Fine structures with a Co-lined barrier layer, Co/TaN and Co/Ru/TaN, were experimentally fabricated by high-vacuum magnetron sputtering, and copper-filling tests were performed with the supercritical carbon dioxide method. 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 for Co/Ru/TaN but not for Co/TaN. The experimental results also show that complete copper filling was possible even for trenches with a width of about 30 nm and an AR of nine for Co/Ru/TaN. The reasons for these results are explained by the dependence of Cu(111) texture on the underlying Co stack.
