| 摘要 |
The electromigration and stress migration of Cu interconnects is significantly reduced by forming a composite capping layer comprising a layer of beta-Ta on the upper surface of the inlaid Cu, a layer of tantalum nitride on the beta-Ta layer and a layer of alpha-Ta on the tantalum nitride layer. Embodiments include forming a recess in an upper surface of Cu inlaid in a dielectric layer, depositing a layer of beta-Ta at a thickness of 25 Å to 40 Å, depositing a layer of tantalum nitride at a thickness of 20 Å to 100 Å and then depositing a layer of alpha-Ta at a thickness of 200 Å to 500 Å. Embodiments further include forming an overlying dielectric layer, forming an opening therein, e.g., a via opening or a dual damascene opening, lining the opening with alpha-Ta, and filling the opening with Cu in electrical contact with the underlying inlaid Cu.
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