Effect of hydrogen peroxide on oxidation of copper in CMP slurries containing glycine and Cu ions

    Authors

    T. Du; A. Vijayakumar;V. Desai

    Comments

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    Abbreviated Journal Title

    Electrochim. Acta

    Keywords

    CMP; oxidation; passivation; electrochemistry; etching; CHEMICAL-MECHANICAL PLANARIZATION; CORROSION-INHIBITOR; ACID; IMPEDANCE; REMOVAL; FILMS; MEDIA; H2O2; Electrochemistry

    Abstract

    This study compares the oxidative dissolution, passivation, and polishing behavior of copper chemical-mechanical polishing in the presence of hydrogen peroxide, glycine, and copper sulfate. High purity discs were used to study the dissolution and oxidation kinetics under static and dynamic conditions at pH 4 with varying H2O2 concentrations. Changes in surface chemistry of the statically etched copper disc were investigated using X-ray photoelectron spectroscopy (XPS). In the presence of H2O2, the copper removal rate reached a maximum at 1% H2O2 concentration, and decreased with further increase in H2O2 concentration. Electrochemical studies indicate a strong passivation process at higher H2O2 concentrations due to the rapid formation of oxide on the surface. With the further addition of glycine and copper sulfate to the slurry, the copper removal rates increased significantly and the maximum removal rate shifted to a H2O2 concentration of 3%. Electrochemical investigation indicates an enhanced dissolution of copper, which might be due to the strong catalytic activity of Cu(II)-glycine complexes in decomposing H2O2 to yield hydroxyl radicals. XPS results suggest that the passivation at higher H2O2 concentrations in the presence of glycine and copper sulfate is provided by the OH radicals adsorbed on Cu surface. (C) 2004 Elsevier Ltd. All rights reserved.

    Journal Title

    Electrochimica Acta

    Volume

    49

    Issue/Number

    25

    Publication Date

    1-1-2004

    Document Type

    Article

    Language

    English

    First Page

    4505

    Last Page

    4512

    WOS Identifier

    WOS:000223113300031

    ISSN

    0013-4686

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