Chemical factors for chemical–mechanical and electrochemical–mechanical planarization of silver examined using potentiodynamic and impedance measurements

Emery, S.; Hubbley, Jennifer L.; Darling, Maria A.; Roy, D.

doi:10.1016/j.matchemphys.2004.09.011

Cited by 13 publications

(8 citation statements)

References 41 publications

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“…The introduction of a constant phase element ( CPE ) to model the double layer significantly enhanced the quality of the fitted results ( F = 8.6). Moreover, because chloride adsorption is known to produce significant changes in the double-layer properties of gold electrodes and the double layer can be better described by considering the adsorption and diffusion of these anions separately, a more detailed description of the interface was carried out by fitting the experimental impedance data by considering the presence of chloride anions at the interface (Table ).…”

Section: Resultssupporting

confidence: 91%

Topological and Electron-Transfer Properties of the 2-Thiobarbituric Acid Adlayer on Polycrystalline Gold Electrodes

et al. 2008

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The voltammetric behavior of [Ru(NH(3))(6)](3+) on bare gold and that on 2-thiobarbituric acid (TBA)-modified gold surfaces are almost identical, with formal rate constants for the electron-transfer process of 0.25 and 0.21 cm s(-1), respectively. A detailed analysis of the modified surface allowed us to establish that this behavior is due to (i) a high surface coverage of 0.67, (ii) a low adsorption resistance that minimizes the potential drop across the TBA monolayer, (iii) the enhanced hydrophilic character of the modified surface compared with that of bare gold, and (iv) a low decay constant for the electronic coupling of the TBA adlayer that minimizes the tunneling barrier for the electron transfer. The electron-transfer process from Au and Au|TBA electrodes to the soluble [Ru(NH(3))(6)](3+/2+) redox couple can be explained according to the multistate model under the Landau-Zener formalism in the nonadiabatic regime that was recently proposed (Feldberg, S. W.; Sutin, N. Chem. Phys. 2006, 324, 216-225). The behavior of soluble [Ru(NH(3))(6)](3+) changes from semi-infinite linear diffusion on Au to finite-length bounded on Au|TBA, in agreement with a surface dimension of 2.17 for the TBA adlayer with a bidimensional underlying gold surface. This value for the surface dimension was determined by two essentially different electrochemical techniques with different sensing capabilities: cyclic voltammetry and electrochemical impedance spectroscopy. The estimated dielectric constant of the adlayer (around 37) and the low potential drop across the monolayer suggest the formation of a "mirror" pattern of water molecules in the diffusion layer, which explains this result.

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Section: Resultssupporting

confidence: 91%

Topological and Electron-Transfer Properties of the 2-Thiobarbituric Acid Adlayer on Polycrystalline Gold Electrodes

et al. 2008

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“…The electrochemical experiments were performed using a homebuilt fast potentiostat, as described elsewhere. 12,[14][15][16][17] A Ta coupon electrode, with its 2 ϫ ͑1.75 ϫ 1.50 cm͒ rectangular area exposed to the solution, was used in a three-electrode cell equipped with a saturated calomel electrode ͑SCE͒ reference and a Pt wire counter electrode. All solutions were prepared with triply distilled water and reagent grade chemicals and pH-adjusted with KOH.…”

Section: Methodsmentioning

confidence: 99%

“…FTEIS used a computer-generated broadband ac perturbation ͑5 mV peak-to-peak͒ containing 190 sinusoidal waves ͑0.1-40 kHz͒. 12,17 The real ͑ZЈ͒ and imaginary ͑ZЉ͒ components of the measured complex impedance ͑Z͒ were used to generate Nyquist plots that were CNLS analyzed using ZSimpWin to obtain EEC models of the interface.…”

Section: Methodsmentioning

confidence: 99%

Electrochemical Investigation of Surface Reactions for Chemical Mechanical Planarization of Tantalum in Oxalic Acid Solutions

Zheng

Klug

Roy

2008

J. Electrochem. Soc.

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Oxalic acid ͑OA͒-based nonalkaline solutions of H 2 O 2 are found to support chemically mediated removal of Ta-oxide surface films on Ta. The associated surface reactions are critical for chemical mechanical planarization ͑CMP͒ of Ta barrier layers in the fabrication of interconnect structures. In the present work, we probe the underlying mechanisms of these reactions using dc and ac electrochemical techniques. A Ta coupon electrode is used as a model system in abrasive-free solutions of 1 wt % OA + x wt % H 2 O 2 at pH 3.0 and 6.0 ͑x = 0, 1, and 5͒, where the chemical component of CMP is selectively examined in the absence of mechanical abrasion. These nonalkaline solutions are essential for preventing chemical damage to low-k dielectrics underlying Ta barriers in interconnects. The electrochemical data presented here explain the recently reported findings of Ta CMP experiments using OA solutions, and provide the necessary framework to put forward a reaction scheme for the chemically mediated disintegration of Ta 2 O 5 films formed on Ta in such solutions. A comparison of the dc and ac electrochemical data helps to identify the relative roles of the different chemical additives in these CMP solutions.

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“…The experimental details are described elsewhere [22][23][24][25][26][27][28][29][30][31]51]. In brief, we used a three-electrode cell, containing a Pt counter electrode and a saturated calomel electrode (SCE) reference.…”

Section: Methodsmentioning

confidence: 99%

“…We have recently explored such a technique of time resolved Fourier transform electrochemical impedance spectroscopy (FT-EIS) [22][23][24][25][26][27][28][29][30][31][32]. We demonstrate here that in the presence of complex multi-step faradaic reactions, the impedance response of the interface does not allow for straightforward determination of C diff through single frequency phase-selective measurements.…”

Section: Introductionmentioning

confidence: 99%

Measurement of differential capacitance for faradaic systems under potentiodynamic conditions: Considerations of Fourier transform and phase-selective techniques

Pettit

Goonetilleke

Roy

2006

Journal of Electroanalytical Chemistry

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Chemical factors for chemical–mechanical and electrochemical–mechanical planarization of silver examined using potentiodynamic and impedance measurements

Cited by 13 publications

References 41 publications

Topological and Electron-Transfer Properties of the 2-Thiobarbituric Acid Adlayer on Polycrystalline Gold Electrodes

Topological and Electron-Transfer Properties of the 2-Thiobarbituric Acid Adlayer on Polycrystalline Gold Electrodes

Electrochemical Investigation of Surface Reactions for Chemical Mechanical Planarization of Tantalum in Oxalic Acid Solutions

Measurement of differential capacitance for faradaic systems under potentiodynamic conditions: Considerations of Fourier transform and phase-selective techniques

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