Method for depositing metal layers using sequential flow deposition

Abstract

A method for depositing metal layers with good surface morphology using sequential flow deposition includes alternately exposing a substrate in a process chamber to a metal-carbonyl precursor gas and a reducing gas. During exposure with the metal-carbonyl precursor gas, a thin metal layer is deposited on the substrate by thermal decomposition, and subsequent exposure of the metal layer to the reducing gas aids in the removal of reaction by-products from the metal layer. The metal-carbonyl precursor gas and a reducing gas exposure steps can be repeated until a metal layer with a desired thickness is achieved. The metalcarbonyl precursor can, for example, be selected from W(CO)6, Ni(CO)4, MO(CO)6, C02(CO)8, Rh4(CO)12, Re2(CO)10, Cr(CO)6, and Ru3(CO)12.

Description

[0001] This PCT application is based on and claims priority from US Nonprovisional Patent Application No. 10 / 673,910, filed September 30, 2003, which is hereby incorporated by reference in its entirety. technical field [0002] The present invention relates to semiconductor processing, and more particularly to methods of depositing metal layers from thermal decomposition of metal-carbonyl precursors. Background technique [0003] The introduction of copper (Cu) metal into multilayer metallization schemes for the production of integrated circuits necessitates the use of diffusion barriers / liners to facilitate the adhesion and growth of the Cu layer and prevent Cu from diffusing into the dielectric material. The barrier / liner deposited onto the dielectric material can include refractive materials such as tungsten (W), molybdenum (Mo) and tantalum (Ta), which are non-reactive and immiscible with Cu and can provide low resistivity. Current integration schemes for integrating Cu ...

AI Technical Summary

Problems solved by technology

However, by thermally decomposing tungsten-carbonyl precursors (such as W(CO) 6 ) The material properties of the deposited W layer may be deteriorated due to the incorporation of CO reaction by-products into the thermally deposited W layer

Incorporating CO reaction by-products may increase the (electrical) resistivity of the W layer and lead to poor surface morphology due to irregular growth of W nodules (particles) on and / or in the W layer

When a metal layer (e.g. copper) is sputter-deposited on the W layer to produce an integrated circuit, for example by creating a shadow effect, the formation of W nodules can affect the etching behavior of the W layer and can affect the integration of the W layer.

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