Embedding of Copper into 30-nm-wide trench by a high-magnetic-field magnetron sputtering method with oxygen added sputtering gas

Abstract

We successfully embedded Cu in 30-nm-wide trenches with an aspect ratio of 10 using a high-magnetic-field, medium vacuum magnetron sputtering method having high deposition speeds. We used a Ru/TaN/SiO2/Si substrate featuring a Ru barrier layer and a sputtering gas formed by adding O2 at 5×10−5 Pa to 1-at.% N2-Ar. The trenches could be completely filled with Cu in a sputtering time of 5 min. This result is discussed on the basis of capillary theory focusing on the wettability of Cu with the Ru barrier layer.