US Patent 11955382 Reverse selective etch stop layer

Methods and apparatus for forming a reverse selective etch stop layer are disclosed. Some embodiments of the disclosure provide interconnects with lower resistance than methods which utilize non-selective (e.g., blanket) etch stop layers. Some embodiments of the disclosure utilize reverse selective etch stop layers within a subtractive etch scheme. Some embodiments of the disclosure selectively deposit the etch stop layer by passivating the surface of the metal material.