Method and apparatus for elimination of micro-trenching during etching of a hardmask layer

Abstract

Described herein are exemplary methods and apparatuses for etching a nitride layer disposed above a substrate to form trenches without micro-trenching in accordance with one embodiment. The method includes forming openings in a resist layer and one or more dielectric layers. The dielectric layers may be disposed on a hard mask layer (e.g., nitride, polysilicon). Next, the method includes etching openings in the hard mask layer disposed above a substrate layer without micro-trenching. The etching occurs in a process chamber during a main etch with a first process gas mixture having a fluorocarbon gas, a hydrofluorocarbon gas, and an oxygenating gas. Next, the method includes etching openings partially into the substrate without micro-trenching with a second process gas mixture during an over etch having the fluorocarbon gas, the hydrofluorocarbon gas, and the oxygenating gas.

Dependencies are inferred from the claim text.