Method of removing a metal hardmask

Abstract

Methods of removing metal hardmasks in the presence of ultra low-k dielectric films are described. In an example, a method of patterning a low-k dielectric film includes forming a pattern in a metal nitride hardmask layer formed above a low-k dielectric film formed above a substrate. The method also includes etching, using the metal nitride hardmask layer as a mask, the pattern at least partially into the low-k dielectric film, the etching involving using a plasma etch based on SiFx. The etching also involves forming an SiOx passivation layer at least on sidewalls of the low-k dielectric film formed during the etching. The method also includes removing the metal nitride hardmask layer by a dry etch process, where the SiOx passivation layer protects the low-k dielectric film during the removing.

Dependencies are inferred from the claim text.