Copper seed layer for an interconnect structure having a doping concentration level gradient

US8729702B1 · kind B1 · utility

Assignees

• STMICROELECTRONICS, INC. · US
• International Business Machines Corporation · US

Inventors

• Chengyu Niu · Hopewell Junction, US
• Andrew H. Simon · Fishkill, US
• Keith Kwong Hon Wong · Wappingers Falls, US
• Yun-Yu Wang · Poughquag, US

Key dates

• Filing date: Nov 20, 2012
• Grant date: May 20, 2014
• Expiry date: Nov 20, 2032

Classification

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

Abstract

A trench is opened in a dielectric layer. The trench is then lined with a barrier layer and a metal seed layer. The metal seed layer is non-uniformly doped and exhibits a vertical doping gradient varying as a function of trench depth. The lined trench is then filled with a metal fill material. A dielectric cap layer is then deposited over the metal filled trench. Dopant from the non-uniformly doped metal seed layer is then migrated to an interface between the metal filled trench and the dielectric cap layer to form a self-aligned metal cap.