Title: Effect of Cu-Ion Concentration in Concentrated H(3)PO(4) Electrolyte on Cu Electrochemical Mechanical Planarization
Authors: Kung, Te-Ming
Liu, Chuan-Pu
Chang, Shih-Chieh
Chen, Kei-Wei
Wang, Ying-Lang
Institute of Lighting and Energy Photonics
Issue Date: 1-Jan-2010
Abstract: The influence of Cu-ion concentration in a concentrated H(3)PO(4) electrolyte on the Cu removal rate and planarization efficiency (PE) of electrochemical mechanical planarization (ECMP) was investigated. With increasing Cu-ion concentration in the electrolyte, results show that the Cu removal rate significantly decreased because more Cu ions in the electrolyte facilitated the formation of a surface passive film. Electrochemical analysis shows that the current density decreased from 91 to 62 mA/cm(2) when the Cu-ion concentration was increased from 35.8 to 158.6 mM. In a low Cu-ion concentration electrolyte, Cu(OH)(2) is dominant, while in a high Cu-ion concentration electrolyte, CuO predominates. A high Cu-ion concentration in the electrolyte during ECMP promotes the formation of CuO, which retards Cu-ion diffusion from the Cu surface to the electrolyte solution, resulting in a decrease in the Cu removal rate. The intensity ratio of CuO/[Cu(OH)(2)+CuO] in the Cu 2p(3/2) X-ray photoelectron spectroscopy spectrum increased from 22.1 to 85.6% when the Cu-ion concentration was increased. The effect of Cu-ion concentration on the microscale PE of Cu ECMP is discussed. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3425807] All rights reserved.
URI: http://dx.doi.org/10.1149/1.3425807
ISSN: 0013-4651
DOI: 10.1149/1.3425807
Volume: 157
Issue: 7
Begin Page: H763
End Page: H770
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