| abstract |
A method is provided for protecting cobalt (Co) metal plugs used to make electrical connections in semiconductor devices. In one example, the method includes providing a substrate comprising a Co metal plug in a dielectric layer, and optionally forming a ruthenium (Ru) metal cap layer on the Co metal plug. In another example, a method includes providing a substrate comprising a Co metal plug in a first dielectric layer, selectively forming a Ru metal cap layer on the Co metal plug, and forming a Ru metal cap layer on the first metal layer and on the first dielectric layer. Depositing a second dielectric layer on the substrate; etching the recessed features in the second dielectric layer to expose the Ru metal cap layer; and a cleaning process to remove polymer etch residue from the Ru metal cap layer in the recessed feature. Performing the steps. |