Composite tantalum capped inlaid copper with reduced electromigration and reduced stress migration

US7071564B1 · kind B1 · utility

Assignee

• Advanced Micro Devices, Inc. · US

Inventors

• Darrell M. Erb · Los Altos, US
• Steven C. Avanzino · Cupertino, US
• Christy Mei-Chu Woo · Cupertino, US

Key dates

• Filing date: Mar 4, 2004
• Grant date: Jul 4, 2006
• Expiry date: Mar 4, 2024

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L2924/0002
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

The electromigration and stress migration of Cu interconnects is significantly reduced by forming a composite capping layer comprising a layer of β-Ta on the upper surface of the inlaid Cu, a layer of tantalum nitride on the β-Ta layer and a layer of α-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 β-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 α-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 α-Ta, and filling the opening with Cu in electrical contact with the underlying inlaid Cu.