US Patent 8992792 Method of fabricating an ultra low-k dielectric self-aligned via

Methods of fabricating ultra low-k dielectric self-aligned vias are described. In an example, a method of forming a self-aligned via (SAV) in a low-k dielectric film includes forming a trench pattern in a metal nitride hardmask layer formed above a low-k dielectric film formed above a substrate. A via pattern is formed in a masking layer formed above the metal nitride hardmask layer. The via pattern is etched at least partially into the low-k dielectric film, the etching comprising using a plasma etch using a chemistry based on CF4, H2, and a diluent inert gas composition.