The Effect of Process Parameters on CVD Cu Seed Layer Deposition on Ru and Ta Under-layer

Abstract

To deposit ultra-thin CVD Cu seed layer, Ru is evaluated as new barrier material, and the morphology and adhesion property of CVD Cu deposition on Ru are compared with that on Ta. CVD Cu films on Ru shows higher nuclei density than that on Ta. Lower (90 o C) deposition temperature, and high source concentration also improves the nucleation density of CVD Cu. About 20 nm of smooth and continuous CVD Cu seed layer is deposited on Ru under-layer at 90 o C and high source concentration condition. CVD Cu on Ru has a good adhesion property because impurity layer, which degrades the adhesion property of CVD Cu, is not formed at the interface. Introducing Ru under-layer and optimizing deposition condition enable thin and smooth CVD Cu seed layer deposition for the future Cu interconnects. .