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Supercritical Fluid Cu Alloy Interconnects and its formation

IP.com Disclosure Number: IPCOM000240434D
Publication Date: 2015-Jan-29
Document File: 1 page(s) / 24K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method to dope the Copper (Cu) seed so that the alloy Cu interconnects and self-forming barrier can be formed. This method uses the Cu seed layer for the supercritical fluid Cu gap fill.

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Supercritical Fluid Cu Alloy Interconnects and its formation

As the device dimension shrinks, the interconnect is also scaled. Interconnect scaling faces to two problems: Copper (Cu) gap fill in fine dimension and the electromigration reliability.

In order to fill a fine dimensioned trench/via, supercritical fluid has been examined in which a Cu precursor is dissolved to form Cu films in the trench /via without being affected by the surface tension. However, the two major problems of the supercritical fluid Cu fill are that doping of alloy elements such as Manganese (Mn) and Aluminum (Al) is not possible, and the Cu has no adhesion to the underlying barrier metals such as Tantalum Nitride (TaN) and dielectrics. This leads to difficulty in applying the supercritical fluid Cu filling to achieve the high reliability and void free Cu gap fill.

The solution is a method to dope the Cu seed so that the alloy Cu interconnects and self-forming barrier can be formed. This method uses the Cu seed layer for the supercritical fluid Cu gap fill.

The implementation steps include doping of alloy elements such as Mn and Al performed into the Cu seed layer, which is normally formed by physical vapor deposition (PVD). Cu growth during the supercritical fluid Cu gap fill takes place on the Cu seed layer. This secures the interface to the barrier or liner materials such as TaN, Cobalt (Co), and Ruthenium (Ru), by the PVD-Cu seed layer. The grain growth is performed without voids on...