Self assembled monolayer for improving adhesion between copper and barrier layer

Abstract

The embodiments fill the need enabling deposition of a thin and conformal barrier layer, and a copper layer in the copper interconnect with good electro-migration performance and with reduced risk of stress-induce voiding of copper interconnect. Electromigration and stress-induced voiding are affected by the adhesion between the barrier layer and the copper layer. A functionalization layer is deposited over the barrier layer to enable the copper layer being deposit in the copper interconnect. The functionalization layer forms strong bonds with barrier layer and with copper to improve adhesion property between the two layers. An exemplary method of preparing a substrate surface of a substrate to deposit a functionalization layer over a metallic barrier layer of a copper interconnect to assist deposition of a copper layer in the copper interconnect in order to improve electromigration performance of the copper interconnect is provided. The method includes depositing the metallic barrier layer to line the copper interconnect structure in the integrated system, and oxidizing a surface of the metallic barrier layer. The method also includes depositing the functionalization layer over the oxidized surface of the metallic barrier layer, and depositing the copper layer in the copper interconnect structure after the funcationalization layer is deposited over the metallic barrier layer.

Description

Background technique [0001] [1] Integrated circuits use conductive interconnects to connect individual devices together on a semiconductor substrate, or to external integrated circuits. Interconnect metals for vias and trenches may include aluminum alloys and copper. As device geometries continue to decrease to 45-nm-node technologies and sub-45-nm technologies, a continuous barrier / seed layer with good step coverage at high aspect ratio geometries is required to ensure void free ) of copper filling, such a requirement is becoming more and more challenging. In 45-nm-node or sub-45nm technologies, the purpose of forming an extremely thin and conformal barrier layer is to reduce the impact of the barrier layer on via and line resistance. However, poor adhesion of copper to the barrier layer can lead to delamination between the barrier layer and copper during processing or thermal stress, which creates problems with electron migration and stress-induced voiding. [0002] [2] A...

AI Technical Summary

Problems solved by technology

However, poor adhesion of copper to the barrier layer can lead to delamination between the barrier layer and copper during processing or thermal stress, which creates problems with electron migration and stress-induced voiding

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