Title

Polishing mechanism of tantalum films by SiO2 particles

Authors

Authors

A. Vijayakumar; T. Du; K. B. Sundaram;V. Desai

Comments

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Abbreviated Journal Title

Microelectron. Eng.

Keywords

tantalum; chemical mechanical polishing; X-ray photoelectron; spectroscopy; electrochemistry; COPPER; PLANARIZATION; METALLIZATION; ULSI; TA; Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Optics; Physics, Applied

Abstract

Dishing and erosion are major problems in conventional chemical mechanical planarization of copper/barrier layers. Understanding the polishing mechanism of the different materials involved can assist in providing a solution to these issues. Chemical mechanical polishing of tantalum was performed using alumina and silica particles dispersed in deionized water at pH 6. Tantalum shows a higher removal rate in silica slurry compared to alumina slurry. To examine the polishing mechanism of tantalum in silica slurry, the surface structure of the film was investigated by X-ray photoelectron spectroscopy (XPS). Various electrochemical techniques were used to characterize the surface film formation, dissolution and the interaction between silica particles and tantalum film. XPS and electrochemical results indicate that tantalum film may react with silica particles to form Ta-O-Si bonds on the surface. The mechanical tearing of Ta-O-Si bonds leads to the removal of Ta2O5 as a lump, resulting in higher removal rates of tantalum in silica slurry. (C) 2003 Elsevier B.V. All rights reserved.

Journal Title

Microelectronic Engineering

Volume

70

Issue/Number

1

Publication Date

1-1-2003

Document Type

Article

Language

English

First Page

93

Last Page

101

WOS Identifier

WOS:000185984900013

ISSN

0167-9317

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