Generally, embodiments described herein relate to methods for manufacturing an interconnect structure for semiconductor devices, such as in a dual subtractive etch process. An embodiment is a method for semiconductor processing. A titanium nitride layer is formed over a substrate. A hardmask layer is formed over the titanium nitride layer. The hardmask layer is patterned into a pattern. The pattern is transferred to the titanium nitride layer, where the transferring comprises etching the titanium nitride layer. After transferring the pattern to the titanium nitride layer, the hardmask layer is removed, where the removal comprises performing an oxygen-containing ash process.