Copper Filling of Deep Submicrometer Trenches with Ruthenium-Lined Barrier Metal by High-Vacuum Magnetron Sputtering Using Argon Gas with Added Oxygen

摘要

A fine structure with a ruthenium-lined barrier layer was experimentally fabricated, and copper-filling tests were performed by high-vacuum sputtering using argon gas with added oxygen. As a result, the complete copper filling of all trenches with a width of about 80 nm and an aspect ratio (AR) of four was accomplished with good reproducibility. The experimental results also show that complete copper filling was even possible in the case of trenches with a width of about 30 nm and an AR of nine. The reasons for these results are explained by applying capillary theory from the viewpoint of copper wettability on a ruthenium-lined layer.