma formed by a bias power of less than 1,000 W;
• modifying at least a portion of the oxidized silicon-containing surface with effluents of the inert plasma;
• forming a plasma of a fluorine-containing precursor in a remote region of the semiconductor processing chamber that is separated from the processing region of the semiconductor processing chamber by a showerhead;
• contacting the modified, oxidized silicon-containing surface with plasma effluents of the fluorine-containing precursor;
• and
• etching the modified, oxidized silicon-containing surface at a temperature of about 100° C., wherein the oxidizing, modifying, contacting, and etching are all performed in the semiconductor processing chamber, and wherein no solid byproducts are produced during the etching.