Intel's leading interconnect material option changed from cobalt to copper, and ruthenium may become the leading option in the future.

“Every te- every technology that we go through, we will evaluate multiple options, and as we get closer to our time horizon for delivering a manufacturing-worthy product, we have to make a decision, and the leading option at the time was cobalt, now it's copper again, and perhaps in the future, it'll be ruthenium.”