スパッタＣｕ膜のリフロー埋め込み特性に与える下地膜の影響

Abstract

Ti, W, Ta and their nitride films grown by sputtering were evaluated as the under layer of the sputtered Cu film with reflow process. The well nitrided films had good endurance against Cu-Si reaction at the annealing temperature higher than 680°C. The reflow characteristics of Cu film depend on a trench configuration and the Cu film thickness as well as the under layer species. Regardless of the reflow conditions, Cu on WNx revealed good reflow characteristics compared with Cu on TiNx or TaNx. This result shows that WNx is appropriate for the under layer material of reflow Cu. It was also found that the Cu reflow characteristics are highly correlated with the crystallinity of Cu film. The Cu film with (200) preferred orientation showed better reflow characteristics than that with (111) preferred orientation. However, in our experiments, there was no correlation between the reflow characteristics and the wettability of Cu on each under layer material.